1 files changed, 177 insertions, 0 deletions
diff --git a/dom/media/gtest/TestAudioMixer.cpp b/dom/media/gtest/TestAudioMixer.cpp
new file mode 100644
index 0000000000..2b1b5cd6a8
--- /dev/null
+++ b/dom/media/gtest/TestAudioMixer.cpp
@@ -0,0 +1,177 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this file,
+ * You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "AudioMixer.h"
+#include "gtest/gtest.h"
+
+using mozilla::AudioDataValue;
+using mozilla::AudioSampleFormat;
+
+namespace audio_mixer {
+
+struct MixerConsumer : public mozilla::MixerCallbackReceiver {
+  /* In this test, the different audio stream and channels are always created to
+   * cancel each other. */
+  void MixerCallback(mozilla::AudioChunk* aMixedBuffer, uint32_t aSampleRate) {
+    bool silent = true;
+    ASSERT_EQ(aMixedBuffer->mBufferFormat, mozilla::AUDIO_FORMAT_FLOAT32);
+    for (uint32_t c = 0; c < aMixedBuffer->ChannelCount(); c++) {
+      const float* channelData = aMixedBuffer->ChannelData<AudioDataValue>()[c];
+      for (uint32_t i = 0; i < aMixedBuffer->mDuration; i++) {
+        if (channelData[i] != 0.0) {
+          fprintf(stderr, "Sample at %d in channel %c is not silent: %f\n", i,
+                  c, channelData[i]);
+          silent = false;
+        }
+      }
+    }
+    ASSERT_TRUE(silent);
+  }
+};
+
+/* Helper function to give us the maximum and minimum value that don't clip,
+ * for a given sample format (integer or floating-point). */
+template <typename T>
+T GetLowValue();
+
+template <typename T>
+T GetHighValue();
+
+template <>
+float GetLowValue<float>() {
+  return -1.0;
+}
+
+template <>
+short GetLowValue<short>() {
+  return -INT16_MAX;
+}
+
+template <>
+float GetHighValue<float>() {
+  return 1.0;
+}
+
+template <>
+short GetHighValue<short>() {
+  return INT16_MAX;
+}
+
+void FillBuffer(AudioDataValue* aBuffer, uint32_t aLength,
+                AudioDataValue aValue) {
+  AudioDataValue* end = aBuffer + aLength;
+  while (aBuffer != end) {
+    *aBuffer++ = aValue;
+  }
+}
+
+TEST(AudioMixer, Test)
+{
+  const uint32_t CHANNEL_LENGTH = 256;
+  const uint32_t AUDIO_RATE = 44100;
+  MixerConsumer consumer;
+  AudioDataValue a[CHANNEL_LENGTH * 2];
+  AudioDataValue b[CHANNEL_LENGTH * 2];
+  FillBuffer(a, CHANNEL_LENGTH, GetLowValue<AudioDataValue>());
+  FillBuffer(a + CHANNEL_LENGTH, CHANNEL_LENGTH,
+             GetHighValue<AudioDataValue>());
+  FillBuffer(b, CHANNEL_LENGTH, GetHighValue<AudioDataValue>());
+  FillBuffer(b + CHANNEL_LENGTH, CHANNEL_LENGTH, GetLowValue<AudioDataValue>());
+
+  {
+    int iterations = 2;
+    mozilla::AudioMixer mixer;
+
+    fprintf(stderr, "Test AudioMixer constant buffer length.\n");
+
+    while (iterations--) {
+      mixer.StartMixing();
+      mixer.Mix(a, 2, CHANNEL_LENGTH, AUDIO_RATE);
+      mixer.Mix(b, 2, CHANNEL_LENGTH, AUDIO_RATE);
+      consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+    }
+  }
+
+  {
+    mozilla::AudioMixer mixer;
+
+    fprintf(stderr, "Test AudioMixer variable buffer length.\n");
+
+    FillBuffer(a, CHANNEL_LENGTH / 2, GetLowValue<AudioDataValue>());
+    FillBuffer(a + CHANNEL_LENGTH / 2, CHANNEL_LENGTH / 2,
+               GetLowValue<AudioDataValue>());
+    FillBuffer(b, CHANNEL_LENGTH / 2, GetHighValue<AudioDataValue>());
+    FillBuffer(b + CHANNEL_LENGTH / 2, CHANNEL_LENGTH / 2,
+               GetHighValue<AudioDataValue>());
+    mixer.StartMixing();
+    mixer.Mix(a, 2, CHANNEL_LENGTH / 2, AUDIO_RATE);
+    mixer.Mix(b, 2, CHANNEL_LENGTH / 2, AUDIO_RATE);
+    consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+    FillBuffer(a, CHANNEL_LENGTH, GetLowValue<AudioDataValue>());
+    FillBuffer(a + CHANNEL_LENGTH, CHANNEL_LENGTH,
+               GetHighValue<AudioDataValue>());
+    FillBuffer(b, CHANNEL_LENGTH, GetHighValue<AudioDataValue>());
+    FillBuffer(b + CHANNEL_LENGTH, CHANNEL_LENGTH,
+               GetLowValue<AudioDataValue>());
+    mixer.StartMixing();
+    mixer.Mix(a, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    mixer.Mix(b, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+    FillBuffer(a, CHANNEL_LENGTH / 2, GetLowValue<AudioDataValue>());
+    FillBuffer(a + CHANNEL_LENGTH / 2, CHANNEL_LENGTH / 2,
+               GetLowValue<AudioDataValue>());
+    FillBuffer(b, CHANNEL_LENGTH / 2, GetHighValue<AudioDataValue>());
+    FillBuffer(b + CHANNEL_LENGTH / 2, CHANNEL_LENGTH / 2,
+               GetHighValue<AudioDataValue>());
+    mixer.StartMixing();
+    mixer.Mix(a, 2, CHANNEL_LENGTH / 2, AUDIO_RATE);
+    mixer.Mix(b, 2, CHANNEL_LENGTH / 2, AUDIO_RATE);
+    consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+  }
+
+  FillBuffer(a, CHANNEL_LENGTH, GetLowValue<AudioDataValue>());
+  FillBuffer(b, CHANNEL_LENGTH, GetHighValue<AudioDataValue>());
+
+  {
+    mozilla::AudioMixer mixer;
+
+    fprintf(stderr, "Test AudioMixer variable channel count.\n");
+
+    mixer.StartMixing();
+    mixer.Mix(a, 1, CHANNEL_LENGTH, AUDIO_RATE);
+    mixer.Mix(b, 1, CHANNEL_LENGTH, AUDIO_RATE);
+    consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+    mixer.StartMixing();
+    mixer.Mix(a, 1, CHANNEL_LENGTH, AUDIO_RATE);
+    mixer.Mix(b, 1, CHANNEL_LENGTH, AUDIO_RATE);
+    consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+    mixer.StartMixing();
+    mixer.Mix(a, 1, CHANNEL_LENGTH, AUDIO_RATE);
+    mixer.Mix(b, 1, CHANNEL_LENGTH, AUDIO_RATE);
+    consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+  }
+
+  {
+    mozilla::AudioMixer mixer;
+    fprintf(stderr, "Test AudioMixer variable stream count.\n");
+
+    mixer.StartMixing();
+    mixer.Mix(a, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    mixer.Mix(b, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+    mixer.StartMixing();
+    mixer.Mix(a, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    mixer.Mix(b, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    mixer.Mix(a, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    mixer.Mix(b, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+    mixer.StartMixing();
+    mixer.Mix(a, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    mixer.Mix(b, 2, CHANNEL_LENGTH, AUDIO_RATE);
+    consumer.MixerCallback(mixer.MixedChunk(), AUDIO_RATE);
+  }
+}
+
+}  // namespace audio_mixer