| // 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_QUEUE_H_ |
| #define MEDIA_BASE_AUDIO_BUFFER_QUEUE_H_ |
| |
| #include "base/containers/circular_deque.h" |
| #include "base/macros.h" |
| #include "media/base/audio_buffer.h" |
| #include "media/base/media_export.h" |
| |
| namespace media { |
| |
| class AudioBus; |
| |
| // A queue of AudioBuffers to support reading of arbitrary chunks of a media |
| // data source. Audio data can be copied into an AudioBus for output. The |
| // current position can be forwarded to anywhere in the buffered data. |
| // |
| // This class is not inherently thread-safe. Concurrent access must be |
| // externally serialized. |
| class MEDIA_EXPORT AudioBufferQueue { |
| public: |
| AudioBufferQueue(); |
| ~AudioBufferQueue(); |
| |
| // Clears the buffer queue. |
| void Clear(); |
| |
| // Appends |buffer_in| to this queue. |
| void Append(const scoped_refptr<AudioBuffer>& buffer_in); |
| |
| // Reads a maximum of |frames| frames into |dest| from the current position. |
| // Returns the number of frames read. The current position will advance by the |
| // amount of frames read. |dest_frame_offset| specifies a starting offset into |
| // |dest|. On each call, the frames are converted from their source format |
| // into the destination AudioBus. |
| int ReadFrames(int frames, int dest_frame_offset, AudioBus* dest); |
| |
| // Copies up to |frames| frames from current position to |dest|. Returns |
| // number of frames copied. Doesn't advance current position. Starts at |
| // |source_frame_offset| from current position. |dest_frame_offset| specifies |
| // a starting offset into |dest|. On each call, the frames are converted from |
| // their source format into the destination AudioBus. |
| int PeekFrames(int frames, |
| int source_frame_offset, |
| int dest_frame_offset, |
| AudioBus* dest); |
| |
| // Moves the current position forward by |frames| frames. If |frames| exceeds |
| // frames available, the seek operation will fail. |
| void SeekFrames(int frames); |
| |
| // Returns the number of frames buffered beyond the current position. |
| int frames() const { return frames_; } |
| |
| private: |
| // Definition of the buffer queue. |
| using BufferQueue = base::circular_deque<scoped_refptr<AudioBuffer>>; |
| |
| // An internal method shared by ReadFrames() and SeekFrames() that actually |
| // does reading. It reads a maximum of |frames| frames into |dest|. Returns |
| // the number of frames read. The current position will be moved forward by |
| // the number of frames read if |advance_position| is set. If |dest| is NULL, |
| // only the current position will advance but no data will be copied. |
| // |source_frame_offset| can be used to skip frames before reading. |
| // |dest_frame_offset| specifies a starting offset into |dest|. |
| int InternalRead(int frames, |
| bool advance_position, |
| int source_frame_offset, |
| int dest_frame_offset, |
| AudioBus* dest); |
| |
| BufferQueue buffers_; |
| int front_buffer_offset_; // Offset into buffers_.front(). |
| |
| // Number of frames available to be read in the buffer. |
| int frames_; |
| |
| DISALLOW_COPY_AND_ASSIGN(AudioBufferQueue); |
| }; |
| |
| } // namespace media |
| |
| #endif // MEDIA_BASE_AUDIO_BUFFER_QUEUE_H_ |