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rB7eb3e77b94f5: FFmpeg: Fix seeking not returning the correct frame when not using TC index
rB14508ef100c9: FFmpeg: Fix seeking not returning the correct frame when not using TC index

Summary

Fixed the logic for seeking in ffmpeg video files.
The main fix is that we now apply a small offset in ffmpeg_get_seek_pos to make sure we don't get the frame in front of the seek position when seeking backward.

The rest of the changes is general cleanup and untangling code.

This incorperates the changes from: D10644
So it can be closed if this is merged.

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Event Timeline

Sebastian Parborg (zeddb) requested review of this revision.Jun 4 2021, 12:27 AM

Sebastian Parborg (zeddb) created this revision.

Sebastian Parborg (zeddb) updated this revision to Diff 37832.Jun 4 2021, 12:31 AM

I have found issue with footage that was working before. Easy to reproduce by seeking manually frame by frame backwards when you can clearly see image will jump.
F10158179

This footage has rigid scheme IBBPBBPBBPBBPBBPBBPBBPBBPBBPBB so I don't think this is due to any variablity of file, haven't checked where in code this fails yet.

Richard Antalik (ISS) added inline comments.Jun 4 2021, 8:29 PM

source/blender/imbuf/intern/anim_movie.c
1326–1332	To change decoding like this you have to do more changes. Currently `anim` contains 2 frames One is processed into `ImBuf` and it has PTS of `anim->last_pts`. This is current frame One is in `anim->pFrameComplete`, unprocessed, but decoded. PTS corresponds to `anim->next_pts` Above is condition that checks `ffmpeg_pts_matches_last_frame(anim, pts_to_search)` but with decoding scheme changed like this `anim->last_pts` and `anim->next_pts` should be same, but this is not changed and will result in error. I can check by pressing Ctrl+R in VSE and it will produce issues

Richard Antalik (ISS) added inline comments.Jun 4 2021, 8:47 PM

source/blender/imbuf/intern/anim_movie.c
1241	I am pretty sure that `AVPacket->pts` may not be the same as `AVFrame->pts`. In fact it rarely is. Double check me on that, though.

Fixed GOP key frame

I think, that seeking portion is fine. Not sure about change to current frame "double bufferring". If I understand it correctly, it is needed only for ffmpeg_pts_matches_last_frame to check if some frames are actually dropped from stream.
Will see if I can get file or create one myself to demonstrate the problem. We are talking edge cases here though...

source/blender/imbuf/intern/anim_movie.c
1155	Did you find necessary to increase this offset? Such change probably won't hurt too much, I am just curious.

Sebastian Parborg (zeddb) updated this revision to Diff 37890.Jun 5 2021, 1:14 AM

Sebastian Parborg (zeddb) marked 2 inline comments as done.

Updated so it now should properly detect when we can reuse the current frame in memory.

Sebastian Parborg (zeddb) marked an inline comment as done.Jun 5 2021, 2:04 AM

Sebastian Parborg (zeddb) retitled this revision from Fix seeking in the the VSE when not using a proxy to FFmpeg: Fix seeking not returning the correct frame when not using TC index.Jun 5 2021, 2:14 AM

Sebastian Parborg (zeddb) edited the summary of this revision. (Show Details)

Sebastian Parborg (zeddb) added a reviewer: Richard Antalik (ISS).

Sebastian Parborg (zeddb) added a project: VFX & Video.

Sebastian Parborg (zeddb) edited the summary of this revision. (Show Details)

Richard Antalik (ISS) accepted this revision.Jun 5 2021, 2:36 AM

This revision is now accepted and ready to land.Jun 5 2021, 2:36 AM

Closed by commit rB14508ef100c9: FFmpeg: Fix seeking not returning the correct frame when not using TC index (authored by Sebastian Parborg (zeddb)). · Explain WhyJun 5 2021, 2:49 AM

This revision was automatically updated to reflect the committed changes.

Sebastian Parborg (zeddb) added a commit: rB14508ef100c9: FFmpeg: Fix seeking not returning the correct frame when not using TC index.

Sebastian Parborg (zeddb) mentioned this in D11561: Fix: VSE indexer seeking not working correctly.Jun 11 2021, 1:52 PM

Sebastian Parborg (zeddb) mentioned this in rB4adbe31e2fc9: Fix: VSE indexer seeking not working correctly.Jun 11 2021, 2:05 PM

Jeroen Bakker (jbakker) added a commit: rB7eb3e77b94f5: FFmpeg: Fix seeking not returning the correct frame when not using TC index.Jun 30 2021, 9:48 AM