I think that snd_pcm_hw_params_set_period_size_near() will not return an error, but you must check the "val" parameter, is it returning the same value that you passed?
"Some periods are not supported" means that some cards may not support periods that aren't power of two. I am not sure, since I am new to ALSA and I am working most with aloop.
anuj aggarwal escreveu:
I am doing the same. I used snd_pcm_hw_params_set_period_size_near() to set the period size and checked the return value also; it was not an error.
I have one more question. When you say 'Some periods are not supported', what does that mean? What are the constraints which make some periods not-supported by the audio codec driver?
On Thu, Jul 3, 2008 at 5:11 PM, Gustavo da Silva Serra <gustavo.serra@tet.com.br mailto:gustavo.serra@tet.com.br> wrote:
Do you check the result of the function that sets the period size? Some periods are not supported and you can't assume that they are valid and proceed in your application. Use snd_pcm_hw_params_set_period_time_near to see what is the nearest possible value for period. <http://www.alsa-project.org/alsa-doc/alsa-lib/group___p_c_m___h_w___params.html#gf5e53bcb748185a4da3b8538720a5792> anuj aggarwal escreveu: My audio driver supports buffer sizes from 128 to 32768 and period sizes from 8 to 2048. I am trying to set the period size as 1030 (just a random number between 8 & 2048, but not multiple of 2^n) and buffer size as 16*buffer_size (i.e. 16480). The output is as follows: Buffer size range from 128 to 32768 Period size range from 8 to 2048 Request period size 1030 and got 1030 Plug PCM: Hardware PCM card 0 'TWL4030' device 0 subdevice 0 Its setup is: stream : PLAYBACK access : RW_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 44100 exact rate : 44100 (44100/1) msbits : 16 buffer_size : 16480 period_size : 1030 period_time : 23356 tstamp_mode : NONE period_step : 1 avail_min : 1030 start_threshold : 16480 stop_threshold : 16480 silence_threshold: 0 silence_size : 0 boundary : 1080033280 The problem with this setup is the application just hangs without playing anything. If I use period size as 2048, the app plays the song but clips the last part of it. If I use 1024/512, it works fine. I have tried alsa lib version 1.0.15 & 1.0.16 but the problem persists. Is there anything wrong with my app or audio driver? Please help. Thanks in advance, Anuj Aggarwal _______________________________________________ Alsa-devel mailing list Alsa-devel@alsa-project.org <mailto:Alsa-devel@alsa-project.org> http://mailman.alsa-project.org/mailman/listinfo/alsa-devel __________ NOD32 3238 (20080703) Information __________ This message was checked by NOD32 antivirus system. http://www.eset.com-- Best Regards, Anuj Aggarwal