[FFmpeg-devel] [PATCH] Fix AAC prediction in when used in conjunction with the CPE
Thu Dec 4 00:27:56 CET 2008
It appears that I neglected to test my AAC predicition implementation
with streams that a CPE with a common window or intensity stereo. The
attached patch fixes this. This should fix the am02 series of
Note: I chose to deviate from the textual description of the
interaction between prediction and intensity stereo given in
14496-3:2005 for parity with the reference software.
For scalefactor bands coded in intensity stereo the corresponding
predictors in the right channel are switched to "off" thus effectively
overriding the status specified by the prediction_used mask. The
update of these predictors is done by feeding the intensity stereo
decoded spectral values of the right channel as the "last quantized
value" xrec(n-1). These values result from the scaling process from
left to right channel as described in the pseudo code.
However in reference files adifdec.c and intensity.c, pre-intensity
right channel values are sent into prediction.
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