Render ass subtitles in advance
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- Dominant language
- C
- Stars
- 37k
- Forks
- 3.5k
- Avg merge
- 1d 10h
- Merged PRs (30d)
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Description
Follow up from an IRC discussion.
The behavior of ass subtitle rendering in mpv is quite poor for more complex scenes. Naturally any raw performance improvements would have to be implemented in libass, but one thing mpv can do to improve the situation is to render subtitles in advance and maintain a buffer of pre-rendered frames of subtitles, so that the CPU can be working on rendering complex frames into a buffer in advance while playing back simpler frames.
Contributor guide
No contributing guide indexed for this repository
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
No source files or tests are identified. Start by tracing mpv's ASS subtitle rendering path and its boundary with libass, then determine how subtitle frames are scheduled during playback. Done should include an agreed buffering design, correct playback behavior, and evidence that complex subtitle scenes no longer cause the same rendering stalls.
Written by the indexing model from the issue text.
Assessment
- Tech stack
- c
- Domain
- performance
- Issue type
- Feature
- Difficulty
- 5/5
- Estimated time
- Over a week
- Activity status
- Stale
- Clarity
- Needs clarification
- Newbie friendliness
- 25/100