mirror of
https://github.com/alsa-project/alsa-lib.git
synced 2025-10-29 05:40:25 -04:00
Changes to show the different transfer methods
This commit is contained in:
Jaroslav Kysela
parent
76abb9738e
commit
56778fa89d
1 changed files with 171 additions and 54 deletions
225
test/pcm.c
225
test/pcm.c
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@ -22,7 +22,6 @@ double freq = 440; /* sinus wave frequency in Hz */
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snd_pcm_sframes_t buffer_size;
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snd_pcm_sframes_t period_size;
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signed short *samples;
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snd_output_t *output = NULL;
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static void generate_sine(signed short *samples, int count, double *_phase)
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@ -145,6 +144,155 @@ static int set_swparams(snd_pcm_t *handle, snd_pcm_sw_params_t *swparams)
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return 0;
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}
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/*
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* Underrun and suspend recovery
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*/
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static int xrun_recovery(snd_pcm_t *handle, int err)
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{
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if (err = -EPIPE) { /* underrun */
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err = snd_pcm_prepare(handle);
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if (err < 0)
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printf("Can't recovery from underrun, prepare failed: %s\n", snd_strerror(err));
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return 0;
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} else if (err = -ESTRPIPE) {
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while ((err = snd_pcm_resume(handle)) == -EAGAIN)
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sleep(1); /* wait until suspend flag is released */
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if (err < 0) {
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err = snd_pcm_prepare(handle);
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if (err < 0)
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printf("Can't recovery from suspend, prepare failed: %s\n", snd_strerror(err));
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}
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return 0;
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}
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return err;
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}
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/*
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* Transfer method - write only
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*/
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static int write_loop(snd_pcm_t *handle, signed short *samples)
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{
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int ufds_count;
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struct pollfd *ufds;
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double phase = 0;
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signed short *ptr;
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int err, count, cptr;
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while (1) {
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generate_sine(ptr = samples, cptr = period_size, &phase);
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while (cptr > 0) {
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err = snd_pcm_writei(handle, ptr, cptr);
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if (err == -EAGAIN)
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continue;
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if (err < 0) {
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if (xrun_recovery(handle, err) < 0) {
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printf("Write error: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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break; /* skip one period */
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}
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ptr += err * channels;
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cptr -= err;
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}
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}
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}
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/*
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* Transfer method - write and wait for room in buffer using poll
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*/
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static int wait_for_poll(struct pollfd *ufds, int count)
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{
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int i;
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unsigned int events;
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while (1) {
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poll(ufds, count, -1);
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for (i = 0; i < count; i++) {
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events = ufds[i].revents;
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if (events & POLLERR) {
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printf("Poll - POLLERR detected\n");
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return -EIO;
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}
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if (events & POLLOUT)
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return 0;
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}
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}
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}
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static int write_and_poll_loop(snd_pcm_t *handle, signed short *samples)
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{
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int ufds_count;
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struct pollfd *ufds;
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double phase = 0;
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signed short *ptr;
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int err, count, cptr;
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count = snd_pcm_poll_descriptors_count (handle);
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if (count <= 0) {
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printf("Invalid poll descriptors count\n");
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return count;
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}
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ufds = malloc(sizeof(struct pollfd) * count);
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if (ufds == NULL) {
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printf("No enough memory\n");
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return err;;
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}
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if ((err = snd_pcm_poll_descriptors(handle, ufds, count)) < 0) {
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printf("Unable to obtain poll descriptors for playback: %s\n", snd_strerror(err));
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return err;
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}
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while (1) {
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err = wait_for_poll(ufds, count);
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if (err < 0) {
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printf("Wait for poll failed\n");
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return err;
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}
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generate_sine(ptr = samples, cptr = period_size, &phase);
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while (cptr > 0) {
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err = snd_pcm_writei(handle, ptr, cptr);
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if (err < 0) {
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if (xrun_recovery(handle, err) < 0) {
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printf("Write error: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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break; /* skip one period */
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}
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ptr += err * channels;
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cptr -= err;
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if (cptr == 0)
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break;
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/* it is possible, that initial buffer cannot store */
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/* all data from last period, so wait awhile */
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err = wait_for_poll(ufds, count);
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if (err < 0) {
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printf("Wait for poll failed\n");
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return err;
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}
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}
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}
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}
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/*
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*
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*/
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struct transfer_method {
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const char *name;
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int (*transfer_loop)(snd_pcm_t *handle, signed short *samples);
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};
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static struct transfer_method transfer_methods[] = {
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{ "write", write_loop },
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{ "write_and_poll", write_and_poll_loop },
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{ NULL, NULL }
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};
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static void help(void)
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{
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int k;
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@ -157,6 +305,8 @@ Usage: latency [OPTION]... [FILE]...
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-f,--frequency sine wave frequency in Hz
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-b,--buffer ring buffer size in samples
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-p,--period period size in us
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-m,--method tranfer method
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");
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printf("Recognized sample formats are:");
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for (k = 0; k < SND_PCM_FORMAT_LAST; ++(unsigned long) k) {
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@ -165,6 +315,10 @@ Usage: latency [OPTION]... [FILE]...
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printf(" %s", s);
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}
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printf("\n");
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printf("Recognized tranfer methods are:");
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for (k = 0; transfer_methods[k].name; k++)
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printf(" %s", transfer_methods[k].name);
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printf("\n");
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}
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int main(int argc, char *argv[])
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@ -178,18 +332,17 @@ int main(int argc, char *argv[])
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{"frequency", 1, NULL, 'f'},
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{"buffer", 1, NULL, 'b'},
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{"period", 1, NULL, 'p'},
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{"method", 1, NULL, 'm'},
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{NULL, 0, NULL, 0},
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};
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snd_pcm_t *handle;
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char *buffer;
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int err, morehelp, i, count;
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int err, morehelp;
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snd_pcm_hw_params_t *hwparams;
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snd_pcm_sw_params_t *swparams;
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struct pollfd *ufds;
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unsigned int events;
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double phase;
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signed short *ptr;
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int cptr;
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int method = 0;
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signed short *samples;
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snd_pcm_hw_params_alloca(&hwparams);
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snd_pcm_sw_params_alloca(&swparams);
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@ -197,7 +350,7 @@ int main(int argc, char *argv[])
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morehelp = 0;
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while (1) {
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int c;
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if ((c = getopt_long(argc, argv, "hD:r:c:f:b:p:", long_option, NULL)) < 0)
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if ((c = getopt_long(argc, argv, "hD:r:c:f:b:p:m:", long_option, NULL)) < 0)
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break;
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switch (c) {
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case 'h':
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@ -231,6 +384,13 @@ int main(int argc, char *argv[])
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period_time = period_time < 1000 ? 1000 : period_time;
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period_time = period_time > 1000000 ? 1000000 : period_time;
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break;
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case 'm':
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for (method = 0; transfer_methods[method].name; method++)
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if (!strcasecmp(transfer_methods[method].name, optarg))
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break;
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if (transfer_methods[method].name == NULL)
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method = 0;
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break;
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}
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}
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@ -248,6 +408,7 @@ int main(int argc, char *argv[])
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printf("Playback device is %s\n", device);
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printf("Stream parameters are %iHz, %s, %i channels\n", rate, snd_pcm_format_name(format), channels);
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printf("Sine wave rate is %.4fHz\n", freq);
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printf("Using transfer method: %s\n", transfer_methods[method].name);
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if ((err = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, SND_PCM_NONBLOCK)) < 0) {
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printf("Playback open error: %s\n", snd_strerror(err));
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@ -263,59 +424,15 @@ int main(int argc, char *argv[])
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exit(EXIT_FAILURE);
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}
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count = snd_pcm_poll_descriptors_count (handle);
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if (count <= 0) {
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printf("Invalid poll descriptors count\n");
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exit(EXIT_FAILURE);
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}
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ufds = malloc(sizeof(struct pollfd) * count);
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if (ufds == NULL) {
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printf("No enough memory\n");
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exit(EXIT_FAILURE);
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}
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if ((err = snd_pcm_poll_descriptors(handle, ufds, count)) < 0) {
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printf("Unable to obtain poll descriptors for playback: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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samples = malloc((period_size * channels * snd_pcm_format_width(format)) / 8);
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if (samples == NULL) {
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printf("No enough memory\n");
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exit(EXIT_FAILURE);
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}
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phase = 0;
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while (1) {
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poll(ufds, count, -1);
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for (i = 0; i < count; i++) {
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events = ufds[i].revents;
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if (events & POLLOUT)
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goto __write;
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}
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continue;
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__write:
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generate_sine(ptr = samples, cptr = period_size, &phase);
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while (cptr > 0) {
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err = snd_pcm_writei(handle, ptr, cptr);
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if (err < 0) {
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printf("Write error: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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ptr += err * channels;
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cptr -= err;
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while (1) {
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poll(ufds, count, -1);
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for (i = 0; i < count; i++) {
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events = ufds[i].revents;
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if (events & POLLOUT)
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goto __write1;
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}
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}
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__write1:
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}
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}
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err = transfer_methods[method].transfer_loop(handle, samples);
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if (err < 0)
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printf("Transfer failed: %s\n", snd_strerror(err));
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snd_pcm_close(handle);
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return 0;
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