[Flac-dev] Decoding Type=Independent

MVallevand mvallevand at gmail.com
Tue Jan 2 12:55:13 PST 2007

On 1/2/07, Josh Coalson <xflac at yahoo.com> wrote:
> I'm not sure I understand... I think the INDEPENDENT you are referring
> to means the interchannel decorrelation method.  this stage is before
> and independent of LPC analysis.


> I'm not sure why "independent" frames would not decode correctly
> though.  more info on exactly how it is not working would help.

Ignoring the fact that I am not doing anything special with the MID
channel samples, (for now they hit the same code), I am using the
following pseudo logic to write to the hardware PCM buffer. (I don't
have the actual code with me but I've tried so many things this is

for (sample= i =0;sample < blocksize; sample++ )
   for (channel = 0; channel < channels; channel++, i++)
       aobuf[i]= flac_decoded_data[channel][sample];

int offset = 0;

while ( i >0 && len >=0 ) {
   len = write(pcm_fd,aobuf+offset, i );
   if (len<=0)  continue;  // device busy or error
   i -= len;
   offset+= len;

With LPC correlation it plays quite well, with Independent it is unlistenable.


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