[FFmpeg-devel] Change 9963 introduces regression - start_time in asf.c

[Neil Brown]

I have a video file:

   Seems stream 1 codec frame rate differs from container frame rate: 1000.00 (1000/1) -> 25.00 (25/1)
   Input #0, asf, from '/var/tmp/100 Celebration Presentation 1 - Final (v3w).wmv':
     Duration: 00:05:00.8, start: 1.579000, bitrate: 1550 kb/s
     Stream #0.0: Audio: wmav2, 44100 Hz, stereo, 160 kb/s
     Stream #0.1: Video: wmv3, yuv420p, 720x576, 1500 kb/s, 25.00 fps(r)

which is (as you can see) 5 minutes long.  When I look at it with
a more recent ffmpeg, I get a different duration:

  Duration: 00:04:41.0, start: 0.000000, bitrate: 1660 kb/s

(The same happens when I load it into kdenlive which uses ffmpeg libraries).

This has only started happening recently and I tracked it down to
change 9963 in ffmpeg.

  r9963 | michael | 2007-08-07 06:36:55 +1000 (Tue, 07 Aug 2007) | 2 lines

  ignore preroll, it is generally not what AVStream.start_time should contain


Could it be that with this change, start_time isn't being set at all?
If it add code to explicitly set it to zero, I get the correct clip
length again.
Before I set it to 0, it's value is
  0x8000000000000000

Thanks,
NeilBrown