Remember that G.729 compresses 16 bits to 1 bit, on average. You want to
have your signal in the highest possible bits to be noticed, otherwise it might not be substantially different than background noise. By not shifting 8 bits to the right, that is the equivalent of 48 dB of attenuation, which I would guess is probably not far from the limit of the dynamic range of G.729. Mark Lakata, Staff Engineer 1225 Charleston Road voice 650-567-5170 MIPS Technologies Mountain View CA 94043 fax 650-567-5002 On Fri, 21 Mar 2003, Bhanu prakash wrote: > Hi Mark, > > Is it not sufficient if we put the data in LSB Byte > and then "sign extend"?. I think only the signal > strength could be less. But, as such there should not > be any problem with the quality. Right? > > David, > Do you mean to say that the Quality of sound is poor > or Just the strength??? I think, in your case, as sign > extension was not done, it treats the values as > positive only and hence Quality of should really be > poor. > > Best Regards, > Bhanu Prakash. > > > --- Mark Lakata <> wrote: > > Use the MSB byte, not the LSB. You might have to > > change from unsigned to > > signed first. > > > > Mark Lakata, Staff Engineer 1225 Charleston Road > > voice 650-567-5170 > > MIPS Technologies Mountain View CA > > 94043 fax 650-567-5002 > > > > On Thu, 20 Mar 2003, T wrote: > > > > > Hi list, > > > > > > I'm involved in integrating G.729 algorithm. > > > > > > I know that G.729 encodes with 16 bits samples but > > our system provides 8 bits input, so > > > I've allocated these 8 bits samples in the LSB > > bytes of the 16 bits words before encoding. > > > But sound after encoding/decoding process is so > > poor. > > > > > > Is there a better way to encode with 8 bits > > samples? > > > Is it possible to modify the ITU's reference code > > to do this? > > > > > > Thanks in advance > > > > > > > > > __________________________________________________ > |