Re: Gnome-media

[Simon Per Soren Kagedal <simon cs uoregon edu>]

Hi,

> Should a replacement be chosen, maybe it shouldn't be Esound reliant?
> I find the sampling frequency convertor in the latter to introduce a
> lot of noise. Users should have the right to listen to audio without
> distortion! Has anyone investigated alternatives to Esound's (linear?)
> interpolation such as band limited interpolation?

The crazy thing is that esound doesn't even use linear interpolation!
I know there has been a few changes to esound recently that I haven't
looked at, but the following is from current cvs and unless
mixing/resampling is now done somewhere else in the source tree, this
is what's happening:

      /* scale the pointer, and copy the data */
             while ( wr_dat < dest_len )
             {
                 rd_dat = wr_dat * src_rate / dest_rate;
 
                 lsample = source_data_uc[ rd_dat ];
                 target_data_uc[ wr_dat++ ] = lsample;
             }

(this is from "mix_from_mono_8u", similar code is found in other
functions) 

My experience is that linear interpolation sounds perfectly ok for
low-end sound use (games, sound events - the kind of stuff esound is
made for anyway), but the above algorithm obviously doesn't.  

My winter break starts like tomorrow and I intend to maybe take a look
at this issue, it's been annoying be for quite a while, but in the
long run I think esound should be replaced and I think that's the
general consenus among GNOME hackers also?  I would very much like to
hear what the current plan is.

Best wishes,
Simon.