Introduce media::AudioPushFifo and a couple of use cases (and clean-ups).

media/base/audio_rechunker_unittest.cc

+// Copyright 2016 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 <limits>
+#include <vector>
+
+#include "base/bind.h"
+#include "base/bind_helpers.h"
+#include "base/macros.h"
+#include "media/base/audio_bus.h"
+#include "media/base/audio_rechunker.h"
+#include "testing/gtest/include/gtest/gtest.h"
+
+namespace media {
+
+namespace {
+
+struct TestParams {
+  int64_t duration_us;
+  int sample_rate;
+  int output_chunk_size;
+  bool expect_evenly_divided;
+  TestParams(int64_t d, int s, int e, bool e2)
+      : duration_us(d),
+        sample_rate(s),
+        output_chunk_size(e),
+        expect_evenly_divided(e2) {}
+};
+
+class AudioRechunkerTest : public testing::TestWithParam<TestParams> {
+ public:
+  AudioRechunkerTest() {}
+  ~AudioRechunkerTest() override {}
+
+  void SetUp() final {
+    rechunker_.reset(new AudioRechunker(
+        output_duration(),
+        base::Bind(&AudioRechunkerTest::ReceiveAndCheckNextChunk,
+                   base::Unretained(this))));
+    ASSERT_EQ(GetParam().expect_evenly_divided,
+              rechunker_->SetSampleRate(GetParam().sample_rate));
+    ASSERT_EQ(GetParam().output_chunk_size, rechunker_->output_frames());
+  }
+
+ protected:
+  struct OutputChunkResult {
+    int num_frames;
+    base::TimeDelta reference_timestamp;
+    float first_sample_value;
+    float last_sample_value;
+  };
+
+  base::TimeDelta output_duration() const {
+    return base::TimeDelta::FromMicroseconds(GetParam().duration_us);
+  }
+
+  // Returns the number of output chunks that should have been emitted given the
+  // number of input frames pushed so far.
+  size_t GetExpectedOutputChunks(int frames_pushed) const {
+    return static_cast<size_t>(frames_pushed / GetParam().output_chunk_size);
+  }
+
+  // Returns the number of Push() calls to make in order to get at least 3
+  // output chunks.
+  int GetNumPushTestIterations(int input_chunk_size) const {
+    return 3 * std::max(1, GetParam().output_chunk_size / input_chunk_size);
+  }
+
+  // Repeatedly pushes constant-sized batches of input samples and checks that
+  // the input data is re-chunked correctly.
+  void RunSimpleRechunkTest(int input_chunk_size) {
+    const int num_iterations = GetNumPushTestIterations(input_chunk_size);
+
+    int sample_value = 0;
+    const scoped_ptr<AudioBus> audio_bus =
+        AudioBus::Create(1, input_chunk_size);
+
+    for (int i = 0; i < num_iterations; ++i) {
+      EXPECT_EQ(GetExpectedOutputChunks(i * input_chunk_size), results_.size());
+
+      // Fill audio data with predictable values.
+      for (int j = 0; j < audio_bus->frames(); ++j)
+        audio_bus->channel(0)[j] = static_cast<float>(sample_value++);
+
+      rechunker_->Push(*audio_bus, base::TimeDelta::FromMicroseconds(
+                                       i * input_chunk_size * INT64_C(1000000) /
+                                       GetParam().sample_rate));
+      // Note: Rechunker has just called ReceiveAndCheckNextChunk() zero or more
+      // times.
+    }
+    EXPECT_EQ(GetExpectedOutputChunks(num_iterations * input_chunk_size),
+              results_.size());
+
+    ASSERT_FALSE(results_.empty());
+    EXPECT_EQ(0.0f, results_.front().first_sample_value);
+    const float last_value_in_last_chunk = static_cast<float>(
+        GetExpectedOutputChunks(num_iterations * input_chunk_size) *
+            GetParam().output_chunk_size -
+        1);
+    EXPECT_EQ(last_value_in_last_chunk, results_.back().last_sample_value);
+  }
+
+  // Returns a "random" integer in the range [begin,end).
+  int GetRandomInRange(int begin, int end) {
+    const int len = end - begin;
+    const int rand_offset = (len == 0) ? 0 : (NextRandomInt() % (end - begin));
+    return begin + rand_offset;
+  }
+
+  scoped_ptr<AudioRechunker> rechunker_;
+  std::vector<OutputChunkResult> results_;
+
+ private:
+  // Called by |rechunker_| to deliver another chunk of audio.  Sanity checks
+  // the sample values are as expected, and without any dropped/duplicated, and
+  // adds a result to |results_|.
+  void ReceiveAndCheckNextChunk(const AudioBus& audio_bus,
+                                base::TimeDelta reference_timestamp) {
+    OutputChunkResult result;
+    result.num_frames = audio_bus.frames();
+    result.reference_timestamp = reference_timestamp;
+    result.first_sample_value = audio_bus.channel(0)[0];
+    result.last_sample_value = audio_bus.channel(0)[audio_bus.frames() - 1];
+
+    // Check that each sample value is the previous sample value plus one.
+    for (int i = 1; i < audio_bus.frames(); ++i) {
+      ASSERT_EQ(result.first_sample_value + i, audio_bus.channel(0)[i])
+          << "Sample at offset " << i << " is incorrect.";
+    }
+
+    // Check that no audio samples were dropped, and that the reference
+    // timestamps are monotonically increasing.
+    if (!results_.empty()) {
+      const OutputChunkResult& last_result = results_.back();
+      ASSERT_EQ(last_result.last_sample_value + 1, result.first_sample_value);
+      ASSERT_LT(last_result.reference_timestamp, result.reference_timestamp);
+    }
+
+    results_.push_back(result);
+  }
+
+  // Note: Not using base::RandInt() because it is horribly slow on debug
+  // builds.  The following is a very simple, deterministic LCG:
+  int NextRandomInt() {
+    rand_seed_ = (1103515245 * rand_seed_ + 12345) % (1 << 31);
+    return static_cast<int>(rand_seed_);
+  }
+
+  uint32_t rand_seed_ = 0x7e110;
+
+  DISALLOW_COPY_AND_ASSIGN(AudioRechunkerTest);
+};
+
+// Tests an atypical edge case: Push()ing one frame at a time.
+TEST_P(AudioRechunkerTest, PushOneFrameAtATime) {
+  RunSimpleRechunkTest(1);
+}
+
+// Tests that re-chunking the audio from common platform input chunk sizes
+// works.
+TEST_P(AudioRechunkerTest, Push128FramesAtATime) {
+  RunSimpleRechunkTest(128);
+}
+TEST_P(AudioRechunkerTest, Push512FramesAtATime) {
+  RunSimpleRechunkTest(512);
+}
+
+// Tests that re-chunking the audio from common "10 ms" input chunk sizes
+// works (44100 Hz * 10 ms = 441, and 48000 Hz * 10 ms = 480).
+TEST_P(AudioRechunkerTest, Push441FramesAtATime) {
+  RunSimpleRechunkTest(441);
+}
+TEST_P(AudioRechunkerTest, Push480FramesAtATime) {
+  RunSimpleRechunkTest(480);
+}
+
+// Tests that re-chunking when input audio is provided in varying chunk sizes
+// works.
+TEST_P(AudioRechunkerTest, PushArbitraryNumbersOfFramesAtATime) {
+  // The loop below will run until both: 1) kMinNumIterations loops have
+  // occurred; and 2) there are at least 3 entries in |results_|.
+  const int kMinNumIterations = 30;
+
+  int sample_value = 0;
+  int frames_pushed_so_far = 0;
+  for (int i = 0; i < kMinNumIterations || results_.size() < 3; ++i) {
+    EXPECT_EQ(GetExpectedOutputChunks(frames_pushed_so_far), results_.size());
+
+    // Create an AudioBus of a random length, populated with sample values.
+    const int input_chunk_size = GetRandomInRange(1, 1920);
+    const scoped_ptr<AudioBus> audio_bus =
+        AudioBus::Create(1, input_chunk_size);
+    for (int j = 0; j < audio_bus->frames(); ++j)
+      audio_bus->channel(0)[j] = static_cast<float>(sample_value++);
+
+    rechunker_->Push(*audio_bus, base::TimeDelta::FromMicroseconds(
+                                     frames_pushed_so_far * INT64_C(1000000) /
+                                     GetParam().sample_rate));
+    // Note: Rechunker has just called ReceiveAndCheckNextChunk() zero or more
+    // times.
+
+    frames_pushed_so_far += input_chunk_size;
+  }
+  EXPECT_EQ(GetExpectedOutputChunks(frames_pushed_so_far), results_.size());
+
+  ASSERT_FALSE(results_.empty());
+  EXPECT_EQ(0.0f, results_.front().first_sample_value);
+  const float last_value_in_last_chunk =
+      static_cast<float>(GetExpectedOutputChunks(frames_pushed_so_far) *
+                             GetParam().output_chunk_size -
+                         1);
+  EXPECT_EQ(last_value_in_last_chunk, results_.back().last_sample_value);
+}
+
+INSTANTIATE_TEST_CASE_P(,
+                        AudioRechunkerTest,
+                        ::testing::Values(
+                            // 1 ms output chunks at common sample rates.
+                            TestParams(1000, 16000, 16, true),
+                            TestParams(1000, 22050, 22, false),
+                            TestParams(1000, 44100, 44, false),
+                            TestParams(1000, 48000, 48, true),
+
+                            // 10 ms output chunks at common sample rates.
+                            TestParams(10000, 16000, 160, true),
+                            TestParams(10000, 22050, 220, false),
+                            TestParams(10000, 44100, 441, true),
+                            TestParams(10000, 48000, 480, true),
+
+                            // 60 ms output chunks at common sample rates.
+                            TestParams(60000, 16000, 960, true),
+                            TestParams(60000, 22050, 1323, true),
+                            TestParams(60000, 44100, 2646, true),
+                            TestParams(60000, 48000, 2880, true)));
+
+}  // namespace
+
+}  // namespace media