Hi,
I am writing an external io type plugin for an ARM based board. In the transfer function of the plugin, I try to grab the audio samples in a temp buffer and send it to the DSP in chunks of period sizes. Somehow the the alsa buffer's audio samples are not copied to the temp buffer which I want to send further.
What I do to copy the buffers, static snd_pcm_sframes_t my_transfer(snd_pcm_ioplug_t *io, const snd_pcm_channel_area_t *areas, snd_pcm_uframes_t offset, snd_pcm_uframes_t size) {
char *temp = NULL; temp = malloc(io->period_size * frame_size); //For malloc,
//I tried all the three approaches here one by one, including the malloc/memcpy one 1. memcpy(temp,areas->addr+ offset*io->channels*2, io->period_size * frame_size); 2. memcpy(temp, (char *)areas->addr + (areas->first + areas->step * offset) /8, io->period_size * frame_size); //This should work straight off.... 3. temp = (char *)areas->addr + (areas->first + areas->step * offset) / 8;
//write temp to DSP here ......... }
Somehow the empty buffers are being sent to DSP, when I try to send some data from a static array then it goes to DSP and is played well. Any idea what I am missing?
-phraoh.