[FFmpeg-devel] Encoding to SWF with -vcodec mjpeg creates an unreadable SWF

Alexander Almaleh sashoalm
Wed Apr 28 09:27:59 CEST 2010

I think this is a bug but I don't know what causes it. I tried it with
different input files and it always happened regardless of the file. This
happens only when -vcodec mjpeg is selected.

The line "ffmpeg -i input.avi -vcodec mjpeg output.swf" produces a corrupt
file, while the line "ffmpeg -i input.avi output.swf" doesn't.

The file isn't really corrupt, but it is missing the initial 3-bytes 'F',
'W', 'S', instead it starts with 0x0, 0x0, 'S'. If I replace the
2 zeros with 'F','W' it is readable.

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