[gijoe77]

I second that - amazing work on this!

[jpstewart]

Thanks for the kind words, folks.

I've finally found the source of the audio/video synchronization problem that was brought to my attention earlier.  After spending far too much time looking at hex dumps and digging into the depths of FFmpeg's approach to synchronization, I spotted a little tidbit that's been staring me in the face since the beginning of this.  Namely, libavformat hard codes the video frame rate to 15 FPS!!!  Actual frame rate is stored in the file.  That's why audio was getting out of sync with the video:  after I fixed the audio issue it was playing at the right speed.  But some videos (notably Hospital.movie) were being played back too fast.  The file said 10 FPS but it was being played at 15 FPS, which meant the video was getting ahead of the audio by 33%.  Videos that were actually 15 FPS (which were most of my samples) were fine, of course

So, now I know where the problem is.  I just have to figure out how to fix it in a way that will be accepted into the upstream project.

[jpstewart]

The patch mentioned in my last post for fixing the sync/framerate issue was pushed to the FFmpeg git repo yesterday. 

So was another patch to correct the duration of SGI .movie files.  Previously they were estimating duration, and doing it incorrectly.  Some GUIs wouldn't use the estimate at all so they'd show no progress bar.  Others would use the incorrect estimate, causing the progress bar to stop abruptly mid-way across and making it look like something bad happened.  E.g., Hospital.movie is just over 36 seconds long but was being estimated at more than 2 minutes.  Now that that's corrected, GUIs will display progress bars correctly.

If you're working with FFmpeg and SGI-format movies, you'll want to build from source from the git repo.  Or wait for the next release of FFmpeg.  And, as I've mentioned previously, the fixes are in FFmpeg's libavformat which is widely used by other multi-media apps such as MPlayer and VLC.  So they'll eventually trickle down to whatever your favourite viewer/editor is, too.

I'm not aware of any further bugs in the handling of SGI .movie files.  If anyone stumbles upon any more, let me know and I'll see what I can do now that I'm familiar with FFmpeg development.