audio_manager_linux.cc revision a3f7b4e666c476898878fa745f637129375cd889 
1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#include "media/audio/linux/audio_manager_linux.h"
6
7#include "base/command_line.h"
8#include "base/environment.h"
9#include "base/files/file_path.h"
10#include "base/logging.h"
11#include "base/metrics/histogram.h"
12#include "base/nix/xdg_util.h"
13#include "base/process/launch.h"
14#include "base/stl_util.h"
15#include "media/audio/audio_output_dispatcher.h"
16#include "media/audio/audio_parameters.h"
17#include "media/audio/audio_util.h"
18#if defined(USE_CRAS)
19#include "media/audio/cras/audio_manager_cras.h"
20#endif
21#include "media/audio/linux/alsa_input.h"
22#include "media/audio/linux/alsa_output.h"
23#include "media/audio/linux/alsa_wrapper.h"
24#if defined(USE_PULSEAUDIO)
25#include "media/audio/pulse/audio_manager_pulse.h"
26#endif
27#include "media/base/channel_layout.h"
28#include "media/base/limits.h"
29#include "media/base/media_switches.h"
30
31namespace media {
32
33// Maximum number of output streams that can be open simultaneously.
34static const int kMaxOutputStreams = 50;
35
36// Default sample rate for input and output streams.
37static const int kDefaultSampleRate = 48000;
38
39// Since "default", "pulse" and "dmix" devices are virtual devices mapped to
40// real devices, we remove them from the list to avoiding duplicate counting.
41// In addition, note that we support no more than 2 channels for recording,
42// hence surround devices are not stored in the list.
43static const char* kInvalidAudioInputDevices[] = {
44  "default",
45  "null",
46  "pulse",
47  "dmix",
48  "surround",
49};
50
51enum LinuxAudioIO {
52  kPulse,
53  kAlsa,
54  kCras,
55  kAudioIOMax  // Must always be last!
56};
57
58// static
59void AudioManagerLinux::ShowLinuxAudioInputSettings() {
60  scoped_ptr<base::Environment> env(base::Environment::Create());
61  CommandLine command_line(CommandLine::NO_PROGRAM);
62  switch (base::nix::GetDesktopEnvironment(env.get())) {
63    case base::nix::DESKTOP_ENVIRONMENT_GNOME:
64      command_line.SetProgram(base::FilePath("gnome-volume-control"));
65      break;
66    case base::nix::DESKTOP_ENVIRONMENT_KDE3:
67    case base::nix::DESKTOP_ENVIRONMENT_KDE4:
68      command_line.SetProgram(base::FilePath("kmix"));
69      break;
70    case base::nix::DESKTOP_ENVIRONMENT_UNITY:
71      command_line.SetProgram(base::FilePath("gnome-control-center"));
72      command_line.AppendArg("sound");
73      command_line.AppendArg("input");
74      break;
75    default:
76      LOG(ERROR) << "Failed to show audio input settings: we don't know "
77                 << "what command to use for your desktop environment.";
78      return;
79  }
80  base::LaunchProcess(command_line, base::LaunchOptions(), NULL);
81}
82
83// Implementation of AudioManager.
84bool AudioManagerLinux::HasAudioOutputDevices() {
85  return HasAnyAlsaAudioDevice(kStreamPlayback);
86}
87
88bool AudioManagerLinux::HasAudioInputDevices() {
89  return HasAnyAlsaAudioDevice(kStreamCapture);
90}
91
92AudioManagerLinux::AudioManagerLinux()
93    : wrapper_(new AlsaWrapper()) {
94  SetMaxOutputStreamsAllowed(kMaxOutputStreams);
95}
96
97AudioManagerLinux::~AudioManagerLinux() {
98  Shutdown();
99}
100
101void AudioManagerLinux::ShowAudioInputSettings() {
102  ShowLinuxAudioInputSettings();
103}
104
105void AudioManagerLinux::GetAudioInputDeviceNames(
106    media::AudioDeviceNames* device_names) {
107  DCHECK(device_names->empty());
108  GetAlsaAudioInputDevices(device_names);
109}
110
111AudioParameters AudioManagerLinux::GetInputStreamParameters(
112    const std::string& device_id) {
113  static const int kDefaultInputBufferSize = 1024;
114
115  return AudioParameters(
116      AudioParameters::AUDIO_PCM_LOW_LATENCY, CHANNEL_LAYOUT_STEREO,
117      kDefaultSampleRate, 16, kDefaultInputBufferSize);
118}
119
120void AudioManagerLinux::GetAlsaAudioInputDevices(
121    media::AudioDeviceNames* device_names) {
122  // Constants specified by the ALSA API for device hints.
123  static const char kPcmInterfaceName[] = "pcm";
124  int card = -1;
125
126  // Loop through the sound cards to get ALSA device hints.
127  while (!wrapper_->CardNext(&card) && card >= 0) {
128    void** hints = NULL;
129    int error = wrapper_->DeviceNameHint(card, kPcmInterfaceName, &hints);
130    if (!error) {
131      GetAlsaDevicesInfo(hints, device_names);
132
133      // Destroy the hints now that we're done with it.
134      wrapper_->DeviceNameFreeHint(hints);
135    } else {
136      DLOG(WARNING) << "GetAudioInputDevices: unable to get device hints: "
137                    << wrapper_->StrError(error);
138    }
139  }
140}
141
142void AudioManagerLinux::GetAlsaDevicesInfo(
143    void** hints, media::AudioDeviceNames* device_names) {
144  static const char kIoHintName[] = "IOID";
145  static const char kNameHintName[] = "NAME";
146  static const char kDescriptionHintName[] = "DESC";
147  static const char kOutputDevice[] = "Output";
148
149  for (void** hint_iter = hints; *hint_iter != NULL; hint_iter++) {
150    // Only examine devices that are input capable.  Valid values are
151    // "Input", "Output", and NULL which means both input and output.
152    scoped_ptr_malloc<char> io(wrapper_->DeviceNameGetHint(*hint_iter,
153                                                           kIoHintName));
154    if (io != NULL && strcmp(kOutputDevice, io.get()) == 0)
155      continue;
156
157    // Found an input device, prepend the default device since we always want
158    // it to be on the top of the list for all platforms. And there is no
159    // duplicate counting here since it is only done if the list is still empty.
160    // Note, pulse has exclusively opened the default device, so we must open
161    // the device via the "default" moniker.
162    if (device_names->empty()) {
163      device_names->push_front(media::AudioDeviceName(
164          AudioManagerBase::kDefaultDeviceName,
165          AudioManagerBase::kDefaultDeviceId));
166    }
167
168    // Get the unique device name for the device.
169    scoped_ptr_malloc<char> unique_device_name(
170        wrapper_->DeviceNameGetHint(*hint_iter, kNameHintName));
171
172    // Find out if the device is available.
173    if (IsAlsaDeviceAvailable(unique_device_name.get())) {
174      // Get the description for the device.
175      scoped_ptr_malloc<char> desc(wrapper_->DeviceNameGetHint(
176          *hint_iter, kDescriptionHintName));
177
178      media::AudioDeviceName name;
179      name.unique_id = unique_device_name.get();
180      if (desc) {
181        // Use the more user friendly description as name.
182        // Replace '\n' with '-'.
183        char* pret = strchr(desc.get(), '\n');
184        if (pret)
185          *pret = '-';
186        name.device_name = desc.get();
187      } else {
188        // Virtual devices don't necessarily have descriptions.
189        // Use their names instead.
190        name.device_name = unique_device_name.get();
191      }
192
193      // Store the device information.
194      device_names->push_back(name);
195    }
196  }
197}
198
199bool AudioManagerLinux::IsAlsaDeviceAvailable(const char* device_name) {
200  if (!device_name)
201    return false;
202
203  // Check if the device is in the list of invalid devices.
204  for (size_t i = 0; i < arraysize(kInvalidAudioInputDevices); ++i) {
205    if (strncmp(kInvalidAudioInputDevices[i], device_name,
206                strlen(kInvalidAudioInputDevices[i])) == 0)
207      return false;
208  }
209
210  return true;
211}
212
213bool AudioManagerLinux::HasAnyAlsaAudioDevice(StreamType stream) {
214  static const char kPcmInterfaceName[] = "pcm";
215  static const char kIoHintName[] = "IOID";
216  const char* kNotWantedDevice =
217      (stream == kStreamPlayback ? "Input" : "Output");
218  void** hints = NULL;
219  bool has_device = false;
220  int card = -1;
221
222  // Loop through the sound cards.
223  // Don't use snd_device_name_hint(-1,..) since there is a access violation
224  // inside this ALSA API with libasound.so.2.0.0.
225  while (!wrapper_->CardNext(&card) && (card >= 0) && !has_device) {
226    int error = wrapper_->DeviceNameHint(card, kPcmInterfaceName, &hints);
227    if (!error) {
228      for (void** hint_iter = hints; *hint_iter != NULL; hint_iter++) {
229        // Only examine devices that are |stream| capable.  Valid values are
230        // "Input", "Output", and NULL which means both input and output.
231        scoped_ptr_malloc<char> io(wrapper_->DeviceNameGetHint(*hint_iter,
232                                                               kIoHintName));
233        if (io != NULL && strcmp(kNotWantedDevice, io.get()) == 0)
234          continue;  // Wrong type, skip the device.
235
236        // Found an input device.
237        has_device = true;
238        break;
239      }
240
241      // Destroy the hints now that we're done with it.
242      wrapper_->DeviceNameFreeHint(hints);
243      hints = NULL;
244    } else {
245      DLOG(WARNING) << "HasAnyAudioDevice: unable to get device hints: "
246                    << wrapper_->StrError(error);
247    }
248  }
249
250  return has_device;
251}
252
253AudioOutputStream* AudioManagerLinux::MakeLinearOutputStream(
254    const AudioParameters& params) {
255  DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
256  return MakeOutputStream(params);
257}
258
259AudioOutputStream* AudioManagerLinux::MakeLowLatencyOutputStream(
260    const AudioParameters& params,
261    const std::string& input_device_id) {
262  DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
263  // TODO(xians): Use input_device_id for unified IO.
264  return MakeOutputStream(params);
265}
266
267AudioInputStream* AudioManagerLinux::MakeLinearInputStream(
268    const AudioParameters& params, const std::string& device_id) {
269  DCHECK_EQ(AudioParameters::AUDIO_PCM_LINEAR, params.format());
270  return MakeInputStream(params, device_id);
271}
272
273AudioInputStream* AudioManagerLinux::MakeLowLatencyInputStream(
274    const AudioParameters& params, const std::string& device_id) {
275  DCHECK_EQ(AudioParameters::AUDIO_PCM_LOW_LATENCY, params.format());
276  return MakeInputStream(params, device_id);
277}
278
279AudioParameters AudioManagerLinux::GetPreferredOutputStreamParameters(
280    const AudioParameters& input_params) {
281  static const int kDefaultOutputBufferSize = 2048;
282  ChannelLayout channel_layout = CHANNEL_LAYOUT_STEREO;
283  int sample_rate = kDefaultSampleRate;
284  int buffer_size = kDefaultOutputBufferSize;
285  int bits_per_sample = 16;
286  int input_channels = 0;
287  if (input_params.IsValid()) {
288    // Some clients, such as WebRTC, have a more limited use case and work
289    // acceptably with a smaller buffer size.  The check below allows clients
290    // which want to try a smaller buffer size on Linux to do so.
291    // TODO(dalecurtis): This should include bits per channel and channel layout
292    // eventually.
293    sample_rate = input_params.sample_rate();
294    bits_per_sample = input_params.bits_per_sample();
295    channel_layout = input_params.channel_layout();
296    input_channels = input_params.input_channels();
297    buffer_size = std::min(input_params.frames_per_buffer(), buffer_size);
298  }
299
300  int user_buffer_size = GetUserBufferSize();
301  if (user_buffer_size)
302    buffer_size = user_buffer_size;
303
304  return AudioParameters(
305      AudioParameters::AUDIO_PCM_LOW_LATENCY, channel_layout, input_channels,
306      sample_rate, bits_per_sample, buffer_size);
307}
308
309AudioOutputStream* AudioManagerLinux::MakeOutputStream(
310    const AudioParameters& params) {
311  std::string device_name = AlsaPcmOutputStream::kAutoSelectDevice;
312  if (CommandLine::ForCurrentProcess()->HasSwitch(
313          switches::kAlsaOutputDevice)) {
314    device_name = CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
315        switches::kAlsaOutputDevice);
316  }
317  return new AlsaPcmOutputStream(device_name, params, wrapper_.get(), this);
318}
319
320AudioInputStream* AudioManagerLinux::MakeInputStream(
321    const AudioParameters& params, const std::string& device_id) {
322  std::string device_name = (device_id == AudioManagerBase::kDefaultDeviceId) ?
323      AlsaPcmInputStream::kAutoSelectDevice : device_id;
324  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kAlsaInputDevice)) {
325    device_name = CommandLine::ForCurrentProcess()->GetSwitchValueASCII(
326        switches::kAlsaInputDevice);
327  }
328
329  return new AlsaPcmInputStream(this, device_name, params, wrapper_.get());
330}
331
332AudioManager* CreateAudioManager() {
333#if defined(USE_CRAS)
334  if (CommandLine::ForCurrentProcess()->HasSwitch(switches::kUseCras)) {
335    UMA_HISTOGRAM_ENUMERATION("Media.LinuxAudioIO", kCras, kAudioIOMax);
336    return new AudioManagerCras();
337  }
338#endif
339
340#if defined(USE_PULSEAUDIO)
341  AudioManager* manager = AudioManagerPulse::Create();
342  if (manager) {
343    UMA_HISTOGRAM_ENUMERATION("Media.LinuxAudioIO", kPulse, kAudioIOMax);
344    return manager;
345  }
346#endif
347
348  UMA_HISTOGRAM_ENUMERATION("Media.LinuxAudioIO", kAlsa, kAudioIOMax);
349  return new AudioManagerLinux();
350}
351
352}  // namespace media
353