Hi alsa-users! I have a software written in C, that's been running for quite some time (about 5 years) on a x86-machine(actually, it's a PC Engines ALIX-Board with a Debian Linux running on it). It is using ALSA for reading from a soundcard, transmitting it via network to another node running roughly the same software that successively plays it back. The software therefore has two buffers - one on transmitter side and one on receiver side. It creates audio packages of 2ms length each, that then get transmitted via network. A short while ago, I came across a new platform - the Intel Edison. I would like to port my software to that hardware, which essentially works out fine, as it also is a x86 platform. The only problem I see is ,that I have not yet been able to configure ALSA to shrink its period size down to 2ms on Intel Edison. I get the following output from snd_pcm_dump(*pcm_handle,NULL); Hardware PCM card 1 'dummy-audio' device 0 subdevice 0 Its setup is: stream : PLAYBACK access : MMAP_INTERLEAVED format : S16_LE subformat : STD channels : 2 rate : 48000 exact rate : 48000 (48000/1) msbits : 16 buffer_size : 768 period_size : 384 period_time : 8000 tstamp_mode : NONE period_step : 1 avail_min : 384 period_event : 0 start_threshold : 384 stop_threshold : 768 silence_threshold: 1 silence_size : 1 boundary : 1610612736 appl_ptr : 0 hw_ptr : 0 As you can see, the period_size is 384 and the period_time is 8000. Its values should be 96 (period_size) and 2000 (period_time). I am setting these values in my C-program with these commands: err = snd_pcm_hw_params_set_period_time_near(*pcm_handle, hwparams, &period_time, &dir); period_time has the value 2000. After having observed this discrepancy, I tried to solve it via another function: err = snd_pcm_hw_params_set_period_size( *pcm_handle, hwparams, val, dir ); The variables val and dir are set as follows: val=96; dir=0; Still, I did not get the result I wanted or needed. The period_size is still at 8000. Could anybody please point me to a hint, that could explain, why the Intel Edison cannot set the period_size below 8000? Is this a hardware issue or am I missing out something on my side? Should I try to configure my system in a different way? Is this maybe even a system-wide setting within ALSA? Any hint would be really appreciated. All the best, Dennis ------------------------------------------------------------------------------ _______________________________________________ Alsa-user mailing list Alsa-user@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-user
