Add methods to ARAB and BufferQueue to allow owners to query it for the timestamp of our next byte.

BUG=16011
TEST=src/media/base/buffer_queue_unittest.cc
Review URL: http://codereview.chromium.org/149494

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@20520 0039d316-1c4b-4281-b951-d872f2087c98

5 files changed, 61 insertions, 0 deletions

diff --git a/media/base/buffer_queue.cc b/media/base/buffer_queue.cc
index 18b30d50..f78fb1d 100644
--- a/media/base/buffer_queue.cc
+++ b/media/base/buffer_queue.cc
@@ -80,6 +80,14 @@ void BufferQueue::Enqueue(Buffer* buffer_in) {
   size_in_bytes_ += buffer_in->GetDataSize();
 }
 
+base::TimeDelta BufferQueue::GetTime(double bytes_to_sec) {
+  double bytes_to_usec = bytes_to_sec * base::Time::kMicrosecondsPerSecond;
+
+  return queue_.front()->GetTimestamp() +
+      base::TimeDelta::FromMicroseconds(static_cast<int64>(
+          data_offset_ * bytes_to_usec));
+}
+
 void BufferQueue::Clear() {
   queue_.clear();
   size_in_bytes_ = 0;
diff --git a/media/base/buffer_queue.h b/media/base/buffer_queue.h
index 363b136..39e1976 100644
--- a/media/base/buffer_queue.h
+++ b/media/base/buffer_queue.h
@@ -14,6 +14,7 @@
 #include <deque>
 
 #include "base/ref_counted.h"
+#include "base/time.h"
 
 namespace media {
 
@@ -38,6 +39,10 @@ class BufferQueue {
   // Enqueues |buffer_in| and adds a reference.
   void Enqueue(Buffer* buffer_in);
 
+  // Returns the timestamp of the first buffer plus |data_offset_| in
+  // microseconds, calculated using the conversion |bytes_to_sec|.
+  base::TimeDelta GetTime(double bytes_to_sec);
+
   // Returns true if the |queue_| is empty.
   bool IsEmpty();
 
diff --git a/media/base/buffer_queue_unittest.cc b/media/base/buffer_queue_unittest.cc
index 7f64b43..91e10e0 100644
--- a/media/base/buffer_queue_unittest.cc
+++ b/media/base/buffer_queue_unittest.cc
@@ -4,6 +4,7 @@
 
 #include "base/scoped_ptr.h"
 #include "base/string_util.h"
+#include "base/time.h"
 #include "media/base/buffer_queue.h"
 #include "media/base/data_buffer.h"
 #include "testing/gtest/include/gtest/gtest.h"
@@ -123,4 +124,44 @@ TEST_F(BufferQueueTest, CopyFromMiddleOfBuffer) {
   EXPECT_EQ(0, memcmp(dataBig, kData, kDataSize));
 }
 
+TEST_F(BufferQueueTest, GetTime) {
+  const struct {
+    int64 first_time_seconds;
+    size_t consume_bytes;
+    double bytes_to_seconds;
+  } tests[] = {
+    { 0, 0, 0.5  },
+    { 0, 0, 1    },
+    { 0, 0, 1.75 },
+    { 0, 4, 0.5  },
+    { 0, 4, 1    },
+    { 0, 4, 1.75 },
+    { 5, 0, 0.5  },
+    { 5, 0, 1    },
+    { 5, 0, 1.75 },
+    { 5, 4, 0.5  },
+    { 5, 4, 1    },
+    { 5, 4, 1.75 },
+  };
+
+  for (size_t i = 0; i < ARRAYSIZE_UNSAFE(tests); ++i) {
+    buffer2->SetTimestamp(base::TimeDelta::FromSeconds(
+        tests[i].first_time_seconds));
+    queue_.Enqueue(buffer2.get());
+    queue_.Consume(tests[i].consume_bytes);
+
+    int64 expected = base::TimeDelta::FromSeconds(static_cast<int64>(
+        tests[i].first_time_seconds + (tests[i].consume_bytes *
+        tests[i].bytes_to_seconds))).ToInternalValue();
+
+    int64 actual = queue_.GetTime(tests[i].bytes_to_seconds).ToInternalValue();
+
+    EXPECT_EQ(expected, actual) << "With test = {"
+        << tests[i].first_time_seconds << ", " << tests[i].consume_bytes
+        << ", " << tests[i].bytes_to_seconds << "}\n";
+
+    queue_.Clear();
+  }
+}
+
 }  // namespace media
diff --git a/media/filters/audio_renderer_algorithm_base.cc b/media/filters/audio_renderer_algorithm_base.cc
index ef6c0ec..8e64656 100644
--- a/media/filters/audio_renderer_algorithm_base.cc
+++ b/media/filters/audio_renderer_algorithm_base.cc
@@ -54,6 +54,10 @@ void AudioRendererAlgorithmBase::FlushBuffers() {
   request_read_callback_->Run();
 }
 
+base::TimeDelta AudioRendererAlgorithmBase::GetTime() {
+  return queue_.GetTime(1.0 / (channels() * sample_rate() * sample_bytes()));
+}
+
 void AudioRendererAlgorithmBase::EnqueueBuffer(Buffer* buffer_in) {
   // If we're at end of stream, |buffer_in| contains no data.
   if (!buffer_in->IsEndOfStream())
diff --git a/media/filters/audio_renderer_algorithm_base.h b/media/filters/audio_renderer_algorithm_base.h
index 3fc8fde..9449c25 100644
--- a/media/filters/audio_renderer_algorithm_base.h
+++ b/media/filters/audio_renderer_algorithm_base.h
@@ -58,6 +58,9 @@ class AudioRendererAlgorithmBase {
   // Clears |queue_|.
   virtual void FlushBuffers();
 
+  // Returns the time of the next byte in our data.
+  virtual base::TimeDelta GetTime();
+
   // Enqueues a buffer. It is called from the owner of the algorithm after a
   // read completes.
   virtual void EnqueueBuffer(Buffer* buffer_in);