Raymond Yau ha scritto: > 2010/1/6 Riccardo Magliocchetti <riccardo.magliocchetti@xxxxxxxxx> > >> Hi Pierre, >> >> pl bossart ha scritto: >>> You haven't specified the buffer/period size in the hw params. See >>> alsa-lib/test/pcm.c >>> - Pierre >> They fail when opening default device so I had to remove them, work fine >> when opening >> plughw:0,0 though. >> >>> On Mon, Jan 4, 2010 at 11:39 AM, Riccardo Magliocchetti >>> <riccardo.magliocchetti@xxxxxxxxx> wrote: >>>> [the same message is waiting in moderator queue, sorry if you receive it >> two times] >>>> Hello, >>>> >>>> i'm trying to capture audio data from the microphone, but i'm not able >> to >>>> read any frames. >>>> The frames are always 0 and delay is fixed to 2730. I've tried calling >>>> snd_pcm_avail_delay, snd_pcm_avail_update but does not make a >> difference. >>>> The soundcard is driven by snd_hda_intel. The code is more or less the >>>> same as Paul Davis' tutorial on using the alsa api. > > Even 4096 bytes is x86 DMA page size , seem to be a good choice for those > PCI sound cards, however you cannot assume all sound cards/plugins support > this buffer size > > If you did not set period_size, buffer_size or periods (period_time, > buffer_time or periods) , you should call > snd_pcm_hw_params_get_buffer_size() and snd_pcm_hw_params_get_period_size() > after snd_pcm_hw_params() Thank you both Pierre and Raymond, using the get functions after snd_pcm_hw_params() is working, now i have some concurrency issues to resolve before i can say everything is working properly. Thanks again, riccardo _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
