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1 // Copyright 2017 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 <memory> | |
8 #include "platform/audio/AudioUtilities.h" | |
9 #include "wtf/PtrUtil.h" | |
10 | |
11 namespace blink { | |
12 | |
13 namespace { | |
14 | |
15 // Suppress the warning log if over/underflow happens more than 100 times. | |
16 const unsigned kMaxMessagesToLog = 100; | |
17 } | |
18 | |
19 const size_t PushPullFIFO::kMaxFIFOLength = 65536; | |
20 | |
21 PushPullFIFO::PushPullFIFO(unsigned numberOfChannels, size_t fifoLength) | |
22 : m_fifoLength(fifoLength), | |
23 m_framesAvailable(0), | |
24 m_indexRead(0), | |
25 m_indexWrite(0), | |
26 m_overflowCount(0), | |
27 m_underflowCount(0) { | |
28 CHECK_LE(m_fifoLength, kMaxFIFOLength); | |
29 m_fifoBus = AudioBus::create(numberOfChannels, m_fifoLength); | |
30 } | |
31 | |
32 PushPullFIFO::~PushPullFIFO() {} | |
33 | |
34 // Push the data from |inputBus| to FIFO. The size of push is determined by | |
35 // the length of |inputBus|. | |
36 void PushPullFIFO::push(const AudioBus* inputBus) { | |
37 CHECK(inputBus); | |
38 CHECK_EQ(inputBus->length(), AudioUtilities::kRenderQuantumFrames); | |
39 SECURITY_CHECK(inputBus->length() <= m_fifoLength); | |
40 SECURITY_CHECK(m_indexWrite < m_fifoLength); | |
41 | |
42 const size_t inputBusLength = inputBus->length(); | |
43 const size_t remainder = m_fifoLength - m_indexWrite; | |
44 | |
45 for (unsigned i = 0; i < m_fifoBus->numberOfChannels(); ++i) { | |
46 float* fifoBusChannel = m_fifoBus->channel(i)->mutableData(); | |
47 const float* inputBusChannel = inputBus->channel(i)->data(); | |
48 if (remainder >= inputBusLength) { | |
49 // The remainder is big enough for the input data. | |
50 memcpy(fifoBusChannel + m_indexWrite, inputBusChannel, | |
51 inputBusLength * sizeof(*fifoBusChannel)); | |
52 } else { | |
53 // The input data overflows the remainder size. Wrap around the index. | |
54 memcpy(fifoBusChannel + m_indexWrite, inputBusChannel, | |
55 remainder * sizeof(*fifoBusChannel)); | |
56 memcpy(fifoBusChannel, inputBusChannel + remainder, | |
57 (inputBusLength - remainder) * sizeof(*fifoBusChannel)); | |
58 } | |
59 } | |
60 | |
61 // Update the write index; wrap it around if necessary. | |
62 m_indexWrite = (m_indexWrite + inputBusLength) % m_fifoLength; | |
63 | |
64 // In case of overflow, move the |indexRead| to the updated |indexWrite| to | |
65 // avoid reading overwritten frames by the next pull. | |
66 if (inputBusLength > m_fifoLength - m_framesAvailable) { | |
67 m_indexRead = m_indexWrite; | |
68 if (++m_overflowCount < kMaxMessagesToLog) { | |
69 LOG(WARNING) << "PushPullFIFO: overflow while pushing (" | |
70 << "overflowCount=" << m_overflowCount | |
71 << ", availableFrames=" << m_framesAvailable | |
72 << ", inputFrames=" << inputBusLength | |
73 << ", fifoLength=" << m_fifoLength << ")"; | |
74 } | |
75 } | |
76 | |
77 // Update the number of frames available in FIFO. | |
78 m_framesAvailable = | |
79 std::min(m_framesAvailable + inputBusLength, m_fifoLength); | |
80 DCHECK_EQ((m_indexRead + m_framesAvailable) % m_fifoLength, m_indexWrite); | |
81 } | |
82 | |
83 // Pull the data out of FIFO to |outputBus|. If remaining frame in the FIFO | |
84 // is less than the frames to pull, provides remaining frame plus the silence. | |
85 void PushPullFIFO::pull(AudioBus* outputBus, size_t framesRequested) { | |
86 CHECK(outputBus); | |
87 SECURITY_CHECK(framesRequested <= outputBus->length()); | |
88 SECURITY_CHECK(framesRequested <= m_fifoLength); | |
89 SECURITY_CHECK(m_indexRead < m_fifoLength); | |
90 | |
91 const size_t remainder = m_fifoLength - m_indexRead; | |
92 const size_t framesToFill = std::min(m_framesAvailable, framesRequested); | |
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 (framesRequested > framesToFill) { | |
115 memset(outputBusChannel + framesToFill, 0, | |
116 (framesRequested - 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 |indexWrite| to the updated |indexRead|. | |
124 if (framesRequested > framesToFill) { | |
125 m_indexWrite = m_indexRead; | |
126 if (m_underflowCount++ < kMaxMessagesToLog) { | |
127 LOG(WARNING) << "PushPullFIFO: underflow while pulling (" | |
128 << "underflowCount=" << m_underflowCount | |
129 << ", availableFrames=" << m_framesAvailable | |
130 << ", requestedFrames=" << framesRequested | |
131 << ", fifoLength=" << m_fifoLength << ")"; | |
132 } | |
133 } | |
134 | |
135 // Update the number of frames in FIFO. | |
136 m_framesAvailable -= framesToFill; | |
137 DCHECK_EQ((m_indexRead + m_framesAvailable) % m_fifoLength, m_indexWrite); | |
138 } | |
139 | |
140 const PushPullFIFOStateForTest PushPullFIFO::getStateForTest() const { | |
141 return {length(), numberOfChannels(), framesAvailable(), m_indexRead, | |
142 m_indexWrite, m_overflowCount, m_underflowCount}; | |
143 } | |
144 | |
145 } // namespace blink | |
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