I am looking for a ducumentation of ms-joint stereo.
I've already patche lamer with ms-joint stereo support
and it sound great - but i am not sure whether i am right.
My questions are:
(from the lamer-hompage:)
MS_stereo processing
...
Sparsing of channel
In every scalefactor band sb all paris of small values (Si + Si+1) are set
to zero:
---
Is Si a scalefactor band or a ordinary subband?
Is it necessary to recalculate the the allowed distortion?
I'va also found a small bug in calc-noise(loop.c/line 970):
for ( sfb = cod_info->sfb_smax; sfb < 12; sfb++ )
IMHO:
for ( sfb = 0; .....
And ther is a big problem with the outer loop at low bitrates(192k-) :
(loop.c)
Function: .... It computes the best scalefac an ...
For low bitrates, this should be signed with a :-)).
IMHO is it better (for low bitrates) not to use scalefactors
because they need to much bits from the signal.
amp_scalefac_bands increase the scalefactor until the
quantisation-distortion is lower then the allowed distortion
or the max. scalefactor is reached, it does not compare the
SNR befor and after amplify the scalefactors.
But at low bitrates the SNR gets worser by the amplifing the
scalefactors.
--
by
Weg.
