Re: [pygame] noise added on OGG playback

[Rene Dudfield <renesd@xxxxxxxxx>]

ah, I guess this is something for sdl_mixer to fix then.

Or pygames use of sdl_mixer.

Out of interest... does this happen with wavs?  What os, pygame
version, sdl version, do you use?

Cheer.



On 9/25/05, David Tweet <davidtweet@xxxxxxxxx> wrote:
> Thanks very much for the suggestion, I hadn't tried it yet.
> It has some effect--when I increase the buffer size to something very
> large, say 1024 * 10, the crackling noise is reduced but not
> eliminated.  Of course something like that would create much too long
> of a delay.
>
> I also tried increasing the quality of the OGG file (less compressed)
> but that has no effect at all.
>
> I've attached a modified version of the Screensaw demo from the PyGame
> website.  It calls my song at 0 seconds for Critter, and then again at
> 4.3 seconds for Ant.
>
> I uploaded the song in question to
> http://davidtweet.com/noise_test_polka.ogg
>
>
> -david.
>
>
> On 9/24/05, Rene Dudfield <renesd@xxxxxxxxx> wrote:
> > Hey,
> > try using the pre_init line below to increase the buffer size.  It
> > works for reducing noise on other systems.
> >
> > pygame.mixer.pre_init(44100,-16,2, 1024 * 3)
> > pygame.init()
> >
> >
> > Cheers,
> >
> >
> >
> > On 9/25/05, David Tweet <davidtweet@xxxxxxxxx> wrote:
> > > I have a problem playing some OGG files with pygame.mixer.music.play():
> > > When I pass a start position that's not zero into this function, on
> > > playback of some files (not all), I get noise mixed in with the
> > > playback of the file for as long as that file continues to play.  The
> > > noise resembles loud crackle from a vinyl record.
> > >
> > > The WAV files were originally 16-bit/44.1kHz, I converted to OGG using
> > > the same consistent settings in Audacity, and I have called
> > > pygame.mixer.init(44100).  All the files sound fine played back from a
> > > zero start position, and some even sound fine with a non-zero start
> > > position, but others consistently have this problem with a non-zero
> > > start position.
> > >
> > > I've considered that it might have to do with whether the music at the
> > > specified start position is at a zero crossing (all nearby samples at
> > > least close to zero amplitude), but no amount of modification of the
> > > file at the chosen time point was able to remove the noise.  Plus, it
> > > seems like the worst that ought to happen is that you would hear an
> > > isolated clipping sound at the beginning of the file (if the
> > > zero-crossing issue were it).
> > >
> > > Can anyone enlighten me somewhat on this?  Has anyone had a similar experience?
> > >
> > > Thank you,
> > > David Tweet.
> > >
> >
>
>
> --
> David Tweet
> __________________
> http://davidtweet.com
>
>
>