Index: third_party/WebKit/Source/platform/audio/PushPullFIFO.cpp |
diff --git a/third_party/WebKit/Source/platform/audio/PushPullFIFO.cpp b/third_party/WebKit/Source/platform/audio/PushPullFIFO.cpp |
new file mode 100644 |
index 0000000000000000000000000000000000000000..5d666cc8b8df1a98594f2b1c5205e6d89ab7e6ed |
--- /dev/null |
+++ b/third_party/WebKit/Source/platform/audio/PushPullFIFO.cpp |
@@ -0,0 +1,142 @@ |
+// Copyright 2017 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. |
+ |
+#include "platform/audio/PushPullFIFO.h" |
+ |
+#include "wtf/PtrUtil.h" |
+#include <memory> |
+ |
+namespace blink { |
+ |
+// Maximum FIFO length. |
+const size_t kMaxFIFOLength = 32768; |
hongchan
2017/01/27 22:39:14
rtoy@ and I believe 32K is good enough based on th
Raymond Toy
2017/02/01 19:02:37
I checked the metrics again. There is one case of
hongchan
2017/02/01 23:09:06
Should FIFO aware of sample rate? Is that what we
Raymond Toy
2017/02/01 23:38:55
Well, I was just thinking it needs to be large eno
hongchan
2017/02/02 19:55:23
Acknowledged.
|
+ |
+// Suppress the warning log if over/underflow happens more than 100 times. |
+const unsigned kLogCapOverUnderflow = 100; |
Raymond Toy
2017/01/30 20:59:28
Maybe kMaxMessagesToLog?
hongchan
2017/02/01 18:07:27
Done.
|
+ |
+PushPullFIFO::PushPullFIFO(unsigned numberOfChannels, size_t fifoLength) |
+ : m_fifoLength(std::min(fifoLength, kMaxFIFOLength)), |
+ m_fifoBus(AudioBus::create(numberOfChannels, m_fifoLength)), |
+ m_framesAvailable(0), |
+ m_indexRead(0), |
+ m_indexWrite(0), |
+ m_overflowCount(0), |
+ m_underflowCount(0) {} |
+ |
+PushPullFIFO::~PushPullFIFO() {} |
+ |
+// Push the data from |inputBus| to FIFO. The size of push is determined by |
+// the length of |inputBus|. |
+void PushPullFIFO::push(const AudioBus* inputBus) { |
+ CHECK(inputBus); |
+ SECURITY_CHECK(inputBus->length() <= m_fifoLength); |
+ SECURITY_CHECK(m_indexWrite < m_fifoLength); |
Raymond Toy
2017/01/30 20:59:28
You said the push size is 128. Shouldn't there be
hongchan
2017/02/01 18:07:27
Done.
|
+ |
+ const size_t inputBusLength = inputBus->length(); |
+ const size_t remainder = m_fifoLength - m_indexWrite; |
+ |
+ for (unsigned i = 0; i < m_fifoBus->numberOfChannels(); ++i) { |
+ float* fifoBusChannel = m_fifoBus->channel(i)->mutableData(); |
+ const float* inputBusChannel = inputBus->channel(i)->data(); |
+ if (remainder >= inputBusLength) { |
+ // The remainder is big enough for the input data. |
+ memcpy(fifoBusChannel + m_indexWrite, inputBusChannel, |
+ inputBusLength * sizeof(*fifoBusChannel)); |
+ } else { |
+ // The input data overflows the remainder size. Wrap around the index. |
+ memcpy(fifoBusChannel + m_indexWrite, inputBusChannel, |
+ remainder * sizeof(*fifoBusChannel)); |
+ memcpy(fifoBusChannel, inputBusChannel + remainder, |
+ (inputBusLength - remainder) * sizeof(*fifoBusChannel)); |
+ } |
+ } |
+ |
+ // Update the write index; wrap it around if necessary. |
+ m_indexWrite = (m_indexWrite + inputBusLength) % m_fifoLength; |
+ |
+ // In case of overflow, move the read index to the updated write index. |
+ if (inputBusLength > m_fifoLength - m_framesAvailable) { |
+ m_indexRead = m_indexWrite; |
+ if (++m_overflowCount < kLogCapOverUnderflow) { |
+ DVLOG(1) << "PushPullFIFO: overflow while pushing (" |
+ << "overflowCount=" << m_overflowCount |
+ << ", availableFrames=" << m_framesAvailable |
+ << ", inputFrames=" << inputBusLength |
+ << ", fifoLength=" << m_fifoLength << ")"; |
+ } |
+ } |
+ |
+ // Update the number of frames available in FIFO. |
+ m_framesAvailable = |
+ std::min(m_framesAvailable + inputBusLength, m_fifoLength); |
+} |
+ |
+// Pull the data out of FIFO to |outputBus|. If the remaining frames in the FIFO |
+// is less than the frames to pull, provides the remaining frames plus the |
Raymond Toy
2017/01/30 20:59:28
s/the//
hongchan
2017/02/01 18:07:27
Done.
|
+// silence. |
+void PushPullFIFO::pull(AudioBus* outputBus, size_t framesRequested) { |
+ CHECK(outputBus); |
+ SECURITY_CHECK(framesRequested <= outputBus->length()); |
Raymond Toy
2017/01/30 20:59:28
You need to add this to your contract.
hongchan
2017/02/01 18:07:27
I can certainly add, but this is more of sanity ch
Raymond Toy
2017/02/01 19:02:38
Well, you could have defined pull to use the min o
hongchan
2017/02/01 23:09:06
// - If |framesRequested| is bigger than the leng
|
+ SECURITY_CHECK(framesRequested <= m_fifoLength); |
Raymond Toy
2017/01/30 20:59:28
This too.
Raymond Toy
2017/02/01 19:02:38
I can imagine that if you request more than the fi
hongchan
2017/02/01 23:09:06
// - If |framesRequested| is bigger than FIFO len
|
+ SECURITY_CHECK(m_indexRead < m_fifoLength); |
+ |
+ // TODO(hongchan): add a tryLock here for this operation when two threads are |
+ // introduced. Pulling operation has a higher priority to ensure the audio |
+ // device callback to be uninterrupted. |
+ |
+ const size_t remainder = m_fifoLength - m_indexRead; |
+ const size_t framesToFill = std::min(m_framesAvailable, framesRequested); |
+ |
+ for (unsigned i = 0; i < m_fifoBus->numberOfChannels(); ++i) { |
+ const float* fifoBusChannel = m_fifoBus->channel(i)->data(); |
+ float* outputBusChannel = outputBus->channel(i)->mutableData(); |
+ |
+ // Fill up the output bus with the available frames first. |
+ if (remainder >= framesToFill) { |
+ // The remainder is big enough for the frames to pull. |
+ memcpy(outputBusChannel, fifoBusChannel + m_indexRead, |
+ framesToFill * sizeof(*fifoBusChannel)); |
+ } else { |
+ // The frames to pull is bigger than the remainder size. |
+ // Wrap around the index. |
+ memcpy(outputBusChannel, fifoBusChannel + m_indexRead, |
+ remainder * sizeof(*fifoBusChannel)); |
+ memcpy(outputBusChannel + remainder, fifoBusChannel, |
+ (framesToFill - remainder) * sizeof(*fifoBusChannel)); |
+ } |
+ |
+ // The frames available was not enough to fulfill the requested frames. Fill |
+ // the rest of the channel with silence. |
+ if (framesRequested > framesToFill) { |
+ memset(outputBusChannel + framesToFill, 0, |
+ (framesRequested - framesToFill) * sizeof(*outputBusChannel)); |
+ } |
+ } |
+ |
+ // Update the read index; wrap it around if necessary. |
+ m_indexRead = (m_indexRead + framesToFill) % m_fifoLength; |
+ |
+ // In case of underflow, move the write index to the updated read index. |
+ if (framesRequested > framesToFill) { |
+ m_indexWrite = m_indexRead; |
+ if (m_underflowCount++ < kLogCapOverUnderflow) { |
+ DVLOG(1) << "PushPullFIFO: underflow while pulling (" |
+ << "underflowCount=" << m_underflowCount |
+ << ", availableFrames=" << m_framesAvailable |
+ << ", requestedFrames=" << framesRequested |
+ << ", fifoLength=" << m_fifoLength << ")"; |
+ } |
+ } |
+ |
+ // Update the number of frames in FIFO. |
+ m_framesAvailable = |
+ m_framesAvailable > framesToFill ? m_framesAvailable - framesToFill : 0; |
Raymond Toy
2017/01/30 20:59:28
Doesn't line 89 guarantees the m_framesAvailable >
hongchan
2017/02/01 18:07:27
Done.
|
+} |
+ |
+const PushPullFIFOStateForTest PushPullFIFO::getStateForTest() const { |
+ return {length(), numberOfChannels(), framesAvailable(), m_indexRead, |
+ m_indexWrite, m_overflowCount, m_underflowCount}; |
+} |
+ |
+} // namespace blink |