Hello,
I'm new to this list.I hope someone could help me with a problem concerning the samplerate converter plugins of the alsa driver.
Firstly some facts about my application.
- Envy24 (VT1270) pci audio chip on a custom mainboard - playback of sounds/music with different sample rates from 8kHz to 48kHz (sample rate of the files) - the hardware (Envy24 chip) must always run with 44.1kHz or 48kHz (selectable by user), because the audio is outputed by a DAC and SPDIF and the SPDIF clock must not be changed according to the sample rate of the files. - Kernel is 2.6.22 and alsa is 1.0.14
So I'm using the samplerate (libsample rate based) plugin from the alsa-plugin package. Generaly it works very good.
My problem is: Every time a playback is started a short plop noise is heard. The noise is on analog and SPDIF output. If I don't use the samplerate converter the noise is not heard at all. So it comes definitely from the rate converter plugin, I think. Changing the quality level of the plugin don't solve the problem. I've also switched to the new Speex rate converter plugin. With this plugin there is no noise at the start of playback. But here I have trouble with awful noise at some rate conversions (6kHz(source) -> 48kHz(output); 11.025kHz -> 44.1kHz; 22.05kHz -> 44.1kHz). So it's even worse than using the libsamplerate plugin. Finaly I've tried the libavcodec plugin, which is the worst according to noise.
Could any comment this problem, please?
This is my asound.conf: ############################################## # Playback over Line-Out and SPDIF simultaniously as default
pcm.!default { type plug slave.pcm { type multi slaves.a.pcm "plughw:0,0" slaves.a.channels 2 slaves.b.pcm "hw:0,1" slaves.b.channels 2 bindings.0.slave a bindings.0.channel 0 bindings.1.slave a bindings.1.channel 1 bindings.2.slave b bindings.2.channel 0 bindings.3.slave b bindings.3.channel 1 } ttable.0.0 1 ttable.1.1 1 ttable.0.2 1 ttable.1.3 1 }
pcm_slave.s1 { pcm default rate 44100 }
pcm_slave.s2 { pcm default rate 48000 }
pcm.rate_convert_44100 { type rate slave s1 converter samplerate }
pcm.rate_convert_48000 { type rate slave s2 converter samplerate } #####################################################
Regards Andreas Rumpler