media/base/audio_timestamp_helper_unittest.cc

   1 // Copyright (c) 2012 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 "media/base/audio_timestamp_helper.h"
   6 #include "media/base/buffers.h"
   7 #include "testing/gtest/include/gtest/gtest.h"
   8
   9 namespace media {
  10
  11 static const int kDefaultSampleRate = 44100;
  12
  13 class AudioTimestampHelperTest : public ::testing::Test {
  14  public:
  15   AudioTimestampHelperTest() : helper_(kDefaultSampleRate) {
  16     helper_.SetBaseTimestamp(base::TimeDelta());
  17   }
  18
  19   // Adds frames to the helper and returns the current timestamp in
  20   // microseconds.
  21   int64 AddFrames(int frames) {
  22     helper_.AddFrames(frames);
  23     return helper_.GetTimestamp().InMicroseconds();
  24   }
  25
  26   int64 FramesToTarget(int target_in_microseconds) {
  27     return helper_.GetFramesToTarget(
  28         base::TimeDelta::FromMicroseconds(target_in_microseconds));
  29   }
  30
  31   void TestGetFramesToTargetRange(int frame_count, int start, int end) {
  32     for (int i = start; i <= end; ++i) {
  33       EXPECT_EQ(frame_count, FramesToTarget(i)) << " Failure for timestamp "
  34                                                 << i << " us.";
  35     }
  36   }
  37
  38  protected:
  39   AudioTimestampHelper helper_;
  40
  41   DISALLOW_COPY_AND_ASSIGN(AudioTimestampHelperTest);
  42 };
  43
  44 TEST_F(AudioTimestampHelperTest, Basic) {
  45   EXPECT_EQ(0, helper_.GetTimestamp().InMicroseconds());
  46
  47   // Verify that the output timestamp is always rounded down to the
  48   // nearest microsecond. 1 frame @ 44100 is ~22.67573 microseconds,
  49   // which is why the timestamp sometimes increments by 23 microseconds
  50   // and other times it increments by 22 microseconds.
  51   EXPECT_EQ(0, AddFrames(0));
  52   EXPECT_EQ(22, AddFrames(1));
  53   EXPECT_EQ(45, AddFrames(1));
  54   EXPECT_EQ(68, AddFrames(1));
  55   EXPECT_EQ(90, AddFrames(1));
  56   EXPECT_EQ(113, AddFrames(1));
  57
  58   // Verify that adding frames one frame at a time matches the timestamp
  59   // returned if the same number of frames are added all at once.
  60   base::TimeDelta timestamp_1  = helper_.GetTimestamp();
  61   helper_.SetBaseTimestamp(kNoTimestamp());
  62   EXPECT_TRUE(kNoTimestamp() == helper_.base_timestamp());
  63   helper_.SetBaseTimestamp(base::TimeDelta());
  64   EXPECT_EQ(0, helper_.GetTimestamp().InMicroseconds());
  65
  66   helper_.AddFrames(5);
  67   EXPECT_EQ(113, helper_.GetTimestamp().InMicroseconds());
  68   EXPECT_TRUE(timestamp_1 == helper_.GetTimestamp());
  69 }
  70
  71
  72 TEST_F(AudioTimestampHelperTest, GetDuration) {
  73   helper_.SetBaseTimestamp(base::TimeDelta::FromMicroseconds(100));
  74
  75   int frame_count = 5;
  76   int64 expected_durations[] = { 113, 113, 114, 113, 113, 114 };
  77   for (size_t i = 0; i < arraysize(expected_durations); ++i) {
  78     base::TimeDelta duration = helper_.GetFrameDuration(frame_count);
  79     EXPECT_EQ(expected_durations[i], duration.InMicroseconds());
  80
  81     base::TimeDelta timestamp_1 = helper_.GetTimestamp() + duration;
  82     helper_.AddFrames(frame_count);
  83     base::TimeDelta timestamp_2 = helper_.GetTimestamp();
  84     EXPECT_TRUE(timestamp_1 == timestamp_2);
  85   }
  86 }
  87
  88 TEST_F(AudioTimestampHelperTest, GetFramesToTarget) {
  89   // Verify GetFramesToTarget() rounding behavior.
  90   // 1 frame @ 44100 is ~22.67573 microseconds,
  91
  92   // Test values less than half of the frame duration.
  93   TestGetFramesToTargetRange(0, 0, 11);
  94
  95   // Test values between half the frame duration & the
  96   // full frame duration.
  97   TestGetFramesToTargetRange(1, 12, 22);
  98
  99   // Verify that the same number of frames is returned up
 100   // to the next half a frame.
 101   TestGetFramesToTargetRange(1, 23, 34);
 102
 103   // Verify the next 3 ranges.
 104   TestGetFramesToTargetRange(2, 35, 56);
 105   TestGetFramesToTargetRange(3, 57, 79);
 106   TestGetFramesToTargetRange(4, 80, 102);
 107   TestGetFramesToTargetRange(5, 103, 124);
 108
 109   // Add frames to the helper so negative frame counts can be tested.
 110   helper_.AddFrames(5);
 111
 112   // Note: The timestamp ranges must match the positive values
 113   // tested above to verify that the code is rounding properly.
 114   TestGetFramesToTargetRange(0, 103, 124);
 115   TestGetFramesToTargetRange(-1, 80, 102);
 116   TestGetFramesToTargetRange(-2, 57, 79);
 117   TestGetFramesToTargetRange(-3, 35, 56);
 118   TestGetFramesToTargetRange(-4, 12, 34);
 119   TestGetFramesToTargetRange(-5, 0, 11);
 120 }
 121
 122 }  // namespace media