Adding cbr support for Opus

webrtc/modules/audio_coding/codecs/opus/opus_unittest.cc

Index: webrtc/modules/audio_coding/codecs/opus/opus_unittest.cc
diff --git a/webrtc/modules/audio_coding/codecs/opus/opus_unittest.cc b/webrtc/modules/audio_coding/codecs/opus/opus_unittest.cc
index febea2f869fe7ca94897015ac2d35df7219233b7..3e0fc7c61ff6de1c0757b2c0aadcf4093a675999 100644
--- a/webrtc/modules/audio_coding/codecs/opus/opus_unittest.cc
+++ b/webrtc/modules/audio_coding/codecs/opus/opus_unittest.cc
@@ -40,6 +40,8 @@ class OpusTest : public TestWithParam<::testing::tuple<int, int>> {
 
   void TestDtxEffect(bool dtx, int block_length_ms);
 
+  void TestCbrEffect(bool dtx, int block_length_ms);
+
   // Prepare |speech_data_| for encoding, read from a hard-coded file.
   // After preparation, |speech_data_.GetNextBlock()| returns a pointer to a
   // block of |block_length_ms| milliseconds. The data is looped every
@@ -300,6 +302,52 @@ void OpusTest::TestDtxEffect(bool dtx, int block_length_ms) {
   EXPECT_EQ(0, WebRtcOpus_DecoderFree(opus_decoder_));
 }
 
+// Test if CBR does what we expect.
+void OpusTest::TestCbrEffect(bool cbr, int block_length_ms) {
+  PrepareSpeechData(channels_, block_length_ms, 2000);
+  const size_t samples = kOpusRateKhz * block_length_ms;
+
+  int32_t max_pkt_size_diff = 0;
+  int32_t prev_pkt_size = 0;
+
+  // Create encoder memory.
+  EXPECT_EQ(0,
+            WebRtcOpus_EncoderCreate(&opus_encoder_, channels_, application_));
+  EXPECT_EQ(0, WebRtcOpus_DecoderCreate(&opus_decoder_, channels_));
+
+  // Set bitrate.
+  EXPECT_EQ(
+      0, WebRtcOpus_SetBitRate(opus_encoder_, channels_ == 1 ? 32000 : 64000));
+
+  // Setting CBR.
+  EXPECT_EQ(0, cbr ? WebRtcOpus_EnableCbr(opus_encoder_)
+                   : WebRtcOpus_DisableCbr(opus_encoder_));
+
+  int16_t audio_type;
+  std::vector<int16_t> audio_out(samples * channels_);
+  for (int i = 0; i < 100; ++i) {
+    EXPECT_EQ(samples, static_cast<size_t>(EncodeDecode(
+                           opus_encoder_, speech_data_.GetNextBlock(),
+                           opus_decoder_, audio_out.data(), &audio_type)));
+
+    if (prev_pkt_size > 0) {
+      int32_t diff = std::abs((int32_t)encoded_bytes_ - prev_pkt_size);
+      max_pkt_size_diff = std::max(max_pkt_size_diff, diff);
+    }
+    prev_pkt_size = encoded_bytes_;
+  }
+
+  if (cbr) {
+    EXPECT_EQ(max_pkt_size_diff, 0);
+  } else {
+    EXPECT_GT(max_pkt_size_diff, 0);
+  }
+
+  // Free memory.
+  EXPECT_EQ(0, WebRtcOpus_EncoderFree(opus_encoder_));
+  EXPECT_EQ(0, WebRtcOpus_DecoderFree(opus_decoder_));
+}
+
 // Test failing Create.
 TEST(OpusTest, OpusCreateFail) {
   WebRtcOpusEncInst* opus_encoder;
@@ -525,6 +573,18 @@ TEST_P(OpusTest, OpusDtxOn) {
   TestDtxEffect(true, 40);
 }
 
+TEST_P(OpusTest, OpusCbrOff) {
+  TestCbrEffect(false, 10);
+  TestCbrEffect(false, 20);
+  TestCbrEffect(false, 40);
+}
+
+TEST_P(OpusTest, OpusCbrOn) {
+  TestCbrEffect(true, 10);
+  TestCbrEffect(true, 20);
+  TestCbrEffect(true, 40);
+}
+
 TEST_P(OpusTest, OpusSetPacketLossRate) {
   // Test without creating encoder memory.
   EXPECT_EQ(-1, WebRtcOpus_SetPacketLossRate(opus_encoder_, 50));