[FFmpeg-trac] #401(avcodec:open): ffmpeg fails to decode MJPG in AVI
FFmpeg
trac at avcodec.org
Fri Sep 9 22:36:03 CEST 2011
#401: ffmpeg fails to decode MJPG in AVI
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Reporter: rectalogic | Owner:
Type: defect | Status: open
Priority: normal | Component: avcodec
Version: git-master | Resolution:
Keywords: mjpeg | Blocked By:
Blocking: | Reproduced by developer: 1
Analyzed by developer: 0 |
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Comment (by michael):
Replying to [comment:2 reimar]:
> This is probably caused by libavfilter. The (vsrc)buffer filter seems to
need a pixfmt from the start.
> However the filters are created before the decoder is actually opened.
> So it is completely reliant on the probe filling in the pix_fmt.
> However since this file is non-interleaved and FFmpeg detects this too
late, the probe never gets any video data, thus does not open the decoder
and thus the pix_fmt is not filled in.
> This seems all rather silly though: it is quite silly that it is not
tried to open the decoder during probe even if no data is available, as is
opening the decoder only after the filter has been set up.
The decoder is opened in av_find_stream_info() but mjpeg can store a wide
varity of pixel formats and iam not sure if the actually used one can be
identified before the first frame.
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Ticket URL: <https://ffmpeg.org/trac/ffmpeg/ticket/401#comment:5>
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