[FFmpeg-devel] [PATCH] ALAC Encoder

[matthieu castet]

Michael Niedermayer wrote:
> On Mon, Aug 18, 2008 at 07:24:23PM +0200, Michael Niedermayer wrote:
>> On Mon, Aug 18, 2008 at 09:55:10PM +0530, Jai Menon wrote:
>> The decoder does:
>>             cl -= (cr * W) >> S;
>>             cr += cl;
>>
>>             l = cr;
>>             r = cl;
>> the encoder does:
>>             l -= r;
>>             r += (l * W) >> S;
>>
>>             cr = l;
>>             cl = r;
>>
>> These hold true for all values of W and S
>>
>> with W=0,S=1  you get l-r, r
>> with W=1,S=1  you get l-r, (r+l)>>1
>> with W=2,S=1  you get l-r, l
> 
> i just realized my suggestion has a little bug, the silly thing only
> applies decorrelation when W!=0 ...

Note that could be a bug in our decoder.

BTW, may be W can be signed.


Matthieu