blob: eb144a8701b065c69d523da5c2ea657aa3d128b6 [file] [log] [blame]
// Copyright 2017 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 "chromecast/media/audio/cast_audio_manager_alsa.h"
#include <utility>
#include "base/logging.h"
#include "base/memory/free_deleter.h"
#include "base/stl_util.h"
#include "base/strings/string_piece.h"
#include "chromecast/media/audio/audio_buildflags.h"
#include "chromecast/media/audio/cast_audio_input_stream.h"
#include "chromecast/media/cma/backend/cma_backend_factory.h"
#include "media/audio/alsa/alsa_input.h"
#include "media/audio/alsa/alsa_wrapper.h"
namespace chromecast {
namespace media {
namespace {
// TODO(alokp): Query the preferred value from media backend.
const int kDefaultSampleRate = BUILDFLAG(AUDIO_INPUT_SAMPLE_RATE);
// TODO(jyw): Query the preferred value from media backend.
const int kDefaultInputBufferSize = 1024;
const int kCommunicationsSampleRate = 16000;
const int kCommunicationsInputBufferSize = 160; // 10 ms.
// Since "default" and "dmix" devices are virtual devices mapped to real
// devices, we remove them from the list to avoiding duplicate counting.
constexpr base::StringPiece kInvalidAudioInputDevices[] = {
// Constants specified by the ALSA API for device hints.
constexpr char kPcmInterfaceName[] = "pcm";
constexpr char kIoHintName[] = "IOID";
constexpr char kNameHintName[] = "NAME";
constexpr char kDescriptionHintName[] = "DESC";
bool IsAlsaDeviceAvailable(CastAudioManagerAlsa::StreamType type,
const char* device_name) {
if (!device_name)
return false;
// We do prefix matches on the device name to see whether to include
// it or not.
if (type == CastAudioManagerAlsa::kStreamCapture) {
// Check if the device is in the list of invalid devices.
for (size_t i = 0; i < base::size(kInvalidAudioInputDevices); ++i) {
if (kInvalidAudioInputDevices[i] == device_name)
return false;
return true;
} else {
DCHECK_EQ(CastAudioManagerAlsa::kStreamPlayback, type);
// We prefer the device type that maps straight to hardware but
// goes through software conversion if needed (e.g. incompatible
// sample rate).
// TODO(joi): Should we prefer "hw" instead?
const std::string kDeviceTypeDesired = "plughw";
return kDeviceTypeDesired == device_name;
std::string UnwantedDeviceTypeWhenEnumerating(
CastAudioManagerAlsa::StreamType wanted_type) {
return wanted_type == CastAudioManagerAlsa::kStreamPlayback ? "Input"
: "Output";
} // namespace
std::unique_ptr<::media::AudioThread> audio_thread,
::media::AudioLogFactory* audio_log_factory,
base::RepeatingCallback<CmaBackendFactory*()> backend_factory_getter,
GetSessionIdCallback get_session_id_callback,
scoped_refptr<base::SingleThreadTaskRunner> browser_task_runner,
scoped_refptr<base::SingleThreadTaskRunner> media_task_runner,
service_manager::Connector* connector,
bool use_mixer)
: CastAudioManager(std::move(audio_thread),
wrapper_(new ::media::AlsaWrapper()) {}
CastAudioManagerAlsa::~CastAudioManagerAlsa() {}
bool CastAudioManagerAlsa::HasAudioInputDevices() {
return true;
void CastAudioManagerAlsa::GetAudioInputDeviceNames(
::media::AudioDeviceNames* device_names) {
// Prepend the default device since we always want it to be on the top of the
// list for all platforms. Note, pulse has exclusively opened the default
// device, so we must open the device via the "default" moniker.
GetAlsaAudioDevices(kStreamCapture, device_names);
::media::AudioParameters CastAudioManagerAlsa::GetInputStreamParameters(
const std::string& device_id) {
if (device_id == ::media::AudioDeviceDescription::kCommunicationsDeviceId) {
<< "Capture Service is not enabled, return a fake AudioParameters.";
return ::media::AudioParameters();
return ::media::AudioParameters(::media::AudioParameters::AUDIO_PCM_LINEAR,
// TODO(jyw): Be smarter about sample rate instead of hardcoding it.
// Need to send a valid AudioParameters object even when it will be unused.
return ::media::AudioParameters(
::media::CHANNEL_LAYOUT_STEREO, kDefaultSampleRate,
::media::AudioInputStream* CastAudioManagerAlsa::MakeLinearInputStream(
const ::media::AudioParameters& params,
const std::string& device_id,
const ::media::AudioManager::LogCallback& log_callback) {
DCHECK_EQ(::media::AudioParameters::AUDIO_PCM_LINEAR, params.format());
return MakeInputStream(params, device_id);
::media::AudioInputStream* CastAudioManagerAlsa::MakeLowLatencyInputStream(
const ::media::AudioParameters& params,
const std::string& device_id,
const ::media::AudioManager::LogCallback& log_callback) {
DCHECK_EQ(::media::AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
return MakeInputStream(params, device_id);
::media::AudioInputStream* CastAudioManagerAlsa::MakeInputStream(
const ::media::AudioParameters& params,
const std::string& device_id) {
std::string device_name =
(device_id == ::media::AudioDeviceDescription::kDefaultDeviceId)
? ::media::AlsaPcmInputStream::kAutoSelectDevice
: device_id;
if (device_name == ::media::AudioDeviceDescription::kCommunicationsDeviceId) {
NOTIMPLEMENTED() << "Capture Service is not enabled, return nullptr.";
return nullptr;
return new CastAudioInputStream(params, device_name);
return new ::media::AlsaPcmInputStream(this, device_name, params,
void CastAudioManagerAlsa::GetAlsaAudioDevices(
StreamType type,
::media::AudioDeviceNames* device_names) {
int card = -1;
// Loop through the sound cards to get ALSA device hints.
while (!wrapper_->CardNext(&card) && card >= 0) {
void** hints = NULL;
int error = wrapper_->DeviceNameHint(card, kPcmInterfaceName, &hints);
if (!error) {
GetAlsaDevicesInfo(type, hints, device_names);
// Destroy the hints now that we're done with it.
} else {
DLOG(WARNING) << "GetAlsaAudioDevices: unable to get device hints: "
<< wrapper_->StrError(error);
void CastAudioManagerAlsa::GetAlsaDevicesInfo(
StreamType type,
void** hints,
::media::AudioDeviceNames* device_names) {
const std::string unwanted_device_type =
for (void** hint_iter = hints; *hint_iter != NULL; hint_iter++) {
// Only examine devices of the right type. Valid values are
// "Input", "Output", and NULL which means both input and output.
std::unique_ptr<char, base::FreeDeleter> io(
wrapper_->DeviceNameGetHint(*hint_iter, kIoHintName));
if (io && unwanted_device_type == io.get())
// Get the unique device name for the device.
std::unique_ptr<char, base::FreeDeleter> unique_device_name(
wrapper_->DeviceNameGetHint(*hint_iter, kNameHintName));
// Find out if the device is available.
if (IsAlsaDeviceAvailable(type, unique_device_name.get())) {
// Get the description for the device.
std::unique_ptr<char, base::FreeDeleter> desc(
wrapper_->DeviceNameGetHint(*hint_iter, kDescriptionHintName));
::media::AudioDeviceName name;
name.unique_id = unique_device_name.get();
if (desc) {
name.device_name = desc.get();
// Use the more user friendly description as name.
// Replace '\n' with '-'.
name.device_name.replace(name.device_name.find('\n'), 1, 1, '-');
} else {
// Virtual devices don't necessarily have descriptions.
// Use their names instead.
name.device_name = unique_device_name.get();
// Store the device information.
} // namespace media
} // namespace chromecast