| { |
| "schema_name": "media", |
| "schema_version": 1, |
| "artifact_suffix": ".mp4", |
| "format": "mp4", |
| "description": "Public video/audio encoding contract for WebDataset MP4 members.", |
| "encoder_policy": { |
| "compatibility_contract": "The public loader contract is the MP4/H.264/AAC bitstream, not a specific encoder implementation.", |
| "render_stage_default_video_encoder": "h264_nvenc", |
| "wds_reencode_video_encoder": "libx264 when WebDataset packing is run with reencode_mode=optimized", |
| "release_environment_source": "stats/release_environment.json records the exact final encoder, FFmpeg version, and packing mode used for the published release." |
| }, |
| "profiles": { |
| "720p": { |
| "container": "mp4", |
| "video_codec": "h264", |
| "width": 1280, |
| "height": 720, |
| "fps": 32, |
| "gop_size": 32, |
| "closed_gop": true, |
| "b_frames": 0, |
| "video_quality": { |
| "mode": "crf", |
| "value": 20, |
| "applies_to": "libx264 WebDataset re-encode path" |
| }, |
| "pixel_format": "yuv420p", |
| "faststart": true, |
| "audio_codec": "aac", |
| "audio_profile": "LC", |
| "audio_channels": 2, |
| "audio_channel_layout": "stereo", |
| "audio_sample_rate_hz": 44100, |
| "audio_bitrate_policy": "CSDM render sets audioBitrate=128 kbps; WebDataset packing copies source AAC audio unless audio is explicitly stripped.", |
| "audio_nominal_bitrate_bps": 128000, |
| "audio_validation_bitrate_bps": { |
| "min": 96000, |
| "max": 192000 |
| } |
| }, |
| "360p": { |
| "container": "mp4", |
| "video_codec": "h264", |
| "width": 640, |
| "height": 360, |
| "fps": 32, |
| "gop_size": 32, |
| "closed_gop": true, |
| "b_frames": 0, |
| "video_quality": { |
| "mode": "crf", |
| "value": 20, |
| "applies_to": "libx264 WebDataset re-encode path" |
| }, |
| "pixel_format": "yuv420p", |
| "faststart": true, |
| "audio_codec": "aac", |
| "audio_profile": "LC", |
| "audio_channels": 2, |
| "audio_channel_layout": "stereo", |
| "audio_sample_rate_hz": 44100, |
| "audio_bitrate_policy": "CSDM render sets audioBitrate=128 kbps; WebDataset packing copies source AAC audio unless audio is explicitly stripped.", |
| "audio_nominal_bitrate_bps": 128000, |
| "audio_validation_bitrate_bps": { |
| "min": 96000, |
| "max": 192000 |
| } |
| } |
| }, |
| "notes": [ |
| "yuv420p is used for broad decoder, browser, OpenCV, PyAV, FFmpeg, torchcodec, and hardware-decoder compatibility.", |
| "faststart places MP4 metadata at the front of the file for browser playback and HTTP range-read friendliness.", |
| "The release stores a stereo game-audio mix. It does not expose multichannel audio or positional audio metadata." |
| ], |
| "validation": [ |
| "video stream is decodable", |
| "video codec is H.264", |
| "video resolution matches the release profile", |
| "video frame rate is 32 FPS", |
| "video pixel format is yuv420p", |
| "audio stream exists", |
| "audio codec is AAC-LC", |
| "audio channel count is 2", |
| "audio sample rate is 44100 Hz", |
| "audio bit rate is within the profile validation range when ffprobe reports bit_rate" |
| ] |
| } |
|
|
