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/* ------------------------------------------------------------------
* Copyright (C) 2011 Martin Storsjo
* Copyright (C) 2013,2014 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 <cstdio>
#include <cstdint>
#include <string>
#include <alsa/asoundlib.h>
#include "AlsaInput.h"
using namespace std;
int AlsaInput::prepare()
{
int err;
snd_pcm_hw_params_t *hw_params;
fprintf(stderr, "Initialising ALSA...\n");
const int open_mode = 0; //|= SND_PCM_NONBLOCK;
if ((err = snd_pcm_open(&m_alsa_handle, alsa_dev,
SND_PCM_STREAM_CAPTURE, open_mode)) < 0) {
fprintf (stderr, "cannot open audio device %s (%s)\n",
alsa_dev, snd_strerror(err));
return 1;
}
if ((err = snd_pcm_hw_params_malloc(&hw_params)) < 0) {
fprintf (stderr, "cannot allocate hardware parameter structure (%s)\n",
snd_strerror(err));
return 1;
}
if ((err = snd_pcm_hw_params_any(m_alsa_handle, hw_params)) < 0) {
fprintf (stderr, "cannot initialize hardware parameter structure (%s)\n",
snd_strerror(err));
return 1;
}
if ((err = snd_pcm_hw_params_set_access(m_alsa_handle, hw_params,
SND_PCM_ACCESS_RW_INTERLEAVED)) < 0) {
fprintf (stderr, "cannot set access type (%s)\n",
snd_strerror(err));
return 1;
}
if ((err = snd_pcm_hw_params_set_format(m_alsa_handle, hw_params,
SND_PCM_FORMAT_S16_LE)) < 0) {
fprintf (stderr, "cannot set sample format (%s)\n",
snd_strerror(err));
return 1;
}
if ((err = snd_pcm_hw_params_set_rate_near(m_alsa_handle,
hw_params, &m_rate, 0)) < 0) {
fprintf (stderr, "cannot set sample rate (%s)\n",
snd_strerror(err));
return 1;
}
if ((err = snd_pcm_hw_params_set_channels(m_alsa_handle,
hw_params, m_channels)) < 0) {
fprintf (stderr, "cannot set channel count (%s)\n",
snd_strerror(err));
return 1;
}
if ((err = snd_pcm_hw_params(m_alsa_handle, hw_params)) < 0) {
fprintf (stderr, "cannot set parameters (%s)\n",
snd_strerror(err));
return 1;
}
snd_pcm_hw_params_free (hw_params);
if ((err = snd_pcm_prepare(m_alsa_handle)) < 0) {
fprintf (stderr, "cannot prepare audio interface for use (%s)\n",
snd_strerror(err));
return 1;
}
fprintf(stderr, "ALSA init done.\n");
return 0;
}
size_t AlsaInput::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;
}
int AlsaInput::start()
{
m_running = true;
m_thread = boost::thread(&AlsaInput::process, this);
}
void AlsaInput::process()
{
uint8_t samplebuf[NUM_SAMPLES_PER_CALL * BYTES_PER_SAMPLE * m_channels];
while (m_running) {
size_t n = read(samplebuf, NUM_SAMPLES_PER_CALL);
m_queue.push(samplebuf, n);
}
}
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