chore(container): build in-tree ffmpeg CLI and route imageio through it

[saturley-hall]

Summary

• wheel_builder: extends the existing ffmpeg build so it also produces the CLI binary, with --enable-nvenc (h264_nvenc for MP4/H.264) and --enable-libvpx (libvpx_vp9 for WebM/VP9). Pulls in nv-codec-headers and libvpx from source so we don't have to track distro package names across the Ubuntu and manylinux base images.
• runtime images: the in-tree ffmpeg CLI + its runtime libs are copied into the SGLang and TRT-LLM runtime images. IMAGEIO_FFMPEG_EXE=/usr/local/bin/ffmpeg makes imageio use it.
• Python: 3 sites switch codec=\"libx264\" → codec=\"h264_nvenc\" (common/utils/video_utils.py × 2, sglang/.../video_generation_handler.py). The WebM/VP9 path is unchanged. Unit-test fixture updated.
• imageio-ffmpeg installation: a --no-binary imageio-ffmpeg directive in requirements.common.txt and requirements.trtllm.txt makes dynamo, trtllm, and frontend runtimes install the Python wrapper from source automatically. The SGLang and vLLM runtimes reinstall the wrapper from source after the upstream base image's install (lmsysorg/sglang and vllm/vllm-openai both pre-install imageio-ffmpeg), so all four images end up with the same shape: pure-Python wrapper + the in-tree ffmpeg CLI as the only encoder backend.

Test plan

• CI image builds (sglang, trtllm, vllm, dynamo runtimes) succeed.
• In each runtime image, python -c \"import imageio_ffmpeg, os; print(os.listdir(os.path.join(os.path.dirname(imageio_ffmpeg.__file__), 'binaries')))\" shows the binaries/ directory is empty or absent.
• In sglang and trtllm runtimes, ffmpeg -hide_banner -encoders | grep -E 'h264_nvenc|libvpx_vp9' lists both, and ffmpeg -version | grep configuration: shows --disable-gpl --disable-nonfree --enable-nvenc.
• End-to-end: text-to-video diffusion (examples/backends/sglang/launch/text-to-video-diffusion.sh) returns a valid MP4. TRT-LLM video diffusion handler returns a valid MP4. Both runtimes require an NVENC-capable GPU.
• pytest components/src/dynamo/common/tests/test_video_utils.py passes.

🤖 Generated with Claude Code

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Summary by CodeRabbit

• New Features

  • Added NVIDIA NVENC H.264 codec support for accelerated MP4 video encoding, enabling GPU-powered compression.

• Bug Fixes

  • Resolved FFmpeg licensing compliance by ensuring LGPL-only binaries are used in container environments instead of GPL-bundled versions.

• Documentation

  • Updated video generation documentation with FFmpeg requirements and setup instructions for both containerized and standalone deployments.

[github-actions]

🌿 Fern Docs Preview: https://nvidia-preview-fdb00987-7f1d-4ad7-a0a8-4f44e1dbb116.docs.buildwithfern.com/dynamo/dev

[coderabbitai]

Walkthrough

This PR migrates video encoding from the libx264 codec to NVIDIA's h264_nvenc codec, rebuilds FFmpeg with NVENC and VP9 encoder support, and replaces GPL-bundled imageio-ffmpeg wheels with source-built LGPL FFmpeg across all container runtimes using IMAGEIO_FFMPEG_EXE redirection.

Changes

Video encoding and container FFmpeg refactor

Layer / File(s)	Summary
Application codec switch to h264_nvenc components/src/dynamo/common/utils/video_utils.py, components/src/dynamo/sglang/request_handlers/video_generation/video_generation_handler.py, components/src/dynamo/common/tests/test_video_utils.py	encode_to_mp4, encode_to_video_bytes, and _frames_to_video update default codec from libx264 to h264_nvenc; test assertion updated to validate the new codec.
Prevent GPL imageio-ffmpeg wheel installation container/deps/requirements.common.txt, container/deps/requirements.trtllm.txt	Both requirements files add --no-binary imageio-ffmpeg directives with comments explaining GPL exposure and directing installs toward in-tree LGPL ffmpeg CLI via IMAGEIO_FFMPEG_EXE.
Build FFmpeg with NVENC and libvpx encoders container/templates/wheel_builder.Dockerfile	New build arguments pin nv-codec-headers and libvpx source refs; build steps clone and compile these dependencies; FFmpeg configure flags enable NVENC (h264_nvenc) and VP9 (libvpx_vp9) encoders as shared libraries.
Runtime image FFmpeg integration container/templates/sglang_runtime.Dockerfile, container/templates/trtllm_runtime.Dockerfile, container/templates/vllm_runtime.Dockerfile	Each runtime copies FFmpeg binary and libraries from wheel_builder, sets IMAGEIO_FFMPEG_EXE environment variable, and conditionally force-reinstalls imageio-ffmpeg with --no-binary to ensure no GPL artifact remains on disk.
Documentation for FFmpeg setup docs/backends/trtllm/trtllm-diffusion.md	Expanded section describing LGPL-only ffmpeg location in container, clarifying absence of wheel-bundled binary, and providing setup instructions for non-container deployments with IMAGEIO_FFMPEG_EXE configuration; notes that MP4 output requires NVIDIA GPU.

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🎯 3 (Moderate) | ⏱️ ~25 minutes

🚥 Pre-merge checks | ✅ 4 | ❌ 1

❌ Failed checks (1 warning)

Check name	Status	Explanation	Resolution
Docstring Coverage	⚠️ Warning	Docstring coverage is 71.43% which is insufficient. The required threshold is 80.00%.	Write docstrings for the functions missing them to satisfy the coverage threshold.

✅ Passed checks (4 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly and specifically describes the main change: building an in-tree ffmpeg CLI and configuring imageio to use it instead of default ffmpeg sources.
Description check	✅ Passed	The description covers all required template sections with comprehensive detail: Summary section explains code changes across wheel_builder, runtime images, Python, and imageio-ffmpeg installation; Details section is thorough; Test plan provides concrete verification steps.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@container/templates/sglang_runtime.Dockerfile`:
- Around line 36-45: The RUN layer copies only unversioned FFmpeg symlinks
(libav*.so and libsw*.so) which can miss the actual versioned SONAME files;
update the cp patterns in the RUN command that currently reference libav*.so and
libsw*.so to copy the versioned shared objects (libav*.so* and libsw*.so*) using
the same flags (cp -nL ...) and preserve the existing error-tolerant redirects
(e.g., 2>/dev/null || true) so the Docker build still succeeds if files are
absent; locate and modify the cp invocation inside the RUN --mount... block that
precedes ENV IMAGEIO_FFMPEG_EXE to use the *.so* glob instead of just *.so.

In `@container/templates/trtllm_runtime.Dockerfile`:
- Around line 149-161: The ENV IMAGEIO_FFMPEG_EXE set in the runtime_full stage
is not carried into the final runtime stage, causing imageio to lose the pinned
/usr/local/bin/ffmpeg; add the same ENV IMAGEIO_FFMPEG_EXE=/usr/local/bin/ffmpeg
to the final runtime stage (the later "runtime" stage that rebases from
runtime_full) so the runtime image preserves the IMAGEIO_FFMPEG_EXE variable
used by the TRT-LLM encoder; ensure you update both occurrences mentioned (the
runtime stage and the later block around lines 195-203) so IMAGEIO_FFMPEG_EXE is
present in the final image.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

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ℹ️ Review info

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📥 Commits

Reviewing files that changed from the base of the PR and between eb98d8b and 7136e98.

📒 Files selected for processing (10)

• components/src/dynamo/common/tests/test_video_utils.py
• components/src/dynamo/common/utils/video_utils.py
• components/src/dynamo/sglang/request_handlers/video_generation/video_generation_handler.py
• container/deps/requirements.common.txt
• container/deps/requirements.trtllm.txt
• container/templates/sglang_runtime.Dockerfile
• container/templates/trtllm_runtime.Dockerfile
• container/templates/vllm_runtime.Dockerfile
• container/templates/wheel_builder.Dockerfile
• docs/backends/trtllm/trtllm-diffusion.md