At Tue, 30 Jun 2009 11:40:20 -0300, Guilherme wrote:
Tks takashi....
The doubt comes from this block of code:
for (chn = 0; chn < channels; chn++) { if ((areas[chn].first % 8) != 0) { printf("areas[%i].first == %i, abortando...\n", chn, areas[chn].first); exit(EXIT_FAILURE); } //pega endereço e offset da area samples[chn] = /*(signed short *)*/(((unsigned char *)areas[chn].addr) + (areas[chn].first / 8));
if ((areas[chn].step % 16) != 0) { printf("areas[%i].step == %i, aborting...\n", chn,areas[chn].step); exit(EXIT_FAILURE); }
steps[chn] = areas[chn].step / 8; samples[chn] += offset * steps[chn]; }first:
areas[chn].first % 8 ( I am using chn = 1). So for the only area that I have, if I get the value of the parameter 'first' isn't divisible by 8, the program exits. The same doubt happens with "areas[chn].step % 16" and "areas[chn].step / 8".
This is the parameter I am using:
static snd_pcm_format_t format = SND_PCM_FORMAT_S16; //sample format unsigned 16 bit endian
Perhaps with this practical example I can understand better.
Oops, I wrote wrongly. The first and step fields are not in bytes but bits. That's why 8 and 16 appear there, corresponding to 1 byte and 2 bytes.
Takashi