Add new class AudioBuffer.

As part of the work to simplify the handling of audio data, adding this
class which is derived from DataBuffer with a few additions to keep
track of the format of the audio data. Using this class will come in a
subsequent CL.

BUG=248989

Review URL: https://chromiumcodereview.appspot.com/16974002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@207067 0039d316-1c4b-4281-b951-d872f2087c98

1 files changed, 98 insertions, 0 deletions

diff --git a/media/base/audio_buffer.h b/media/base/audio_buffer.h
new file mode 100644
index 0000000..f0ca772
--- /dev/null
+++ b/media/base/audio_buffer.h
@@ -0,0 +1,98 @@
+// Copyright 2013 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef MEDIA_BASE_AUDIO_BUFFER_H_
+#define MEDIA_BASE_AUDIO_BUFFER_H_
+
+#include <vector>
+
+#include "base/memory/aligned_memory.h"
+#include "base/memory/ref_counted.h"
+#include "base/memory/scoped_ptr.h"
+#include "base/time.h"
+#include "media/base/media_export.h"
+#include "media/base/sample_format.h"
+
+namespace media {
+class AudioBus;
+
+// An audio buffer that takes a copy of the data passed to it, holds it, and
+// copies it into an AudioBus when needed. Also supports an end of stream
+// marker.
+class MEDIA_EXPORT AudioBuffer
+    : public base::RefCountedThreadSafe<AudioBuffer> {
+ public:
+  // Create an AudioBuffer whose channel data is copied from |data|. For
+  // interleaved data, only the first buffer is used. For planar data, the
+  // number of buffers must be equal to |channel_count|. |frame_count| is the
+  // number of frames in each buffer. |data| must not be null and |frame_count|
+  // must be >= 0.
+  //
+  // TODO(jrummell): Compute duration rather than pass it in.
+  static scoped_refptr<AudioBuffer> CopyFrom(SampleFormat sample_format,
+                                             int channel_count,
+                                             int frame_count,
+                                             const uint8* const* data,
+                                             const base::TimeDelta timestamp,
+                                             const base::TimeDelta duration);
+
+  // Create a AudioBuffer indicating we've reached end of stream.
+  // Calling any method other than end_of_stream() on the resulting buffer
+  // is disallowed.
+  static scoped_refptr<AudioBuffer> CreateEOSBuffer();
+
+  // Copy frames into |dest|. |frames_to_copy| is the number of frames to copy.
+  // |source_frame_offset| specified how many frames in the buffer to skip
+  // first. |dest_frame_offset| is the frame offset in |dest|. The frames are
+  // converted from their source format into planar float32 data (which is all
+  // that AudioBus handles).
+  void ReadFrames(int frames_to_copy,
+                  int source_frame_offset,
+                  int dest_frame_offset,
+                  AudioBus* dest);
+
+  // Return the number of frames held.
+  int frame_count() const { return frame_count_; }
+
+  // Access to constructor parameters.
+  base::TimeDelta timestamp() const { return timestamp_; }
+  base::TimeDelta duration() const { return duration_; }
+
+  // If there's no data in this buffer, it represents end of stream.
+  bool end_of_stream() const { return data_ == NULL; }
+
+ private:
+  friend class base::RefCountedThreadSafe<AudioBuffer>;
+
+  // Allocates aligned contiguous buffer to hold all channel data (1 block for
+  // interleaved data, |channel_count| blocks for planar data), copies
+  // [data,data+data_size) to the allocated buffer(s). If |data| is null an end
+  // of stream buffer is created.
+  AudioBuffer(SampleFormat sample_format,
+              int channel_count,
+              int frame_count,
+              const uint8* const* data,
+              const base::TimeDelta timestamp,
+              const base::TimeDelta duration);
+
+  virtual ~AudioBuffer();
+
+  SampleFormat sample_format_;
+  int channel_count_;
+  int frame_count_;
+  base::TimeDelta timestamp_;
+  base::TimeDelta duration_;
+
+  // Contiguous block of channel data.
+  scoped_ptr_malloc<uint8, base::ScopedPtrAlignedFree> data_;
+
+  // For planar data, points to each channels data.
+  std::vector<uint8*> channel_data_;
+
+  DISALLOW_IMPLICIT_CONSTRUCTORS(AudioBuffer);
+};
+
+}  // namespace media
+
+#endif  // MEDIA_BASE_AUDIO_BUFFER_H_