see http://contributing.appspot.com/deadbeef
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You need to make GDB backtrace.
by default, version 0.5 uses resampler provided by ALSA (or PulseAudio, or OSS - depending on chosen output plugin), and ALSA is not always capable to resample. and, in some cases, ALSA resampling cannot be used at all, depending on which output device is selected in Preferences.
version 0.4.4 (and below) resampled output using libsamplerate by default, without using ALSA resampling -- that's why it always worked.
To use libsamplerate resampling, go to Edit -> Preferences -> DSP, add Resampler plugin, and configure it to any samplerate that your output supports.
That's not perfect, but it should fix most of the problems.
Perfect solution would be to add an option to Resampler plugin, so that it can determine resampling ratio automatically, like 0.4.4 did. I'm aiming to do that in 0.5.1.
In most cases - yes, I can. But that doesn't mean I ever will, and I won't give any promises.
Information is here