Index: media/base/audio_push_fifo.h |
diff --git a/media/base/audio_push_fifo.h b/media/base/audio_push_fifo.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..4f95b13da1590560f20ea047a8ee2f018daed5e9 |
--- /dev/null |
+++ b/media/base/audio_push_fifo.h |
@@ -0,0 +1,68 @@ |
+// Copyright 2016 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_PUSH_FIFO_H_ |
+#define MEDIA_BASE_AUDIO_PUSH_FIFO_H_ |
+ |
+#include "base/callback.h" |
+#include "base/macros.h" |
+#include "base/memory/scoped_ptr.h" |
+#include "media/base/audio_bus.h" |
+#include "media/base/media_export.h" |
+ |
+namespace media { |
+ |
+// Yet another FIFO for audio data that re-buffers audio to a desired buffer |
+// size. Unlike AudioFifo and AudioBlockFifo, this FIFO cannot overflow: The |
+// client is required to provide a callback that is called synchronously during |
+// a push whenever enough data becomes available. In addition, this FIFO |
+// shifts reference timestamps to account for any samples that were pending in |
DaleCurtis
2016/02/23 20:34:26
Remove comments on reference timestamps?
miu
2016/02/23 23:32:33
Done.
|
+// internal buffers from prior pushes. This implementation eliminates redundant |
+// memory copies when the input buffer size always matches the desired buffer |
+// size. |
+class MEDIA_EXPORT AudioPushFifo final { |
+ public: |
+ // Called synchronously zero, one, or multiple times during a call to Push() |
+ // to deliver re-buffered audio. |frame_offset| refers to the position of the |
+ // first frame in |output| relative to the first frame in the Push() call. If |
+ // negative, this indicates the output contains some data from a prior call to |
+ // Push(). If zero or positive, the output contains data from the current |
+ // call to Push(). Clients can use this to adjust timestmaps. |
DaleCurtis
2016/02/23 20:34:26
timestamps.
miu
2016/02/23 23:32:33
Done.
|
+ using OutputCallback = |
+ base::Callback<void(const AudioBus& output_bus, int frame_offset)>; |
DaleCurtis
2016/02/23 20:34:26
We typically call this frame_delay (see SincResamp
miu
2016/02/23 23:32:33
Done.
|
+ |
+ // Creates a new AudioPushFifo delivers re-buffered audio by running |
+ // |callback|. |
+ explicit AudioPushFifo(const OutputCallback& callback); |
+ |
+ ~AudioPushFifo(); |
+ |
+ // Returns the number of frames in each AudioBus delivered to the |
+ // OutputCallback. |
+ int output_frames() const { return output_frames_; } |
+ |
+ // Must be called at least once before the first call to Push(). May be |
+ // called later (e.g., to support an audio format change). |
+ void Reset(int frames_per_buffer); |
+ |
+ // Pushes all audio channel data from |input_bus| through the FIFO. This will |
+ // result in zero, one, or multiple synchronous calls to the OutputCallback |
+ // provided in the constructor. |
+ void Push(const AudioBus& input_bus); |
+ |
+ private: |
+ const OutputCallback callback_; |
+ |
+ int output_frames_; |
+ |
+ // Queue of frames pending for delivery. |
+ scoped_ptr<AudioBus> audio_queue_; |
+ int queued_frames_; |
+ |
+ DISALLOW_COPY_AND_ASSIGN(AudioPushFifo); |
+}; |
+ |
+} // namespace media |
+ |
+#endif // MEDIA_BASE_AUDIO_PUSH_FIFO_H_ |