Fix AudioBuffer verification tests.

media/base/audio_buffer_unittest.cc

Index: media/base/audio_buffer_unittest.cc
diff --git a/media/base/audio_buffer_unittest.cc b/media/base/audio_buffer_unittest.cc
index c0fbf6b85befa1c79a3ed401363e44ced0d341bf..d28669f78c25bc9c77c737c33cdbe291af424692 100644
--- a/media/base/audio_buffer_unittest.cc
+++ b/media/base/audio_buffer_unittest.cc
@@ -11,23 +11,23 @@ namespace media {
 
 static const int kSampleRate = 48000;
 
-
 static void VerifyBusWithOffset(AudioBus* bus,
                                 int offset,
                                 int frames,
                                 float start,
+                                float start_offset,

[wolenetz, 2014/05/05 20:28:45]

Is there really a difference between start and start_offset? (Why do we need to
split out start_offset from start?)

[DaleCurtis, 2014/05/05 21:28:50]

Yes.  |start| is used to calculate a new |v| at the first frame of each channel.
 However if it's computed using |start_offset| it'll be completely wrong since
|start_offset| wasn't what was used to construct the buffer.

[wolenetz, 2014/05/05 22:16:29]

nit: Hmm. Then maybe lift the constant 'start_offset + ' out of the inner loop
into the calculation of v in the outer loop?

[DaleCurtis, 2014/05/05 22:54:44]

Done.

                                 float increment) {
   for (int ch = 0; ch < bus->channels(); ++ch) {
     const float v = start + ch * bus->frames() * increment;
-    for (int i = offset; i < frames; ++i) {
-      ASSERT_FLOAT_EQ(v + i * increment, bus->channel(ch)[i]) << "i=" << i
-                                                              << ", ch=" << ch;
+    for (int i = offset; i < offset + frames; ++i) {
+      ASSERT_FLOAT_EQ(start_offset + v + i * increment, bus->channel(ch)[i])
+          << "i=" << i << ", ch=" << ch;
     }
   }
 }
 
 static void VerifyBus(AudioBus* bus, int frames, float start, float increment) {
-  VerifyBusWithOffset(bus, 0, frames, start, increment);
+  VerifyBusWithOffset(bus, 0, frames, start, 0, increment);
 }
 
 static void TrimRangeTest(SampleFormat sample_format) {
@@ -65,8 +65,12 @@ static void TrimRangeTest(SampleFormat sample_format) {
   bus->Zero();
   buffer->ReadFrames(buffer->frame_count(), 0, 0, bus.get());
   VerifyBus(bus.get(), trim_start, 0, 1);
-  VerifyBusWithOffset(
-      bus.get(), trim_start, buffer->frame_count() - trim_start, 0, 1);
+  VerifyBusWithOffset(bus.get(),
+                      trim_start,
+                      buffer->frame_count() - trim_start,
+                      0,
+                      trim_length,
+                      1);
 
   // Trim 10ms of frames from the start, which just adjusts the buffer's
   // internal start offset.
@@ -78,8 +82,12 @@ static void TrimRangeTest(SampleFormat sample_format) {
   bus->Zero();
   buffer->ReadFrames(buffer->frame_count(), 0, 0, bus.get());
   VerifyBus(bus.get(), trim_start, trim_length, 1);
-  VerifyBusWithOffset(
-      bus.get(), trim_start, buffer->frame_count() - trim_start, 0, 1);
+  VerifyBusWithOffset(bus.get(),
+                      trim_start,
+                      buffer->frame_count() - trim_start,
+                      trim_length,
+                      trim_length,
+                      1);
 
   // Trim 10ms of frames from the end, which just adjusts the buffer's frame
   // count.
@@ -90,8 +98,12 @@ static void TrimRangeTest(SampleFormat sample_format) {
   bus->Zero();
   buffer->ReadFrames(buffer->frame_count(), 0, 0, bus.get());
   VerifyBus(bus.get(), trim_start, trim_length, 1);
-  VerifyBusWithOffset(
-      bus.get(), trim_start, buffer->frame_count() - trim_start, 0, 1);
+  VerifyBusWithOffset(bus.get(),
+                      trim_start,
+                      buffer->frame_count() - trim_start,
+                      trim_length,
+                      trim_length,
+                      1);
 
   // Trim another 10ms from the inner portion of the buffer.
   buffer->TrimRange(trim_start, trim_start + trim_length);
@@ -101,8 +113,12 @@ static void TrimRangeTest(SampleFormat sample_format) {
   bus->Zero();
   buffer->ReadFrames(buffer->frame_count(), 0, 0, bus.get());
   VerifyBus(bus.get(), trim_start, trim_length, 1);
-  VerifyBusWithOffset(
-      bus.get(), trim_start, buffer->frame_count() - trim_start, 0, 1);
+  VerifyBusWithOffset(bus.get(),
+                      trim_start,
+                      buffer->frame_count() - trim_start,
+                      trim_length,
+                      trim_length * 2,
+                      1);
 
   // Trim off the end using TrimRange() to ensure end index is exclusive.
   buffer->TrimRange(buffer->frame_count() - trim_length, buffer->frame_count());
@@ -112,8 +128,12 @@ static void TrimRangeTest(SampleFormat sample_format) {
   bus->Zero();
   buffer->ReadFrames(buffer->frame_count(), 0, 0, bus.get());
   VerifyBus(bus.get(), trim_start, trim_length, 1);
-  VerifyBusWithOffset(
-      bus.get(), trim_start, buffer->frame_count() - trim_start, 0, 1);
+  VerifyBusWithOffset(bus.get(),
+                      trim_start,
+                      buffer->frame_count() - trim_start,
+                      trim_length,
+                      trim_length * 2,
+                      1);
 
   // Trim off the start using TrimRange() to ensure start index is inclusive.
   buffer->TrimRange(0, trim_length);
@@ -124,8 +144,12 @@ static void TrimRangeTest(SampleFormat sample_format) {
   bus->Zero();
   buffer->ReadFrames(buffer->frame_count(), 0, 0, bus.get());
   VerifyBus(bus.get(), trim_start, 2 * trim_length, 1);
-  VerifyBusWithOffset(
-      bus.get(), trim_start, buffer->frame_count() - trim_start, 0, 1);
+  VerifyBusWithOffset(bus.get(),
+                      trim_start,
+                      buffer->frame_count() - trim_start,
+                      trim_length * 2,
+                      trim_length * 2,
+                      1);
 }
 
 TEST(AudioBufferTest, CopyFrom) {