MediaRecorder: support sampling rate adaption in AudioTrackRecorder

content/renderer/media/audio_track_recorder_unittest.cc

Index: content/renderer/media/audio_track_recorder_unittest.cc
diff --git a/content/renderer/media/audio_track_recorder_unittest.cc b/content/renderer/media/audio_track_recorder_unittest.cc
index 07c0b5339e3ca15da2a6ac228eec662ccb14655c..2c5d23fb534be0631f1cbd15c5fdb9878fd4f1f5 100644
--- a/content/renderer/media/audio_track_recorder_unittest.cc
+++ b/content/renderer/media/audio_track_recorder_unittest.cc
@@ -31,14 +31,19 @@ using ::testing::ValuesIn;
 
 namespace {
 
-// Input audio format.
-const media::AudioParameters::Format kDefaultInputFormat =
-    media::AudioParameters::AUDIO_PCM_LOW_LATENCY;
 const int kDefaultBitsPerSample = 16;
 const int kDefaultSampleRate = 48000;
 // The |frames_per_buffer| field of AudioParameters is not used by ATR.
 const int kIgnoreFramesPerBuffer = 1;
-const int kOpusMaxBufferDurationMS = 120;
+
+// The following parameters replicate those in audio_track_recorder.cc, see this
+// file for explanations.
+const int kMediaStreamAudioTrackBufferDurationMs = 10;
+const int kOpusBufferDurationMs = 60;
+const int kRatioInputToOutputFrames =
+    kOpusBufferDurationMs / kMediaStreamAudioTrackBufferDurationMs;
+
+const int kFramesPerBuffer = kOpusBufferDurationMs * kDefaultSampleRate / 1000;
 
 }  // namespace
 
@@ -62,13 +67,32 @@ const ATRTestParams kATRTestParams[] = {
      kDefaultSampleRate,                            /* sample rate */
      kDefaultBitsPerSample},                        /* bits per sample */
     // Change to mono:
-    {media::AudioParameters::AUDIO_PCM_LOW_LATENCY, media::CHANNEL_LAYOUT_MONO,
-     kDefaultSampleRate, kDefaultBitsPerSample},
+    {media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
+     media::CHANNEL_LAYOUT_MONO,
+     kDefaultSampleRate,
+     kDefaultBitsPerSample},
     // Different sampling rate as well:
-    {media::AudioParameters::AUDIO_PCM_LOW_LATENCY, media::CHANNEL_LAYOUT_MONO,
-     24000, kDefaultBitsPerSample},
     {media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
-     media::CHANNEL_LAYOUT_STEREO, 8000, kDefaultBitsPerSample},
+      media::CHANNEL_LAYOUT_MONO,
+     24000,
+     kDefaultBitsPerSample},
+    {media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
+     media::CHANNEL_LAYOUT_STEREO,
+     8000,
+     kDefaultBitsPerSample},
+    // Using a non-default Opus sampling rate (48, 24, 16, 12, or 8 kHz).
+    {media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
+     media::CHANNEL_LAYOUT_MONO,
+     22050,
+     kDefaultBitsPerSample},
+    {media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
+     media::CHANNEL_LAYOUT_STEREO,
+     44100,
+     kDefaultBitsPerSample},
+    {media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
+     media::CHANNEL_LAYOUT_STEREO,
+     96000,
+     kDefaultBitsPerSample},
 };
 
 class AudioTrackRecorderTest : public TestWithParam<ATRTestParams> {
@@ -81,7 +105,7 @@ class AudioTrackRecorderTest : public TestWithParam<ATRTestParams> {
                       GetParam().sample_rate,
                       GetParam().bits_per_sample,
                       kIgnoreFramesPerBuffer),
-        second_params_(kDefaultInputFormat,
+        second_params_(media::AudioParameters::AUDIO_PCM_LOW_LATENCY,
                        media::CHANNEL_LAYOUT_STEREO,
                        kDefaultSampleRate,
                        kDefaultBitsPerSample,
@@ -104,9 +128,11 @@ class AudioTrackRecorderTest : public TestWithParam<ATRTestParams> {
   ~AudioTrackRecorderTest() {
     opus_decoder_destroy(opus_decoder_);
     opus_decoder_ = nullptr;
-    audio_track_recorder_.reset();
     blink_track_.reset();
     blink::WebHeap::collectAllGarbageForTesting();
+    audio_track_recorder_.reset();
+    // Let the message loop run to finish destroying the recorder properly.
+    base::RunLoop().RunUntilIdle();
   }
 
   void ResetDecoder(const media::AudioParameters& params) {
@@ -117,31 +143,25 @@ class AudioTrackRecorderTest : public TestWithParam<ATRTestParams> {
 
     int error;
     opus_decoder_ =
-        opus_decoder_create(params.sample_rate(), params.channels(), &error);
+        opus_decoder_create(kDefaultSampleRate, params.channels(), &error);
     EXPECT_TRUE(error == OPUS_OK && opus_decoder_);
 
-    max_frames_per_buffer_ =
-        kOpusMaxBufferDurationMS * params.sample_rate() / 1000;
-    buffer_.reset(new float[max_frames_per_buffer_ * params.channels()]);
+    buffer_.reset(new float[kFramesPerBuffer * params.channels()]);
   }
 
   scoped_ptr<media::AudioBus> GetFirstSourceAudioBus() {
     scoped_ptr<media::AudioBus> bus(media::AudioBus::Create(
-        first_params_.channels(),
-        first_params_.sample_rate() *
-            audio_track_recorder_->GetOpusBufferDuration(
-                first_params_.sample_rate()) /
-            1000));
+        first_params_.channels(), first_params_.sample_rate() *
+                                      kMediaStreamAudioTrackBufferDurationMs /
+                                      base::Time::kMillisecondsPerSecond));
     first_source_.OnMoreData(bus.get(), 0, 0);
     return bus;
   }
   scoped_ptr<media::AudioBus> GetSecondSourceAudioBus() {
     scoped_ptr<media::AudioBus> bus(media::AudioBus::Create(
-        second_params_.channels(),
-        second_params_.sample_rate() *
-            audio_track_recorder_->GetOpusBufferDuration(
-                second_params_.sample_rate()) /
-            1000));
+        second_params_.channels(), second_params_.sample_rate() *
+                                       kMediaStreamAudioTrackBufferDurationMs /
+                                       base::Time::kMillisecondsPerSecond));
     second_source_.OnMoreData(bus.get(), 0, 0);
     return bus;
   }
@@ -155,17 +175,13 @@ class AudioTrackRecorderTest : public TestWithParam<ATRTestParams> {
                       scoped_ptr<std::string> encoded_data,
                       base::TimeTicks timestamp) {
     EXPECT_TRUE(!encoded_data->empty());
-
     // Decode |encoded_data| and check we get the expected number of frames
     // per buffer.
-    EXPECT_EQ(
-        params.sample_rate() *
-            audio_track_recorder_->GetOpusBufferDuration(params.sample_rate()) /
-            1000,
-        opus_decode_float(
-            opus_decoder_,
-            reinterpret_cast<uint8_t*>(string_as_array(encoded_data.get())),
-            encoded_data->size(), buffer_.get(), max_frames_per_buffer_, 0));
+    EXPECT_EQ(kDefaultSampleRate * kOpusBufferDurationMs / 1000,
+              opus_decode_float(
+                  opus_decoder_, reinterpret_cast<uint8_t*>(
+                                     string_as_array(encoded_data.get())),
+                  encoded_data->size(), buffer_.get(), kFramesPerBuffer, 0));
 
     DoOnEncodedAudio(params, *encoded_data, timestamp);
   }
@@ -186,7 +202,6 @@ class AudioTrackRecorderTest : public TestWithParam<ATRTestParams> {
 
   // Decoder for verifying data was properly encoded.
   OpusDecoder* opus_decoder_;
-  int max_frames_per_buffer_;
   scoped_ptr<float[]> buffer_;
 
  private:
@@ -223,30 +238,49 @@ TEST_P(AudioTrackRecorderTest, OnData) {
 
   // Give ATR initial audio parameters.
   audio_track_recorder_->OnSetFormat(first_params_);
+
   // TODO(ajose): consider adding WillOnce(SaveArg...) and inspecting, as done
   // in VTR unittests. http://crbug.com/548856
-  const base::TimeTicks time1 = base::TimeTicks::Now();
-  EXPECT_CALL(*this, DoOnEncodedAudio(_, _, time1)).Times(1);
-  audio_track_recorder_->OnData(*GetFirstSourceAudioBus(), time1);
+  EXPECT_CALL(*this, DoOnEncodedAudio(_, _, _)).Times(1);
+  audio_track_recorder_->OnData(*GetFirstSourceAudioBus(),
+                                base::TimeTicks::Now());
+  for (int i = 0; i < kRatioInputToOutputFrames - 1; ++i) {
+    audio_track_recorder_->OnData(*GetFirstSourceAudioBus(),
+                                  base::TimeTicks::Now());
+  }
 
-  // Send more audio.
-  const base::TimeTicks time2 = base::TimeTicks::Now();
   EXPECT_CALL(*this, DoOnEncodedAudio(_, _, _))
       .Times(1)
       // Only reset the decoder once we've heard back:
       .WillOnce(RunClosure(base::Bind(&AudioTrackRecorderTest::ResetDecoder,
                                       base::Unretained(this), second_params_)));
-  audio_track_recorder_->OnData(*GetFirstSourceAudioBus(), time2);
+  audio_track_recorder_->OnData(*GetFirstSourceAudioBus(),
+                                base::TimeTicks::Now());
+  for (int i = 0; i < kRatioInputToOutputFrames - 1; ++i) {
+    audio_track_recorder_->OnData(*GetFirstSourceAudioBus(),
+                                  base::TimeTicks::Now());
+  }
+
+  // If the amount of samples/10ms buffer is not an integer (e.g. 22050Hz) we
+  // need an extra OnData() to account for the round-off error.
+  if (GetParam().sample_rate % 100) {
+    audio_track_recorder_->OnData(*GetFirstSourceAudioBus(),
+                                  base::TimeTicks::Now());
+  }
 
   // Give ATR new audio parameters.
   audio_track_recorder_->OnSetFormat(second_params_);
 
   // Send audio with different params.
-  const base::TimeTicks time3 = base::TimeTicks::Now();
   EXPECT_CALL(*this, DoOnEncodedAudio(_, _, _))
       .Times(1)
       .WillOnce(RunClosure(quit_closure));
-  audio_track_recorder_->OnData(*GetSecondSourceAudioBus(), time3);
+  audio_track_recorder_->OnData(*GetSecondSourceAudioBus(),
+                                base::TimeTicks::Now());
+  for (int i = 0; i < kRatioInputToOutputFrames - 1; ++i) {
+    audio_track_recorder_->OnData(*GetSecondSourceAudioBus(),
+                                  base::TimeTicks::Now());
+  }
 
   run_loop.Run();
   Mock::VerifyAndClearExpectations(this);