1 /*
2  * Copyright (C) 2010, Google Inc. All rights reserved.
3  *
4  * Redistribution and use in source and binary forms, with or without
5  * modification, are permitted provided that the following conditions
6  * are met:
7  * 1.  Redistributions of source code must retain the above copyright
8  *    notice, this list of conditions and the following disclaimer.
9  * 2.  Redistributions in binary form must reproduce the above copyright
10  *    notice, this list of conditions and the following disclaimer in the
11  *    documentation and/or other materials provided with the distribution.
12  *
13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' AND
14  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
16  * ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS BE LIABLE
17  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
18  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
19  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
20  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
21  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
22  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
23  * DAMAGE.
24  */
25 
26 #ifndef THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_AUDIO_RESAMPLER_H_
27 #define THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_AUDIO_RESAMPLER_H_
28 
29 #include <memory>
30 
31 #include "base/macros.h"
32 #include "third_party/blink/renderer/platform/audio/audio_bus.h"
33 #include "third_party/blink/renderer/platform/audio/audio_resampler_kernel.h"
34 #include "third_party/blink/renderer/platform/audio/audio_source_provider.h"
35 #include "third_party/blink/renderer/platform/wtf/allocator/allocator.h"
36 #include "third_party/blink/renderer/platform/wtf/vector.h"
37 
38 namespace blink {
39 
40 // AudioResampler resamples the audio stream from an AudioSourceProvider.
41 // The audio stream may be single or multi-channel.
42 // The default constructor defaults to single-channel (mono).
43 
44 class PLATFORM_EXPORT AudioResampler {
45   DISALLOW_NEW();
46 
47  public:
48   AudioResampler();
49   AudioResampler(unsigned number_of_channels);
50   ~AudioResampler() = default;
51 
52   // Given an AudioSourceProvider, process() resamples the source stream into
53   // destinationBus.
54   void Process(AudioSourceProvider*,
55                AudioBus* destination_bus,
56                uint32_t frames_to_process);
57 
58   // Resets the processing state.
59   void Reset();
60 
61   void ConfigureChannels(unsigned number_of_channels);
62 
63   // 0 < rate <= MaxRate
64   void SetRate(double rate);
Rate()65   double Rate() const { return rate_; }
66 
67   static const double kMaxRate;
68 
69  private:
70   double rate_;
71   Vector<std::unique_ptr<AudioResamplerKernel>> kernels_;
72   scoped_refptr<AudioBus> source_bus_;
73 
74   DISALLOW_COPY_AND_ASSIGN(AudioResampler);
75 };
76 
77 }  // namespace blink
78 
79 #endif  // THIRD_PARTY_BLINK_RENDERER_PLATFORM_AUDIO_AUDIO_RESAMPLER_H_
80