[vorbis-dev] recent Vorbis, sound quality problems

[Segher Boessenkool]

David Riley wrote:
> 
> Segher Boessenkool wrote:
> >
> > Hello all,
> >
> > I'm having some problems with the sound quality of recent Vorbis.
> > There is some kind of metallic echo/tremolo effect in the lower
> > frequencies. This is on my iMac; haven't seen this problem on x86.
> > If you need a sample, I can put one up somewhere, or mail it to
> > someone with a good ftp server, preferably.
> >
> > It could be caused by the iMac sound system doing surround sound,
> > (Dolby Spatializer or something); I don't know if/how it can be
> > turned off.
> 
> What player are you using?  I've noticed that ones closely based off the

No player, cat x.wav | encoder_example | decoder_example > x.decode.wav, and
then tug the wav header back on. Oh, and the decoder_example needs a byte
swab at the output, to be little-endian. Then I can just "play a.decode.wav".

> decoder_example are prone to sending Sound Manager buffers that are way
> too small (128 bytes).  This isn't a problem on the decoder_example,
> since it's writing to a file, nor is it a problem on many architectures
> where one writes directly to the sound hardware (or at least directly
> into a DMA buffer).  On the Mac it's a problem because you need to
> double-buffer the sound and sending Sound Manger lots of tiny little

The AWACS uses DMA soundbuffers, not doubly-buffered I think. Not sure,
though. I got a new-generation iMac, it's basically the new iBook, but
embedded in a terribly nice looking monitor. I love this baby :-)

Ciao, and thanks anyway,

Segher

--- >8 ----
List archives:  http://www.xiph.org/archives/
Ogg project homepage: http://www.xiph.org/ogg/
To unsubscribe from this list, send a message to 'vorbis-dev-request at xiph.org'
containing only the word 'unsubscribe' in the body.  No subject is needed.
Unsubscribe messages sent to the list will be ignored/filtered.