MediaRecorder: support sampling rate adaption in AudioTrackRecorder

content/renderer/media/media_recorder_handler_unittest.cc

Index: content/renderer/media/media_recorder_handler_unittest.cc
diff --git a/content/renderer/media/media_recorder_handler_unittest.cc b/content/renderer/media/media_recorder_handler_unittest.cc
index 4a92b223b26d5d55755dd62eeadb3999f94916b6..0769a263b2ec746e2358e28fbd3a5c18682f5606 100644
--- a/content/renderer/media/media_recorder_handler_unittest.cc
+++ b/content/renderer/media/media_recorder_handler_unittest.cc
@@ -41,7 +41,11 @@ static const std::string kTestAudioTrackId = "audio_track_id";
 static const int kTestAudioChannels = 2;
 static const int kTestAudioBitsPerSample = 16;
 static const int kTestAudioSampleRate = 48000;
-static const int kTestAudioBufferDurationMS = 60;
+// MediaStream Audio Track always provides audio in chunks of 10 ms.
+static const int kMediaStreamAudioTrackBufferDurationMs = 10;
+// Opus works with 60ms buffers, so 6 MediaStreamAudioTrack Buffers are needed
+// to encode one output buffer.
+static const int kRatioOpusToMediaStreamTrackBuffers = 6;
 
 struct MediaRecorderTestParams {
   const bool has_video;
@@ -59,7 +63,7 @@ struct MediaRecorderTestParams {
 static const MediaRecorderTestParams kMediaRecorderTestParams[] = {
     {true, false, "video/webm", "vp8", 52, 32, 0, 0},
     {true, false, "video/webm", "vp9", 33, 18, 0, 0},
-    {false, true, "video/webm", "vp8", 0, 0, 990, 706}};
+    {false, true, "video/webm", "vp8", 0, 0, 996, 746}};
 
 class MediaRecorderHandlerTest : public TestWithParam<MediaRecorderTestParams>,
                                  public blink::WebMediaRecorderHandlerClient {
@@ -113,7 +117,7 @@ class MediaRecorderHandlerTest : public TestWithParam<MediaRecorderTestParams>,
   scoped_ptr<media::AudioBus> NextAudioBus() {
     scoped_ptr<media::AudioBus> bus(media::AudioBus::Create(
         kTestAudioChannels,
-        kTestAudioSampleRate * kTestAudioBufferDurationMS / 1000));
+        kTestAudioSampleRate * kMediaStreamAudioTrackBufferDurationMs / 1000));
     audio_source_.OnMoreData(bus.get(), 0, 0);
     return bus;
   }
@@ -284,7 +288,7 @@ TEST_P(MediaRecorderHandlerTest, EncodeAudioFrames) {
   media::AudioParameters params(
       media::AudioParameters::AUDIO_PCM_LINEAR, media::CHANNEL_LAYOUT_STEREO,
       kTestAudioSampleRate, kTestAudioBitsPerSample,
-      kTestAudioSampleRate * kTestAudioBufferDurationMS / 1000);
+      kTestAudioSampleRate * kMediaStreamAudioTrackBufferDurationMs / 1000);
   SetAudioFormatForTesting(params);
 
   {
@@ -298,7 +302,8 @@ TEST_P(MediaRecorderHandlerTest, EncodeAudioFrames) {
         .Times(1)
         .WillOnce(RunClosure(quit_closure));
 
-    OnAudioBusForTesting(*audio_bus1);
+    for (int i = 0; i < kRatioOpusToMediaStreamTrackBuffers; ++i)
+      OnAudioBusForTesting(*audio_bus1);
     run_loop.Run();
   }
 
@@ -315,7 +320,8 @@ TEST_P(MediaRecorderHandlerTest, EncodeAudioFrames) {
         .Times(1)
         .WillOnce(RunClosure(quit_closure));
 
-    OnAudioBusForTesting(*audio_bus2);
+    for (int i = 0; i < kRatioOpusToMediaStreamTrackBuffers; ++i)
+      OnAudioBusForTesting(*audio_bus2);
     run_loop.Run();
   }