Implement disabling and enabling media tracks

media/test/pipeline_integration_test.cc

 // Copyright (c) 2012 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 <stddef.h>
 #include <stdint.h>
 
 #include <memory>
 #include <utility>
 
@@ skipping 926 matching lines @@
 
   Play();
 
   ASSERT_TRUE(WaitUntilOnEnded());
 
   EXPECT_HASH_EQ("f0be120a90a811506777c99a2cdf7cc1", GetVideoHash());
   EXPECT_HASH_EQ("-3.59,-2.06,-0.43,2.15,0.77,-0.95,", GetAudioHash());
   EXPECT_TRUE(demuxer_->GetTimelineOffset().is_null());
 }
 
+TEST_F(PipelineIntegrationTest, PlaybackWithAudioTrackDisabledThenEnabled) {
+  ASSERT_EQ(PIPELINE_OK, Start("bear-320x240.webm", kHashed));
+
+  // Disable audio.
+  std::vector<MediaTrack::Id> empty;
+  pipeline_->OnEnabledAudioTracksChanged(empty);
+  message_loop_.RunUntilIdle();
+
+  // Seek to flush the pipeline and ensure there's no prerolled audio data.
+  ASSERT_TRUE(Seek(base::TimeDelta::FromSeconds(0)));
+
+  Play();
+  const base::TimeDelta k500ms = base::TimeDelta::FromMilliseconds(500);
+  ASSERT_TRUE(WaitUntilCurrentTimeIsAfter(k500ms));
+  Pause();
+
+  // Verify that no audio has been rendered, since we disabled audio tracks.
+  EXPECT_HASH_EQ(kNullAudioHash, GetAudioHash());
+
+  // Re-enable audio.
+  std::vector<MediaTrack::Id> audioTrackId;
+  audioTrackId.push_back("2");
+  pipeline_->OnEnabledAudioTracksChanged(audioTrackId);
+  message_loop_.RunUntilIdle();
+
+  // Restart playback from 500ms position.
+  ASSERT_TRUE(Seek(k500ms));
+  Play();
+  ASSERT_TRUE(WaitUntilOnEnded());
+
+  // Verify that audio has been rendered after being enabled.
+  EXPECT_HASH_EQ("-1.53,0.21,1.23,1.56,-0.34,-0.94,", GetAudioHash());
+}
+
+TEST_F(PipelineIntegrationTest, PlaybackWithVideoTrackDisabledThenEnabled) {
+  ASSERT_EQ(PIPELINE_OK, Start("bear-320x240.webm", kHashed));
+
+  // Disable video.
+  std::vector<MediaTrack::Id> empty;
+  pipeline_->OnSelectedVideoTrackChanged(empty);
+  message_loop_.RunUntilIdle();
+
+  // Seek to flush the pipeline and ensure there's no prerolled video data.
+  ASSERT_TRUE(Seek(base::TimeDelta::FromSeconds(0)));
+
+  // Reset the video hash in case some of the prerolled video frames have been
+  // hashed already.
+  ResetVideoHash();
+
+  Play();
+  const base::TimeDelta k500ms = base::TimeDelta::FromMilliseconds(500);
+  ASSERT_TRUE(WaitUntilCurrentTimeIsAfter(k500ms));
+  Pause();
+
+  // Verify that no audio has been rendered, since we disabled audio tracks.
+  EXPECT_HASH_EQ(kNullVideoHash, GetVideoHash());
+
+  // Re-enable video.
+  std::vector<MediaTrack::Id> videoTrackId;
+  videoTrackId.push_back("1");
+  pipeline_->OnSelectedVideoTrackChanged(videoTrackId);
+  message_loop_.RunUntilIdle();
+
+  // Seek to flush video pipeline and reset the video hash again to clear state
+  // if some prerolled frames got hashed after enabling video.
+  ASSERT_TRUE(Seek(base::TimeDelta()));
+  ResetVideoHash();
+
+  // Restart playback from 500ms position.
+  ASSERT_TRUE(Seek(k500ms));
+  Play();
+  ASSERT_TRUE(WaitUntilOnEnded());
+
+  // Verify that video has been rendered after being enabled.
+  EXPECT_HASH_EQ("fd59357dfd9c144ab4fb8181b2de32c3", GetVideoHash());

[chcunningham, 2016/06/29 22:58:29]

Make sure you run these 10 times or so on your local machine. I've hit bugs
where checking a hash after a seek is not reliable. See http://crbug.com/583190
(though it may just be the mp3 demuxer... not sure).

[servolk, 2016/06/29 23:40:13]

Yes, my first attempts were also flaky at first, since I didn't take into
account that video preroll might result in video frames being processed (hashed)
even before playback is started. That's why I had to introduce those extra seeks
and ResetVideoHash. Now it's been stable, I ran those tests individually and as
part of the whole media_unittests suite about ~20 times now and haven't seen a
single failure.

+}
+
 TEST_F(PipelineIntegrationTest,
        MAYBE_CLOCKLESS(BasicPlaybackOpusOggTrimmingHashed)) {
   ASSERT_EQ(PIPELINE_OK,
             Start("opus-trimming-test.webm", kHashed | kClockless));
 
   Play();
 
   ASSERT_TRUE(WaitUntilOnEnded());
   EXPECT_HASH_EQ(kOpusEndTrimmingHash_1, GetAudioHash());
 
@@ skipping 1364 matching lines @@
 
 TEST_F(PipelineIntegrationTest, BasicPlaybackPositiveStartTime) {
   ASSERT_EQ(PIPELINE_OK, Start("nonzero-start-time.webm"));
   Play();
   ASSERT_TRUE(WaitUntilOnEnded());
   ASSERT_EQ(base::TimeDelta::FromMicroseconds(396000),
             demuxer_->GetStartTime());
 }
 
 }  // namespace media