[Ffmpeg-devel] Some FLV files no longer work in new ffmpeg

Alex Beregszaszi alex
Sat Feb 24 18:48:15 CET 2007


> The new one comes from svn (Feb 13)
> newffmpeg -i x.flv
> FFmpeg version SVN-rUNKNOWN, Copyright (c) 2000-2007 Fabrice Bellard, et al.
>   configuration: --enable-pthreads --disable-network
> --disable-audio-oss --disable-v4l --disable-bktr --disable-dv1394
> --disable-vhook --disable-ffserver --disable-ffplay --disable-debug
> --enable-memalign-hack --enable-faac --enable-a52 --enable-x264
> --enable-gpl
>   libavutil version: 49.3.0
>   libavcodec version: 51.33.0
>   libavformat version: 51.10.0
>   built on Feb 23 2007 22:55:43, gcc: 4.0.0 20041026 (Apple Computer,
> Inc. build 4061)
> Input #0, flv, from 'x.flv':
>   Duration: N/A, start: 0.000000, bitrate: N/A
> Must supply at least one output file
> What files would cause this? flvdec? Where should I start digging? Or
> can someone else who has a clue help figure it out?

I faced this problem too. The old flvtool scripts, which adds metadata
to FLVs, was broken. Presumably (at least I know some such sites) video
sharing sites used flvtool for ffmpeg generated files some time ago,
thus they have been corrupted by flvtool.

The corruption is that the flags byte is zero, however, flash player
checks the metadata too, where the stream information is duplicated.

Old flvdec was checking the data frames instead relying on the flags
byte, while currently it bails out if the the flags says there are no

Alex Beregszaszi

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