Re: [Audacity-devel] Added play looped function
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From: Markus M. <me...@me...> - 2003-05-27 10:41:12
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Am Die, 2003-05-27 um 04.23 schrieb Dominic Mazzoni: > > I noticed that the loop function still sometimes clicks, but only when > > compiling with libsndfile support. This is supposedly a bug in the Mixer > > code (maybe the comment in Mix.cpp, line 392ff gives a hint?). As soon > > as I have managed to understand the code in Mix.cpp completely, I may be > > able to track this down. > > I'm assuming you mean libsamplerate? Well, this code should never get > called unless the sample rate of the track doesn't match the sample rate > of the project. For the case where no sample rate conversion is needed, > it calls MixSameRate and there aren't any bugs in that code that I know > of. Heh, it needs sample rate conversion on my machine, because I'm trying this with 44.1kHz WAV files, and the Linux driver of my soundcard only support 48kHz. > > I tried a few loops and didn't hear any clicks. Are you sure they're > not just natural clicks? Try using the Repeat effect on the same > selection - if the clicks are still there, they're natural. You may > want to try to find zero-crossings at the selection boundaries to > smooth it out a little. I guess I didn't explain the "clicking" effect right. It sounds like sometimes (but not always) ocassionally samples get left out, or only parts of the selection are looped. This only happens on larger selections. So it can be that, when playing looped the first 5 loops or so sound ok, then there is some clicking / skipping, then again, 5 loops sound okay etc. This looks like a buffer issue in Mix.cpp (or in libsamplerate, if you will). Also, it may well be that I have not implemented the Mixer::Restart() function right. So that there is anything left which is not reset correctly? Markus |