Decoding WebM files with alpha
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- Dominant language
- HTML
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Description
Do webcodec decoding operation support alpha channels in webm files?
I'm using https://github.com/Yahweasel/mkvdemuxjs demuxer for getting chunks and webcodes VideoDecoder for getting VideoFrames. But when I draw frame on canvas, alpha layer from input webm file is missing.
I'm not sure if it's problem of demuxer or of webcodecs..
I noticed that encoder does support alpha: 'keep' option, I looked for something similar for decoder but with no luck
Contributor guide
First steps
- Read the whole issue, then the project's contributing guide.
- Comment on the issue to say you are picking it up — it saves two people doing the same work.
- Fork the repository and make your change on a branch.
- Open a pull request that references the issue number.
Research direction
Start with the VideoDecoder and VideoFrame behavior described in the issue, then compare it with the mkvdemuxjs output and the canvas drawing step. Determine whether the missing alpha originates in demuxing, WebCodecs decoding, or rendering; done means the responsible component and expected alpha-channel behavior are established and documented or tracked for a fix.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- javascript
- Domain
- api, audio-video-rtc
- Issue type
- Bug
- Difficulty
- 4/5
- Estimated time
- 3-5 days
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 30/100