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1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. | 1 // Copyright (c) 2012 The Chromium Authors. All rights reserved. |
2 // Use of this source code is governed by a BSD-style license that can be | 2 // Use of this source code is governed by a BSD-style license that can be |
3 // found in the LICENSE file. | 3 // found in the LICENSE file. |
4 // MSVC++ requires this to be set before any other includes to get M_PI. | 4 // MSVC++ requires this to be set before any other includes to get M_PI. |
5 #define _USE_MATH_DEFINES | 5 #define _USE_MATH_DEFINES |
6 #include <cmath> | 6 #include <cmath> |
7 | 7 |
8 #include "media/audio/simple_sources.h" | 8 #include "media/audio/simple_sources.h" |
9 | 9 |
10 #include <algorithm> | 10 #include <algorithm> |
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22 f_(freq / sample_freq), | 22 f_(freq / sample_freq), |
23 time_state_(0), | 23 time_state_(0), |
24 cap_(0), | 24 cap_(0), |
25 callbacks_(0), | 25 callbacks_(0), |
26 errors_(0) { | 26 errors_(0) { |
27 } | 27 } |
28 | 28 |
29 // The implementation could be more efficient if a lookup table is constructed | 29 // The implementation could be more efficient if a lookup table is constructed |
30 // but it is efficient enough for our simple needs. | 30 // but it is efficient enough for our simple needs. |
31 int SineWaveAudioSource::OnMoreData(AudioBus* audio_bus, | 31 int SineWaveAudioSource::OnMoreData(AudioBus* audio_bus, |
32 AudioBuffersState audio_buffers) { | 32 uint32 total_bytes_delay) { |
33 base::AutoLock auto_lock(time_lock_); | 33 base::AutoLock auto_lock(time_lock_); |
34 callbacks_++; | 34 callbacks_++; |
35 | 35 |
36 // The table is filled with s(t) = kint16max*sin(Theta*t), | 36 // The table is filled with s(t) = kint16max*sin(Theta*t), |
37 // where Theta = 2*PI*fs. | 37 // where Theta = 2*PI*fs. |
38 // We store the discrete time value |t| in a member to ensure that the | 38 // We store the discrete time value |t| in a member to ensure that the |
39 // next pass starts at a correct state. | 39 // next pass starts at a correct state. |
40 int max_frames = cap_ > 0 ? | 40 int max_frames = cap_ > 0 ? |
41 std::min(audio_bus->frames(), cap_ - time_state_) : audio_bus->frames(); | 41 std::min(audio_bus->frames(), cap_ - time_state_) : audio_bus->frames(); |
42 for (int i = 0; i < max_frames; ++i) | 42 for (int i = 0; i < max_frames; ++i) |
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57 DCHECK_GT(cap, 0); | 57 DCHECK_GT(cap, 0); |
58 cap_ = cap; | 58 cap_ = cap; |
59 } | 59 } |
60 | 60 |
61 void SineWaveAudioSource::Reset() { | 61 void SineWaveAudioSource::Reset() { |
62 base::AutoLock auto_lock(time_lock_); | 62 base::AutoLock auto_lock(time_lock_); |
63 time_state_ = 0; | 63 time_state_ = 0; |
64 } | 64 } |
65 | 65 |
66 } // namespace media | 66 } // namespace media |
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