[FFmpeg-trac] #377(undetermined:new): ffmpeg reports inaccurate length of some gxf files
FFmpeg
trac at avcodec.org
Tue Aug 2 20:51:08 CEST 2011
#377: ffmpeg reports inaccurate length of some gxf files
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Reporter: acloutier | Owner:
Type: defect | Status: new
Priority: important | Component: undetermined
Version: git | Resolution:
Keywords: gxf ffmpeg length bug | Blocked By:
Blocking: | Reproduced: 0
Analyzed: 0 |
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Comment (by reimar):
By my understanding of the format, the best guess it does right now is the
best that is possible reliably.
The problem with this file is that it does not contain FPS in the track
tags.
So FFmpeg is forced to fall back to the UMF tag (which is rather
unreliable).
That one specifies 60 FPS, i.e. 120 fields per second (which is obviously
not correct).
The file also claims to contain 438170 fields.
And that gives the calculated result.
Obviously it would be possible to just guess that 120 fields per second is
not correct, but that does not seem like a good solution to me.
So unless you can give me some other info my conclusion would be that the
file is broken and will only work correctly with programs/equipment that
will break if you ever want to use it with 60 fps / 120 fields per second
input.
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Ticket URL: <https://avcodec.org/trac/ffmpeg/ticket/377#comment:4>
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