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// Copyright 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "media/audio/alsa/alsa_util.h"
#include <string>
#include "base/logging.h"
#include "media/audio/alsa/alsa_wrapper.h"
namespace alsa_util {
static snd_pcm_t* OpenDevice(media::AlsaWrapper* wrapper,
const char* device_name,
snd_pcm_stream_t type,
int channels,
int sample_rate,
snd_pcm_format_t pcm_format,
int latency_us) {
snd_pcm_t* handle = NULL;
int error = wrapper->PcmOpen(&handle, device_name, type, SND_PCM_NONBLOCK);
if (error < 0) {
LOG(WARNING) << "PcmOpen: " << device_name << ","
<< wrapper->StrError(error);
return NULL;
}
error = wrapper->PcmSetParams(handle, pcm_format,
SND_PCM_ACCESS_RW_INTERLEAVED, channels,
sample_rate, 1, latency_us);
if (error < 0) {
LOG(WARNING) << "PcmSetParams: " << device_name << ", "
<< wrapper->StrError(error) << " - Format: " << pcm_format
<< " Channels: " << channels << " Latency: " << latency_us;
if (alsa_util::CloseDevice(wrapper, handle) < 0) {
// TODO(ajwong): Retry on certain errors?
LOG(WARNING) << "Unable to close audio device. Leaking handle.";
}
return NULL;
}
return handle;
}
static std::string DeviceNameToControlName(const std::string& device_name) {
const char kMixerPrefix[] = "hw";
std::string control_name;
size_t pos1 = device_name.find(':');
if (pos1 == std::string::npos) {
control_name = device_name;
} else {
// Examples:
// deviceName: "front:CARD=Intel,DEV=0", controlName: "hw:CARD=Intel".
// deviceName: "default:CARD=Intel", controlName: "CARD=Intel".
size_t pos2 = device_name.find(',');
control_name = (pos2 == std::string::npos) ?
device_name.substr(pos1) :
kMixerPrefix + device_name.substr(pos1, pos2 - pos1);
}
return control_name;
}
snd_pcm_format_t BitsToFormat(int bits_per_sample) {
switch (bits_per_sample) {
case 8:
return SND_PCM_FORMAT_U8;
case 16:
return SND_PCM_FORMAT_S16;
case 24:
return SND_PCM_FORMAT_S24;
case 32:
return SND_PCM_FORMAT_S32;
default:
return SND_PCM_FORMAT_UNKNOWN;
}
}
int CloseDevice(media::AlsaWrapper* wrapper, snd_pcm_t* handle) {
std::string device_name = wrapper->PcmName(handle);
int error = wrapper->PcmClose(handle);
if (error < 0) {
LOG(ERROR) << "PcmClose: " << device_name << ", "
<< wrapper->StrError(error);
}
return error;
}
snd_pcm_t* OpenCaptureDevice(media::AlsaWrapper* wrapper,
const char* device_name,
int channels,
int sample_rate,
snd_pcm_format_t pcm_format,
int latency_us) {
return OpenDevice(wrapper, device_name, SND_PCM_STREAM_CAPTURE, channels,
sample_rate, pcm_format, latency_us);
}
snd_pcm_t* OpenPlaybackDevice(media::AlsaWrapper* wrapper,
const char* device_name,
int channels,
int sample_rate,
snd_pcm_format_t pcm_format,
int latency_us) {
return OpenDevice(wrapper, device_name, SND_PCM_STREAM_PLAYBACK, channels,
sample_rate, pcm_format, latency_us);
}
snd_mixer_t* OpenMixer(media::AlsaWrapper* wrapper,
const std::string& device_name) {
snd_mixer_t* mixer = NULL;
int error = wrapper->MixerOpen(&mixer, 0);
if (error < 0) {
LOG(ERROR) << "MixerOpen: " << device_name << ", "
<< wrapper->StrError(error);
return NULL;
}
std::string control_name = DeviceNameToControlName(device_name);
error = wrapper->MixerAttach(mixer, control_name.c_str());
if (error < 0) {
LOG(ERROR) << "MixerAttach, " << control_name << ", "
<< wrapper->StrError(error);
alsa_util::CloseMixer(wrapper, mixer, device_name);
return NULL;
}
error = wrapper->MixerElementRegister(mixer, NULL, NULL);
if (error < 0) {
LOG(ERROR) << "MixerElementRegister: " << control_name << ", "
<< wrapper->StrError(error);
alsa_util::CloseMixer(wrapper, mixer, device_name);
return NULL;
}
return mixer;
}
void CloseMixer(media::AlsaWrapper* wrapper, snd_mixer_t* mixer,
const std::string& device_name) {
if (!mixer)
return;
wrapper->MixerFree(mixer);
int error = 0;
if (!device_name.empty()) {
std::string control_name = DeviceNameToControlName(device_name);
error = wrapper->MixerDetach(mixer, control_name.c_str());
if (error < 0) {
LOG(WARNING) << "MixerDetach: " << control_name << ", "
<< wrapper->StrError(error);
}
}
error = wrapper->MixerClose(mixer);
if (error < 0) {
LOG(WARNING) << "MixerClose: " << wrapper->StrError(error);
}
}
snd_mixer_elem_t* LoadCaptureMixerElement(media::AlsaWrapper* wrapper,
snd_mixer_t* mixer) {
if (!mixer)
return NULL;
int error = wrapper->MixerLoad(mixer);
if (error < 0) {
LOG(ERROR) << "MixerLoad: " << wrapper->StrError(error);
return NULL;
}
snd_mixer_elem_t* elem = NULL;
snd_mixer_elem_t* mic_elem = NULL;
const char kCaptureElemName[] = "Capture";
const char kMicElemName[] = "Mic";
for (elem = wrapper->MixerFirstElem(mixer);
elem;
elem = wrapper->MixerNextElem(elem)) {
if (wrapper->MixerSelemIsActive(elem)) {
const char* elem_name = wrapper->MixerSelemName(elem);
if (strcmp(elem_name, kCaptureElemName) == 0)
return elem;
else if (strcmp(elem_name, kMicElemName) == 0)
mic_elem = elem;
}
}
// Did not find any Capture handle, use the Mic handle.
return mic_elem;
}
} // namespace alsa_util
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