2010/1/11 Jaroslav Kysela <perex@xxxxxxxx> > 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 > > Are there any PCM state diagram ? http://equalarea.com/paul/alsa-audio.html http://www.alsa-project.org/main/index.php/Tutorials_and_Presentations The tutorial program call snd_pcm_hw_params_free() before any playback and capture, this cause au88x0 fail since callback snd_vortex_pcm_hw_free() delete the dynamic route between SRC , mixer if ((err = snd_pcm_hw_params (playback_handle, hw_params)) < 0) { fprintf (stderr, "cannot set parameters (%s)\n", snd_strerror (err)); exit (1); } snd_pcm_hw_params_free (hw_params); if ((err = snd_pcm_prepare (playback_handle)) < 0) { fprintf (stderr, "cannot prepare audio interface for use (%s)\n", snd_strerror (err)); exit (1); } _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
