Segher Boessenkool
2000-Nov-16 06:51 UTC
[vorbis-dev] recent Vorbis, sound quality problems
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. Ciao, 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@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.
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 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 buffers burdens it a lot. I've noticed this problem in Unsanity Echo's vorbis player; it's the same sound artifact my vorbis player was giving before Monty pointed out my problem. If you want an example of a Mac player that's *very* basic but doesn't have that specific problem, try <http://oscar.the-rileys.net/programming/vorbis/vorbis.tar.gz> or to browse the main source file <http://oscar.the-rileys.net/programming/vorbis/mac/macogg.c>. It sends buffers that are somewhat larger. --- >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@xiph.org' containing only the word 'unsubscribe' in the body. No subject is needed. Unsubscribe messages sent to the list will be ignored/filtered.