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https://github.com/alsa-project/alsa-lib.git
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Enhanced, added async and direct (mmap) mode
This commit is contained in:
Jaroslav Kysela
parent
67cc9dbc75
commit
0f67a428be
1 changed files with 185 additions and 25 deletions
210
test/pcm.c
210
test/pcm.c
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@ -24,20 +24,40 @@ snd_pcm_sframes_t buffer_size;
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snd_pcm_sframes_t period_size;
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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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static void generate_sine(const snd_pcm_channel_area_t *areas,
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snd_pcm_uframes_t offset,
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int count, double *_phase)
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{
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double phase = *_phase;
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double max_phase = 1.0 / freq;
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double step = 1.0 / (double)rate;
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double res;
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signed short *samples[channels];
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int steps[channels];
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int chn, ires;
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/* verify and prepare the contents of areas */
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for (chn = 0; chn < channels; chn++) {
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if ((areas[chn].first % 8) != 0) {
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printf("areas[%i].first == %i, aborting...\n", chn, areas[chn].first);
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exit(EXIT_FAILURE);
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}
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samples[chn] = (signed short *)(((unsigned char *)areas[chn].addr) + (areas[chn].first / 8));
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if ((areas[chn].step % 16) != 0) {
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printf("areas[%i].step == %i, aborting...\n", chn, areas[chn].step);
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exit(EXIT_FAILURE);
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}
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steps[chn] = areas[chn].step / 16;
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samples[chn] += offset * steps[chn];
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}
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/* fill the channel areas */
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while (count-- > 0) {
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res = sin((phase * 2 * M_PI) / max_phase - M_PI) * 32767;
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ires = res;
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for (chn = 0; chn < channels; chn++)
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*samples++ = ires;
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// printf("phase: %.8f, max_phase: %.8f, res: %.8f, smp = %i\n", phase, max_phase, res, *(samples-1));
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for (chn = 0; chn < channels; chn++) {
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*samples[chn] = ires;
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samples[chn] += steps[chn];
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}
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phase += step;
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if (phase >= max_phase)
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phase -= max_phase;
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@ -46,7 +66,8 @@ static void generate_sine(signed short *samples, int count, double *_phase)
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}
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static int set_hwparams(snd_pcm_t *handle,
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snd_pcm_hw_params_t *params)
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snd_pcm_hw_params_t *params,
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snd_pcm_access_t access)
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{
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int err, dir;
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@ -57,7 +78,7 @@ static int set_hwparams(snd_pcm_t *handle,
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return err;
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}
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/* set the interleaved read/write format */
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err = snd_pcm_hw_params_set_access(handle, params, SND_PCM_ACCESS_RW_INTERLEAVED);
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err = snd_pcm_hw_params_set_access(handle, params, access);
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if (err < 0) {
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printf("Access type not available for playback: %s\n", snd_strerror(err));
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return err;
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@ -150,12 +171,12 @@ static int set_swparams(snd_pcm_t *handle, snd_pcm_sw_params_t *swparams)
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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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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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} 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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@ -172,16 +193,18 @@ static int xrun_recovery(snd_pcm_t *handle, int err)
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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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static int write_loop(snd_pcm_t *handle,
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signed short *samples,
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snd_pcm_channel_area_t *areas)
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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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int err, cptr;
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while (1) {
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generate_sine(ptr = samples, cptr = period_size, &phase);
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generate_sine(areas, 0, period_size, &phase);
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ptr = samples;
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cptr = period_size;
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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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@ -222,9 +245,10 @@ static int wait_for_poll(struct pollfd *ufds, int count)
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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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static int write_and_poll_loop(snd_pcm_t *handle,
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signed short *samples,
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snd_pcm_channel_area_t *areas)
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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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@ -253,7 +277,9 @@ static int write_and_poll_loop(snd_pcm_t *handle, signed short *samples)
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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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generate_sine(areas, 0, period_size, &phase);
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ptr = samples;
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cptr = period_size;
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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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@ -278,19 +304,140 @@ static int write_and_poll_loop(snd_pcm_t *handle, signed short *samples)
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}
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}
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/*
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* Transfer method - asynchronous notification
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*/
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struct async_private_data {
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signed short *samples;
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snd_pcm_channel_area_t *areas;
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double phase;
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};
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static void async_callback(snd_async_handler_t *ahandler)
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{
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snd_pcm_t *handle = snd_async_handler_get_pcm(ahandler);
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struct async_private_data *data = snd_async_handler_get_callback_private(ahandler);
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signed short *samples = data->samples;
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snd_pcm_channel_area_t *areas = data->areas;
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snd_pcm_sframes_t avail;
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int err;
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avail = snd_pcm_avail_update(handle);
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while (avail >= period_size) {
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generate_sine(areas, 0, period_size, &data->phase);
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err = snd_pcm_writei(handle, samples, period_size);
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if (err < 0) {
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printf("Initial write error: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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if (err != period_size) {
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printf("Initial write error: written %i expected %li\n", err, period_size);
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exit(EXIT_FAILURE);
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}
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avail = snd_pcm_avail_update(handle);
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}
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}
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static int async_loop(snd_pcm_t *handle,
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signed short *samples,
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snd_pcm_channel_area_t *areas)
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{
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struct async_private_data data;
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snd_async_handler_t *ahandler;
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int err, count;
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data.samples = samples;
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data.areas = areas;
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data.phase = 0;
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err = snd_async_add_pcm_handler(&ahandler, handle, async_callback, &data);
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if (err < 0) {
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printf("Unable to register async handler\n");
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exit(EXIT_FAILURE);
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}
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for (count = 0; count < 2; count++) {
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generate_sine(areas, 0, period_size, &data.phase);
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err = snd_pcm_writei(handle, samples, period_size);
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if (err < 0) {
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printf("Initial write error: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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if (err != period_size) {
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printf("Initial write error: written %i expected %li\n", err, period_size);
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exit(EXIT_FAILURE);
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}
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}
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err = snd_pcm_start(handle);
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if (err < 0) {
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printf("Start error: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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/* because all other work is done in the signal handler,
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suspend the process */
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while (1) {
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sleep(1);
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}
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}
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/*
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* Transfer method - direct write only
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*/
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static int direct_loop(snd_pcm_t *handle,
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signed short *samples,
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snd_pcm_channel_area_t *areas)
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{
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double phase = 0;
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const snd_pcm_channel_area_t *my_areas;
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snd_pcm_uframes_t offset, frames;
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int err, first = 1;
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while (1) {
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frames = period_size;
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err = snd_pcm_mmap_begin(handle, &my_areas, &offset, &frames);
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if (err < 0) {
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printf("MMAP begin error: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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if (frames > period_size)
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frames = period_size;
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generate_sine(my_areas, offset, frames, &phase);
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err = snd_pcm_mmap_commit(handle, offset, frames);
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if (err < 0) {
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printf("MMAP commit error: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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if (frames == 0 && first) { /* trigger playback */
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first = 0;
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err = snd_pcm_start(handle);
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if (err < 0) {
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printf("Start error: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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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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snd_pcm_access_t access;
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int (*transfer_loop)(snd_pcm_t *handle,
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signed short *samples,
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snd_pcm_channel_area_t *areas);
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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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{ "write", SND_PCM_ACCESS_RW_INTERLEAVED, write_loop },
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{ "write_and_poll", SND_PCM_ACCESS_RW_INTERLEAVED, write_and_poll_loop },
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{ "async", SND_PCM_ACCESS_RW_INTERLEAVED, async_loop },
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{ "direct_interleaved", SND_PCM_ACCESS_MMAP_INTERLEAVED, direct_loop },
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{ "direct_noninterleaved", SND_PCM_ACCESS_MMAP_NONINTERLEAVED, direct_loop },
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{ NULL, SND_PCM_ACCESS_RW_INTERLEAVED, NULL }
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};
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static void help(void)
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@ -336,13 +483,13 @@ int main(int argc, char *argv[])
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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;
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snd_pcm_hw_params_t *hwparams;
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snd_pcm_sw_params_t *swparams;
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double phase;
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int method = 0;
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signed short *samples;
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int chn;
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snd_pcm_channel_area_t *areas;
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snd_pcm_hw_params_alloca(&hwparams);
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snd_pcm_sw_params_alloca(&swparams);
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@ -410,12 +557,12 @@ int main(int argc, char *argv[])
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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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if ((err = snd_pcm_open(&handle, device, SND_PCM_STREAM_PLAYBACK, 0)) < 0) {
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printf("Playback open error: %s\n", snd_strerror(err));
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return 0;
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}
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if ((err = set_hwparams(handle, hwparams)) < 0) {
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if ((err = set_hwparams(handle, hwparams, transfer_methods[method].access)) < 0) {
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printf("Setting of hwparams failed: %s\n", snd_strerror(err));
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exit(EXIT_FAILURE);
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}
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@ -429,11 +576,24 @@ int main(int argc, char *argv[])
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printf("No enough memory\n");
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exit(EXIT_FAILURE);
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}
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areas = calloc(channels, sizeof(snd_pcm_channel_area_t));
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if (areas == 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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for (chn = 0; chn < channels; chn++) {
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areas[chn].addr = samples;
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areas[chn].first = chn * 16;
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areas[chn].step = channels * 16;
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}
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err = transfer_methods[method].transfer_loop(handle, samples);
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err = transfer_methods[method].transfer_loop(handle, samples, areas);
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if (err < 0)
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printf("Transfer failed: %s\n", snd_strerror(err));
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free(areas);
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free(samples);
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snd_pcm_close(handle);
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return 0;
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}
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