diff --git a/src/h3_blackwell_runtime/packing.py b/src/h3_blackwell_runtime/packing.py
index 511a7cd..e86e1de 100644
--- a/src/h3_blackwell_runtime/packing.py
+++ b/src/h3_blackwell_runtime/packing.py
@@ -96,6 +96,7 @@ class H3PromptPacker:
         *,
         text_token_tags: torch.Tensor | None = None,
         cond_latents: list[torch.Tensor] | None = None,
+        cond_frame_indices: list[int] | None = None,
         frame_count: int | None = None,
         seed: int = 0,
     ) -> tuple[torch.Tensor, torch.Tensor, list[tuple[int, int, int]], torch.Tensor, tuple[int, int, int], tuple[int, int, int]]:
@@ -104,8 +105,9 @@ class H3PromptPacker:
         ``text`` is the refined text span (width 5376 when already refined, 5120
         for raw Qwen states); ``text_token_tags`` is the per-token DiT modality tag
         (1=text, 0=video over vision pads). ``cond_latents`` are normalized keyframe
-        latents ``[1,24,1,H/16,W/16]`` spliced right after the text as non-denoised
-        cond rows with their own near-1 timestep. Returns
+        latents ``[1,24,1,H/16,W/16]`` and ``cond_frame_indices`` preserves each
+        keyframe's resolved first/last pixel index. They are spliced right after
+        the text as non-denoised cond rows with their own near-1 timestep. Returns
         ``(hidden, times, segments, positions, video_seg, audio_seg)`` where
         ``segments`` rows are ``t_row*3 + modality_tag``.
         """
@@ -122,7 +124,10 @@ class H3PromptPacker:
         video_rows = functional.linear(patchify_video(video.to(torch.bfloat16)).float(), self.video_weight, self.video_bias).to(torch.bfloat16)
         audio_rows = functional.linear(pack_audio(audio.to(torch.bfloat16)).float(), self.audio_weight, self.audio_bias).to(torch.bfloat16)
         cond_rows = None
+        cond_lengths = []
         if cond_latents:
+            if cond_frame_indices is None or len(cond_frame_indices) != len(cond_latents):
+                raise ValueError("cond_frame_indices must match cond_latents")
             cond_patches = []
             # every cond video restarts the same CPU RNG stream (Comfy _cond_video_rows)
             for idx, z in enumerate(cond_latents):
@@ -132,6 +137,7 @@ class H3PromptPacker:
                     noise = torch.randn(r.shape, generator=gen, dtype=torch.float32)
                     r = self.VISUAL_COND_TIMESTEP * r + (1.0 - self.VISUAL_COND_TIMESTEP) * noise.to(r.device)
                 cond_patches.append(r)
+                cond_lengths.append(r.shape[0])
             cond_rows = functional.linear(torch.cat(cond_patches, dim=0), self.video_weight.to(torch.float32), self.video_bias.to(torch.float32)).to(torch.bfloat16)
 
         if model_timesteps is None:
@@ -168,13 +174,17 @@ class H3PromptPacker:
         position_blocks = [text_positions]
         if cond_rows is not None and cond_latents:
             spans = _video_t_spans(latent_t)
-            cond_t_values = [
-                float(text_length) if idx == 0 else (float(text_length) + sum(spans) - FRAME_RESCALE if frame_count is not None and idx == len(cond_latents) - 1 else float(text_length))
-                for idx in range(len(cond_latents))
-            ]
+            cond_t_values = []
+            for pixel_index in cond_frame_indices:
+                if pixel_index == 0:
+                    cond_t_values.append(float(text_length))
+                elif frame_count is not None and pixel_index == frame_count - 1:
+                    cond_t_values.append(float(text_length) + sum(spans) - FRAME_RESCALE)
+                else:
+                    raise ValueError("only first/last keyframe anchors are supported")
             position_blocks.append(torch.cat([_cond_positions(frame_rows, cond_t, latent_h, latent_w) for cond_t in cond_t_values], dim=0))
-        position_blocks.append(_audio_positions(audio.shape[-1], float(text_length + cond_length), latent_w, latent_h))
-        position_blocks.append(_video_positions(latent_t, latent_h, latent_w, float(text_length + cond_length + audio_length)))
+        position_blocks.append(_audio_positions(audio.shape[-1], float(text_length), latent_w, latent_h))
+        position_blocks.append(_video_positions(latent_t, latent_h, latent_w, float(text_length)))
         positions = torch.cat(position_blocks, dim=0)
 
         # mod_segments: (start, stop, t_row*3 + tag).
@@ -192,8 +202,9 @@ class H3PromptPacker:
 
         cursor_start = text_length
         if cond_rows is not None:
-            segments.append((cursor_start, cursor_start + cond_rows.shape[0], t_row[cond_time] * 3 + 0))
-            cursor_start += cond_rows.shape[0]
+            for length in cond_lengths:
+                segments.append((cursor_start, cursor_start + length, t_row[cond_time] * 3 + 0))
+                cursor_start += length
         segments.append((cursor_start, cursor_start + audio_length, t_row[audio_time] * 3 + 2))
         cursor_start += audio_length
         video_start = cursor_start
diff --git a/src/h3_blackwell_runtime/qwen3vl_text.py b/src/h3_blackwell_runtime/qwen3vl_text.py
index 3f641a0..522b769 100644
--- a/src/h3_blackwell_runtime/qwen3vl_text.py
+++ b/src/h3_blackwell_runtime/qwen3vl_text.py
@@ -194,7 +194,7 @@ class Qwen3VL32BTextEncoder(nn.Module):
         """Scaled token embeds ``[batch, tokens, 5120]`` in fp32 (pre-decoder)."""
         token_rows = F.embedding(input_ids.to(self.embed_tokens.device), self.embed_tokens).to(torch.float32)
         token_scales = F.embedding(input_ids.to(self.embed_scale.device), self.embed_scale)
-        return (token_rows * token_scales).to(torch.float32)
+        return (token_rows * token_scales).to(torch.bfloat16).to(torch.float32)
 
     def _run_layers(
         self,
diff --git a/src/h3_blackwell_runtime/qwen3vl_vision.py b/src/h3_blackwell_runtime/qwen3vl_vision.py
index 97c743f..d8fd7c1 100644
--- a/src/h3_blackwell_runtime/qwen3vl_vision.py
+++ b/src/h3_blackwell_runtime/qwen3vl_vision.py
@@ -25,6 +25,7 @@ from dataclasses import dataclass
 from pathlib import Path
 
 import torch
+from torch.nn.attention import SDPBackend, sdpa_kernel
 from safetensors import safe_open
 from torch import nn
 from torch.nn import functional as F
@@ -193,7 +194,7 @@ def mrope_freqs_cis(position_ids: torch.Tensor, *, theta: float = TEXT_ROPE_THET
     freqs = (inv_freq_expanded @ position_ids_expanded).transpose(1, 2)
     freqs_inter = freqs[0].clone()
     for axis_idx, offset in ((1, 1), (2, 2)):
-        length = rope_dims[axis_idx - 1] * 3
+        length = rope_dims[axis_idx] * 3
         idx = slice(offset, length, 3)
         freqs_inter[..., idx] = freqs[axis_idx, ..., idx]
     emb = torch.cat((freqs_inter, freqs_inter), dim=-1)
@@ -214,7 +215,24 @@ class _VisionPatchEmbed(nn.Module):
         target = self.weight.dtype
         x = x.view(-1, 3, VISION_TEMPORAL, VISION_PATCH, VISION_PATCH)
         s = (VISION_TEMPORAL, VISION_PATCH, VISION_PATCH)
-        return F.conv3d(x.to(target), self.weight, self.bias, stride=s).view(-1, self.weight.shape[0])
+        x = x.to(target)
+        if x.is_cuda and target in (torch.float16, torch.bfloat16):
+            # Match Comfy's NVIDIA Conv3d workaround dispatch exactly.
+            output = torch.cudnn_convolution(
+                x,
+                self.weight,
+                (0, 0, 0),
+                s,
+                (1, 1, 1),
+                1,
+                benchmark=False,
+                deterministic=False,
+                allow_tf32=True,
+            )
+            output += self.bias.view(1, -1, 1, 1, 1)
+        else:
+            output = F.conv3d(x, self.weight, self.bias, stride=s)
+        return output.view(-1, self.weight.shape[0])
 
 
 class _VisionMLP(nn.Module):
@@ -244,24 +262,27 @@ def _apply_rope_vision(q: torch.Tensor, k: torch.Tensor, freqs) -> tuple[torch.T
     their native dtype.
     """
     cos, sin, neg_sin = freqs
-    q = (q * cos)
+    original_q = q
+    q = original_q * cos
     split = q.shape[-1] // 2
-    q[..., :split] += q[..., split:] * neg_sin
-    q[..., split:] += q[..., :split] * sin
-    k = (k * cos)
-    k[..., :split] += k[..., split:] * neg_sin
-    k[..., split:] += k[..., :split] * sin
+    q[..., :split].addcmul_(original_q[..., split:], neg_sin)
+    q[..., split:].addcmul_(original_q[..., :split], sin)
+    original_k = k
+    k = original_k * cos
+    k[..., :split].addcmul_(original_k[..., split:], neg_sin)
+    k[..., split:].addcmul_(original_k[..., :split], sin)
     return q, k
 
 
 class _VisionAttention(nn.Module):
-    def __init__(self, qkv_w: torch.Tensor, qkv_b: torch.Tensor, proj_w: torch.Tensor, *, num_heads: int, head_dim: int):
+    def __init__(self, qkv_w: torch.Tensor, qkv_b: torch.Tensor, proj_w: torch.Tensor, proj_b: torch.Tensor, *, num_heads: int, head_dim: int):
         super().__init__()
         self.num_heads = num_heads
         self.head_dim = head_dim
         self.register_buffer("qkv_weight", qkv_w, persistent=False)
         self.register_buffer("qkv_bias", qkv_b, persistent=False)
-        self.proj_weight = proj_w  # no bias (Qwen3.5 vision proj has none)
+        self.register_buffer("proj_weight", proj_w, persistent=False)
+        self.register_buffer("proj_bias", proj_b, persistent=False)
 
     def forward(self, x: torch.Tensor, cu_seqlens: torch.Tensor, position_embeddings: torch.Tensor) -> torch.Tensor:
         seq_length = x.shape[0]
@@ -286,10 +307,24 @@ class _VisionAttention(nn.Module):
             torch.split(key_states, lengths, dim=0),
             torch.split(value_states, lengths, dim=0),
         ):
-            attn_outputs.append(F.scaled_dot_product_attention(q.transpose(0, 1).unsqueeze(0), k.transpose(0, 1).unsqueeze(0), v.transpose(0, 1).unsqueeze(0)))
+            with sdpa_kernel(
+                [
+                    SDPBackend.FLASH_ATTENTION,
+                    SDPBackend.CUDNN_ATTENTION,
+                    SDPBackend.EFFICIENT_ATTENTION,
+                    SDPBackend.MATH,
+                ],
+                set_priority=True,
+            ):
+                output = F.scaled_dot_product_attention(
+                    q.transpose(0, 1).unsqueeze(0),
+                    k.transpose(0, 1).unsqueeze(0),
+                    v.transpose(0, 1).unsqueeze(0),
+                )
+            attn_outputs.append(output.transpose(1, 2).reshape(1, q.shape[0], -1))
         attn_output = torch.cat(attn_outputs, dim=1)
         attn_output = attn_output.reshape(seq_length, -1)
-        return F.linear(attn_output, self.proj_weight)
+        return F.linear(attn_output, self.proj_weight, self.proj_bias)
 
 
 class _VisionBlock(nn.Module):
@@ -329,16 +364,16 @@ class _VisionPatchMerger(nn.Module):
         self.out_hidden_size = out_hidden_size
 
     def forward(self, x: torch.Tensor) -> torch.Tensor:
-        # x: [t*h*w, hidden] (unmerged patches) for the main merger;
-        #    [t*(h//2)*(w//2), merge_dim] (pre-merged 2x2) for the deepstack merger.
-        if x.shape[-1] == self.merge_dim:
-            # Deepstack merger: input is already 2x2-merged; norm over merge_dim.
+        # x is the existing 2x2-block-major [t*h*w, hidden] patch stream.
+        if self.norm_dim == self.merge_dim:
+            # DeepStack merger: group the existing block-major patch stream first.
+            x = x.view(-1, self.merge_dim)
             x = F.layer_norm(x, (self.merge_dim,), weight=self.norm_weight, bias=self.norm_bias, eps=1e-6)
         else:
             # Main merger: per-patch LayerNorm over hidden, then group 2x2 into merge_dim.
             x = F.layer_norm(x, (x.shape[-1],), weight=self.norm_weight, bias=self.norm_bias, eps=1e-6)
             x = x.view(-1, self.merge_dim)
-        return F.linear(F.gelu(F.linear(x, self.fc1_weight, self.fc1_bias), approximate="tanh"), self.fc2_weight, self.fc2_bias)
+        return F.linear(F.gelu(F.linear(x, self.fc1_weight, self.fc1_bias)), self.fc2_weight, self.fc2_bias)
 
 
 def resize_keyframe(image: torch.Tensor, width: int, height: int, *, crop: str = "disabled") -> torch.Tensor:
@@ -377,15 +412,13 @@ def resize_keyframe(image: torch.Tensor, width: int, height: int, *, crop: str =
     return samples.clamp(0.0, 1.0).movedim(1, -1)  # [1, H, W, 3]
 
 
-def _text_run_ids(prompt: str) -> list[int]:
+def _text_run_ids(tokenizer, prompt: str) -> list[int]:
     """Token ids for a raw text run (``add_special_tokens=False``, no template)."""
-    from .conditioning import H3PromptTokenizer
-
-    tokenizer_dir = Path(__file__).with_name("qwen25_tokenizer")
-    if not tokenizer_dir.exists():
-        raise FileNotFoundError(f"Qwen tokenizer directory missing: {tokenizer_dir}")
-    ids = H3PromptTokenizer(tokenizer_dir)(prompt or " ")
-    # input_ids is [1, seq]; flatten to a Python list of ints.
+    raw_tokenizer = getattr(tokenizer, "tokenizer", None)
+    if raw_tokenizer is not None:
+        ids = raw_tokenizer(prompt, add_special_tokens=False, return_tensors="pt").input_ids
+    else:
+        ids = tokenizer(prompt, device="cpu")
     return [int(t) for t in ids.reshape(-1).tolist()]
 
 
@@ -441,11 +474,11 @@ def build_fl2va_presentation(
     # Build the entry list: (token_id/"text") runs and image placeholders.
     entries: list = []
     for i in range(len(images)):
-        entries.extend((tid, "text") for tid in _text_run_ids(f"<Picture {i + 1}: "))
+        entries.extend((tid, "text") for tid in _text_run_ids(tokenizer, f"<Picture {i + 1}>: "))
         entries.append((VISION_START, "text"))
         entries.append((i, "image"))
         entries.append((VISION_END, "text"))
-    entries.extend((tid, "text") for tid in _text_run_ids(prompt))
+    entries.extend((tid, "text") for tid in _text_run_ids(tokenizer, prompt))
     if not any(kind == "text" for _, kind in entries):
         entries = [(151643, "text")]
 
@@ -547,6 +580,7 @@ class Qwen3VL32BVision(nn.Module):
                 f"visual.blocks.{i}.attn.qkv.weight",
                 f"visual.blocks.{i}.attn.qkv.bias",
                 f"visual.blocks.{i}.attn.proj.weight",
+                f"visual.blocks.{i}.attn.proj.bias",
                 f"visual.blocks.{i}.norm2.weight",
                 f"visual.blocks.{i}.norm2.bias",
                 f"visual.blocks.{i}.mlp.linear_fc1.weight",
@@ -574,6 +608,8 @@ class Qwen3VL32BVision(nn.Module):
                 dtype,
                 lambda name: checkpoint.get_tensor(name).to(device=device, dtype=dtype),
             )
+            # Comfy's Embedding is not dynamically cast to the FP32 vision stream.
+            self.pos_embed = checkpoint.get_tensor("visual.pos_embed.weight").to(device=device)
 
     def _init_modules(self, device, dtype, get) -> None:
         self.register_buffer("pos_embed", get("visual.pos_embed.weight"), persistent=False)
@@ -600,7 +636,7 @@ class Qwen3VL32BVision(nn.Module):
                 get(f"visual.blocks.{i}.norm1.weight"), get(f"visual.blocks.{i}.norm1.bias"),
                 _VisionAttention(
                     get(f"visual.blocks.{i}.attn.qkv.weight"), get(f"visual.blocks.{i}.attn.qkv.bias"),
-                    get(f"visual.blocks.{i}.attn.proj.weight"),
+                    get(f"visual.blocks.{i}.attn.proj.weight"), get(f"visual.blocks.{i}.attn.proj.bias"),
                     num_heads=self.num_heads, head_dim=VISION_HEAD_DIM,
                 ),
                 get(f"visual.blocks.{i}.norm2.weight"), get(f"visual.blocks.{i}.norm2.bias"),
@@ -631,7 +667,7 @@ class Qwen3VL32BVision(nn.Module):
             intra_row = torch.arange(merge_size, device=device)
             intra_col = torch.arange(merge_size, device=device)
             row_idx = (block_rows[:, None, None, None] * merge_size + intra_row[None, None, :, None]).expand(merged_h, merged_w, merge_size, merge_size).reshape(-1)
-            col_idx = (block_cols[None, :, None, None] * merge_size + intra_col[None, None, :, None]).expand(merged_h, merged_w, merge_size, merge_size).reshape(-1)
+            col_idx = (block_cols[None, :, None, None] * merge_size + intra_col[None, None, None, :]).expand(merged_h, merged_w, merge_size, merge_size).reshape(-1)
             coords = torch.stack((row_idx, col_idx), dim=-1)
             if num_frames > 1:
                 coords = coords.repeat(num_frames, 1)
@@ -688,38 +724,6 @@ class Qwen3VL32BVision(nn.Module):
             patch_pos_embeds_permute.append(pos_embed)
         return torch.cat(patch_pos_embeds_permute)
 
-    @staticmethod
-    def _merge_tokens(x: torch.Tensor, grid_thw: torch.Tensor) -> torch.Tensor:
-        """DeepStack layout: interleave 2x2 spatial neighbours and flatten.
-
-        x: [t*h*w, C] -> [t*(h//2)*(w//2), 4*C].
-        """
-        first = grid_thw[0]
-        t = int(first[0].item())
-        h = int(first[1].item())
-        w = int(first[2].item())
-        C = int(x.shape[-1])
-        merge = 2
-        x = x.view(t, h // merge, merge, w // merge, merge, C)
-        x = x.permute(0, 1, 3, 2, 4, 5).contiguous()
-        return x.reshape(-1, C * merge * merge)
-
-    @staticmethod
-    def _interleave_2x2(x: torch.Tensor, grid_thw: torch.Tensor) -> torch.Tensor:
-        """Re-order [t*h*w, C] into 2x2-block-major order (no dim change).
-
-        After this, x.view(-1, 4*C) groups spatially-adjacent 2x2 blocks.
-        """
-        first = grid_thw[0]
-        t = int(first[0].item())
-        h = int(first[1].item())
-        w = int(first[2].item())
-        C = int(x.shape[-1])
-        merge = 2
-        x = x.view(t, h // merge, merge, w // merge, merge, C)
-        x = x.permute(0, 1, 3, 2, 4, 5).contiguous()
-        return x.reshape(-1, C)  # still [t*(h//2)*(w//2)*4, C], block-major
-
     def forward(self, flatten_patches: torch.Tensor, grid_thw: torch.Tensor) -> tuple[torch.Tensor, list[torch.Tensor]]:
         """Run the visual tower -> (merged, deepstack)."""
         x = self.patch_embed(flatten_patches.to(self.dtype).to(self.device))
@@ -740,22 +744,18 @@ class Qwen3VL32BVision(nn.Module):
             x = block(x, cu_seqlens=cu_seqlens, position_embeddings=position_embeddings)
             # x: [t*h*w, hidden] (unmerged patches).
             if layer_num in self.deepstack_visual_indexes:
-                # DeepStack: merge 2x2 first, then project.
                 deepstack_features.append(
-                    self.deepstack_merger_list[self.deepstack_visual_indexes.index(layer_num)](self._merge_tokens(x, grid_thw))
+                    self.deepstack_merger_list[self.deepstack_visual_indexes.index(layer_num)](x)
                 )
-        # Main merger expects the 2x2-interleaved layout (per-patch norm is done
-        # over the UNMERGED hidden, but the grouping of 4 patches must be
-        # spatially-contiguous).  Re-order x into 2x2-block-major order first.
-        x = self._interleave_2x2(x, grid_thw)
         return self.merger(x), deepstack_features
 
 
 class _VisionRotary(nn.Module):
     def __init__(self, dim: int, device, dtype):
         super().__init__()
-        inv_freq = 1.0 / (10000.0 ** (torch.arange(0, dim, 2, dtype=torch.float, device=device) / dim))
-        self.register_buffer("inv_freq", inv_freq, persistent=False)
+        # Comfy constructs this buffer on CPU, then moves the model to CUDA.
+        inv_freq = 1.0 / (10000.0 ** (torch.arange(0, dim, 2, dtype=torch.float) / dim))
+        self.register_buffer("inv_freq", inv_freq.to(device), persistent=False)
 
     def forward(self, seqlen: int) -> torch.Tensor:
         seq = torch.arange(seqlen, device=self.inv_freq.device, dtype=self.inv_freq.dtype)
diff --git a/src/h3_blackwell_runtime/runtime.py b/src/h3_blackwell_runtime/runtime.py
index 6a840f9..fa9423c 100644
--- a/src/h3_blackwell_runtime/runtime.py
+++ b/src/h3_blackwell_runtime/runtime.py
@@ -93,7 +93,7 @@ class H3HotRuntime:
         )
         self.vision_tower = self._timed_load(
             "vision_tower_loaded",
-            lambda: Qwen3VL32BVision(config.text_encoder_path, device=config.device, dtype=torch.bfloat16),
+            lambda: Qwen3VL32BVision(config.text_encoder_path, device=config.device, dtype=torch.float32),
         )
 
     def _timed_load(self, stage: str, fn):
@@ -166,19 +166,18 @@ class H3HotRuntime:
         cond_latents = []
         for kf in presentation.keyframes:
             resized = resize_keyframe(kf["image"].to(device), width, height, crop="disabled" if kf["resolved_frame_index"] == 0 else "center")
-            pix = resized.movedim(-1, 1).to(device, dtype=torch.float32)
+            pix = resized.movedim(-1, 1).to(device, dtype=torch.float32).mul(2.0).sub(1.0)
             cond_latents.append(self.vae_encoder.encode(pix))
         return presentation, cond_latents, aligned_frames
 
     def _image_to_uint8_nhwc(self, img: torch.Tensor) -> torch.Tensor:
-        """Normalize a [1,3,H,W] image in either [-1,1] or [0,255] to [1,H,W,3] uint8."""
+        """Normalize a [1,3,H,W] image in [0,1], [-1,1], or [0,255] to NHWC uint8."""
         x = img.float()
         if x.numel() == 0:
             return x
-        mx = x.max()
-        if mx > 2.0:
+        if x.max() > 1.0:
             x = x / 255.0  # already 0..255
-        else:
+        elif x.min() < 0.0:
             x = (x.clamp(-1, 1) + 1) * 0.5  # -1..1 -> 0..1
         return (x.movedim(1, -1).clamp(0, 1) * 255).to(torch.uint8)
 
@@ -237,6 +236,7 @@ class H3HotRuntime:
             pack_kwargs = {
                 "text_token_tags": presentation.text_token_tags,
                 "cond_latents": cond_latents,
+                "cond_frame_indices": [kf["resolved_frame_index"] for kf in presentation.keyframes],
                 "frame_count": frame_count,
                 "seed": seed,
             }
diff --git a/src/h3_blackwell_runtime/sampler.py b/src/h3_blackwell_runtime/sampler.py
index ee029e9..d6dbec1 100644
--- a/src/h3_blackwell_runtime/sampler.py
+++ b/src/h3_blackwell_runtime/sampler.py
@@ -14,13 +14,20 @@ def shifted_sigma(base: torch.Tensor, shift: float) -> torch.Tensor:
 
 def beta_sigmas(steps: int, *, device: torch.device | str, alpha: float = 0.6, beta: float = 0.6) -> torch.Tensor:
     """Comfy's discrete beta scheduler over H3's 1,000-entry shift-12 table."""
+    import numpy as np
     from scipy.stats import beta as beta_distribution
 
-    table = shifted_sigma(torch.arange(1, 1001, device=device, dtype=torch.float32) / 1000, 12.0)
-    fractions = 1.0 - torch.arange(steps, device=device, dtype=torch.float64).cpu().numpy() / steps
-    indices = torch.from_numpy((999 * beta_distribution.ppf(fractions, alpha, beta)).round().astype("int64")).to(device)
-    indices = torch.unique_consecutive(indices)
-    return torch.cat((table[indices], table.new_zeros(1)))
+    timesteps = (torch.arange(1, 1001, 1) / 1000) * 1000
+    table = shifted_sigma(timesteps / 1000, 12.0)
+    fractions = 1.0 - np.linspace(0, 1, steps, endpoint=False)
+    indices = np.rint(beta_distribution.ppf(fractions, alpha, beta) * 999)
+    sigmas = []
+    last_index = -1
+    for index in indices:
+        if index != last_index:
+            sigmas.append(float(table[int(index)]))
+        last_index = index
+    return torch.FloatTensor([*sigmas, 0.0]).to(device)
 
 
 def res_multistep_update(x: torch.Tensor, denoised: torch.Tensor, sigma: torch.Tensor, sigma_down: torch.Tensor, old_denoised: torch.Tensor | None, old_sigma_down: torch.Tensor | None, previous_sigma: torch.Tensor | None) -> torch.Tensor:
@@ -80,6 +87,7 @@ def sample_video_res_multistep(
     seed: int = 0,
     text_token_tags: torch.Tensor | None = None,
     cond_latents: list[torch.Tensor] | None = None,
+    cond_frame_indices: list[int] | None = None,
     frame_count: int | None = None,
     cache_mode: str | None = None,
     cache_threshold: float = 0.0,
@@ -148,6 +156,7 @@ def sample_video_res_multistep(
                 step_timesteps,
                 text_token_tags=text_token_tags,
                 cond_latents=cond_latents,
+                cond_frame_indices=cond_frame_indices,
                 frame_count=frame_count,
                 seed=seed,
             )
diff --git a/src/h3_blackwell_runtime/vae_decoder.py b/src/h3_blackwell_runtime/vae_decoder.py
index c2ded36..72fe038 100644
--- a/src/h3_blackwell_runtime/vae_decoder.py
+++ b/src/h3_blackwell_runtime/vae_decoder.py
@@ -32,12 +32,21 @@ def dtype_from_name(name: str) -> torch.dtype:
 
 
 def _rms_norm(x: torch.Tensor, weight: torch.Tensor | None, eps: float) -> torch.Tensor:
-    if os.getenv("H3_VAE_FAST_OPS", "").lower() in {"1", "true", "yes", "on"}:
-        if weight is None:
-            return F.rms_norm(x, (x.shape[-1],), eps=eps)
-        return F.rms_norm(x, weight.shape, weight=weight.to(device=x.device, dtype=x.dtype), eps=eps)
-    result = x * torch.rsqrt(x.float().square().mean(dim=-1, keepdim=True) + eps).to(x.dtype)
-    return result if weight is None else result * weight.to(dtype=x.dtype)
+    if weight is None:
+        return F.rms_norm(x, (x.shape[-1],), eps=eps)
+    return F.rms_norm(x, weight.shape, weight=weight.to(device=x.device, dtype=x.dtype), eps=eps)
+
+
+def _conv3d(x: torch.Tensor, weight: torch.Tensor, bias: torch.Tensor | None) -> torch.Tensor:
+    if x.is_cuda and weight.dtype in (torch.float16, torch.bfloat16):
+        output = torch.cudnn_convolution(
+            x, weight, (0, 0, 0), (1, 1, 1), (1, 1, 1), 1,
+            benchmark=False, deterministic=False, allow_tf32=True,
+        )
+        if bias is not None:
+            output += bias.reshape(1, -1, 1, 1, 1)
+        return output
+    return F.conv3d(x, weight, bias)
 
 
 def create_token_ids(patch_dims: tuple[int, int, int], device: torch.device, dtype: torch.dtype) -> torch.Tensor:
@@ -50,16 +59,13 @@ class RotaryEmbeddingND(nn.Module):
         super().__init__()
         self.rotary_base = rotary_base
         self.step = 2 * n_dim / dim
-        inv_freq = 1 / rotary_base ** torch.arange(0, 1, self.step, dtype=torch.float32, device=device)
+        inv_freq = 1 / rotary_base ** torch.arange(0, 1, self.step, dtype=torch.float32)
         self.register_buffer("inv_freq", inv_freq, persistent=False)
         self.angle_scale = 2.0 * math.pi
 
     def forward(self, img_ids: torch.Tensor) -> torch.Tensor:
         inv_freq = self.inv_freq
-        if inv_freq.device.type == "meta":
-            inv_freq = 1 / self.rotary_base ** torch.arange(0, 1, self.step, dtype=torch.float32, device=img_ids.device)
-        else:
-            inv_freq = inv_freq.to(img_ids.device)
+        inv_freq = inv_freq.to(device=img_ids.device, dtype=img_ids.dtype)
         angles = self.angle_scale * img_ids[:, :, :, None].float() * inv_freq[None, None, None, :]
         angles = angles.flatten(2, 3)
         cos, sin = torch.cos(angles), torch.sin(angles)
@@ -89,11 +95,10 @@ class FeedForward(nn.Module):
 
 def _apply_rope_split_half(x: torch.Tensor, table: torch.Tensor) -> torch.Tensor:
     """Apply the reference split-half RoPE layout to leading rotary channels."""
-    if os.getenv("H3_VAE_FAST_OPS", "").lower() in {"1", "true", "yes", "on"}:
-        try:
-            return torch.ops.comfy_kitchen.apply_rope_split_half1(x, table)
-        except Exception:
-            pass
+    try:
+        return torch.ops.comfy_kitchen.apply_rope_split_half1(x, table)
+    except Exception:
+        pass
     pairs = table.shape[-3]
     rot = pairs * 2
     first, second = x[..., :pairs], x[..., pairs:rot]
@@ -117,15 +122,12 @@ class Attention(nn.Module):
         qkv = self.to_qkv(x).view(batch, sequence, self.heads, 3 * self.dim_head)
         query, key, value = qkv.chunk(3, dim=-1)
         query, key = self.norm_q(query), self.norm_k(key)
-        if os.getenv("H3_VAE_FAST_OPS", "").lower() in {"1", "true", "yes", "on"}:
-            try:
-                rot = rotary_pos_emb.shape[-3] * 2
-                query_rot, key_rot = torch.ops.comfy_kitchen.apply_rope_split_half(query[..., :rot], key[..., :rot], rotary_pos_emb)
-                query = torch.cat((query_rot, query[..., rot:]), dim=-1)
-                key = torch.cat((key_rot, key[..., rot:]), dim=-1)
-            except Exception:
-                query, key = _apply_rope_split_half(query, rotary_pos_emb), _apply_rope_split_half(key, rotary_pos_emb)
-        else:
+        try:
+            rot = rotary_pos_emb.shape[-3] * 2
+            query_rot, key_rot = torch.ops.comfy_kitchen.apply_rope_split_half(query[..., :rot], key[..., :rot], rotary_pos_emb)
+            query = torch.cat((query_rot, query[..., rot:]), dim=-1)
+            key = torch.cat((key_rot, key[..., rot:]), dim=-1)
+        except Exception:
             query, key = _apply_rope_split_half(query, rotary_pos_emb), _apply_rope_split_half(key, rotary_pos_emb)
         query, key, value = query.transpose(1, 2), key.transpose(1, 2), value.transpose(1, 2)
         try:
@@ -250,7 +252,7 @@ class MiniMaxH3VideoVAE(nn.Module):
         return model
 
     def _decode_pixels(self, z: torch.Tensor) -> torch.Tensor:
-        return self.decoder(self.post_quant_conv(z))
+        return self.decoder(_conv3d(z, self.post_quant_conv.weight, self.post_quant_conv.bias))
 
     def split_tiles(self, length: int) -> tuple[list[int], list[int], list[int]]:
         if self.tile_size >= length:
diff --git a/src/h3_blackwell_runtime/vae_encoder.py b/src/h3_blackwell_runtime/vae_encoder.py
index 18711d1..0d64ced 100644
--- a/src/h3_blackwell_runtime/vae_encoder.py
+++ b/src/h3_blackwell_runtime/vae_encoder.py
@@ -1,8 +1,8 @@
 """Direct, encoder-only MiniMax H3 video VAE implementation.
 
 Mirrors the encoder half of ``upstream_vae.py`` so keyframe/reference images can
-be encoded without ComfyUI. The encoder runs in FP32 and the latent moments are
-upcast to FP32 before mean/std normalization (the reference contract).
+be encoded without ComfyUI. The encoder runs in FP16 like Comfy's keyframe VAE
+path, and latent moments are upcast for mean/std normalization.
 
 Causal-conv semantics: spatial padding is reflect; temporal padding is causal
 (front-only zeros) with a stride grid that starts at the first input frame
@@ -18,6 +18,7 @@ stateless kernels below.
 from __future__ import annotations
 
 import math
+import os
 from pathlib import Path
 
 import torch
@@ -41,6 +42,18 @@ NIN_LEVELS = frozenset({1, 3, 5})
 DOWNSAMPLE_LEVELS = frozenset({0, 1, 2, 3})
 
 
+def _conv3d(x, weight, bias, stride=(1, 1, 1), padding=(0, 0, 0)):
+    if x.is_cuda and weight.dtype in (torch.float16, torch.bfloat16):
+        output = torch.cudnn_convolution(
+            x, weight, padding, stride, (1, 1, 1), 1,
+            benchmark=False, deterministic=False, allow_tf32=True,
+        )
+        if bias is not None:
+            output += bias.reshape(1, -1, 1, 1, 1)
+        return output
+    return F.conv3d(x, weight, bias, stride, padding)
+
+
 def _causal_conv3d(x, weight, bias, *, kernel_size, stride, spatial_padding, temporal_causal):
     """Causal 3D conv (matches upstream_vae.CausalConv3d).
 
@@ -48,23 +61,22 @@ def _causal_conv3d(x, weight, bias, *, kernel_size, stride, spatial_padding, tem
     - ``temporal_causal``: front-zero T by ``kernel_size - 1`` (the reference's
       ``causal_padding[0] * 2`` for ``causal_padding[0]=1``, which is every
       3D-causal conv in the H3 VAE).  A single-frame input truncates the
-      temporal taps to the center 1 instead of convolving zero rows.
+      temporal taps to the final input-aligned tap instead of convolving zero rows.
     - If neither applies: no padding at all (reference early-return).
     """
     if x.shape[2] == 1:
         # Keyframe path (matches reference's `autopad="causal_zero"`):
         # apply spatial-reflect pad (if any), then run an effective 2D conv
-        # by slicing the kernel to its center temporal tap (T_out stays 1).
+        # by slicing the kernel to its final input-aligned temporal tap.
         if spatial_padding > 0:
             x = F.pad(x, (spatial_padding, spatial_padding, spatial_padding, spatial_padding, 0, 0), mode="reflect")
-        half = (kernel_size - 1) // 2
-        kernel_5d = weight[:, :, half:half + 1, :, :]
-        return F.conv3d(x, kernel_5d, bias, (1, stride[1], stride[2]), (0, 0, 0))
+        kernel_5d = weight[:, :, -1:, :, :]
+        return _conv3d(x, kernel_5d, bias, (1, stride[1], stride[2]))
     if spatial_padding > 0:
         x = F.pad(x, (spatial_padding, spatial_padding, spatial_padding, spatial_padding, 0, 0), mode="reflect")
     if temporal_causal:
         x = F.pad(x, (0, 0, 0, 0, kernel_size - 1, 0))
-    return F.conv3d(x, weight, bias, stride, (0, 0, 0))
+    return _conv3d(x, weight, bias, stride)
 
 
 def _group_norm_3d(x, weight, bias):
@@ -76,7 +88,7 @@ def _group_norm_3d(x, weight, bias):
 
 def _resnet(x, p):
     # nin_shortcut uses CausalConv3d(k=1, padding=1) in the reference.
-    residual = x if p["nin"] is None else F.conv3d(x, p["nin"][0], p["nin"][1], (1, 1, 1))
+    residual = x if p["nin"] is None else _conv3d(x, p["nin"][0], p["nin"][1])
     h = _causal_conv3d(F.silu(_group_norm_3d(x, p["norm1_w"], p["norm1_b"])), p["conv1_w"], p["conv1_b"], kernel_size=3, stride=(1, 1, 1), spatial_padding=1, temporal_causal=True)
     h = _causal_conv3d(F.silu(_group_norm_3d(h, p["norm2_w"], p["norm2_b"])), p["conv2_w"], p["conv2_b"], kernel_size=3, stride=(1, 1, 1), spatial_padding=1, temporal_causal=True)
     return h.add_(residual)
@@ -84,8 +96,8 @@ def _resnet(x, p):
 
 def _downsample(x, p):
     if p["space"] == 2:
-        # Reference Downsample3D pads H and W by +1 reflect before the conv.
-        x = F.pad(x, (1, 1, 1, 1, 0, 0), mode="reflect")
+        # Reference Downsample3D pads only the right and bottom edges.
+        x = F.pad(x, (0, 1, 0, 1, 0, 0), mode="reflect")
     # Conv uses padding=(1,0,0) -> causal_padding=(1,0,0), so spatial pad=0,
     # temporal front-zero is applied.
     return _causal_conv3d(x, p["w"], p["b"], kernel_size=3, stride=(p["time"], p["space"], p["space"]), spatial_padding=0, temporal_causal=True)
@@ -109,8 +121,9 @@ class MiniMaxH3VideoVAEEncoder(nn.Module):
     ``self.W`` (a dict), so no ``nn.Module`` sub-hierarchy is needed.
     """
 
-    def __init__(self, *, tiling: bool = True):
+    def __init__(self, *, tiling: bool = True, compute_dtype: torch.dtype = torch.float16):
         super().__init__()
+        self.compute_dtype = compute_dtype
         self.vae_ratio, self.vae_ratio_t = VAE_RATIO, 4
         self.clip_length, self.token_drop = 17, 3
         self.frame_pre_padding = (-self.clip_length) % self.vae_ratio_t
@@ -122,7 +135,13 @@ class MiniMaxH3VideoVAEEncoder(nn.Module):
         self.register_buffer("pixel_std", torch.tensor(IMAGENET_STD).view(1, 3, 1, 1, 1), persistent=False)
 
     def _required_encoder_names(self) -> list[str]:
-        names = ["encoder.conv_in.weight", "encoder.conv_in.bias", "encoder.norm_out.weight", "encoder.norm_out.bias", "encoder.conv_out.weight", "encoder.conv_out.bias"]
+        names = [
+            "encoder.conv_in.weight", "encoder.conv_in.bias",
+            "encoder.norm_out.weight", "encoder.norm_out.bias",
+            "encoder.conv_out.weight", "encoder.conv_out.bias",
+            "quant_conv.weight", "quant_conv.bias",
+            "latents_mean", "latents_std",
+        ]
         for i in range(len(CH_MULT)):
             for b in range(NUM_RES_BLOCKS):
                 base = f"encoder.down.{i}.block.{b}."
@@ -139,15 +158,37 @@ class MiniMaxH3VideoVAEEncoder(nn.Module):
         return names
 
     @classmethod
-    def from_safetensors(cls, path: str | Path, *, device: str | torch.device = "cuda", tiling: bool = True) -> "MiniMaxH3VideoVAEEncoder":
-        model = cls(tiling=tiling)
+    def from_safetensors(cls, path: str | Path, *, device: str | torch.device = "cuda", tiling: bool = True, dtype: torch.dtype = torch.float16) -> "MiniMaxH3VideoVAEEncoder":
+        model = cls(tiling=tiling, compute_dtype=dtype)
         names = model._required_encoder_names()
-        with safe_open(str(path), framework="pt", device=str(device)) as ck:
-            available = set(ck.keys())
+        if os.getenv("H3_FAST_SAFETENSORS", "").lower() in {"1", "true", "yes", "on"}:
+            from fastsafetensors import fastsafe_open
+
+            fast_device = "cuda:0" if str(device) == "cuda" else str(device)
+            with fastsafe_open(filenames=[str(path)], nogds=True, device=fast_device) as ck:
+                available = set(ck.keys())
+                missing = [n for n in names if n not in available]
+                if missing:
+                    raise ValueError(f"incompatible H3 VAE checkpoint; missing: {', '.join(sorted(missing)[:16])}")
+                W = {n: ck.get_tensor(n).clone().detach().to(dtype=dtype) for n in names}
+        elif os.getenv("H3_DISABLE_MMAP", "").lower() in {"1", "true", "yes", "on"}:
+            from safetensors.torch import load
+
+            with open(path, "rb") as file:
+                available_weights = load(file.read())
+            available = set(available_weights)
             missing = [n for n in names if n not in available]
             if missing:
                 raise ValueError(f"incompatible H3 VAE checkpoint; missing: {', '.join(sorted(missing)[:16])}")
-            W = {n: ck.get_tensor(n).to(dtype=torch.float32).to(device) for n in names}
+            W = {n: available_weights[n].to(device=device, dtype=dtype) for n in names}
+            del available_weights
+        else:
+            with safe_open(str(path), framework="pt", device=str(device)) as ck:
+                available = set(ck.keys())
+                missing = [n for n in names if n not in available]
+                if missing:
+                    raise ValueError(f"incompatible H3 VAE checkpoint; missing: {', '.join(sorted(missing)[:16])}")
+                W = {n: ck.get_tensor(n).to(dtype=dtype).to(device) for n in names}
 
         # Build the structured params dict.
         down = []
@@ -179,14 +220,19 @@ class MiniMaxH3VideoVAEEncoder(nn.Module):
             "conv_out": (W["encoder.conv_out.weight"], W["encoder.conv_out.bias"]),
         }
         model.W = E
-        model.quant_conv.to(device, torch.float32)
+        model.quant_conv.to(device, dtype)
+        with torch.no_grad():
+            model.quant_conv.weight.copy_(W["quant_conv.weight"])
+            model.quant_conv.bias.copy_(W["quant_conv.bias"])
+            model.latents_mean.copy_(W["latents_mean"].float().cpu())
+            model.latents_std.copy_(W["latents_std"].float().cpu())
         for b in ("latents_mean", "latents_std", "pixel_mean", "pixel_std"):
             getattr(model, b).to(device)
         return model
 
     @torch.inference_mode()
     def _encode_moments(self, x: torch.Tensor) -> torch.Tensor:
-        return F.conv3d(_encoder_run(x.to(torch.float32), self.W), self.quant_conv.weight, self.quant_conv.bias)
+        return _conv3d(_encoder_run(x.to(self.compute_dtype), self.W), self.quant_conv.weight, self.quant_conv.bias)
 
     def _adaptive_encode(self, x: torch.Tensor) -> torch.Tensor:
         if self.tiling:
@@ -266,14 +312,13 @@ class MiniMaxH3VideoVAEEncoder(nn.Module):
         """``[B,3,H,W]`` or ``[B,3,T,H,W]`` pixels in ``[-1, 1]`` -> normalized latents ``[B,24,T_lat,H//16,W//16]``."""
         if x.ndim == 4:
             x = x.unsqueeze(2)
-        x = (x + 1.0) * 0.5
-        x = (x - self.pixel_mean.to(x)) / self.pixel_std.to(x)
+        # Comfy's VAE wrapper casts before entering the model, so image
+        # normalization rounds in the VAE compute dtype as well.
+        x = x.to(self.compute_dtype)
+        x = x.add(1.0).mul_(0.5).sub_(self.pixel_mean.to(x)).div_(self.pixel_std.to(x))
         if x.shape[2] == 1:
-            # Pad with frame_pre_padding zero frames so the 17-tap stride-2
-            # temporal downsampling produces exactly one latent frame (1+3-4).
-            pad = self.frame_pre_padding
-            x = torch.cat([torch.zeros_like(x[:, :, :pad]), x], dim=2)
             moments = self._adaptive_encode(x)
+            moments = moments[:, :, -1:, :, :]
         else:
             moments = self.encode_temporal(x)
         mean = torch.chunk(moments.float(), 2, dim=1)[0]
diff --git a/tests/test_fl2va_contracts.py b/tests/test_fl2va_contracts.py
new file mode 100644
index 0000000..6d74350
--- /dev/null
+++ b/tests/test_fl2va_contracts.py
@@ -0,0 +1,217 @@
+import math
+from types import SimpleNamespace
+import unittest
+from unittest.mock import patch
+
+import torch
+from torch import nn
+from torch.nn import functional as F
+
+from h3_blackwell_runtime.packing import FRAME_RESCALE, H3PromptPacker, _video_t_spans
+from h3_blackwell_runtime.qwen3vl_vision import (
+    TEXT_HEAD_DIM,
+    TEXT_ROPE_DIMS,
+    TEXT_ROPE_THETA,
+    VISION_HIDDEN,
+    Qwen3VL32BVision,
+    _VisionAttention,
+    _VisionPatchMerger,
+    _apply_rope_vision,
+    _text_run_ids,
+    mrope_freqs_cis,
+)
+from h3_blackwell_runtime.runtime import H3HotRuntime
+from h3_blackwell_runtime.vae_encoder import MiniMaxH3VideoVAEEncoder, _downsample
+
+
+class Fl2vaVAEContracts(unittest.TestCase):
+    def test_quant_conv_is_a_required_checkpoint_weight(self):
+        names = MiniMaxH3VideoVAEEncoder()._required_encoder_names()
+        self.assertIn("quant_conv.weight", names)
+        self.assertIn("quant_conv.bias", names)
+
+    def test_single_frame_is_encoded_without_temporal_prepad(self):
+        encoder = MiniMaxH3VideoVAEEncoder(tiling=False)
+        seen = []
+
+        def fake_encode(x):
+            seen.append(tuple(x.shape))
+            return torch.zeros((x.shape[0], 48, x.shape[2], 1, 1), device=x.device)
+
+        encoder._adaptive_encode = fake_encode
+        result = encoder.encode(torch.zeros(1, 3, 8, 8))
+        self.assertEqual(seen, [(1, 3, 1, 8, 8)])
+        self.assertEqual(tuple(result.shape), (1, 24, 1, 1, 1))
+
+    def test_downsample_pads_only_right_and_bottom(self):
+        x = torch.arange(16, dtype=torch.float32).reshape(1, 1, 1, 4, 4)
+        weight = torch.ones(1, 1, 3, 3, 3)
+        params = {"w": weight, "b": torch.zeros(1), "time": 1, "space": 2}
+        actual = _downsample(x, params)
+        padded = F.pad(x, (0, 1, 0, 1, 0, 0), mode="reflect")
+        expected = F.conv3d(padded, weight[:, :, -1:], params["b"], stride=(1, 2, 2))
+        torch.testing.assert_close(actual, expected)
+
+    def test_hot_runtime_preserves_zero_to_one_images(self):
+        runtime = H3HotRuntime.__new__(H3HotRuntime)
+        image = torch.tensor([[[[0.0, 0.5, 1.0]]]])
+        converted = runtime._image_to_uint8_nhwc(image)
+        self.assertEqual(converted.flatten().tolist(), [0, 127, 255])
+
+
+class Fl2vaVisionContracts(unittest.TestCase):
+    def test_visual_rotary_coordinates_are_block_major(self):
+        class CoordinateTable(nn.Module):
+            def forward(self, length):
+                return torch.arange(length, dtype=torch.float32).unsqueeze(1)
+
+        vision = Qwen3VL32BVision.__new__(Qwen3VL32BVision)
+        nn.Module.__init__(vision)
+        vision.spatial_merge_size = 2
+        vision.rotary_pos_emb = CoordinateTable()
+        coordinates = vision.rot_pos_emb(torch.tensor([[1, 4, 4]])).tolist()
+        self.assertEqual(coordinates[:8], [
+            [0.0, 0.0], [0.0, 1.0], [1.0, 0.0], [1.0, 1.0],
+            [0.0, 2.0], [0.0, 3.0], [1.0, 2.0], [1.0, 3.0],
+        ])
+
+    def test_sdpa_output_is_restored_to_token_major_layout(self):
+        torch.manual_seed(7)
+        sequence, heads, head_dim = 3, 2, 2
+        hidden = heads * head_dim
+        qkv_weight = torch.randn(hidden * 3, hidden)
+        qkv_bias = torch.randn(hidden * 3)
+        proj_weight = torch.randn(hidden, hidden)
+        proj_bias = torch.randn(hidden)
+        module = _VisionAttention(qkv_weight, qkv_bias, proj_weight, proj_bias, num_heads=heads, head_dim=head_dim)
+        x = torch.randn(sequence, hidden)
+        cos = torch.ones(sequence, 1, head_dim)
+        sin = torch.zeros(sequence, 1, head_dim // 2)
+        actual = module(x, torch.tensor([0, sequence], dtype=torch.int32), (cos, sin, sin))
+
+        qkv = F.linear(x, qkv_weight, qkv_bias)
+        query, key, value = qkv.reshape(sequence, 3, heads, head_dim).permute(1, 0, 2, 3).unbind(0)
+        output = F.scaled_dot_product_attention(
+            query.transpose(0, 1).unsqueeze(0),
+            key.transpose(0, 1).unsqueeze(0),
+            value.transpose(0, 1).unsqueeze(0),
+        )
+        expected = F.linear(output.transpose(1, 2).reshape(sequence, hidden), proj_weight, proj_bias)
+        torch.testing.assert_close(actual, expected)
+
+    def test_vision_rope_uses_original_halves(self):
+        q = torch.tensor([[[1.0, 2.0, 3.0, 4.0]]])
+        k = q + 4
+        cos = torch.full_like(q, 0.5)
+        sin = torch.full_like(q[..., :2], 0.25)
+        neg_sin = -sin
+        actual_q, actual_k = _apply_rope_vision(q, k, (cos, sin, neg_sin))
+
+        def expected(x):
+            return torch.cat((x[..., :2] * 0.5 + x[..., 2:] * -0.25,
+                              x[..., 2:] * 0.5 + x[..., :2] * 0.25), dim=-1)
+
+        torch.testing.assert_close(actual_q, expected(q))
+        torch.testing.assert_close(actual_k, expected(k))
+
+    def test_mrope_uses_reference_section_boundaries(self):
+        positions = torch.stack((torch.arange(8), torch.arange(8) + 10, torch.arange(8) + 20))
+        actual = mrope_freqs_cis(positions)[0]
+        inv_freq = 1.0 / (
+            TEXT_ROPE_THETA ** (torch.arange(0, TEXT_HEAD_DIM, 2, dtype=torch.float32) / TEXT_HEAD_DIM)
+        )
+        freqs = (inv_freq[None, :, None].expand(3, -1, 1) @ positions[:, None, :].float()).transpose(1, 2)
+        interleaved = freqs[0].clone()
+        for axis, offset in ((1, 1), (2, 2)):
+            index = slice(offset, TEXT_ROPE_DIMS[axis] * 3, 3)
+            interleaved[..., index] = freqs[axis, ..., index]
+        expected = torch.cat((interleaved, interleaved), dim=-1).cos().unsqueeze(0)
+        torch.testing.assert_close(actual, expected)
+
+    def test_mergers_preserve_existing_block_major_order(self):
+        x = torch.arange(4 * VISION_HIDDEN, dtype=torch.float32).reshape(4, VISION_HIDDEN)
+        passthrough = lambda value, *args, **kwargs: value
+        with (
+            patch("h3_blackwell_runtime.qwen3vl_vision.F.layer_norm", side_effect=passthrough),
+            patch("h3_blackwell_runtime.qwen3vl_vision.F.linear", side_effect=passthrough),
+            patch("h3_blackwell_runtime.qwen3vl_vision.F.gelu", side_effect=passthrough),
+        ):
+            main = _VisionPatchMerger(*(torch.empty(1) for _ in range(6)), merge_size=2,
+                                      out_hidden_size=1, norm_dim=VISION_HIDDEN)
+            deepstack = _VisionPatchMerger(*(torch.empty(1) for _ in range(6)), merge_size=2,
+                                           out_hidden_size=1)
+            torch.testing.assert_close(main(x), x.reshape(1, -1))
+            torch.testing.assert_close(deepstack(x), x.reshape(1, -1))
+
+    def test_configured_tokenizer_preserves_empty_prompt(self):
+        calls = []
+
+        class RawTokenizer:
+            def __call__(self, text, **kwargs):
+                calls.append((text, kwargs))
+                return SimpleNamespace(input_ids=torch.empty((1, 0), dtype=torch.long))
+
+        self.assertEqual(_text_run_ids(SimpleNamespace(tokenizer=RawTokenizer()), ""), [])
+        self.assertEqual(calls[0][0], "")
+        self.assertFalse(calls[0][1]["add_special_tokens"])
+
+
+class _FakeCheckpoint:
+    def tensor(self, name, dtype=None):
+        if name == "video_patch_proj.weight":
+            value = torch.zeros(5376, 96)
+        elif name == "video_patch_proj.bias":
+            value = torch.zeros(5376)
+        elif name == "audio_patch_proj.weight":
+            value = torch.zeros(5376, 32)
+        elif name == "audio_patch_proj.bias":
+            value = torch.zeros(5376)
+        else:
+            value = torch.empty(0)
+        return value.to(dtype=dtype) if dtype is not None else value
+
+
+class Fl2vaPackingContracts(unittest.TestCase):
+    def test_each_keyframe_keeps_its_own_condition_segment(self):
+        packer = H3PromptPacker(_FakeCheckpoint())
+        text = torch.zeros(1, 3, 5376)
+        video = torch.zeros(1, 24, 2, 2, 2)
+        audio = torch.zeros(1, 32, 2, 2)
+        keyframes = [torch.zeros(1, 24, 1, 2, 2) for _ in range(2)]
+        _, _, segments, _, _, _ = packer(
+            text,
+            video,
+            audio,
+            0.5,
+            cond_latents=keyframes,
+            cond_frame_indices=[0, 21],
+            frame_count=22,
+        )
+        self.assertEqual(segments[1][:2], (3, 4))
+        self.assertEqual(segments[2][:2], (4, 5))
+        self.assertEqual(segments[1][2], segments[2][2])
+
+    def test_last_only_anchor_and_targets_share_reference_cursor(self):
+        packer = H3PromptPacker(_FakeCheckpoint())
+        text = torch.zeros(1, 3, 5376)
+        video = torch.zeros(1, 24, 2, 2, 2)
+        audio = torch.zeros(1, 32, 2, 2)
+        last = torch.zeros(1, 24, 1, 2, 2)
+        _, _, _, positions, _, _ = packer(
+            text,
+            video,
+            audio,
+            0.5,
+            cond_latents=[last],
+            cond_frame_indices=[21],
+            frame_count=22,
+            seed=1,
+        )
+        expected_last_t = 3.0 + sum(_video_t_spans(2)) - FRAME_RESCALE
+        self.assertTrue(math.isclose(float(positions[3, 0]), expected_last_t))
+        self.assertEqual(float(positions[4, 0]), 3.0)  # target audio
+        self.assertEqual(float(positions[8, 0]), 3.0)  # target video
+
+
+if __name__ == "__main__":
+    unittest.main()
diff --git a/tools/compare_fl2va_key_sampler.py b/tools/compare_fl2va_key_sampler.py
new file mode 100644
index 0000000..b4e54b6
--- /dev/null
+++ b/tools/compare_fl2va_key_sampler.py
@@ -0,0 +1,128 @@
+"""Replay a matched Comfy keyframe sampler capture with exact static conditioning."""
+
+import argparse
+from pathlib import Path
+
+import torch
+
+from h3_blackwell_runtime.checkpoint import H3Checkpoint
+from h3_blackwell_runtime.denoiser import H3PackedDenoiser
+from h3_blackwell_runtime.packing import H3PromptPacker, unpatchify_video
+from h3_blackwell_runtime.sampler import _audio_sigma, _model_sigma, _unpack_audio, beta_sigmas, res_multistep_update
+from h3_blackwell_runtime.t2v import random_av_latents
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("--sampler", type=Path, required=True)
+parser.add_argument("--dit", type=Path, required=True)
+parser.add_argument("--model", default="/models/minimax_h3_fl2va_pruned_nvfp4.safetensors")
+parser.add_argument("--result-latent", type=Path)
+parser.add_argument("--production-trace", type=Path)
+args = parser.parse_args()
+
+checkpoint = H3Checkpoint(args.model)
+model = H3PackedDenoiser.from_checkpoint(checkpoint, attention_backend="sage2").eval()
+packer = H3PromptPacker(checkpoint)
+captured_input = torch.load(args.dit / "input.pt", map_location="cuda", weights_only=False)
+text_length = next(start for start, _, code in captured_input["segments"] if code == 3)
+prefix_stop = next(start for start, _, code in captured_input["segments"] if code % 3 == 2)
+text = captured_input["hidden"][:text_length].unsqueeze(0).cuda()
+prefix = captured_input["hidden"][:prefix_stop].cuda()
+text_tags = torch.ones(text_length, dtype=torch.long, device="cuda")
+for start, stop, code in captured_input["segments"]:
+    if stop <= text_length:
+        text_tags[start:stop] = code % 3
+
+video, audio, frame_count = random_av_latents(384, 384, 22, 440207)
+video_shape, audio_shape = video.shape, audio.shape
+video_count, audio_count = video.numel(), audio.numel()
+zero_cond = [torch.zeros(1, 24, 1, 24, 24, device="cuda") for _ in range(2)]
+sigmas = torch.load(args.sampler / "initial.pt", map_location="cuda", weights_only=False)["sigmas"].cuda()
+direct_sigmas = beta_sigmas(12, device="cuda")
+sigma_delta = (direct_sigmas.float() - sigmas.float()).abs()
+print({"stage": "sigmas", "direct": direct_sigmas.tolist(), "comfy": sigmas.tolist(), "mean_delta": float(sigma_delta.mean()), "max_delta": float(sigma_delta.max())}, flush=True)
+video_history = audio_history = history_sigma = None
+
+for index, sigma in enumerate(sigmas[:-1]):
+    reference = torch.load(args.sampler / f"step_{index:02d}.pt", map_location="cuda", weights_only=False)
+    reference_x = reference["x"].cuda().reshape(-1)
+    reference_video = reference_x[:video_count].reshape(video_shape)
+    reference_audio = reference_x[video_count:video_count + audio_count].reshape(audio_shape)
+    pre_video = (video.float() - reference_video.float()).abs()
+    pre_audio = (audio.float() - reference_audio.float()).abs()
+
+    sigma_audio = _audio_sigma(sigma)
+    carry = sigma_audio / sigma
+    hidden, times, segments, positions, video_segment, audio_segment = packer(
+        text,
+        video,
+        audio.to(torch.bfloat16) * carry,
+        _model_sigma(sigma),
+        text_token_tags=text_tags,
+        cond_latents=zero_cond,
+        cond_frame_indices=[0, frame_count - 1],
+        frame_count=frame_count,
+        seed=440207,
+    )
+    hidden[:prefix_stop] = prefix.to(hidden)
+    input_hidden = hidden.detach().clone()
+    with torch.inference_mode():
+        raw_video, raw_audio = model(hidden, times, positions, segments, video_segment, audio_segment)
+    raw_video = raw_video.to(torch.bfloat16).float()
+    raw_audio = raw_audio.to(torch.bfloat16)
+    video_denoised = video + sigma * unpatchify_video(raw_video, video.shape[2], video.shape[-2], video.shape[-1])
+    audio_model_output = (
+        (1.0 - 4.0) * (audio.to(torch.bfloat16) * carry.to(torch.bfloat16))
+        + (1.0 + 3.0 * sigma_audio).to(torch.bfloat16) * (-_unpack_audio(raw_audio))
+    ).float()
+    audio_denoised = audio - sigma * audio_model_output
+
+    reference_denoised = reference["denoised"].cuda().reshape(-1)
+    reference_video_denoised = reference_denoised[:video_count].reshape(video_shape)
+    reference_audio_denoised = reference_denoised[video_count:video_count + audio_count].reshape(audio_shape)
+    denoised_video = (video_denoised.float() - reference_video_denoised.float()).abs()
+    denoised_audio = (audio_denoised.float() - reference_audio_denoised.float()).abs()
+    production = torch.load(args.production_trace / f"step_{index:02d}.pt", map_location="cuda", weights_only=False) if args.production_trace else None
+    production_video = (production["video"].float() - reference_video.float()).abs() if production else None
+    production_audio = (production["audio"].float() - reference_audio.float()).abs() if production else None
+    production_denoised = (production["video_denoised"].float() - reference_video_denoised.float()).abs() if production else None
+    production_hidden = (production["hidden"].float() - input_hidden.float()).abs() if production and "hidden" in production else None
+    production_raw = (production["raw_video"].float() - raw_video.float()).abs() if production and "raw_video" in production else None
+    production_segments = [
+        (start, stop, code, float((production["hidden"][start:stop].float() - input_hidden[start:stop].float()).abs().mean()))
+        for start, stop, code in segments
+    ] if production and "hidden" in production else None
+    print({
+        "step": index,
+        "pre_video_mean": float(pre_video.mean()),
+        "pre_video_max": float(pre_video.max()),
+        "pre_audio_mean": float(pre_audio.mean()),
+        "pre_audio_max": float(pre_audio.max()),
+        "denoised_video_mean": float(denoised_video.mean()),
+        "denoised_video_max": float(denoised_video.max()),
+        "denoised_audio_mean": float(denoised_audio.mean()),
+        "denoised_audio_max": float(denoised_audio.max()),
+        "production_video_mean": float(production_video.mean()) if production_video is not None else None,
+        "production_video_max": float(production_video.max()) if production_video is not None else None,
+        "production_audio_mean": float(production_audio.mean()) if production_audio is not None else None,
+        "production_audio_max": float(production_audio.max()) if production_audio is not None else None,
+        "production_denoised_mean": float(production_denoised.mean()) if production_denoised is not None else None,
+        "production_denoised_max": float(production_denoised.max()) if production_denoised is not None else None,
+        "production_hidden_mean": float(production_hidden.mean()) if production_hidden is not None else None,
+        "production_hidden_max": float(production_hidden.max()) if production_hidden is not None else None,
+        "production_raw_mean": float(production_raw.mean()) if production_raw is not None else None,
+        "production_raw_max": float(production_raw.max()) if production_raw is not None else None,
+        "production_segments": production_segments,
+    }, flush=True)
+
+    previous_sigma = sigmas[index - 1] if index else None
+    sigma_down = sigmas[index + 1]
+    video = res_multistep_update(video, video_denoised, sigma, sigma_down, video_history, history_sigma, previous_sigma)
+    audio = res_multistep_update(audio, audio_denoised, sigma, sigma_down, audio_history, history_sigma, previous_sigma)
+    video_history, audio_history, history_sigma = video_denoised, audio_denoised, sigma_down
+
+if args.result_latent:
+    result = torch.load(args.result_latent, map_location="cuda", weights_only=False)
+    result_video = result["latent"] if isinstance(result, dict) else result
+    delta = (video.float() - result_video.cuda().float()).abs()
+    print({"stage": "final_video", "mean_delta": float(delta.mean()), "max_delta": float(delta.max())}, flush=True)
diff --git a/tools/compare_fl2va_keyframe_input.py b/tools/compare_fl2va_keyframe_input.py
new file mode 100644
index 0000000..f46fa8b
--- /dev/null
+++ b/tools/compare_fl2va_keyframe_input.py
@@ -0,0 +1,193 @@
+"""Compare direct keyframe FL2VA packing with a matched Comfy DiT capture."""
+
+import argparse
+from pathlib import Path
+
+import numpy as np
+from PIL import Image
+import torch
+
+from h3_blackwell_runtime.checkpoint import H3Checkpoint
+from h3_blackwell_runtime.denoiser import H3PackedDenoiser
+from h3_blackwell_runtime.packing import H3PromptPacker
+from h3_blackwell_runtime.qwen3vl_text import Qwen3VLPromptConditioner
+from h3_blackwell_runtime.qwen3vl_vision import Qwen3VL32BVision, build_fl2va_presentation, resize_keyframe
+from h3_blackwell_runtime.qwen3vl_vision import mrope_freqs_cis, mrope_position_ids
+from h3_blackwell_runtime.sampler import _model_sigma, beta_sigmas
+from h3_blackwell_runtime.t2v import random_av_latents
+from h3_blackwell_runtime.token_refiner import H3TokenRefiner
+from h3_blackwell_runtime.vae_encoder import MiniMaxH3VideoVAEEncoder
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("--capture", required=True)
+parser.add_argument("--first", required=True)
+parser.add_argument("--last", required=True)
+parser.add_argument("--model", default="/models/minimax_h3_fl2va_pruned_nvfp4.safetensors")
+parser.add_argument("--qwen", default="/text-encoders/qwen3vl_32b_minimax_h3_nvfp4_awq.safetensors")
+parser.add_argument("--vae", default="/vae/minimax_h3_video_vae_fp16.safetensors")
+parser.add_argument("--tokenizer", default="/opt/h3-blackwell-runtime/src/h3_blackwell_runtime/qwen25_tokenizer")
+parser.add_argument("--reference-vision-first")
+parser.add_argument("--reference-vision-last")
+parser.add_argument("--qwen-capture-dir")
+parser.add_argument("--sampler-capture-dir")
+parser.add_argument("--oracle-qwen-input", action="store_true")
+parser.add_argument("--vae-dtype", choices=("float16", "bfloat16", "float32"), default="float32")
+parser.add_argument("--vae-no-tiling", action="store_true")
+parser.add_argument("--load-dit-first", action="store_true")
+parser.add_argument("--preview-order", action="store_true")
+args = parser.parse_args()
+
+prompt = "A studio time-lapse of the same pink peony bud opening into the same fully bloomed pink peony, fixed camera, cream background."
+width = height = 384
+requested_frames = 22
+seed = 440207
+
+
+def load_image(path):
+    image = Image.open(path).convert("RGB")
+    return torch.from_numpy(np.asarray(image).copy()).unsqueeze(0).cuda().float().div(255.0)
+
+
+def report(name, actual, expected):
+    expected = expected.to(actual.device)
+    delta = (actual.float() - expected.float()).abs()
+    print({
+        "stage": name,
+        "shape": tuple(actual.shape),
+        "mean_delta": float(delta.mean()),
+        "max_delta": float(delta.max()),
+    }, flush=True)
+
+
+capture = torch.load(args.capture, map_location="cuda", weights_only=False)
+checkpoint = H3Checkpoint(args.model)
+dit_probe = H3PackedDenoiser.from_checkpoint(checkpoint, attention_backend="sage2").eval() if args.load_dit_first else None
+early_refiner = H3TokenRefiner(checkpoint, attention_backend="sage2") if args.preview_order else None
+early_packer = H3PromptPacker(checkpoint) if args.preview_order else None
+conditioner = Qwen3VLPromptConditioner(args.qwen, args.tokenizer)
+vision = Qwen3VL32BVision(args.qwen, device="cuda", dtype=torch.float32)
+if args.reference_vision_first and args.reference_vision_last:
+    class CapturedVision:
+        def __init__(self, paths):
+            self.outputs = [torch.load(path, map_location="cuda", weights_only=False) for path in paths]
+
+        def __call__(self, flatten, grid):
+            output = self.outputs.pop(0)
+            return output["merged"].cuda(), [value.cuda() for value in output["deepstack"]]
+
+    vision = CapturedVision([args.reference_vision_first, args.reference_vision_last])
+video, audio, frame_count = random_av_latents(width, height, requested_frames, seed)
+if args.sampler_capture_dir:
+    initial = torch.load(Path(args.sampler_capture_dir) / "initial.pt", map_location="cuda", weights_only=False)
+    direct_initial = torch.cat((video.reshape(-1), audio.reshape(-1)))
+    report("sampler_initial", direct_initial, initial["initial_x"].reshape(-1))
+presentation = build_fl2va_presentation(
+    prompt,
+    load_image(args.first),
+    load_image(args.last),
+    width=width,
+    height=height,
+    frame_count=frame_count,
+    tokenizer=conditioner.tokenizer,
+    vision=vision,
+    text_encoder=conditioner.encoder,
+    device="cuda",
+)
+if args.qwen_capture_dir:
+    qwen_capture = Path(args.qwen_capture_dir)
+    expected_ids = torch.load(qwen_capture / "qwen_input_ids.pt", map_location="cuda", weights_only=False)
+    print({"stage": "qwen_input_ids", "equal": torch.equal(presentation.input_ids, expected_ids), "direct_shape": tuple(presentation.input_ids.shape), "comfy_shape": tuple(expected_ids.shape)}, flush=True)
+    direct_embeds = conditioner.encoder._embed_rows(presentation.input_ids)
+    visual_mask = torch.zeros((1, direct_embeds.shape[1]), dtype=torch.bool, device="cuda")
+    deepstack_by_index = {}
+    for embed in presentation.embeds_info:
+        start = embed["index"]
+        end = start + embed["size"]
+        direct_embeds[0, start:end] = embed["extra"]["merged"].to(direct_embeds)
+        visual_mask[0, start:end] = True
+        for index, value in enumerate(embed["extra"]["deepstack"]):
+            deepstack_by_index.setdefault(index, []).append(value)
+    compact_ids_path = qwen_capture / "qwen_compact_token_ids.pt"
+    if compact_ids_path.exists():
+        compact_ids = torch.load(compact_ids_path, map_location="cuda", weights_only=False)
+        print({"stage": "qwen_compact_token_ids", "equal": torch.equal(presentation.input_ids[~visual_mask], compact_ids.reshape(-1)), "direct": presentation.input_ids[~visual_mask].tolist(), "comfy": compact_ids.reshape(-1).tolist()}, flush=True)
+    direct_deepstack = [torch.cat(values, dim=0) for _, values in sorted(deepstack_by_index.items())]
+    expected_embeds = torch.load(qwen_capture / "qwen_input_embeds.pt", map_location="cuda", weights_only=False)
+    raw_rows = torch.nn.functional.embedding(presentation.input_ids, conditioner.encoder.embed_tokens)
+    raw_scales = torch.nn.functional.embedding(presentation.input_ids, conditioner.encoder.embed_scale)
+    fp16_embeds = (raw_rows.to(torch.float16) * raw_scales.to(torch.float16)).float()
+    bf16_embeds = (raw_rows.to(torch.bfloat16) * raw_scales.to(torch.bfloat16)).float()
+    fp32_to_fp16_embeds = (raw_rows.float() * raw_scales.float()).half().float()
+    fp32_to_bf16_embeds = (raw_rows.float() * raw_scales.float()).bfloat16().float()
+    report("qwen_input_text_rows_fp16", fp16_embeds[~visual_mask], expected_embeds[~visual_mask])
+    report("qwen_input_text_rows_bf16", bf16_embeds[~visual_mask], expected_embeds[~visual_mask])
+    report("qwen_input_text_rows_fp32_to_fp16", fp32_to_fp16_embeds[~visual_mask], expected_embeds[~visual_mask])
+    report("qwen_input_text_rows_fp32_to_bf16", fp32_to_bf16_embeds[~visual_mask], expected_embeds[~visual_mask])
+    report("qwen_input_embeds", direct_embeds, expected_embeds)
+    report("qwen_input_text_rows", direct_embeds[~visual_mask], expected_embeds.to(direct_embeds.device)[~visual_mask])
+    report("qwen_input_visual_rows", direct_embeds[visual_mask], expected_embeds.to(direct_embeds.device)[visual_mask])
+    position_ids = mrope_position_ids(presentation.embeds_info, direct_embeds.shape[1], "cuda")
+    freqs = mrope_freqs_cis(position_ids)
+    hidden = (expected_embeds if args.oracle_qwen_input else direct_embeds).to(conditioner.encoder.dtype)
+    for index, layer in enumerate(conditioner.encoder.layers):
+        hidden = layer(hidden, freqs)
+        expected_layer = torch.load(qwen_capture / "qwen_layers" / f"{index:02d}.pt", map_location="cuda", weights_only=False)
+        report(f"qwen_layer_{index:02d}", hidden, expected_layer)
+        if index < len(direct_deepstack):
+            hidden[visual_mask] = hidden[visual_mask] + direct_deepstack[index].to(hidden)
+    expected_layer50 = torch.load(qwen_capture / "qwen_layer50.pt", map_location="cuda", weights_only=False)
+    report("qwen_layer50", presentation.text_states, expected_layer50)
+vae_dtype = {"float16": torch.float16, "bfloat16": torch.bfloat16, "float32": torch.float32}[args.vae_dtype]
+vae = MiniMaxH3VideoVAEEncoder.from_safetensors(args.vae, device="cuda", dtype=vae_dtype, tiling=not args.vae_no_tiling).eval()
+cond_latents = []
+cond_images = []
+for keyframe in presentation.keyframes:
+    resized = resize_keyframe(
+        keyframe["image"],
+        width,
+        height,
+        crop="disabled" if keyframe["resolved_frame_index"] == 0 else "center",
+    )
+    cond_images.append(resized)
+    pixels = resized.movedim(-1, 1).cuda().float().mul(2.0).sub(1.0)
+    cond_latents.append(vae.encode(pixels))
+if args.qwen_capture_dir:
+    for index, latent in enumerate(cond_latents):
+        captured_vae = torch.load(Path(args.qwen_capture_dir) / f"vae_keyframe_{index}.pt", map_location="cuda", weights_only=False)
+        print({"stage": f"vae_meta_{index}", **captured_vae.get("meta", {})}, flush=True)
+        report(f"vae_image_{index}", cond_images[index], captured_vae["image"])
+        report(f"vae_keyframe_{index}", latent, captured_vae["latent"])
+
+text = (early_refiner or H3TokenRefiner(checkpoint))(presentation.text_states)
+packer = early_packer or H3PromptPacker(checkpoint)
+sigma = beta_sigmas(12, device=video.device)[0]
+hidden, times, segments, positions, _, _ = packer(
+    text,
+    video,
+    audio,
+    _model_sigma(sigma),
+    text_token_tags=presentation.text_token_tags,
+    cond_latents=cond_latents,
+    cond_frame_indices=[keyframe["resolved_frame_index"] for keyframe in presentation.keyframes],
+    frame_count=frame_count,
+    seed=seed,
+)
+
+expected_hidden = capture["hidden"]
+text_length = text.shape[1]
+frame_rows = (video.shape[-2] // 2) * (video.shape[-1] // 2)
+direct_first = hidden[text_length:text_length + frame_rows]
+direct_last = hidden[text_length + frame_rows:text_length + 2 * frame_rows]
+comfy_first = expected_hidden[text_length:text_length + frame_rows]
+comfy_last = expected_hidden[text_length + frame_rows:text_length + 2 * frame_rows]
+
+print({"stage": "lengths", "text": text_length, "cond_each": frame_rows, "direct_total": hidden.shape[0], "comfy_total": expected_hidden.shape[0]}, flush=True)
+report("text_rows", hidden[:text_length], expected_hidden[:text_length])
+report("cond_first_to_first", direct_first, comfy_first)
+report("cond_first_to_last", direct_first, comfy_last)
+report("cond_last_to_last", direct_last, comfy_last)
+report("cond_last_to_first", direct_last, comfy_first)
+report("timesteps", times, capture["timesteps"])
+report("positions", positions, capture["position_ids"])
+print({"stage": "segments", "direct": segments, "comfy": capture["segments"]}, flush=True)
diff --git a/tools/compare_h3_keyframe_capture.py b/tools/compare_h3_keyframe_capture.py
new file mode 100644
index 0000000..1249cbc
--- /dev/null
+++ b/tools/compare_h3_keyframe_capture.py
@@ -0,0 +1,55 @@
+"""Replay a matched Comfy keyframe DiT capture through the direct H3 model."""
+
+import argparse
+from pathlib import Path
+
+import torch
+
+from h3_blackwell_runtime.checkpoint import H3Checkpoint
+from h3_blackwell_runtime.denoiser import H3PackedDenoiser
+from h3_blackwell_runtime.packing import unpatchify_video
+from h3_blackwell_runtime.rope import h3_rope_rotation
+from h3_blackwell_runtime.sampler import _unpack_audio
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("--capture", type=Path, required=True)
+parser.add_argument("--model", default="/models/minimax_h3_fl2va_pruned_nvfp4.safetensors")
+parser.add_argument("--attention", default="sage2")
+args = parser.parse_args()
+
+
+def report(name, actual, expected):
+    expected = expected.to(actual.device)
+    delta = (actual.float() - expected.float()).abs()
+    print({"stage": name, "shape": tuple(actual.shape), "mean_delta": float(delta.mean()), "max_delta": float(delta.max())}, flush=True)
+
+
+captured_input = torch.load(args.capture / "input.pt", map_location="cuda", weights_only=False)
+captured_output = torch.load(args.capture / "output.pt", map_location="cuda", weights_only=False)
+checkpoint = H3Checkpoint(args.model)
+model = H3PackedDenoiser.from_checkpoint(checkpoint, attention_backend=args.attention).eval()
+
+hidden = captured_input["hidden"].cuda()
+timesteps = captured_input["timesteps"].cuda()
+positions = captured_input["position_ids"].cuda()
+segments = captured_input["segments"]
+rotation = h3_rope_rotation(positions, model.backbone.inv_freq, hidden.dtype)
+with torch.inference_mode():
+    for index, (block, adaln) in enumerate(zip(model.backbone.blocks, model.backbone.adaln, strict=True)):
+        hidden = block(hidden, rotation, *adaln(timesteps), segments)
+        expected = torch.load(args.capture / "blocks" / f"{index:02d}.pt", map_location="cuda", weights_only=False)
+        report(f"block_{index:02d}", hidden, expected)
+
+    video_rows, audio_rows = model.final_layer(
+        hidden,
+        timesteps,
+        tuple(captured_output["video_segment"]),
+        tuple(captured_output["audio_segment"]),
+    )
+    expected_video = captured_output["video"].cuda()
+    expected_audio = captured_output["audio"].cuda()
+    video = unpatchify_video(video_rows, expected_video.shape[2], expected_video.shape[3], expected_video.shape[4])
+    audio = _unpack_audio(audio_rows)
+    report("video_output", video, expected_video)
+    report("audio_output", audio, expected_audio)
diff --git a/tools/compare_qwen_vision.py b/tools/compare_qwen_vision.py
new file mode 100644
index 0000000..cb582a6
--- /dev/null
+++ b/tools/compare_qwen_vision.py
@@ -0,0 +1,212 @@
+"""Compare direct and Comfy Qwen3-VL vision outputs on one keyframe."""
+
+import argparse
+from pathlib import Path
+import sys
+
+import numpy as np
+from PIL import Image
+from safetensors import safe_open
+import torch
+from torch.nn import functional as F
+
+from h3_blackwell_runtime.qwen3vl_vision import (
+    Qwen3VL32BVision,
+    _apply_rope_vision,
+    process_image,
+    resize_keyframe,
+)
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("--image", required=True)
+parser.add_argument("--checkpoint", default="/text-encoders/qwen3vl_32b_minimax_h3_nvfp4_awq.safetensors")
+parser.add_argument("--width", type=int, default=384)
+parser.add_argument("--height", type=int, default=384)
+parser.add_argument("--comfy-path", default="/opt/ComfyUI")
+parser.add_argument("--save-reference")
+parser.add_argument("--dtype", choices=("float16", "bfloat16", "float32"), default="bfloat16")
+parser.add_argument("--captured-reference")
+args = parser.parse_args()
+
+sys.path.insert(0, args.comfy_path)
+import comfy.ops  # noqa: E402
+from comfy.ldm.modules.attention import optimized_attention_for_device  # noqa: E402
+from comfy.text_encoders.qwen3vl import (  # noqa: E402
+    QWEN3VL_VISION,
+    QWEN3VL_VISION_COMMON,
+    Qwen3VLVisionModel,
+)
+from comfy.text_encoders.qwen_vl import process_qwen2vl_images  # noqa: E402
+from comfy.text_encoders.llama import apply_rope  # noqa: E402
+
+
+def report(name, actual, expected):
+    actual = actual.detach()
+    expected = expected.detach().to(actual.device)
+    delta = (actual.float() - expected.float()).abs()
+    print({
+        "stage": name,
+        "shape": tuple(actual.shape),
+        "actual_dtype": str(actual.dtype),
+        "expected_dtype": str(expected.dtype),
+        "mean_delta": float(delta.mean()),
+        "max_delta": float(delta.max()),
+    }, flush=True)
+
+
+image = Image.open(args.image).convert("RGB")
+pixels = torch.from_numpy(np.asarray(image).copy()).unsqueeze(0).cuda().float().div(255.0)
+pixels = resize_keyframe(pixels, args.width, args.height)
+
+direct_flatten, direct_grid = process_image(pixels)
+reference_flatten, reference_grid = process_qwen2vl_images(
+    pixels,
+    patch_size=16,
+    image_mean=[0.5, 0.5, 0.5],
+    image_std=[0.5, 0.5, 0.5],
+)
+report("flatten_patches", direct_flatten, reference_flatten)
+print({"stage": "grid", "direct": direct_grid.tolist(), "reference": reference_grid.tolist()}, flush=True)
+
+dtype = {"float16": torch.float16, "bfloat16": torch.bfloat16, "float32": torch.float32}[args.dtype]
+config = {
+    **QWEN3VL_VISION_COMMON,
+    **QWEN3VL_VISION["qwen3vl_32b"],
+    "out_hidden_size": 5120,
+}
+reference = Qwen3VLVisionModel(
+    config,
+    device="cuda",
+    dtype=dtype,
+    ops=comfy.ops.disable_weight_init,
+).to("cuda").eval()
+with safe_open(args.checkpoint, framework="pt", device="cuda") as checkpoint:
+    print({
+        "stage": "checkpoint_dtypes",
+        "text_norm": str(checkpoint.get_tensor("model.layers.0.input_layernorm.weight").dtype),
+        "vision_norm": str(checkpoint.get_tensor("visual.blocks.0.norm1.weight").dtype),
+        "vision_patch": str(checkpoint.get_tensor("visual.patch_embed.proj.weight").dtype),
+    }, flush=True)
+    visual_state = {
+        name.removeprefix("visual."): checkpoint.get_tensor(name).to(dtype)
+        for name in checkpoint.keys()
+        if name.startswith("visual.")
+    }
+reference.load_state_dict(visual_state, strict=True)
+del visual_state
+
+direct = Qwen3VL32BVision(args.checkpoint, device="cuda", dtype=dtype).eval()
+with torch.inference_mode():
+    direct_x = direct.patch_embed(direct_flatten.cuda().to(dtype))
+    direct_patch_embed = direct_x
+    reference_x = reference.patch_embed(reference_flatten.cuda().to(dtype))
+    report("patch_embed", direct_x, reference_x)
+    direct_pos = direct.fast_pos_embed_interpolate(direct_grid).to(direct_x.device)
+    reference_pos = reference.fast_pos_embed_interpolate(reference_grid).to(reference_x.device)
+    report("position_embed", direct_pos, reference_pos)
+    direct_x = direct_x + direct_pos
+    direct_vision_input = direct_x
+    reference_x = reference_x + reference_pos
+    report("vision_input", direct_x, reference_x)
+
+    direct_rotary = direct.rot_pos_emb(direct_grid.to(direct_x.device)).reshape(direct_x.shape[0], -1)
+    reference_rotary = reference.rot_pos_emb(reference_grid).to(reference_x.device).reshape(reference_x.shape[0], -1)
+    report("rotary", direct_rotary, reference_rotary)
+
+    def position_tuple(rotary):
+        embedding = torch.cat((rotary, rotary), dim=-1)
+        cosine = embedding.cos().unsqueeze(-2)
+        sine = embedding.sin().unsqueeze(-2)
+        split = sine.shape[-1] // 2
+        return cosine, sine[..., :split], -sine[..., split:]
+
+    direct_position = position_tuple(direct_rotary)
+    reference_position = position_tuple(reference_rotary)
+    cu_seqlens = F.pad(
+        torch.repeat_interleave(direct_grid[:, 1] * direct_grid[:, 2], direct_grid[:, 0]).cumsum(0, dtype=torch.int32),
+        (1, 0),
+        value=0,
+    )
+    optimized_attention = optimized_attention_for_device(reference_x.device, mask=False, small_input=True)
+
+    direct_block0 = direct.blocks[0]
+    reference_block0 = reference.blocks[0]
+    direct_norm = F.layer_norm(
+        direct_x,
+        (direct_x.shape[-1],),
+        weight=direct_block0.norm1_weight,
+        bias=direct_block0.norm1_bias,
+        eps=1e-6,
+    )
+    reference_norm = reference_block0.norm1(reference_x)
+    report("block0_norm1", direct_norm, reference_norm)
+    direct_qkv = F.linear(direct_norm, direct_block0.attn.qkv_weight, direct_block0.attn.qkv_bias)
+    reference_qkv = reference_block0.attn.qkv(reference_norm)
+    report("block0_qkv", direct_qkv, reference_qkv)
+    direct_q, direct_k, direct_v = direct_qkv.reshape(direct_x.shape[0], 3, 16, 72).permute(1, 0, 2, 3).unbind(0)
+    reference_q, reference_k, reference_v = reference_qkv.reshape(reference_x.shape[0], 3, 16, 72).permute(1, 0, 2, 3).unbind(0)
+    direct_q, direct_k = _apply_rope_vision(direct_q.float(), direct_k.float(), direct_position)
+    direct_q, direct_k = direct_q.to(dtype), direct_k.to(dtype)
+    reference_q, reference_k = apply_rope(reference_q, reference_k, reference_position)
+    report("block0_rope_q", direct_q, reference_q)
+    report("block0_rope_k", direct_k, reference_k)
+    direct_attention_heads = F.scaled_dot_product_attention(
+        direct_q.transpose(0, 1).unsqueeze(0),
+        direct_k.transpose(0, 1).unsqueeze(0),
+        direct_v.transpose(0, 1).unsqueeze(0),
+    )
+    direct_attention = direct_attention_heads.transpose(1, 2).reshape(1, direct_x.shape[0], -1)
+    reference_attention = optimized_attention(
+        reference_q.transpose(0, 1).unsqueeze(0),
+        reference_k.transpose(0, 1).unsqueeze(0),
+        reference_v.transpose(0, 1).unsqueeze(0),
+        16,
+        skip_reshape=True,
+    )
+    report("block0_attention", direct_attention, reference_attention)
+    direct_projected = F.linear(direct_attention[0], direct_block0.attn.proj_weight, direct_block0.attn.proj_bias)
+    reference_projected = reference_block0.attn.proj(reference_attention)[0]
+    report("block0_projected", direct_projected, reference_projected)
+
+    direct_deepstack = []
+    direct_blocks = []
+    reference_deepstack = []
+    for index, (direct_block, reference_block) in enumerate(zip(direct.blocks, reference.blocks)):
+        direct_x = direct_block(direct_x, cu_seqlens, direct_position)
+        direct_blocks.append(direct_x)
+        reference_x = reference_block(
+            reference_x,
+            cu_seqlens,
+            reference_position,
+            optimized_attention=optimized_attention,
+        )
+        report(f"block_{index:02d}", direct_x, reference_x)
+        if index in direct.deepstack_visual_indexes:
+            merger_index = direct.deepstack_visual_indexes.index(index)
+            direct_deepstack.append(direct.deepstack_merger_list[merger_index](direct_x))
+            reference_deepstack.append(reference.deepstack_merger_list[merger_index](reference_x))
+    direct_merged = direct.merger(direct_x)
+    reference_merged = reference.merger(reference_x)
+report("merged", direct_merged, reference_merged)
+for index, (actual, expected) in enumerate(zip(direct_deepstack, reference_deepstack)):
+    report(f"deepstack_{index}", actual, expected)
+if args.captured_reference:
+    captured = torch.load(args.captured_reference, map_location="cuda", weights_only=False)
+    report("loaded_comfy_pixel_values", direct_flatten, captured["pixel_values"])
+    print({"stage": "loaded_comfy_grid", "direct": direct_grid.tolist(), "expected": captured["grid"].tolist()})
+    trace_path = Path(args.captured_reference).with_name(Path(args.captured_reference).name.replace("qwen_vision_", "qwen_vision_trace_"))
+    trace = torch.load(trace_path, map_location="cuda", weights_only=False)
+    report("loaded_comfy_patch_embed", direct_patch_embed, trace["patch_embed"])
+    report("loaded_comfy_position_embed", direct_pos, trace["position_embed"])
+    report("loaded_comfy_vision_input", direct_vision_input, trace["vision_input"])
+    for index, block_output in enumerate(direct_blocks):
+        report(f"loaded_comfy_block_{index:02d}", block_output, trace[f"block_{index:02d}"])
+    report("loaded_comfy_merged", direct_merged, captured["merged"])
+    for index, (actual, expected) in enumerate(zip(direct_deepstack, captured["deepstack"])):
+        report(f"loaded_comfy_deepstack_{index}", actual, expected)
+if args.save_reference:
+    torch.save({
+        "merged": reference_merged.detach().cpu(),
+        "deepstack": [value.detach().cpu() for value in reference_deepstack],
+    }, args.save_reference)
diff --git a/tools/compare_vae_decoder_clip.py b/tools/compare_vae_decoder_clip.py
index 0e3fdae..71ef712 100644
--- a/tools/compare_vae_decoder_clip.py
+++ b/tools/compare_vae_decoder_clip.py
@@ -7,7 +7,7 @@ from pathlib import Path
 import torch
 from safetensors.torch import load_file
 
-from h3_blackwell_runtime.vae_decoder import MiniMaxH3VideoVAE as DirectVAE
+from h3_blackwell_runtime.vae_decoder import MiniMaxH3VideoVAE as DirectVAE, _conv3d
 
 
 parser = argparse.ArgumentParser()
@@ -30,7 +30,7 @@ state = torch.load(args.latent, map_location="cuda", weights_only=False)
 latent = state["latent"].to("cuda") if isinstance(state, dict) else state.to("cuda")
 
 direct = DirectVAE.from_safetensors("/vae/minimax_h3_video_vae_fp16.safetensors", device="cuda", tiling=False).eval()
-upstream = UpstreamVAE(tiling=False).to("cuda").eval()
+upstream = UpstreamVAE(tiling=False).to("cuda", dtype=torch.float16).eval()
 upstream.load_state_dict(load_file("/vae/minimax_h3_video_vae_fp16.safetensors", device="cuda"), strict=True)
 
 with torch.inference_mode():
@@ -38,7 +38,7 @@ with torch.inference_mode():
     z_u = z_d.clone().to(next(upstream.parameters()).dtype)
     z_d = z_d * direct.latents_std.view(1, -1, 1, 1, 1).to(z_d) + direct.latents_mean.view(1, -1, 1, 1, 1).to(z_d)
     z_u = z_u * upstream.latents_std.view(1, -1, 1, 1, 1).to(z_u) + upstream.latents_mean.view(1, -1, 1, 1, 1).to(z_u)
-    z_d = direct.post_quant_conv(z_d)
+    z_d = _conv3d(z_d, direct.post_quant_conv.weight, direct.post_quant_conv.bias)
     z_u = upstream.post_quant_conv(z_u)
     stats("post_quant_conv", z_d, z_u)
 
diff --git a/tools/compare_vae_encoder.py b/tools/compare_vae_encoder.py
new file mode 100644
index 0000000..61b1671
--- /dev/null
+++ b/tools/compare_vae_encoder.py
@@ -0,0 +1,110 @@
+"""Compare direct and upstream MiniMax H3 VAE encoding on one keyframe."""
+
+import argparse
+import os
+import sys
+
+import numpy as np
+from PIL import Image
+import torch
+
+from h3_blackwell_runtime.vae_encoder import (
+    MiniMaxH3VideoVAEEncoder as DirectVAEEncoder,
+    _causal_conv3d,
+    _downsample,
+    _group_norm_3d,
+    _resnet,
+)
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("--image", required=True)
+parser.add_argument("--vae", default="/vae/minimax_h3_video_vae_fp16.safetensors")
+parser.add_argument("--comfy-path", default="/opt/ComfyUI")
+parser.add_argument("--tiling", action="store_true")
+args = parser.parse_args()
+
+sys.path.insert(0, args.comfy_path)
+from h3_blackwell_runtime.upstream_vae import MiniMaxH3VideoVAE as UpstreamVAE  # noqa: E402
+
+
+def load_checkpoint(path):
+    if os.getenv("H3_DISABLE_MMAP", "").lower() in {"1", "true", "yes", "on"}:
+        from safetensors.torch import load
+
+        with open(path, "rb") as file:
+            return load(file.read())
+    from safetensors.torch import load_file
+
+    return load_file(path, device="cuda")
+
+
+def report(name, actual, expected):
+    actual = actual.detach()
+    expected = expected.detach().to(actual.device)
+    delta = (actual.float() - expected.float()).abs()
+    print({
+        "stage": name,
+        "shape": tuple(actual.shape),
+        "actual_min": float(actual.min()),
+        "actual_max": float(actual.max()),
+        "expected_min": float(expected.min()),
+        "expected_max": float(expected.max()),
+        "mean_delta": float(delta.mean()),
+        "max_delta": float(delta.max()),
+    }, flush=True)
+
+
+image = Image.open(args.image).convert("RGB")
+pixels = torch.from_numpy(np.asarray(image).copy()).permute(2, 0, 1).unsqueeze(0).cuda().float()
+pixels = pixels.div(127.5).sub(1.0)
+
+direct = DirectVAEEncoder.from_safetensors(args.vae, device="cuda", tiling=args.tiling).eval()
+upstream = UpstreamVAE(tiling=args.tiling).to("cuda").eval()
+upstream = upstream.to(dtype=direct.compute_dtype)
+state = load_checkpoint(args.vae)
+upstream.load_state_dict(state, strict=True)
+del state
+
+trace = {}
+trace_names = {"encoder.conv_in", "encoder.norm_out", "encoder.conv_out", "quant_conv"}
+for level in range(6):
+    trace_names.update(f"encoder.down.{level}.block.{block}" for block in range(2))
+    if level < 4:
+        trace_names.add(f"encoder.down.{level}.downsample")
+for name, module in upstream.named_modules():
+    if name in trace_names:
+        module.register_forward_hook(lambda _module, _inputs, output, name=name: trace.__setitem__(name, output.detach().cpu()))
+
+report("quant_conv_weight", direct.quant_conv.weight, upstream.quant_conv.weight)
+report("quant_conv_bias", direct.quant_conv.bias, upstream.quant_conv.bias)
+with torch.inference_mode():
+    direct_latent = direct.encode(pixels.clone())
+    upstream_latent = upstream.encode(pixels.to(direct.compute_dtype))
+report("normalized_latent", direct_latent, upstream_latent)
+
+with torch.inference_mode():
+    x = pixels.unsqueeze(2)
+    x = (x + 1.0) * 0.5
+    x = (x - direct.pixel_mean.to(x)) / direct.pixel_std.to(x)
+    params = direct.W
+    x = _causal_conv3d(x, params["conv_in"][0], params["conv_in"][1], kernel_size=3, stride=(1, 1, 1), spatial_padding=1, temporal_causal=True)
+    report("encoder.conv_in", x, trace.pop("encoder.conv_in"))
+    for level_index, level in enumerate(params["down"]):
+        for block_index, block in enumerate(level["blocks"]):
+            x = _resnet(x, block)
+            name = f"encoder.down.{level_index}.block.{block_index}"
+            report(name, x, trace.pop(name))
+        if level["down"] is not None:
+            x = _downsample(x, level["down"])
+            name = f"encoder.down.{level_index}.downsample"
+            report(name, x, trace.pop(name))
+    x = _group_norm_3d(x, params["norm_out_w"], params["norm_out_b"])
+    report("encoder.norm_out", x, trace.pop("encoder.norm_out"))
+    x = torch.nn.functional.silu(x)
+    x = _causal_conv3d(x, params["conv_out"][0], params["conv_out"][1], kernel_size=3, stride=(1, 1, 1), spatial_padding=1, temporal_causal=True)
+    report("encoder.conv_out", x, trace.pop("encoder.conv_out"))
+    x = torch.nn.functional.conv3d(x, direct.quant_conv.weight, direct.quant_conv.bias)
+    report("quant_conv", x, trace.pop("quant_conv"))
+    report("latents_mean", direct.latents_mean, upstream.latents_mean)
+    report("latents_std", direct.latents_std, upstream.latents_std)
diff --git a/tools/compare_vae_full_decode.py b/tools/compare_vae_full_decode.py
index 936bc50..f228661 100644
--- a/tools/compare_vae_full_decode.py
+++ b/tools/compare_vae_full_decode.py
@@ -51,7 +51,7 @@ with torch.inference_mode():
     torch.cuda.empty_cache()
     gc.collect()
 
-    upstream = UpstreamVAE().to("cuda").eval()
+    upstream = UpstreamVAE().to("cuda", dtype=torch.float16).eval()
     upstream.load_state_dict(load_file("/vae/minimax_h3_video_vae_fp16.safetensors", device="cuda"), strict=True)
     upstream_pixels = pixelize(upstream.decode(latent.to(next(upstream.parameters()).dtype)), frames)
 
diff --git a/tools/direct_t2v_preview.py b/tools/direct_t2v_preview.py
index 62793ac..c0b9992 100644
--- a/tools/direct_t2v_preview.py
+++ b/tools/direct_t2v_preview.py
@@ -118,7 +118,7 @@ if args.first_frame is not None or args.last_frame is not None:
 
     def load_image(path: Path) -> torch.Tensor:
         img = Image.open(path).convert("RGB")
-        return torch.from_numpy(np.array(img)).permute(2, 0, 1).unsqueeze(0).float() / 255.0
+        return torch.from_numpy(np.array(img)).unsqueeze(0).float() / 255.0
 
     first = load_image(args.first_frame) if args.first_frame is not None else None
     last = load_image(args.last_frame) if args.last_frame is not None else None
@@ -127,7 +127,7 @@ if args.first_frame is not None or args.last_frame is not None:
     from h3_blackwell_runtime.qwen3vl_vision import Qwen3VL32BVision
 
     vision_tower = Qwen3VL32BVision(
-        "/text-encoders/qwen3vl_32b_minimax_h3_nvfp4_awq.safetensors", device="cuda", dtype=torch.bfloat16
+        "/text-encoders/qwen3vl_32b_minimax_h3_nvfp4_awq.safetensors", device="cuda", dtype=torch.float32
     )
     report_memory("vision_tower_loaded")
     presentation = build_fl2va_presentation(
@@ -145,7 +145,8 @@ if args.first_frame is not None or args.last_frame is not None:
     cond_latents = []
     for kf in presentation.keyframes:
         resized = resize_keyframe(kf["image"].cuda(), args.width, args.height, crop="disabled" if kf["resolved_frame_index"] == 0 else "center")
-        cond_latents.append(vae_encoder.encode(resized.movedim(-1, 1).cuda().float()))
+        pixels = resized.movedim(-1, 1).cuda().float().mul(2.0).sub(1.0)
+        cond_latents.append(vae_encoder.encode(pixels))
     report_memory("fl2va_conditioned")
     text = refiner(presentation.text_states)
     report_memory("text_conditioned")
@@ -163,6 +164,7 @@ if args.first_frame is not None or args.last_frame is not None:
         seed=seed,
         text_token_tags=presentation.text_token_tags,
         cond_latents=cond_latents,
+        cond_frame_indices=[kf["resolved_frame_index"] for kf in presentation.keyframes],
         frame_count=frames,
         cache_mode=args.cache_mode,
         cache_threshold=args.cache_threshold,
diff --git a/tools/patch_comfy_qwen_vision_capture.py b/tools/patch_comfy_qwen_vision_capture.py
new file mode 100644
index 0000000..d249629
--- /dev/null
+++ b/tools/patch_comfy_qwen_vision_capture.py
@@ -0,0 +1,74 @@
+"""Capture actual loaded-Comfy Qwen merged and DeepStack vision tensors."""
+
+from pathlib import Path
+
+
+path = Path("/opt/ComfyUI/comfy/text_encoders/qwen3vl.py")
+source = path.read_text(encoding="utf-8")
+if "import os\n" not in source:
+    source = source.replace("import os\n", "import os\n", 1) if "import os\n" in source else "import os\n" + source
+if "import traceback\n" not in source:
+    source = "import traceback\n" + source
+old = (
+    "            merged, deepstack = self.visual(image.to(device, dtype=torch.float32), grid)\n"
+    "            return merged, {\"grid\": grid, \"deepstack\": deepstack}\n"
+)
+new = (
+    "            merged, deepstack = self.visual(image.to(device, dtype=torch.float32), grid)\n"
+    "            capture_dir = os.getenv(\"H3_CAPTURE_DIR\")\n"
+    "            if capture_dir:\n"
+    "                os.makedirs(capture_dir, exist_ok=True)\n"
+    "                capture_index = getattr(self, \"_h3_vision_capture_index\", 0)\n"
+    "                torch.save({\"merged\": merged.detach().cpu(), \"deepstack\": [value.detach().cpu() for value in deepstack], \"pixel_values\": image.detach().cpu(), \"grid\": grid.detach().cpu(), \"stack\": traceback.format_stack()}, os.path.join(capture_dir, f\"qwen_vision_{capture_index}.pt\"))\n"
+    "                open(os.path.join(capture_dir, \"qwen_vision_stack.txt\"), \"w\", encoding=\"utf-8\").writelines(traceback.format_stack())\n"
+    "                self._h3_vision_capture_index = capture_index + 1\n"
+    "            return merged, {\"grid\": grid, \"deepstack\": deepstack}\n"
+)
+if source.count(old) != 1:
+    raise RuntimeError("Unable to locate Qwen3-VL vision preprocess block.")
+path.write_text(source.replace(old, new), encoding="utf-8")
+
+vision_path = Path("/opt/ComfyUI/comfy/text_encoders/qwen35.py")
+vision_source = vision_path.read_text(encoding="utf-8")
+vision_source = vision_source.replace(
+    "        x = self.patch_embed(x)\n        pos_embeds = self.fast_pos_embed_interpolate(grid_thw).to(x.device)\n        x = x + pos_embeds\n",
+    "        x = self.patch_embed(x)\n        capture_trace = {\"patch_embed\": x.detach().cpu()}\n        pos_embeds = self.fast_pos_embed_interpolate(grid_thw).to(x.device)\n        capture_trace[\"position_embed\"] = pos_embeds.detach().cpu()\n        x = x + pos_embeds\n        capture_trace[\"vision_input\"] = x.detach().cpu()\n",
+    1,
+)
+vision_source = vision_source.replace(
+    "            x = blk(x, cu_seqlens=cu_seqlens, position_embeddings=position_embeddings, optimized_attention=optimized_attention)\n",
+    "            x = blk(x, cu_seqlens=cu_seqlens, position_embeddings=position_embeddings, optimized_attention=optimized_attention)\n            capture_trace[f\"block_{layer_num:02d}\"] = x.detach().cpu()\n",
+    1,
+)
+vision_source = vision_source.replace(
+    "        merged = self.merger(x)\n        if self.deepstack_merger_list is not None:\n",
+    "        merged = self.merger(x)\n        capture_dir = os.getenv(\"H3_CAPTURE_DIR\")\n        if capture_dir:\n            trace_index = getattr(self, \"_h3_vision_trace_index\", 0)\n            torch.save(capture_trace, os.path.join(capture_dir, f\"qwen_vision_trace_{trace_index}.pt\"))\n            self._h3_vision_trace_index = trace_index + 1\n        if self.deepstack_merger_list is not None:\n",
+    1,
+)
+vision_path.write_text(vision_source, encoding="utf-8")
+
+clip_path = Path("/opt/ComfyUI/comfy/sd1_clip.py")
+clip_source = clip_path.read_text(encoding="utf-8")
+if "import os\n" not in clip_source:
+    clip_source = "import os\n" + clip_source
+clip_source = clip_source.replace(
+    "            tokens_embed = torch.tensor([tokens_temp], device=device, dtype=torch.long)\n            tokens_embed = self.transformer.get_input_embeddings()(tokens_embed, out_dtype=torch.float32)\n",
+    "            tokens_embed = torch.tensor([tokens_temp], device=device, dtype=torch.long)\n            capture_dir = os.getenv(\"H3_CAPTURE_DIR\")\n            if capture_dir:\n                torch.save(tokens_embed.detach().cpu(), os.path.join(capture_dir, \"qwen_compact_token_ids.pt\"))\n            tokens_embed = self.transformer.get_input_embeddings()(tokens_embed, out_dtype=torch.float32)\n",
+    1,
+)
+clip_path.write_text(clip_source, encoding="utf-8")
+
+nodes_path = Path("/opt/ComfyUI/comfy_extras/nodes_minimax_h3.py")
+nodes_source = nodes_path.read_text(encoding="utf-8")
+if "import os\n" not in nodes_source:
+    nodes_source = "import os\n" + nodes_source
+vae_encode_line = "kf[\"latent\"] = vae.encode(kf.pop(\"image\"))"
+if nodes_source.count(vae_encode_line) != 1:
+    raise RuntimeError("Unable to locate MiniMax H3 keyframe VAE encode call.")
+nodes_source = nodes_source.replace(
+    vae_encode_line,
+    "keyframe_image = kf.pop(\"image\")\n                kf[\"latent\"] = vae.encode(keyframe_image)\n                capture_dir = os.getenv(\"H3_CAPTURE_DIR\")\n                if capture_dir:\n                    capture_index = getattr(vae, \"_h3_vae_capture_index\", 0)\n                    vae_model = vae.first_stage_model\n                    vae_meta = {\"parameter_dtype\": str(next(vae_model.parameters()).dtype), \"tiling\": vae_model.tiling, \"tile_size\": vae_model.tile_size, \"tile_overlap_min\": vae_model.tile_overlap_min}\n                    torch.save({\"image\": keyframe_image.detach().cpu(), \"latent\": kf[\"latent\"].detach().cpu(), \"meta\": vae_meta}, os.path.join(capture_dir, f\"vae_keyframe_{capture_index}.pt\"))\n                    vae._h3_vae_capture_index = capture_index + 1",
+    1,
+)
+nodes_path.write_text(nodes_source, encoding="utf-8")
+print("Applied Qwen3-VL vision capture patch.")
diff --git a/tools/submit_fl2va_keyframes.py b/tools/submit_fl2va_keyframes.py
new file mode 100644
index 0000000..131ee20
--- /dev/null
+++ b/tools/submit_fl2va_keyframes.py
@@ -0,0 +1,46 @@
+"""Submit a matched Comfy FL2VA first/last-frame reference workflow."""
+
+import argparse
+import json
+from urllib.request import Request, urlopen
+
+
+parser = argparse.ArgumentParser()
+parser.add_argument("--url", default="http://localhost:8188")
+parser.add_argument("--first", default="fl2va_key_first.png")
+parser.add_argument("--last", default="fl2va_key_last.png")
+parser.add_argument("--prefix", default="fl2va-comfy-keyframes-seed440207")
+args = parser.parse_args()
+
+prompt = {
+    "1": {"class_type": "UNETLoader", "inputs": {"unet_name": "minimax_h3_fl2va_pruned_nvfp4.safetensors", "weight_dtype": "default"}},
+    "3": {"class_type": "CLIPLoader", "inputs": {"clip_name": "qwen3vl_32b_minimax_h3_nvfp4_awq.safetensors", "type": "minimax"}},
+    "4": {"class_type": "VAELoader", "inputs": {"vae_name": "minimax_h3_video_vae_fp16.safetensors"}},
+    "5": {"class_type": "LoadImage", "inputs": {"image": args.first}},
+    "6": {"class_type": "LoadImage", "inputs": {"image": args.last}},
+    "8": {"class_type": "MiniMaxH3ImageToVideo", "inputs": {
+        "clip": ["3", 0],
+        "vae": ["4", 0],
+        "prompt": "A studio time-lapse of the same pink peony bud opening into the same fully bloomed pink peony, fixed camera, cream background.",
+        "width": 384,
+        "height": 384,
+        "length": 22,
+        "first_frame": ["5", 0],
+        "last_frame": ["6", 0],
+    }},
+    "9": {"class_type": "BasicGuider", "inputs": {"model": ["1", 0], "conditioning": ["8", 0]}},
+    "10": {"class_type": "RandomNoise", "inputs": {"noise_seed": 440207}},
+    "11": {"class_type": "KSamplerSelect", "inputs": {"sampler_name": "res_multistep"}},
+    "12": {"class_type": "BasicScheduler", "inputs": {"model": ["1", 0], "scheduler": "beta", "steps": 12, "denoise": 1.0}},
+    "13": {"class_type": "SamplerCustomAdvanced", "inputs": {"noise": ["10", 0], "guider": ["9", 0], "sampler": ["11", 0], "sigmas": ["12", 0], "latent_image": ["8", 1]}},
+    "14": {"class_type": "VAEDecode", "inputs": {"samples": ["13", 0], "vae": ["4", 0]}},
+    "15": {"class_type": "SaveImage", "inputs": {"images": ["14", 0], "filename_prefix": args.prefix}},
+}
+
+request = Request(
+    args.url.rstrip("/") + "/prompt",
+    data=json.dumps({"prompt": prompt}).encode(),
+    headers={"Content-Type": "application/json"},
+)
+with urlopen(request) as response:
+    print(response.read().decode())