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1 // Copyright 2016 The Chromium Authors. All rights reserved. | |
2 // Use of this source code is governed by a BSD-style license that can be | |
3 // found in the LICENSE file. | |
4 | |
5 #include "platform/audio/PushPullFIFO.h" | |
6 | |
7 #include "wtf/PtrUtil.h" | |
8 #include <memory> | |
9 | |
10 namespace blink { | |
11 | |
12 // Suppress the warning log if over/underflow happens more than 100 times. | |
13 const int kLogCapOverUnderflow = 100; | |
14 | |
15 PushPullFIFO::PushPullFIFO(unsigned numberOfChannels, size_t fifoLength) | |
16 : m_fifoBus(AudioBus::create(numberOfChannels, fifoLength)), | |
17 m_fifoLength(static_cast<int>(fifoLength)), | |
18 m_framesAvailable(0), | |
19 m_indexRead(0), | |
20 m_indexWrite(0), | |
21 m_overflowCount(0), | |
22 m_underflowCount(0) {} | |
23 | |
24 PushPullFIFO::~PushPullFIFO() {} | |
25 | |
26 // Push the data from |inputBus| to FIFO. The size of push is determined by | |
27 // the length of |inputBus|. | |
28 void PushPullFIFO::push(const AudioBus* inputBus) { | |
29 DCHECK(inputBus); | |
30 if (!inputBus) | |
31 return; | |
32 | |
33 const int inputBusLength = static_cast<int>(inputBus->length()); | |
o1ka
2017/01/24 11:09:02
unsafe
hongchan
2017/01/26 22:33:18
Done.
| |
34 const int remainder = m_fifoLength - m_indexWrite; | |
35 SECURITY_CHECK(inputBusLength < m_fifoLength); | |
36 SECURITY_CHECK(m_indexWrite < m_fifoLength); | |
37 | |
38 for (unsigned i = 0; i < m_fifoBus->numberOfChannels(); ++i) { | |
39 float* fifoBusChannel = m_fifoBus->channel(i)->mutableData(); | |
40 const float* inputBusChannel = inputBus->channel(i)->data(); | |
41 if (remainder >= inputBusLength) { | |
42 // The remainder is big enough for the input data. | |
43 memcpy(fifoBusChannel + m_indexWrite, inputBusChannel, | |
44 inputBusLength * sizeof(*fifoBusChannel)); | |
45 } else { | |
46 // The input data overflows the remainder size. Wrap around the index. | |
47 memcpy(fifoBusChannel + m_indexWrite, inputBusChannel, | |
48 remainder * sizeof(*fifoBusChannel)); | |
49 memcpy(fifoBusChannel, inputBusChannel + remainder, | |
50 (inputBusLength - remainder) * sizeof(*fifoBusChannel)); | |
51 } | |
52 } | |
53 | |
54 // Update the write index; wrap it around if necessary. | |
55 m_indexWrite = (m_indexWrite + inputBusLength) % m_fifoLength; | |
56 | |
57 // In case of overflow, move the read index to the updated write index. | |
58 if (m_fifoLength < inputBusLength + m_framesAvailable) { | |
59 m_indexRead = m_indexWrite; | |
60 if (++m_overflowCount < kLogCapOverUnderflow) { | |
61 LOG(WARNING) << "PushPullFIFO::pushing overflown. " | |
62 << "(count = " << m_overflowCount << ") \n" | |
63 << "in-FIFO frames = " << m_framesAvailable | |
64 << ", input frames = " << inputBusLength | |
65 << ", FIFO size = " << m_fifoLength; | |
66 } | |
67 } | |
68 | |
69 // Update the number of frames available in FIFO. | |
70 m_framesAvailable = | |
71 std::min(m_fifoLength, m_framesAvailable + inputBusLength); | |
72 } | |
73 | |
74 // Pull the data out of FIFO to |outputBus|. If the remaining frames in the FIFO | |
75 // is less than the frames to pull, provides the remaining frames plus the | |
76 // silence. | |
77 void PushPullFIFO::pull(AudioBus* outputBus, size_t framesRequested) { | |
78 DCHECK(outputBus); | |
79 SECURITY_CHECK(framesRequested <= outputBus->length()); | |
80 if (!outputBus) | |
81 return; | |
82 | |
83 // TODO(hongchan): add a mutex here for this operation when two threads are | |
84 // introduced. Pulling operation has a higher priority to ensure the audio | |
85 // device callback to be uninterrupted. | |
86 | |
87 const int remainder = m_fifoLength - m_indexRead; | |
88 const int framesToProvide = static_cast<int>(framesRequested); | |
o1ka
2017/01/24 11:09:02
unsafe
hongchan
2017/01/26 22:33:18
Done.
| |
89 SECURITY_CHECK(framesToProvide < m_fifoLength); | |
90 SECURITY_CHECK(m_indexRead < m_fifoLength); | |
91 | |
92 const int framesToFill = std::min(m_framesAvailable, framesToProvide); | |
93 | |
94 for (unsigned i = 0; i < m_fifoBus->numberOfChannels(); ++i) { | |
95 const float* fifoBusChannel = m_fifoBus->channel(i)->data(); | |
96 float* outputBusChannel = outputBus->channel(i)->mutableData(); | |
97 | |
98 // Fill up the output bus with the available frames first. | |
99 if (remainder >= framesToFill) { | |
100 // The remainder is big enough for the frames to pull. | |
101 memcpy(outputBusChannel, fifoBusChannel + m_indexRead, | |
102 framesToFill * sizeof(*fifoBusChannel)); | |
103 } else { | |
104 // The frames to pull is bigger than the remainder size. | |
105 // Wrap around the index. | |
106 memcpy(outputBusChannel, fifoBusChannel + m_indexRead, | |
107 remainder * sizeof(*fifoBusChannel)); | |
108 memcpy(outputBusChannel + remainder, fifoBusChannel, | |
109 (framesToFill - remainder) * sizeof(*fifoBusChannel)); | |
110 } | |
111 | |
112 // The frames available was not enough to fulfill the requested frames. Fill | |
113 // the rest of the channel with silence. | |
114 if (framesToProvide > framesToFill) { | |
115 memset(outputBusChannel + framesToFill, 0, | |
116 (framesToProvide - framesToFill) * sizeof(*outputBusChannel)); | |
117 } | |
118 } | |
119 | |
120 // Update the read index; wrap it around if necessary. | |
121 m_indexRead = (m_indexRead + framesToFill) % m_fifoLength; | |
122 | |
123 // In case of underflow, move the write index to the updated read index. | |
124 if (framesToProvide > framesToFill) { | |
125 m_indexWrite = m_indexRead; | |
126 if (m_underflowCount++ < kLogCapOverUnderflow) { | |
127 LOG(WARNING) << "PushPullFIFO::pulling underflown. " | |
128 << "(count = " << m_underflowCount << ") \n" | |
129 << "in-FIFO frames = " << m_framesAvailable | |
130 << ", requested frames = " << framesToProvide | |
131 << ", FIFO size = " << m_fifoLength << ")"; | |
132 } | |
133 } | |
134 | |
135 // Update the number of frames in FIFO. | |
136 m_framesAvailable = std::max(0, m_framesAvailable - framesToFill); | |
137 } | |
138 | |
139 } // namespace blink | |
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