media/base/audio_buffer_queue_unittest.cc

   1 // Copyright 2013 The Chromium Authors. All rights reserved.
   2 // Use of this source code is governed by a BSD-style license that can be
   3 // found in the LICENSE file.
   4
   5 #include "base/basictypes.h"
   6 #include "base/logging.h"
   7 #include "base/memory/scoped_ptr.h"
   8 #include "base/strings/stringprintf.h"
   9 #include "base/time/time.h"
  10 #include "media/base/audio_buffer.h"
  11 #include "media/base/audio_buffer_queue.h"
  12 #include "media/base/audio_bus.h"
  13 #include "media/base/buffers.h"
  14 #include "media/base/test_helpers.h"
  15 #include "testing/gtest/include/gtest/gtest.h"
  16
  17 namespace media {
  18
  19 static void VerifyResult(float* channel_data,
  20                          int frames,
  21                          float start,
  22                          float increment) {
  23   for (int i = 0; i < frames; ++i) {
  24     SCOPED_TRACE(base::StringPrintf(
  25         "i=%d/%d start=%f, increment=%f", i, frames, start, increment));
  26     ASSERT_EQ(start, channel_data[i]);
  27     start += increment;
  28   }
  29 }
  30
  31 TEST(AudioBufferQueueTest, AppendAndClear) {
  32   const int channels = 1;
  33   const int frames = 8;
  34   const base::TimeDelta kNoTime = kNoTimestamp();
  35   AudioBufferQueue buffer;
  36   EXPECT_EQ(0, buffer.frames());
  37   buffer.Append(MakeInterleavedAudioBuffer<uint8>(
  38       kSampleFormatU8, channels, 10, 1, frames, kNoTime, kNoTime));
  39   EXPECT_EQ(frames, buffer.frames());
  40   buffer.Clear();
  41   EXPECT_EQ(0, buffer.frames());
  42   buffer.Append(MakeInterleavedAudioBuffer<uint8>(
  43       kSampleFormatU8, channels, 20, 1, frames, kNoTime, kNoTime));
  44   EXPECT_EQ(frames, buffer.frames());
  45 }
  46
  47 TEST(AudioBufferQueueTest, MultipleAppend) {
  48   const int channels = 1;
  49   const int frames = 8;
  50   const base::TimeDelta kNoTime = kNoTimestamp();
  51   AudioBufferQueue buffer;
  52
  53   // Append 40 frames in 5 buffers.
  54   buffer.Append(MakeInterleavedAudioBuffer<uint8>(
  55       kSampleFormatU8, channels, 10, 1, frames, kNoTime, kNoTime));
  56   EXPECT_EQ(8, buffer.frames());
  57   buffer.Append(MakeInterleavedAudioBuffer<uint8>(
  58       kSampleFormatU8, channels, 10, 1, frames, kNoTime, kNoTime));
  59   EXPECT_EQ(16, buffer.frames());
  60   buffer.Append(MakeInterleavedAudioBuffer<uint8>(
  61       kSampleFormatU8, channels, 10, 1, frames, kNoTime, kNoTime));
  62   EXPECT_EQ(24, buffer.frames());
  63   buffer.Append(MakeInterleavedAudioBuffer<uint8>(
  64       kSampleFormatU8, channels, 10, 1, frames, kNoTime, kNoTime));
  65   EXPECT_EQ(32, buffer.frames());
  66   buffer.Append(MakeInterleavedAudioBuffer<uint8>(
  67       kSampleFormatU8, channels, 10, 1, frames, kNoTime, kNoTime));
  68   EXPECT_EQ(40, buffer.frames());
  69 }
  70
  71 TEST(AudioBufferQueueTest, IteratorCheck) {
  72   const int channels = 1;
  73   const int frames = 8;
  74   const base::TimeDelta kNoTime = kNoTimestamp();
  75   AudioBufferQueue buffer;
  76   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
  77
  78   // Append 40 frames in 5 buffers. Intersperse ReadFrames() to make the
  79   // iterator is pointing to the correct position.
  80   buffer.Append(MakeInterleavedAudioBuffer<float>(
  81       kSampleFormatF32, channels, 10.0f, 1.0f, frames, kNoTime, kNoTime));
  82   EXPECT_EQ(8, buffer.frames());
  83
  84   EXPECT_EQ(4, buffer.ReadFrames(4, 0, bus.get()));
  85   EXPECT_EQ(4, buffer.frames());
  86   VerifyResult(bus->channel(0), 4, 10.0f, 1.0f);
  87
  88   buffer.Append(MakeInterleavedAudioBuffer<float>(
  89       kSampleFormatF32, channels, 20.0f, 1.0f, frames, kNoTime, kNoTime));
  90   EXPECT_EQ(12, buffer.frames());
  91   buffer.Append(MakeInterleavedAudioBuffer<float>(
  92       kSampleFormatF32, channels, 30.0f, 1.0f, frames, kNoTime, kNoTime));
  93   EXPECT_EQ(20, buffer.frames());
  94
  95   buffer.SeekFrames(16);
  96   EXPECT_EQ(4, buffer.ReadFrames(4, 0, bus.get()));
  97   EXPECT_EQ(0, buffer.frames());
  98   VerifyResult(bus->channel(0), 4, 34.0f, 1.0f);
  99
 100   buffer.Append(MakeInterleavedAudioBuffer<float>(
 101       kSampleFormatF32, channels, 40.0f, 1.0f, frames, kNoTime, kNoTime));
 102   EXPECT_EQ(8, buffer.frames());
 103   buffer.Append(MakeInterleavedAudioBuffer<float>(
 104       kSampleFormatF32, channels, 50.0f, 1.0f, frames, kNoTime, kNoTime));
 105   EXPECT_EQ(16, buffer.frames());
 106
 107   EXPECT_EQ(4, buffer.ReadFrames(4, 0, bus.get()));
 108   VerifyResult(bus->channel(0), 4, 40.0f, 1.0f);
 109
 110   // Read off the end of the buffer.
 111   EXPECT_EQ(12, buffer.frames());
 112   buffer.SeekFrames(8);
 113   EXPECT_EQ(4, buffer.ReadFrames(100, 0, bus.get()));
 114   VerifyResult(bus->channel(0), 4, 54.0f, 1.0f);
 115 }
 116
 117 TEST(AudioBufferQueueTest, Seek) {
 118   const int channels = 2;
 119   const int frames = 6;
 120   const base::TimeDelta kNoTime = kNoTimestamp();
 121   AudioBufferQueue buffer;
 122
 123   // Add 6 frames of data.
 124   buffer.Append(MakeInterleavedAudioBuffer<float>(
 125       kSampleFormatF32, channels, 1.0f, 1.0f, frames, kNoTime, kNoTime));
 126   EXPECT_EQ(6, buffer.frames());
 127
 128   // Seek past 2 frames.
 129   buffer.SeekFrames(2);
 130   EXPECT_EQ(4, buffer.frames());
 131
 132   // Seek to end of data.
 133   buffer.SeekFrames(4);
 134   EXPECT_EQ(0, buffer.frames());
 135
 136   // At end, seek now fails unless 0 specified.
 137   buffer.SeekFrames(0);
 138 }
 139
 140 TEST(AudioBufferQueueTest, ReadF32) {
 141   const int channels = 2;
 142   const base::TimeDelta kNoTime = kNoTimestamp();
 143   AudioBufferQueue buffer;
 144
 145   // Add 76 frames of data.
 146   buffer.Append(MakeInterleavedAudioBuffer<float>(
 147       kSampleFormatF32, channels, 1.0f, 1.0f, 6, kNoTime, kNoTime));
 148   buffer.Append(MakeInterleavedAudioBuffer<float>(
 149       kSampleFormatF32, channels, 13.0f, 1.0f, 10, kNoTime, kNoTime));
 150   buffer.Append(MakeInterleavedAudioBuffer<float>(
 151       kSampleFormatF32, channels, 33.0f, 1.0f, 60, kNoTime, kNoTime));
 152   EXPECT_EQ(76, buffer.frames());
 153
 154   // Read 3 frames from the buffer. F32 is interleaved, so ch[0] should be
 155   // 1, 3, 5, and ch[1] should be 2, 4, 6.
 156   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
 157   EXPECT_EQ(3, buffer.ReadFrames(3, 0, bus.get()));
 158   EXPECT_EQ(73, buffer.frames());
 159   VerifyResult(bus->channel(0), 3, 1.0f, 2.0f);
 160   VerifyResult(bus->channel(1), 3, 2.0f, 2.0f);
 161
 162   // Now read 5 frames, which will span buffers. Append the data into AudioBus.
 163   EXPECT_EQ(5, buffer.ReadFrames(5, 3, bus.get()));
 164   EXPECT_EQ(68, buffer.frames());
 165   VerifyResult(bus->channel(0), 8, 1.0f, 2.0f);
 166   VerifyResult(bus->channel(1), 8, 2.0f, 2.0f);
 167
 168   // Now skip into the third buffer.
 169   buffer.SeekFrames(20);
 170   EXPECT_EQ(48, buffer.frames());
 171
 172   // Now read 2 frames, which are in the third buffer.
 173   EXPECT_EQ(2, buffer.ReadFrames(2, 0, bus.get()));
 174   VerifyResult(bus->channel(0), 2, 57.0f, 2.0f);
 175   VerifyResult(bus->channel(1), 2, 58.0f, 2.0f);
 176 }
 177
 178 TEST(AudioBufferQueueTest, ReadU8) {
 179   const int channels = 4;
 180   const int frames = 4;
 181   const base::TimeDelta kNoTime = kNoTimestamp();
 182   AudioBufferQueue buffer;
 183
 184   // Add 4 frames of data.
 185   buffer.Append(MakeInterleavedAudioBuffer<uint8>(
 186       kSampleFormatU8, channels, 128, 1, frames, kNoTime, kNoTime));
 187
 188   // Read all 4 frames from the buffer. Data is interleaved, so ch[0] should be
 189   // 128, 132, 136, 140, other channels similar. However, values are converted
 190   // from [0, 255] to [-1.0, 1.0] with a bias of 128. Thus the first buffer
 191   // value should be 0.0, then 1/127, 2/127, etc.
 192   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
 193   EXPECT_EQ(4, buffer.ReadFrames(4, 0, bus.get()));
 194   EXPECT_EQ(0, buffer.frames());
 195   VerifyResult(bus->channel(0), 4, 0.0f, 4.0f / 127.0f);
 196   VerifyResult(bus->channel(1), 4, 1.0f / 127.0f, 4.0f / 127.0f);
 197   VerifyResult(bus->channel(2), 4, 2.0f / 127.0f, 4.0f / 127.0f);
 198   VerifyResult(bus->channel(3), 4, 3.0f / 127.0f, 4.0f / 127.0f);
 199 }
 200
 201 TEST(AudioBufferQueueTest, ReadS16) {
 202   const int channels = 2;
 203   const base::TimeDelta kNoTime = kNoTimestamp();
 204   AudioBufferQueue buffer;
 205
 206   // Add 24 frames of data.
 207   buffer.Append(MakeInterleavedAudioBuffer<int16>(
 208       kSampleFormatS16, channels, 1, 1, 4, kNoTime, kNoTime));
 209   buffer.Append(MakeInterleavedAudioBuffer<int16>(
 210       kSampleFormatS16, channels, 9, 1, 20, kNoTime, kNoTime));
 211   EXPECT_EQ(24, buffer.frames());
 212
 213   // Read 6 frames from the buffer. Data is interleaved, so ch[0] should be
 214   // 1, 3, 5, 7, 9, 11, and ch[1] should be 2, 4, 6, 8, 10, 12.
 215   // Data is converted to float from -1.0 to 1.0 based on int16 range.
 216   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
 217   EXPECT_EQ(6, buffer.ReadFrames(6, 0, bus.get()));
 218   EXPECT_EQ(18, buffer.frames());
 219   VerifyResult(bus->channel(0), 6, 1.0f / kint16max, 2.0f / kint16max);
 220   VerifyResult(bus->channel(1), 6, 2.0f / kint16max, 2.0f / kint16max);
 221 }
 222
 223 TEST(AudioBufferQueueTest, ReadS32) {
 224   const int channels = 2;
 225   const base::TimeDelta kNoTime = kNoTimestamp();
 226   AudioBufferQueue buffer;
 227
 228   // Add 24 frames of data.
 229   buffer.Append(MakeInterleavedAudioBuffer<int32>(
 230       kSampleFormatS32, channels, 1, 1, 4, kNoTime, kNoTime));
 231   buffer.Append(MakeInterleavedAudioBuffer<int32>(
 232       kSampleFormatS32, channels, 9, 1, 20, kNoTime, kNoTime));
 233   EXPECT_EQ(24, buffer.frames());
 234
 235   // Read 6 frames from the buffer. Data is interleaved, so ch[0] should be
 236   // 1, 3, 5, 7, 100, 106, and ch[1] should be 2, 4, 6, 8, 103, 109.
 237   // Data is converted to float from -1.0 to 1.0 based on int32 range.
 238   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
 239   EXPECT_EQ(6, buffer.ReadFrames(6, 0, bus.get()));
 240   EXPECT_EQ(18, buffer.frames());
 241   VerifyResult(bus->channel(0), 6, 1.0f / kint32max, 2.0f / kint32max);
 242   VerifyResult(bus->channel(1), 6, 2.0f / kint32max, 2.0f / kint32max);
 243
 244   // Read the next 2 frames.
 245   EXPECT_EQ(2, buffer.ReadFrames(2, 0, bus.get()));
 246   EXPECT_EQ(16, buffer.frames());
 247   VerifyResult(bus->channel(0), 2, 13.0f / kint32max, 2.0f / kint32max);
 248   VerifyResult(bus->channel(1), 2, 14.0f / kint32max, 2.0f / kint32max);
 249 }
 250
 251 TEST(AudioBufferQueueTest, ReadF32Planar) {
 252   const int channels = 2;
 253   const base::TimeDelta kNoTime = kNoTimestamp();
 254   AudioBufferQueue buffer;
 255
 256   // Add 14 frames of data.
 257   buffer.Append(MakePlanarAudioBuffer<float>(
 258       kSampleFormatPlanarF32, channels, 1.0f, 1.0f, 4, kNoTime, kNoTime));
 259   buffer.Append(MakePlanarAudioBuffer<float>(
 260       kSampleFormatPlanarF32, channels, 50.0f, 1.0f, 10, kNoTime, kNoTime));
 261   EXPECT_EQ(14, buffer.frames());
 262
 263   // Read 6 frames from the buffer. F32 is planar, so ch[0] should be
 264   // 1, 2, 3, 4, 50, 51, and ch[1] should be 5, 6, 7, 8, 60, 61.
 265   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
 266   EXPECT_EQ(6, buffer.ReadFrames(6, 0, bus.get()));
 267   EXPECT_EQ(8, buffer.frames());
 268   VerifyResult(bus->channel(0), 4, 1.0f, 1.0f);
 269   VerifyResult(bus->channel(0) + 4, 2, 50.0f, 1.0f);
 270   VerifyResult(bus->channel(1), 4, 5.0f, 1.0f);
 271   VerifyResult(bus->channel(1) + 4, 2, 60.0f, 1.0f);
 272 }
 273
 274 TEST(AudioBufferQueueTest, ReadS16Planar) {
 275   const int channels = 2;
 276   const base::TimeDelta kNoTime = kNoTimestamp();
 277   AudioBufferQueue buffer;
 278
 279   // Add 24 frames of data.
 280   buffer.Append(MakePlanarAudioBuffer<int16>(
 281       kSampleFormatPlanarS16, channels, 1, 1, 4, kNoTime, kNoTime));
 282   buffer.Append(MakePlanarAudioBuffer<int16>(
 283       kSampleFormatPlanarS16, channels, 100, 5, 20, kNoTime, kNoTime));
 284   EXPECT_EQ(24, buffer.frames());
 285
 286   // Read 6 frames from the buffer. Data is planar, so ch[0] should be
 287   // 1, 2, 3, 4, 100, 105, and ch[1] should be 5, 6, 7, 8, 200, 205.
 288   // Data is converted to float from -1.0 to 1.0 based on int16 range.
 289   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
 290   EXPECT_EQ(6, buffer.ReadFrames(6, 0, bus.get()));
 291   EXPECT_EQ(18, buffer.frames());
 292   VerifyResult(bus->channel(0), 4, 1.0f / kint16max, 1.0f / kint16max);
 293   VerifyResult(bus->channel(0) + 4, 2, 100.0f / kint16max, 5.0f / kint16max);
 294   VerifyResult(bus->channel(1), 4, 5.0f / kint16max, 1.0f / kint16max);
 295   VerifyResult(bus->channel(1) + 4, 2, 200.0f / kint16max, 5.0f / kint16max);
 296 }
 297
 298 TEST(AudioBufferQueueTest, ReadManyChannels) {
 299   const int channels = 16;
 300   const base::TimeDelta kNoTime = kNoTimestamp();
 301   AudioBufferQueue buffer;
 302
 303   // Add 76 frames of data.
 304   buffer.Append(MakeInterleavedAudioBuffer<float>(
 305       kSampleFormatF32, channels, 0.0f, 1.0f, 6, kNoTime, kNoTime));
 306   buffer.Append(MakeInterleavedAudioBuffer<float>(
 307       kSampleFormatF32, channels, 6.0f * channels, 1.0f, 10, kNoTime, kNoTime));
 308   buffer.Append(MakeInterleavedAudioBuffer<float>(kSampleFormatF32,
 309                                                   channels,
 310                                                   16.0f * channels,
 311                                                   1.0f,
 312                                                   60,
 313                                                   kNoTime,
 314                                                   kNoTime));
 315   EXPECT_EQ(76, buffer.frames());
 316
 317   // Read 3 frames from the buffer. F32 is interleaved, so ch[0] should be
 318   // 1, 17, 33, and ch[1] should be 2, 18, 34. Just check a few channels.
 319   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
 320   EXPECT_EQ(30, buffer.ReadFrames(30, 0, bus.get()));
 321   EXPECT_EQ(46, buffer.frames());
 322   for (int i = 0; i < channels; ++i) {
 323     VerifyResult(bus->channel(i), 30, static_cast<float>(i), 16.0f);
 324   }
 325 }
 326
 327 TEST(AudioBufferQueueTest, Peek) {
 328   const int channels = 4;
 329   const base::TimeDelta kNoTime = kNoTimestamp();
 330   AudioBufferQueue buffer;
 331
 332   // Add 60 frames of data.
 333   buffer.Append(MakeInterleavedAudioBuffer<float>(
 334       kSampleFormatF32, channels, 0.0f, 1.0f, 60, kNoTime, kNoTime));
 335   EXPECT_EQ(60, buffer.frames());
 336
 337   // Peek at the first 30 frames.
 338   scoped_ptr<AudioBus> bus1 = AudioBus::Create(channels, 100);
 339   EXPECT_EQ(60, buffer.frames());
 340   EXPECT_EQ(60, buffer.PeekFrames(100, 0, 0, bus1.get()));
 341   EXPECT_EQ(30, buffer.PeekFrames(30, 0, 0, bus1.get()));
 342   EXPECT_EQ(60, buffer.frames());
 343
 344   // Now read the next 30 frames (which should be the same as those peeked at).
 345   scoped_ptr<AudioBus> bus2 = AudioBus::Create(channels, 100);
 346   EXPECT_EQ(30, buffer.ReadFrames(30, 0, bus2.get()));
 347   for (int i = 0; i < channels; ++i) {
 348     VerifyResult(bus1->channel(i),
 349                  30,
 350                  static_cast<float>(i),
 351                  static_cast<float>(channels));
 352     VerifyResult(bus2->channel(i),
 353                  30,
 354                  static_cast<float>(i),
 355                  static_cast<float>(channels));
 356   }
 357
 358   // Peek 10 frames forward
 359   EXPECT_EQ(5, buffer.PeekFrames(5, 10, 0, bus1.get()));
 360   for (int i = 0; i < channels; ++i) {
 361     VerifyResult(bus1->channel(i),
 362                  5,
 363                  static_cast<float>(i + 40 * channels),
 364                  static_cast<float>(channels));
 365   }
 366
 367   // Peek to the end of the buffer.
 368   EXPECT_EQ(30, buffer.frames());
 369   EXPECT_EQ(30, buffer.PeekFrames(100, 0, 0, bus1.get()));
 370   EXPECT_EQ(30, buffer.PeekFrames(30, 0, 0, bus1.get()));
 371 }
 372
 373 TEST(AudioBufferQueueTest, Time) {
 374   const int channels = 2;
 375   const base::TimeDelta start_time1;
 376   const base::TimeDelta start_time2 = base::TimeDelta::FromSeconds(30);
 377   const base::TimeDelta duration = base::TimeDelta::FromSeconds(10);
 378   AudioBufferQueue buffer;
 379   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
 380
 381   // Add two buffers (second one added later):
 382   //   first:  start=0s,  duration=10s
 383   //   second: start=30s, duration=10s
 384   buffer.Append(MakeInterleavedAudioBuffer<int16>(
 385       kSampleFormatS16, channels, 1, 1, 10, start_time1, duration));
 386   EXPECT_EQ(10, buffer.frames());
 387
 388   // Check starting time.
 389   EXPECT_EQ(start_time1, buffer.current_time());
 390
 391   // Read 2 frames, should be 2s in (since duration is 1s per sample).
 392   EXPECT_EQ(2, buffer.ReadFrames(2, 0, bus.get()));
 393   EXPECT_EQ(start_time1 + base::TimeDelta::FromSeconds(2),
 394             buffer.current_time());
 395
 396   // Skip 2 frames.
 397   buffer.SeekFrames(2);
 398   EXPECT_EQ(start_time1 + base::TimeDelta::FromSeconds(4),
 399             buffer.current_time());
 400
 401   // Add second buffer for more data.
 402   buffer.Append(MakeInterleavedAudioBuffer<int16>(
 403       kSampleFormatS16, channels, 1, 1, 10, start_time2, duration));
 404   EXPECT_EQ(16, buffer.frames());
 405
 406   // Read until almost the end of buffer1.
 407   EXPECT_EQ(5, buffer.ReadFrames(5, 0, bus.get()));
 408   EXPECT_EQ(start_time1 + base::TimeDelta::FromSeconds(9),
 409             buffer.current_time());
 410
 411   // Read 1 value, so time moved to buffer2.
 412   EXPECT_EQ(1, buffer.ReadFrames(1, 0, bus.get()));
 413   EXPECT_EQ(start_time2, buffer.current_time());
 414
 415   // Read all 10 frames in buffer2, timestamp should be last time from buffer2.
 416   EXPECT_EQ(10, buffer.ReadFrames(10, 0, bus.get()));
 417   EXPECT_EQ(start_time2 + base::TimeDelta::FromSeconds(10),
 418             buffer.current_time());
 419
 420   // Try to read more frames (which don't exist), timestamp should remain.
 421   EXPECT_EQ(0, buffer.ReadFrames(5, 0, bus.get()));
 422   EXPECT_EQ(start_time2 + base::TimeDelta::FromSeconds(10),
 423             buffer.current_time());
 424 }
 425
 426 TEST(AudioBufferQueueTest, NoTime) {
 427   const int channels = 2;
 428   const base::TimeDelta kNoTime = kNoTimestamp();
 429   AudioBufferQueue buffer;
 430   scoped_ptr<AudioBus> bus = AudioBus::Create(channels, 100);
 431
 432   // Add two buffers with no timestamps. Time should always be unknown.
 433   buffer.Append(MakeInterleavedAudioBuffer<int16>(
 434       kSampleFormatS16, channels, 1, 1, 10, kNoTime, kNoTime));
 435   buffer.Append(MakeInterleavedAudioBuffer<int16>(
 436       kSampleFormatS16, channels, 1, 1, 10, kNoTime, kNoTime));
 437   EXPECT_EQ(20, buffer.frames());
 438
 439   // Check starting time.
 440   EXPECT_EQ(kNoTime, buffer.current_time());
 441
 442   // Read 2 frames.
 443   EXPECT_EQ(2, buffer.ReadFrames(2, 0, bus.get()));
 444   EXPECT_EQ(kNoTime, buffer.current_time());
 445
 446   // Skip 2 frames.
 447   buffer.SeekFrames(2);
 448   EXPECT_EQ(kNoTime, buffer.current_time());
 449
 450   // Read until almost the end of buffer1.
 451   EXPECT_EQ(5, buffer.ReadFrames(5, 0, bus.get()));
 452   EXPECT_EQ(kNoTime, buffer.current_time());
 453
 454   // Read 1 value, so time moved to buffer2.
 455   EXPECT_EQ(1, buffer.ReadFrames(1, 0, bus.get()));
 456   EXPECT_EQ(kNoTime, buffer.current_time());
 457
 458   // Read all 10 frames in buffer2.
 459   EXPECT_EQ(10, buffer.ReadFrames(10, 0, bus.get()));
 460   EXPECT_EQ(kNoTime, buffer.current_time());
 461
 462   // Try to read more frames (which don't exist), timestamp should remain.
 463   EXPECT_EQ(0, buffer.ReadFrames(5, 0, bus.get()));
 464   EXPECT_EQ(kNoTime, buffer.current_time());
 465 }
 466
 467 }  // namespace media