[FFmpeg-devel] [PATCH] fix crash on incorrectly framed STR

Alexander Strange astrange
Wed Jan 23 22:54:52 CET 2008

On Jan 23, 2008 4:30 PM, Mike Melanson <mike at multimedia.cx> wrote:
> Alexander Strange wrote:
> > http://samples.mplayerhq.hu/game-formats/psx-str/logo.iki
> >
> > This file doesn't seem like a real STR; the video is some other codec
> It's incredibly difficult to qualify a file as being "real STR", as you
> probably know. PS1 games were free to use any ad-hoc framing they chose,
> just as long as they accumulated proper blocks of data for the MDEC
> hardware unit.

Well, the official "definition" (in filefrmt.pdf) implies one video frame isn't
going to have anything else in between it. Of course it doesn't enforce
anything, so there might be other stuff like this out there. Do you have any
samples like that? I'm pretty sure they'd all crash the demuxer right now.

This file also claims to have multiple video streams, which the demuxer is
already dropping anyway, but of course you'd have to go and check all the
other fields to see if it isn't just reusing them all for something else :(

> Are you sure the video is some other codec? Could it just be standard
> MDEC data compressed with a custom Huffman scheme?

All I know is, it doesn't decode. It probably is one of those, since the PS1
was pretty weak and nobody is going to go write an entire new codec that
can't use MDEC...

Does anyone know where that file even came from? I've never seen ".iki"
before, and without knowing the original game we can't get more samples.
If we had those, it would be interesting to fix this to play them back.

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