Parse colr box CICP data for video tracks#447
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kinetiknz merged 3 commits intomozilla:masterfrom Apr 18, 2026
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Add parsing of the ISO BMFF `colr` box (ISO 14496-12:2020 §12.1.5) in `read_video_sample_entry`, storing the result in a new `colour_info` field on `VideoSampleEntry`. Expose the nclx CICP values through the C API via four new fields on `Mp4parseTrackVideoSampleInfo`: `has_colour_info`, `colour_primaries`, `transfer_characteristics`, `matrix_coefficients`, and `full_range_flag`. This enables Firefox's MP4 demuxer to set `mVideoInfo.mTransferFunction` for fMP4 content (Netflix, Prime Video, DRM), fixing HDR10/HLG video appearing near-black on Windows HDR displays. - `read_video_sample_entry` now takes `strictness` (consistent with `read_audio_sample_entry`) and passes it to `read_colr`. - Duplicate `colr` boxes in a sample entry violate ISO 14496-12:2020 §12.1.5; we warn and keep the first rather than failing playback. - `has_colour_info: bool` is the canonical "present" flag; avoids misinterpreting MC=0 (Identity/GBR) as "absent". - `NclxColourInformation` fields made public for Rust callers. - Seven integration tests added. Test MP4 files were generated with ffmpeg using `-movflags +write_colr` and `-x264-params colorprim/transfer/colormatrix`: HDR10 (cp=9,tc=16,mc=9), HLG (tc=18), HDR10 full-range, HLG full-range, RGB/Identity (mc=0, exercises has_colour_info), and no-colr variants.
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@kinetiknz could you help review this? This is a fix for bug 2030296 where we miss parse |
kinetiknz
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Apr 17, 2026
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Thanks! Looks good, just a couple of things to address.
- Add ColrBadQuantityBMFF status (distinct from the HEIF-specific ColrBadQuantity) and enforce it via fail_with_status_if when strictness != Permissive for duplicate colr boxes in video tracks. - Introduce ParsedColourInformation enum so read_colr returns Supported/Unsupported instead of always erroring on unknown colour_type values; the AVIF call site converts Unsupported to ColrBadType, while the video call site warns and continues. - Document that VideoSampleEntry::colour_info only surfaces Nclx through the C API.
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Summary
The
read_colrfunction andColourInformationBoxparsing already existed in this codebase, but were only wired upto the AVIF/image item path (
read_iprp). The video track path (read_video_sample_entry) silently discarded thecolrbox via the defaultskip_box_contentarm.This PR connects the existing
read_colrto video tracks and exposes the CICP values through the C API.Changes
mp4parse(Layer 1 — parser)colour_info: Option<ColourInformation>field toVideoSampleEntryBoxType::ColourInformationBoxarm inread_video_sample_entryto call the existingread_colrstrictnessparameter toread_video_sample_entry(needed to pass toread_colr, consistent withread_audio_sample_entry)NclxColourInformationfieldspubsomp4parse_capican read themcolrboxes violate ISO 14496-12:2020 §12.1.5 — we warn and keep the first rather than failing, toavoid breaking playback of malformed content
mp4parse_capi(Layer 2 — C API)Mp4parseTrackVideoSampleInfo:has_colour_info: bool— canonical presence flag; needed because MC=0 is a valid CICP value (Identity/GBR), notan absence indicator
colour_primaries: u8transfer_characteristics: u8matrix_coefficients: u8full_range_flag: boolvideo.colour_infoinmp4parse_get_track_video_info_safeTests
Six integration tests with ffmpeg-generated MP4 files (
-movflags +write_colr,-x264-params colorprim/transfer/colormatrix):colrbox