Colourisation Input — pan-city, Rec. 709 luma
The pan-city plate desaturated using Rec. 709 luma weights. Converted with Rec. 709 luma weights, the correct coefficients for HD material. All chroma is gone, so a colouriser has nothing to recover from and must infer it entirely.
Browser-playable test video · 2 seconds
Specifications
- Resolution
- 640x360
- Fps
- 24
- Luma Weights
- 0.2126, 0.7152, 0.0722
- Standard
- Rec. 709 luma
- Role
- colourisation input
- Reference
- vid-colour-pan-city-gt
- Crf
- 19
- Base Plate
- pan-city
Testing contract
Expected to pass- Scenario
- Colourise the clip and score the result against the full-colour ground truth.
- Expected result
- The input is greyscale, produced with Rec. 709 luma luma weights 0.2126, 0.7152, 0.0722, from the pan-city plate at 640x360 24 fps; the reference is vid-colour-pan-city-gt. The two greyscale members of each plate in this group differ only in those weights, so any output difference between them is caused by the luma standard - which is the confound most colourisation benchmarks leave uncontrolled.
What is a .mp4 file?
MP4 (MPEG-4 Part 14) is the dominant container for digital video, holding video, audio, subtitle, and metadata tracks in a tree of typed boxes. `ftyp` declares the brand, `moov` carries the sample tables that make seeking possible, and `mdat` holds the media; when an encoder writes `moov` last, playback cannot begin until the file has fully downloaded, which a faststart remux fixes. It derives from Apple's QuickTime format, generalized by ISO into the ISOBMFF base that MOV, 3GP, and HEIF share.
How to use this file
Use an example MP4 to test box parsing and track detection, seeking, range-request streaming, and transcode or thumbnail pipelines: verifying that a file with a trailing `moov` box is still handled, and that codec support is checked per track rather than inferred from the extension.
How to use this file for testing
“Colourisation Input — pan-city, Rec. 709 luma” is a deterministic Novus Examples fixture for Video colourisation, Video QA. Greyscale, sepia and partially-desaturated clips shipped beside the full-colour original they were derived from, including a 24-patch chart with documented values, so a colourisation model's output can be scored per patch rather than judged by eye.
Documented properties for this file: colourisation input · 24 fps. Compare results against paired or grouped companions on this page when present (clean↔damaged, searchable↔scanned, or format twins) so scores stay reproducible across runs.
Download the file once, keep the path stable in CI or local scripts, and treat the spec table as the contract: dimensions, seeds, field lists, and roles are intentional. Corrupt or invalid samples are labelled as such, expect parsers to fail loudly rather than silently accept them.
Media fixtures are short and synthetic by design. Prefer waveform or transcript ground truth in the same group when measuring ASR, trim, upscale, or sync tools; do not assume broadcast-quality masters.
Code examples
<video controls preload="metadata" width="640" src="pan-city-greyscale.mp4"></video>Related files
- mp4Colourisation Ground Truth — colour-patchesThe full-colour reference for the colour-patches colourisation set. Every desaturated clip in this group was derived from these exact pixels with a documented luma transform, so a colouriser's output can be scored against the true colours — and on this plate the 24 patch values are fixed and published, so the comparison can be made per patch rather than as a whole-frame average.
- mp4Colourisation Ground Truth — gradient-skyThe full-colour reference for the gradient-sky colourisation set. Every desaturated clip in this group was derived from these exact pixels with a documented luma transform, so a colouriser's output can be scored against the true colours.
- mp4Colourisation Input — colour-patches, 50% DesaturatedThe colour-patches plate with 50% of its saturation removed, leaving 50% of the original chroma. This is the faded-archive case rather than the black-and-white one: some colour information survives, so the task is restoration rather than invention, and a model that ignores the residual chroma is throwing away the strongest signal it has.
- mp4Colourisation Input — colour-patches, 80% DesaturatedThe colour-patches plate with 80% of its saturation removed, leaving 19% of the original chroma. This is the faded-archive case rather than the black-and-white one: some colour information survives, so the task is restoration rather than invention, and a model that ignores the residual chroma is throwing away the strongest signal it has.
- mp4Colourisation Input — colour-patches, Rec. 601 lumaThe colour-patches plate desaturated using Rec. 601 luma weights. Rec. 601 weights instead — the SD standard, and still the default in a surprising amount of software. The greys differ measurably from the 709 version, which is a good check on whether a pipeline knows which standard it is using.
- mp4Colourisation Input — colour-patches, Rec. 709 lumaThe colour-patches plate desaturated using Rec. 709 luma weights. Converted with Rec. 709 luma weights, the correct coefficients for HD material. All chroma is gone, so a colouriser has nothing to recover from and must infer it entirely.
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