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/*
* Copyright (C) 2022 Javier S. Pedro
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*/
#define LOG_ENABLED 1
#define LOG_ENABLE_FLOW 1
#define LOG_GROUP LOG_GROUP_DEV_SB16
#include <VBox/err.h>
#include <VBox/log.h>
#include <alsa/asoundlib.h>
#include "pcmalsa.h"
PCMOutAlsa::PCMOutAlsa() : _pcm(NULL)
{
}
PCMOutAlsa::~PCMOutAlsa()
{
}
int PCMOutAlsa::open(const char *dev, unsigned int sampleRate, unsigned int channels)
{
int err;
err = snd_pcm_open(&_pcm, dev, SND_PCM_STREAM_PLAYBACK, 0);
if (err < 0) {
LogWarn(("ALSA playback open error: %s\n", snd_strerror(err)));
return VERR_AUDIO_STREAM_COULD_NOT_CREATE;
}
// TODO: Right now, setting a too large period size means we will not let the main
// thread run long enough to actually change notes/voices. Need some actual synchronization.
int periodSize = 10 /*msec*/;
int bufferSize = 100 /*msec*/;
err = setParams(sampleRate, channels, bufferSize * 1000 /*usec*/, periodSize * 1000);
if (err < 0) {
snd_pcm_close(_pcm);
_pcm = NULL;
return VERR_AUDIO_STREAM_COULD_NOT_CREATE;
}
return VINF_SUCCESS;
}
int PCMOutAlsa::close()
{
if (_pcm) {
snd_pcm_drain(_pcm);
snd_pcm_close(_pcm);
}
return VINF_SUCCESS;
}
ssize_t PCMOutAlsa::avail()
{
snd_pcm_sframes_t frames = snd_pcm_avail(_pcm);
if (frames < 0) {
LogWarn(("ALSA trying to recover from avail error: %s\n", snd_strerror(frames)));
frames = snd_pcm_recover(_pcm, frames, 0);
if (frames == 0) {
frames = snd_pcm_avail(_pcm);
}
}
if (frames < 0) {
LogWarn(("ALSA avail error: %s\n", snd_strerror(frames)));
return VERR_AUDIO_STREAM_NOT_READY;
}
return frames;
}
int PCMOutAlsa::wait()
{
int err = snd_pcm_wait(_pcm, -1);
if (err < 0) {
LogWarn(("ALSA trying to recover from wait error: %s\n", snd_strerror(err)));
err = snd_pcm_recover(_pcm, err, 0);
}
if (err < 0) {
LogWarn(("ALSA wait error: %s\n", snd_strerror(err)));
return VERR_AUDIO_STREAM_NOT_READY;
}
return VINF_SUCCESS;
}
ssize_t PCMOutAlsa::write(int16_t *buf, size_t n)
{
snd_pcm_sframes_t frames = snd_pcm_writei(_pcm, buf, n);
if (frames < 0) {
LogFlow(("ALSA trying to recover from error: %s\n", snd_strerror(frames)));
frames = snd_pcm_recover(_pcm, frames, 0);
}
if (frames < 0) {
LogWarn(("ALSA write error: %s\n", snd_strerror(frames)));
return VERR_AUDIO_STREAM_NOT_READY;
}
return frames;
}
int PCMOutAlsa::setParams(unsigned int sampleRate, unsigned int channels, unsigned int bufferTime, unsigned int periodTime)
{
snd_pcm_hw_params_t *hwparams;
snd_pcm_sw_params_t *swparams;
int err;
snd_pcm_hw_params_alloca(&hwparams);
snd_pcm_sw_params_alloca(&swparams);
/* choose all parameters */
err = snd_pcm_hw_params_any(_pcm, hwparams);
if (err < 0) {
LogWarnFunc(("Broken PCM configuration: no configurations available: %s", snd_strerror(err)));
return err;
}
/* set software resampling */
err = snd_pcm_hw_params_set_rate_resample(_pcm, hwparams, 1);
if (err < 0) {
LogWarnFunc(("Resampling setup failed: %s", snd_strerror(err)));
return err;
}
/* set the selected read/write format */
err = snd_pcm_hw_params_set_access(_pcm, hwparams, SND_PCM_ACCESS_RW_INTERLEAVED);
if (err < 0) {
LogWarnFunc(("Access type not available: %s", snd_strerror(err)));
return err;
}
/* set the sample format */
err = snd_pcm_hw_params_set_format(_pcm, hwparams, SND_PCM_FORMAT_S16);
if (err < 0) {
LogWarnFunc(("Sample format not available: %s", snd_strerror(err)));
return err;
}
/* set the count of channels */
err = snd_pcm_hw_params_set_channels(_pcm, hwparams, channels);
if (err < 0) {
LogWarnFunc(("Channels count (%i) not available: %s", channels, snd_strerror(err)));
return err;
}
/* set the stream rate */
unsigned int rrate = sampleRate;
err = snd_pcm_hw_params_set_rate_near(_pcm, hwparams, &rrate, 0);
if (err < 0) {
LogWarnFunc(("Rate %iHz not available for playback: %s", sampleRate, snd_strerror(err)));
return err;
}
if (rrate != sampleRate) {
LogWarnFunc(("Rate doesn't match (requested %iHz, get %iHz)", sampleRate, rrate));
return -EINVAL;
}
/* set the buffer time */
err = snd_pcm_hw_params_set_buffer_time_near(_pcm, hwparams, &bufferTime, NULL);
if (err < 0) {
LogWarnFunc(("Unable to set buffer time %u for playback: %s\n", bufferTime, snd_strerror(err)));
return err;
}
err = snd_pcm_hw_params_get_buffer_size(hwparams, &_bufferSize);
if (err < 0) {
LogWarnFunc(("Unable to get buffer size for playback: %s\n", snd_strerror(err)));
return err;
}
/* set the period time */
err = snd_pcm_hw_params_set_period_time_near(_pcm, hwparams, &periodTime, NULL);
if (err < 0) {
LogWarnFunc(("Unable to set period time %u for playback: %s\n", periodTime, snd_strerror(err)));
return err;
}
err = snd_pcm_hw_params_get_period_size(hwparams, &_periodSize, NULL);
if (err < 0) {
LogWarnFunc(("Unable to get period size for playback: %s\n", snd_strerror(err)));
return err;
}
/* write the parameters to device */
err = snd_pcm_hw_params(_pcm, hwparams);
if (err < 0) {
LogWarnFunc(("Unable to set hw params: %s", snd_strerror(err)));
return err;
}
LogFunc(("Using bufferSize=%lu periodSize=%lu\n", _bufferSize, _periodSize));
/* get the current swparams */
err = snd_pcm_sw_params_current(_pcm, swparams);
if (err < 0) {
LogWarnFunc(("Unable to determine current swparams: %s", snd_strerror(err)));
return err;
}
/* start the transfer when the buffer is almost full: */
/* (buffer_size / avail_min) * avail_min */
err = snd_pcm_sw_params_set_start_threshold(_pcm, swparams, (_bufferSize / _periodSize) * _periodSize);
if (err < 0) {
LogWarnFunc(("Unable to set start threshold mode: %s", snd_strerror(err)));
return err;
}
/* allow the transfer when at least period_size samples can be processed */
err = snd_pcm_sw_params_set_avail_min(_pcm, swparams, _periodSize);
if (err < 0) {
LogWarnFunc(("Unable to set avail min: %s", snd_strerror(err)));
return err;
}
/* write the parameters to the playback device */
err = snd_pcm_sw_params(_pcm, swparams);
if (err < 0) {
LogWarnFunc(("Unable to set sw params: %s", snd_strerror(err)));
return err;
}
return 0;
}
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