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/* ------------------------------------------------------------------
* Copyright (C) 2011 Martin Storsjo
* Copyright (C) 2017 Matthias P. Braendli
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
* express or implied.
* See the License for the specific language governing permissions
* and limitations under the License.
* -------------------------------------------------------------------
*/
#include "config.h"
#if HAVE_ALSA
#include "AlsaInput.h"
#include <cstdio>
#include <stdexcept>
#include <string>
#include <alsa/asoundlib.h>
#include <sys/time.h>
using namespace std;
AlsaInput::~AlsaInput()
{
if (m_alsa_handle) {
snd_pcm_close(m_alsa_handle);
m_alsa_handle = nullptr;
}
}
static std::string alsa_strerror(int err)
{
string s(snd_strerror(err));
return s;
}
void AlsaInput::m_init_alsa()
{
int err;
snd_pcm_hw_params_t *hw_params;
fprintf(stderr, "Initialising ALSA...\n");
const int open_mode = 0;
if ((err = snd_pcm_open(&m_alsa_handle, m_alsa_dev.c_str(),
SND_PCM_STREAM_CAPTURE, open_mode)) < 0) {
throw runtime_error("cannot open audio device " +
m_alsa_dev + "(" + alsa_strerror(err) + ")");
}
if ((err = snd_pcm_hw_params_malloc(&hw_params)) < 0) {
throw runtime_error("cannot allocate hardware parameter structure (" +
alsa_strerror(err) + ")");
}
if ((err = snd_pcm_hw_params_any(m_alsa_handle, hw_params)) < 0) {
throw runtime_error("cannot initialize hardware parameter structure (" +
alsa_strerror(err) + ")");
}
if ((err = snd_pcm_hw_params_set_access(m_alsa_handle, hw_params,
SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
throw runtime_error("cannot set access type (" + alsa_strerror(err) + ")");
}
if ((err = snd_pcm_hw_params_set_format(m_alsa_handle, hw_params,
SND_PCM_FORMAT_S16_LE)) < 0) {
throw runtime_error("cannot set sample format (" +
alsa_strerror(err) + ")");
}
if ((err = snd_pcm_hw_params_set_rate_near(m_alsa_handle,
hw_params, &m_rate, 0)) < 0) {
throw runtime_error("cannot set sample rate (" + alsa_strerror(err) + ")");
}
if ((err = snd_pcm_hw_params_set_channels(m_alsa_handle,
hw_params, m_channels)) < 0) {
throw runtime_error("cannot set channel count (" +
alsa_strerror(err) + ")");
}
if ((err = snd_pcm_hw_params(m_alsa_handle, hw_params)) < 0) {
throw runtime_error("cannot set parameters (" + alsa_strerror(err) + ")");
}
snd_pcm_hw_params_free (hw_params);
if ((err = snd_pcm_prepare(m_alsa_handle)) < 0) {
throw runtime_error("cannot prepare audio interface for use (" +
alsa_strerror(err) + ")");
}
fprintf(stderr, "ALSA init done.\n");
}
ssize_t AlsaInput::m_read(uint8_t* buf, snd_pcm_uframes_t length)
{
int i;
int err;
err = snd_pcm_readi(m_alsa_handle, buf, length);
if (err != length) {
if (err < 0) {
fprintf (stderr, "read from audio interface failed (%s)\n",
snd_strerror(err));
}
else {
fprintf(stderr, "short alsa read: %d\n", err);
}
}
return err;
}
void AlsaInputThreaded::prepare()
{
if (m_fault) {
fprintf(stderr, "Cannot start alsa input. Fault detected previsouly!\n");
}
else {
m_init_alsa();
m_running = true;
m_thread = std::thread(&AlsaInputThreaded::process, this);
}
}
void AlsaInputThreaded::process()
{
uint8_t samplebuf[NUM_SAMPLES_PER_CALL * BYTES_PER_SAMPLE * m_channels];
while (m_running) {
ssize_t n = m_read(samplebuf, NUM_SAMPLES_PER_CALL);
if (n < 0) {
m_running = false;
m_fault = true;
break;
}
m_queue.push(samplebuf, BYTES_PER_SAMPLE*m_channels*n);
}
}
void AlsaInputDirect::prepare()
{
m_init_alsa();
}
ssize_t AlsaInputDirect::read(uint8_t* buf, size_t length)
{
int bytes_per_frame = m_channels * BYTES_PER_SAMPLE;
assert(length % bytes_per_frame == 0);
ssize_t read = m_read(buf, length / bytes_per_frame);
return (read > 0) ? read * bytes_per_frame : read;
}
#endif // HAVE_ALSA
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