media/audio/pulse/pulse_output.cc

   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/pulse/pulse_output.h"
   6
   7 #include <pulse/pulseaudio.h>
   8
   9 #include "base/single_thread_task_runner.h"
  10 #include "media/audio/audio_manager_base.h"
  11 #include "media/audio/pulse/pulse_util.h"
  12
  13 namespace media {
  14
  15 using pulse::AutoPulseLock;
  16 using pulse::WaitForOperationCompletion;
  17
  18 // static, pa_stream_notify_cb
  19 void PulseAudioOutputStream::StreamNotifyCallback(pa_stream* s, void* p_this) {
  20   PulseAudioOutputStream* stream = static_cast<PulseAudioOutputStream*>(p_this);
  21
  22   // Forward unexpected failures to the AudioSourceCallback if available.  All
  23   // these variables are only modified under pa_threaded_mainloop_lock() so this
  24   // should be thread safe.
  25   if (s && stream->source_callback_ &&
  26       pa_stream_get_state(s) == PA_STREAM_FAILED) {
  27     stream->source_callback_->OnError(stream);
  28   }
  29
  30   pa_threaded_mainloop_signal(stream->pa_mainloop_, 0);
  31 }
  32
  33 // static, pa_stream_request_cb_t
  34 void PulseAudioOutputStream::StreamRequestCallback(pa_stream* s, size_t len,
  35                                                    void* p_this) {
  36   // Fulfill write request; must always result in a pa_stream_write() call.
  37   static_cast<PulseAudioOutputStream*>(p_this)->FulfillWriteRequest(len);
  38 }
  39
  40 PulseAudioOutputStream::PulseAudioOutputStream(const AudioParameters& params,
  41                                                const std::string& device_id,
  42                                                AudioManagerBase* manager)
  43     : params_(params),
  44       device_id_(device_id),
  45       manager_(manager),
  46       pa_context_(NULL),
  47       pa_mainloop_(NULL),
  48       pa_stream_(NULL),
  49       volume_(1.0f),
  50       source_callback_(NULL) {
  51   CHECK(params_.IsValid());
  52   audio_bus_ = AudioBus::Create(params_);
  53 }
  54
  55 PulseAudioOutputStream::~PulseAudioOutputStream() {
  56   // All internal structures should already have been freed in Close(), which
  57   // calls AudioManagerBase::ReleaseOutputStream() which deletes this object.
  58   DCHECK(!pa_stream_);
  59   DCHECK(!pa_context_);
  60   DCHECK(!pa_mainloop_);
  61 }
  62
  63 bool PulseAudioOutputStream::Open() {
  64   DCHECK(thread_checker_.CalledOnValidThread());
  65   return pulse::CreateOutputStream(
  66       &pa_mainloop_, &pa_context_, &pa_stream_, params_, device_id_,
  67       AudioManager::GetGlobalAppName(), &StreamNotifyCallback,
  68       &StreamRequestCallback, this);
  69 }
  70
  71 void PulseAudioOutputStream::Reset() {
  72   if (!pa_mainloop_) {
  73     DCHECK(!pa_stream_);
  74     DCHECK(!pa_context_);
  75     return;
  76   }
  77
  78   {
  79     AutoPulseLock auto_lock(pa_mainloop_);
  80
  81     // Close the stream.
  82     if (pa_stream_) {
  83       // Ensure all samples are played out before shutdown.
  84       pa_operation* operation = pa_stream_flush(
  85           pa_stream_, &pulse::StreamSuccessCallback, pa_mainloop_);
  86       WaitForOperationCompletion(pa_mainloop_, operation);
  87
  88       // Release PulseAudio structures.
  89       pa_stream_disconnect(pa_stream_);
  90       pa_stream_set_write_callback(pa_stream_, NULL, NULL);
  91       pa_stream_set_state_callback(pa_stream_, NULL, NULL);
  92       pa_stream_unref(pa_stream_);
  93       pa_stream_ = NULL;
  94     }
  95
  96     if (pa_context_) {
  97       pa_context_disconnect(pa_context_);
  98       pa_context_set_state_callback(pa_context_, NULL, NULL);
  99       pa_context_unref(pa_context_);
 100       pa_context_ = NULL;
 101     }
 102   }
 103
 104   pa_threaded_mainloop_stop(pa_mainloop_);
 105   pa_threaded_mainloop_free(pa_mainloop_);
 106   pa_mainloop_ = NULL;
 107 }
 108
 109 void PulseAudioOutputStream::Close() {
 110   DCHECK(thread_checker_.CalledOnValidThread());
 111
 112   Reset();
 113
 114   // Signal to the manager that we're closed and can be removed.
 115   // This should be the last call in the function as it deletes "this".
 116   manager_->ReleaseOutputStream(this);
 117 }
 118
 119 void PulseAudioOutputStream::FulfillWriteRequest(size_t requested_bytes) {
 120   int bytes_remaining = requested_bytes;
 121   while (bytes_remaining > 0) {
 122     void* buffer = NULL;
 123     size_t bytes_to_fill = params_.GetBytesPerBuffer();
 124     CHECK_GE(pa_stream_begin_write(pa_stream_, &buffer, &bytes_to_fill), 0);
 125     CHECK_EQ(bytes_to_fill, static_cast<size_t>(params_.GetBytesPerBuffer()));
 126
 127     // NOTE: |bytes_to_fill| may be larger than |requested_bytes| now, this is
 128     // okay since pa_stream_begin_write() is the authoritative source on how
 129     // much can be written.
 130
 131     int frames_filled = 0;
 132     if (source_callback_) {
 133       const uint32 hardware_delay = pulse::GetHardwareLatencyInBytes(
 134           pa_stream_, params_.sample_rate(), params_.GetBytesPerFrame());
 135       frames_filled = source_callback_->OnMoreData(
 136           audio_bus_.get(), hardware_delay);
 137
 138       // Zero any unfilled data so it plays back as silence.
 139       if (frames_filled < audio_bus_->frames()) {
 140         audio_bus_->ZeroFramesPartial(
 141             frames_filled, audio_bus_->frames() - frames_filled);
 142       }
 143
 144       // Note: If this ever changes to output raw float the data must be clipped
 145       // and sanitized since it may come from an untrusted source such as NaCl.
 146       audio_bus_->Scale(volume_);
 147       audio_bus_->ToInterleaved(
 148           audio_bus_->frames(), params_.bits_per_sample() / 8, buffer);
 149     } else {
 150       memset(buffer, 0, bytes_to_fill);
 151     }
 152
 153     if (pa_stream_write(pa_stream_, buffer, bytes_to_fill, NULL, 0LL,
 154                         PA_SEEK_RELATIVE) < 0) {
 155       if (source_callback_) {
 156         source_callback_->OnError(this);
 157       }
 158     }
 159
 160     // NOTE: As mentioned above, |bytes_remaining| may be negative after this.
 161     bytes_remaining -= bytes_to_fill;
 162
 163     // Despite telling Pulse to only request certain buffer sizes, it will not
 164     // always obey.  In these cases we need to avoid back to back reads from
 165     // the renderer as it won't have time to complete the request.
 166     //
 167     // We can't defer the callback as Pulse will never call us again until we've
 168     // satisfied writing the requested number of bytes.
 169     //
 170     // TODO(dalecurtis): It might be worth choosing the sleep duration based on
 171     // the hardware latency return above.  Watch http://crbug.com/366433 to see
 172     // if a more complicated wait process is necessary.  We may also need to see
 173     // if a PostDelayedTask should be used here to avoid blocking the PulseAudio
 174     // command thread.
 175     if (source_callback_ && bytes_remaining > 0)
 176       base::PlatformThread::Sleep(params_.GetBufferDuration() / 4);
 177   }
 178 }
 179
 180 void PulseAudioOutputStream::Start(AudioSourceCallback* callback) {
 181   DCHECK(thread_checker_.CalledOnValidThread());
 182   CHECK(callback);
 183   CHECK(pa_stream_);
 184
 185   AutoPulseLock auto_lock(pa_mainloop_);
 186
 187   // Ensure the context and stream are ready.
 188   if (pa_context_get_state(pa_context_) != PA_CONTEXT_READY &&
 189       pa_stream_get_state(pa_stream_) != PA_STREAM_READY) {
 190     callback->OnError(this);
 191     return;
 192   }
 193
 194   source_callback_ = callback;
 195
 196   // Uncork (resume) the stream.
 197   pa_operation* operation = pa_stream_cork(
 198       pa_stream_, 0, &pulse::StreamSuccessCallback, pa_mainloop_);
 199   WaitForOperationCompletion(pa_mainloop_, operation);
 200 }
 201
 202 void PulseAudioOutputStream::Stop() {
 203   DCHECK(thread_checker_.CalledOnValidThread());
 204
 205   // Cork (pause) the stream.  Waiting for the main loop lock will ensure
 206   // outstanding callbacks have completed.
 207   AutoPulseLock auto_lock(pa_mainloop_);
 208
 209   // Set |source_callback_| to NULL so all FulfillWriteRequest() calls which may
 210   // occur while waiting on the flush and cork exit immediately.
 211   source_callback_ = NULL;
 212
 213   // Flush the stream prior to cork, doing so after will cause hangs.  Write
 214   // callbacks are suspended while inside pa_threaded_mainloop_lock() so this
 215   // is all thread safe.
 216   pa_operation* operation = pa_stream_flush(
 217       pa_stream_, &pulse::StreamSuccessCallback, pa_mainloop_);
 218   WaitForOperationCompletion(pa_mainloop_, operation);
 219
 220   operation = pa_stream_cork(pa_stream_, 1, &pulse::StreamSuccessCallback,
 221                              pa_mainloop_);
 222   WaitForOperationCompletion(pa_mainloop_, operation);
 223 }
 224
 225 void PulseAudioOutputStream::SetVolume(double volume) {
 226   DCHECK(thread_checker_.CalledOnValidThread());
 227
 228   volume_ = static_cast<float>(volume);
 229 }
 230
 231 void PulseAudioOutputStream::GetVolume(double* volume) {
 232   DCHECK(thread_checker_.CalledOnValidThread());
 233
 234   *volume = volume_;
 235 }
 236
 237 }  // namespace media