[FFmpeg-devel] [PATCH] alac : check readsamplesize

[Jai Menon]

Hi,

> Hi,
> 
> Jai Menon wrote:
> > Hi,
> 
> > 
> >> check readsamplesize in alac, with the current code, it could be 
> >> negative or bigger than 17 (and get_bits will fail).
> >>
> > 
> > And what about 24-bit alac streams? not to mention multi-channel alac if
> possible
> > that is...
> ATM ffmpeg decoder doesn't support 24-bit stream, nor multi-channel :
> - get_bits will return garbage if readsamplesize > 17

So isn't it better if we just check if channels>2 or wasted_bytes is nonzero

> - in the 24-bit stream I saw on mplayer sample, wasted_bytes is used, so 
> readsamplesize could be less than 17, but our decoder doesn't handle it 
> correctly
> - for not 16-bit stream, we got 'FIXME: unimplemented sample size'.
> - MAX_CHANNELS is 2
> 
> So until we implement correct support for multi-channel and other bits 
> per sample, I think this check is safe.
> 

Hmm..couldn't we just add a check to see if the stream is multichannel or > 16
bits sample size and return an error from decode_frame instead of checking each value
explicitly? or maybe i'm confused...
Anyway michael is ffalac maintainer so he will surely comment.

> 
> Matthieu

Regards,

Jai Menon
<realityman at gmx.net>

-- 
Ist Ihr Browser Vista-kompatibel? Jetzt die neuesten 
Browser-Versionen downloaden: http://www.gmx.net/de/go/browser