[mythtv] [mythtv-commits] Ticket #1104: multichannelaudio support

Ma Begaj derliebegott at gmail.com
Mon Jan 7 00:37:27 UTC 2008


2008/1/6, Paul Catchpole <paul at paulcatchpole.co.uk>:
> Mark Spieth wrote:
> >> But, I'm seeing the same clipping/conversion-clicking issue that I saw
> >> in TV, in mythmusic. TV is still fine. It's the centre channel only
> >> again, and seems to happen on any album I pick.
> >>
> >> Any ideas?
> >>
> >
> > does the same clipping happen in 2ch mode?
> > I had an issue with mad (mp3) in that the audio was distorted (clipped) but
> > no clicking.
> > I think it got introduced with the latest upgrade of libmad but not sure.
> > I saw it in the stereo wave visualization where the waves went all the way
> > peak to peak with rounding of the peaks which provided the clue.
> >
> > my fix was the following. note it shouldnt be happening but this is where
> > the clipping occurs.
> >
> > mark
> >
> > --- maddecoder.cpp      (revision 15263)
> > +++ maddecoder.cpp      (working copy)
> > @@ -448,6 +448,7 @@
> >  static inline signed long fix_sample(unsigned int bits, mad_fixed_t sample)
> >  {
> >      mad_fixed_t quantized, check;
> > +    sample >>= 1;   // MRS fudge for clipping problem
> >      quantized = sample;
> >      check = (sample >> MAD_F_FRACBITS) + 1;
> >      if (check & ~1) {
> >
> > _______________________________________________
> > mythtv-dev mailing list
> > mythtv-dev at mythtv.org
> > http://mythtv.org/cgi-bin/mailman/listinfo/mythtv-dev
> >
> Sorry about the delay in testing this, Mark, been a busy week back at work!
>
> It works fine with the audio device for the frontend changed to a
> 2-channel one. It's only when using the real 6-channel device and hence
> the upmixer where the clipping occurs.
>
> Is there anything I can do to narrow this down further?
>

fyi ... I have the same problem. I changed it to 2ch because of mythmusic.

I remember that I did not have this problem when I was using old patch
(around #30) and manually setting output device to
surround51m|whetever.


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