w3c / w3c/webcodecs

YCoCg matrix support

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Question
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Description

Currently the VideoColorSpace: matrix property supports the following values:

  • "rgb"
    Matrix coefficients used by sRGB.
  • "bt709"
    Matrix coefficients used by BT.709.
  • "bt470bg"
    Matrix coefficients used by BT.601 PAL.
  • "smpte170m"
    Matrix coefficients used by BT.601 NTSC.

It is known that:

  • At least H.264/MPEG-4 AVC and HEVC are fully supporting such color space
  • It has good coding gain (at least comparable to ycbcr/bt.601 with full range)
  • Conversion from/to rgb color space should be faster than with ycbcr/bt.601 since it results in additions/shifts for integer arithmetic, or just multiplies by 0.25 and 0.5 for float ones)

Are there any plans to support such color space?

Thanks,
Fabio

Contributor guide

Open the contributing guide

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Start with the VideoColorSpace.matrix definition and the existing rgb, bt709, bt470bg, and smpte170m values. Determine the standards and implementation changes needed to represent YCoCg, then verify that the new matrix value is supported and its RGB conversions behave as intended.

Written by the indexing model from the issue text.

Assessment

Domain
api, audio-video-rtc
Issue type
Feature
Difficulty
5/5
Estimated time
Over a week
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
35/100

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