On Mon, 11 Jan 2010, Riccardo Magliocchetti wrote: > Riccardo Magliocchetti ha scritto: >> 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. > > The init works fine but snd_pcm_avail() always returns 0, full code is here > http://pastebin.com/f687bf37a The PCM stream must be triggered via snd_pcm_start() or using snd_pcm_read*() when sw_param->start_threshold is set appropriately. Jaroslav ----- Jaroslav Kysela <perex@xxxxxxxx> Linux Kernel Sound Maintainer ALSA Project, Red Hat, Inc. _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
