commit b09aac27a243546e6ccf11596e66c56d07327af1
author Linus Nilsson <lnilsson@google.com> Wed Jul 29 11:56:53 2020 -0700
committer Linus Nilsson <lnilsson@google.com> Thu Jul 30 12:54:16 2020 -0700
tree 79cfe87cd672d1b2ed680a276c43bef2dcdf9954
parent 8f0b876fc10fecd817aa1f6a69646d9ce049e26a

Transcoder: Improve video transcoding with audio passthrough performance

MediaSampleWriter was stalling the video transcoding when processing
chunks of audio samples at a time. Since the underlying muxer
buffers ~1 sec worth of data and interleaves tracks anyway the
sample writer now prioritizes pulling samples from the track that is
farthest behind while making sure the tracks are kept reasonably
in sync, i.e. max ~1 second divergence.

This change also raises the priority of the video transcoding thread
since that will be the bottleneck when audio is pased through.

Test: Unit tests
Fixes: 160268606
Change-Id: I004583b2a31a57882ea543072be321f9f1347508

media/libmediatranscoding/transcoder/tests/MediaSampleQueueTests.cpp

diff --git a/media/libmediatranscoding/transcoder/tests/MediaSampleQueueTests.cpp b/media/libmediatranscoding/transcoder/tests/MediaSampleQueueTests.cpp
index 2046ca0..6357e4d 100644
--- a/media/libmediatranscoding/transcoder/tests/MediaSampleQueueTests.cpp
+++ b/media/libmediatranscoding/transcoder/tests/MediaSampleQueueTests.cpp
@@ -46,10 +46,12 @@
 
     static constexpr int kNumSamples = 4;
     MediaSampleQueue sampleQueue;
+    EXPECT_TRUE(sampleQueue.isEmpty());
 
     // Enqueue loop.
     for (int i = 0; i < kNumSamples; ++i) {
         sampleQueue.enqueue(newSample(i));
+        EXPECT_FALSE(sampleQueue.isEmpty());
     }
 
     // Dequeue loop.
@@ -60,6 +62,7 @@
         EXPECT_EQ(sample->bufferId, i);
         EXPECT_FALSE(aborted);
     }
+    EXPECT_TRUE(sampleQueue.isEmpty());
 }
 
 TEST_F(MediaSampleQueueTests, TestInterleavedDequeueOrder) {
@@ -71,12 +74,14 @@
     // Enqueue and dequeue.
     for (int i = 0; i < kNumSamples; ++i) {
         sampleQueue.enqueue(newSample(i));
+        EXPECT_FALSE(sampleQueue.isEmpty());
 
         std::shared_ptr<MediaSample> sample;
         bool aborted = sampleQueue.dequeue(&sample);
         EXPECT_NE(sample, nullptr);
         EXPECT_EQ(sample->bufferId, i);
         EXPECT_FALSE(aborted);
+        EXPECT_TRUE(sampleQueue.isEmpty());
     }
 }
 
@@ -98,6 +103,7 @@
     EXPECT_NE(sample, nullptr);
     EXPECT_EQ(sample->bufferId, 1);
     EXPECT_FALSE(aborted);
+    EXPECT_TRUE(sampleQueue.isEmpty());
 
     enqueueThread.join();
 }
@@ -160,7 +166,9 @@
         EXPECT_FALSE(bufferReleased[i]);
     }
 
+    EXPECT_FALSE(sampleQueue.isEmpty());
     sampleQueue.abort();
+    EXPECT_TRUE(sampleQueue.isEmpty());
 
     for (int i = 0; i < kNumSamples; ++i) {
         EXPECT_TRUE(bufferReleased[i]);