Bug #3011

Fix endless loop when generating thumbnails on certain files

Added by Daren K over 5 years ago. Updated over 5 years ago.

Status:FixedStart date:02/28/2016
Priority:NormalDue date:
Assignee:-% Done:


Target version:-
Found in version:4.99.749 Platform:Linux



My "fix" is terribad though, you can get the idea I think. I'm sure you can manage to evade this more efficiently (or even manage to get it working).

As mentioned in the Pull request I could provide a sample, though not sure if appropriate here (maybe via PM).


#1 Updated by Daren K over 5 years ago

I did some further digging, the mentioned files have something in common:

1. When loaded into Avidemux, they show one single I-frame at the beginning of the video, followed by only P-frames until the end. This may have something to do with an open GOP structure saved in the wrong container format (http://forum.doom9.org/showthread.php?t=161226), which results non-IDR I-frames not being referenced as I-frames.

2. A variable frame rate.

I tried to find a fix for seeking in these files but couldn't get it working.

What I tried:

Using avformat_seek_file(ifv_fctx, ifv_stream, INT64_MIN, ts, INT64_MAX, <flag>;) instead of av_seek_frame(ifv_fctx, ifv_stream, ts, AVSEEK_FLAG_BACKWARD) with flags such as AVSEEK_FLAG_ANY right before the loop starts, still no frames extracted.

Also checked if avcodec_decode_video2(ifv_ctx, frame, &got_pic, &pkt) does return errors when hit with those files, but on all tries it returned > 0.

The guys over at Kodi somehow manage to extract frames out of those files for thumbnails with the last function mentioned, but C++ is too scattered for me to get to the bottom of it and adapt.

#2 Updated by Andreas Smas over 5 years ago

  • Status changed from New to Fixed

I'm setting this to Fixed for now.

Also available in: Atom PDF