On Wed, 2008-06-04 at 11:46 +0200, Stefano D'Angelo wrote: > For example, I'm not sure whether not having that feature prevents or > makes it hard somehow to do stuff like DJ-style scratching or speed > changing effects with sample-level accuracy.
To do a scratching effect, you actually need a resampler and then play the resampled data back at the original samplerate. When scratching, both the pitch and the speed of the sound goes up and down depending on the speed of the disc. To do that with digital audio you must either change the sample rate of the data or the interface. Because you can't continuously change the sample rate of a pc sound interface, you must resample the data. The pitch or and speed matching stuff dj's do is exactly the same. They can just match either one (unless they're really lucky) because both change when the one parameter (the speed of the disc). Rubberband ( http://breakfastquay.com/rubberband/ ) contains a plugin (ladspa) that can change only the pitch of an audio stream. All of these effects have a strict 1:1 ratio between samples going in and going out. The only effect which differs in this would be changing the 'length' of the signal, but that is a different story altogether. I hope I got your original question right. If I didn't, sorry for the noise everyone :) Sampo _______________________________________________ Linux-audio-dev mailing list [email protected] http://lists.linuxaudio.org/mailman/listinfo/linux-audio-dev
