Index: third_party/WebKit/Source/platform/audio/PushPullFIFO.h |
diff --git a/third_party/WebKit/Source/platform/audio/PushPullFIFO.h b/third_party/WebKit/Source/platform/audio/PushPullFIFO.h |
new file mode 100644 |
index 0000000000000000000000000000000000000000..dd930015a046a796e9dd90c7161e59dfbff9cbc3 |
--- /dev/null |
+++ b/third_party/WebKit/Source/platform/audio/PushPullFIFO.h |
@@ -0,0 +1,61 @@ |
+// 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 PushPullFIFO_h |
+#define PushPullFIFO_h |
+ |
+#include "platform/audio/AudioBus.h" |
+#include "public/platform/WebCommon.h" |
+#include "wtf/Allocator.h" |
+ |
+namespace blink { |
+ |
+// PushPullFIFO class is an intermediate audio sample storage between |
+// Blink-WebAudio and the renderer. The renderer's hardware callback buffer size |
+// varies on the platform, but the WebAudio always operates by 128 frames of |
+// render quantum; thus FIFO is needed. |
+class BLINK_PLATFORM_EXPORT PushPullFIFO { |
+ USING_FAST_MALLOC(PushPullFIFO); |
+ WTF_MAKE_NONCOPYABLE(PushPullFIFO); |
+ |
+ public: |
+ PushPullFIFO(unsigned numberOfChannels, size_t fifoLength); |
+ ~PushPullFIFO(); |
+ |
+ // Pushing audio data is done by the WebAudio render-backing thread. The |
o1ka
2017/01/24 11:09:02
Do you plan to first finalize all the index calcul
hongchan
2017/01/26 22:33:18
Yes. That's the plan.
The FIFO in this CL should
|
+ // priority of this thread is lower than the actual audio device thread, |
+ // thus the thread can be blocked when the audio device thread is pulling |
+ // data from the FIFO. |
+ void push(const AudioBus* inputBus); |
+ |
+ // Pulling audio data is done by the audio device thread. In the case of |
+ // underflow, the rest will be filled up with zeros (thus glitches). Pulling |
+ // an empty FIFO is a valid operation, and the consumer will get a block of |
+ // silence. |
+ void pull(AudioBus* outputBus, size_t framesRequested); |
+ |
+ int framesAvailable() const { return m_framesAvailable; } |
+ int length() const { return m_fifoLength; } |
+ unsigned numberOfChannels() const { return m_fifoBus->numberOfChannels(); } |
+ AudioBus* bus() { return m_fifoBus.get(); } |
+ |
+ private: |
+ RefPtr<AudioBus> m_fifoBus; |
+ |
+ // The size of the FIFO. |
+ const int m_fifoLength; |
o1ka
2017/01/24 11:09:02
You can use "= 0" initialization here.
hongchan
2017/01/26 22:33:18
Done.
|
+ |
+ // The number of frames in the FIFO actually available for pulling. |
+ int m_framesAvailable; |
+ |
+ int m_indexRead; |
+ int m_indexWrite; |
+ |
+ unsigned m_overflowCount; |
o1ka
2017/01/24 11:09:02
We should not use a mix of size_t, int and unsigne
hongchan
2017/01/26 22:33:18
This is a great resource. Thanks and we will follo
|
+ unsigned m_underflowCount; |
+}; |
+ |
+} // namespace blink |
+ |
+#endif // PushPullFIFO_h |