Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Processing Pipeline: Timing Model #9

Open
aboba opened this issue Dec 28, 2022 · 0 comments
Open

Processing Pipeline: Timing Model #9

aboba opened this issue Dec 28, 2022 · 0 comments

Comments

@aboba
Copy link
Collaborator

aboba commented Dec 28, 2022

Dom & Francois have demonstrated a way of tracking timing at each stage of the processing pipeline, by inserting a timestamp overlay.

It would be nice to have a consistent timing model built in so as to make this more straightforward.

The requestVideoFrameCallback specification defines VideoFrameCallbackMetadata, which includes some timing information.

It has been proposed that some fields from VideoFrameCallbackMetadata be added to VideoFrameMetadata:
w3c/webcodecs#601

However, currently timing metadata is not consistently exposed across media processing APIs. For example:

  • VideoFrame.captureTime is not exposed within the mediacapture-transform API (e.g. in a VideoFrame produced from a MediaStreamTrack)
  • When aVideoFrame is passed to WebCodecs Encoder, the timing metadata is not copied to the encoded Chunk

Related slides: https://docs.google.com/presentation/d/1DEk4urMPNufIYX88jzRqXddxoGRZXv10iOTGbKvLe5s/edit#slide=id.g159ea124a3f_8_221

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

1 participant