Switch audio code from DataBuffer to AudioBuffer.

These are the changes to have the audio code use the new AudioBuffer and
AudioBufferQueue classes. The goal is to simplify the number of times the
audio data is copied and transformed.

BUG=248989

Review URL: https://chromiumcodereview.appspot.com/17737004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@210730 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 22 insertions, 17 deletions

diff --git a/media/base/audio_buffer_queue.cc b/media/base/audio_buffer_queue.cc
index 3fa3775..abe8fce 100644
--- a/media/base/audio_buffer_queue.cc
+++ b/media/base/audio_buffer_queue.cc
@@ -26,8 +26,7 @@ void AudioBufferQueue::Clear() {
 void AudioBufferQueue::Append(const scoped_refptr<AudioBuffer>& buffer_in) {
   // If we have just written the first buffer, update |current_time_| to be the
   // start time.
-  if (buffers_.empty()) {
-    DCHECK_EQ(frames_, 0);
+  if (buffers_.empty() && buffer_in->timestamp() != kNoTimestamp()) {
     current_time_ = buffer_in->timestamp();
   }
 
@@ -41,35 +40,40 @@ void AudioBufferQueue::Append(const scoped_refptr<AudioBuffer>& buffer_in) {
   CHECK_GT(frames_, 0);  // make sure it doesn't overflow.
 }
 
-int AudioBufferQueue::ReadFrames(int frames, AudioBus* dest) {
-  DCHECK_GE(dest->frames(), frames);
-  return InternalRead(frames, true, 0, dest);
+int AudioBufferQueue::ReadFrames(int frames,
+                                 int dest_frame_offset,
+                                 AudioBus* dest) {
+  DCHECK_GE(dest->frames(), frames + dest_frame_offset);
+  return InternalRead(frames, true, 0, dest_frame_offset, dest);
 }
 
 int AudioBufferQueue::PeekFrames(int frames,
-                                 int forward_offset,
+                                 int source_frame_offset,
+                                 int dest_frame_offset,
                                  AudioBus* dest) {
   DCHECK_GE(dest->frames(), frames);
-  return InternalRead(frames, false, forward_offset, dest);
+  return InternalRead(
+      frames, false, source_frame_offset, dest_frame_offset, dest);
 }
 
 void AudioBufferQueue::SeekFrames(int frames) {
   // Perform seek only if we have enough bytes in the queue.
   CHECK_LE(frames, frames_);
-  int taken = InternalRead(frames, true, 0, NULL);
+  int taken = InternalRead(frames, true, 0, 0, NULL);
   DCHECK_EQ(taken, frames);
 }
 
 int AudioBufferQueue::InternalRead(int frames,
                                    bool advance_position,
-                                   int forward_offset,
+                                   int source_frame_offset,
+                                   int dest_frame_offset,
                                    AudioBus* dest) {
   // Counts how many frames are actually read from the buffer queue.
   int taken = 0;
   BufferQueue::iterator current_buffer = current_buffer_;
   int current_buffer_offset = current_buffer_offset_;
 
-  int frames_to_skip = forward_offset;
+  int frames_to_skip = source_frame_offset;
   while (taken < frames) {
     // |current_buffer| is valid since the first time this buffer is appended
     // with data. Make sure there is data to be processed.
@@ -94,8 +98,10 @@ int AudioBufferQueue::InternalRead(int frames,
       int copied = std::min(frames - taken, remaining_frames_in_buffer);
 
       // if |dest| is NULL, there's no need to copy.
-      if (dest)
-        buffer->ReadFrames(copied, current_buffer_offset, taken, dest);
+      if (dest) {
+        buffer->ReadFrames(
+            copied, current_buffer_offset, dest_frame_offset + taken, dest);
+      }
 
       // Increase total number of frames copied, which regulates when to end
       // this loop.
@@ -131,14 +137,13 @@ int AudioBufferQueue::InternalRead(int frames,
     DCHECK_GE(frames_, 0);
     DCHECK(current_buffer_ != buffers_.end() || frames_ == 0);
 
-    current_buffer_ = current_buffer;
-    current_buffer_offset_ = current_buffer_offset;
-
-    UpdateCurrentTime(current_buffer_, current_buffer_offset_);
+    UpdateCurrentTime(current_buffer, current_buffer_offset);
 
     // Remove any buffers before the current buffer as there is no going
     // backwards.
-    buffers_.erase(buffers_.begin(), current_buffer_);
+    buffers_.erase(buffers_.begin(), current_buffer);
+    current_buffer_ = buffers_.begin();
+    current_buffer_offset_ = current_buffer_offset;
   }
 
   return taken;