[MEncoder-users] Decoding mjpeg with mencoder

[Reimar Döffinger]

On Tue, Nov 10, 2009 at 11:29:10AM +0100, Dirk Plate wrote:
> If I play the original files with mplayer, it stops with a 'Seek
> failed' error too. I found a hint that '-demuxer lavf' can solve
> this problem in mplayer and this works for me too.
> But in mencoder this parameter has no effect. No 'unknown parameter'
> error, but the result hasn't changed.

-demuxer lavf works just fine with mencoder, too. I'd say you must have
done something wrong when you tried it.

> You can download a sample file here:
> 
> http://www.file-upload.net/download-2001649/sample.AVI.html
> 
> Any tips?

Flame whoever created it.
The file is _not_ a valid AVI file.
In AVI files the chunks (e.g. the stuff that starts with 00dc to mark a
video frame) _must_ be aligned to be at a file offset that is divisible
by 2.
This in addition leads to the AVIIF_LIST flag being set for the index
entries, causing MPlayer to ignore them.
I suspect that if you remove the index (e.g. cut away the last few 100 kB)
not even Windows Media Player will be able to play it.