Line data Source code
1 : /*
2 : * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved.
3 : *
4 : * Use of this source code is governed by a BSD-style license
5 : * that can be found in the LICENSE file in the root of the source
6 : * tree. An additional intellectual property rights grant can be found
7 : * in the file PATENTS. All contributing project authors may
8 : * be found in the AUTHORS file in the root of the source tree.
9 : */
10 :
11 : // Modified from the Chromium original here:
12 : // src/media/base/sinc_resampler.h
13 :
14 : #ifndef WEBRTC_COMMON_AUDIO_RESAMPLER_SINC_RESAMPLER_H_
15 : #define WEBRTC_COMMON_AUDIO_RESAMPLER_SINC_RESAMPLER_H_
16 :
17 : #include <memory>
18 :
19 : #include "webrtc/base/constructormagic.h"
20 : #include "webrtc/base/gtest_prod_util.h"
21 : #include "webrtc/system_wrappers/include/aligned_malloc.h"
22 : #include "webrtc/typedefs.h"
23 :
24 : namespace webrtc {
25 :
26 : // Callback class for providing more data into the resampler. Expects |frames|
27 : // of data to be rendered into |destination|; zero padded if not enough frames
28 : // are available to satisfy the request.
29 0 : class SincResamplerCallback {
30 : public:
31 0 : virtual ~SincResamplerCallback() {}
32 : virtual void Run(size_t frames, float* destination) = 0;
33 : };
34 :
35 : // SincResampler is a high-quality single-channel sample-rate converter.
36 : class SincResampler {
37 : public:
38 : // The kernel size can be adjusted for quality (higher is better) at the
39 : // expense of performance. Must be a multiple of 32.
40 : // TODO(dalecurtis): Test performance to see if we can jack this up to 64+.
41 : static const size_t kKernelSize = 32;
42 :
43 : // Default request size. Affects how often and for how much SincResampler
44 : // calls back for input. Must be greater than kKernelSize.
45 : static const size_t kDefaultRequestSize = 512;
46 :
47 : // The kernel offset count is used for interpolation and is the number of
48 : // sub-sample kernel shifts. Can be adjusted for quality (higher is better)
49 : // at the expense of allocating more memory.
50 : static const size_t kKernelOffsetCount = 32;
51 : static const size_t kKernelStorageSize =
52 : kKernelSize * (kKernelOffsetCount + 1);
53 :
54 : // Constructs a SincResampler with the specified |read_cb|, which is used to
55 : // acquire audio data for resampling. |io_sample_rate_ratio| is the ratio
56 : // of input / output sample rates. |request_frames| controls the size in
57 : // frames of the buffer requested by each |read_cb| call. The value must be
58 : // greater than kKernelSize. Specify kDefaultRequestSize if there are no
59 : // request size constraints.
60 : SincResampler(double io_sample_rate_ratio,
61 : size_t request_frames,
62 : SincResamplerCallback* read_cb);
63 : virtual ~SincResampler();
64 :
65 : // Resample |frames| of data from |read_cb_| into |destination|.
66 : void Resample(size_t frames, float* destination);
67 :
68 : // The maximum size in frames that guarantees Resample() will only make a
69 : // single call to |read_cb_| for more data.
70 : size_t ChunkSize() const;
71 :
72 0 : size_t request_frames() const { return request_frames_; }
73 :
74 : // Flush all buffered data and reset internal indices. Not thread safe, do
75 : // not call while Resample() is in progress.
76 : void Flush();
77 :
78 : // Update |io_sample_rate_ratio_|. SetRatio() will cause a reconstruction of
79 : // the kernels used for resampling. Not thread safe, do not call while
80 : // Resample() is in progress.
81 : //
82 : // TODO(ajm): Use this in PushSincResampler rather than reconstructing
83 : // SincResampler. We would also need a way to update |request_frames_|.
84 : void SetRatio(double io_sample_rate_ratio);
85 :
86 : float* get_kernel_for_testing() { return kernel_storage_.get(); }
87 :
88 : private:
89 : FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve);
90 : FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark);
91 :
92 : void InitializeKernel();
93 : void UpdateRegions(bool second_load);
94 :
95 : // Selects runtime specific CPU features like SSE. Must be called before
96 : // using SincResampler.
97 : // TODO(ajm): Currently managed by the class internally. See the note with
98 : // |convolve_proc_| below.
99 : void InitializeCPUSpecificFeatures();
100 :
101 : // Compute convolution of |k1| and |k2| over |input_ptr|, resultant sums are
102 : // linearly interpolated using |kernel_interpolation_factor|. On x86 and ARM
103 : // the underlying implementation is chosen at run time.
104 : static float Convolve_C(const float* input_ptr, const float* k1,
105 : const float* k2, double kernel_interpolation_factor);
106 : #if defined(WEBRTC_ARCH_X86_FAMILY)
107 : static float Convolve_SSE(const float* input_ptr, const float* k1,
108 : const float* k2,
109 : double kernel_interpolation_factor);
110 : #elif defined(WEBRTC_HAS_NEON)
111 : static float Convolve_NEON(const float* input_ptr, const float* k1,
112 : const float* k2,
113 : double kernel_interpolation_factor);
114 : #endif
115 :
116 : // The ratio of input / output sample rates.
117 : double io_sample_rate_ratio_;
118 :
119 : // An index on the source input buffer with sub-sample precision. It must be
120 : // double precision to avoid drift.
121 : double virtual_source_idx_;
122 :
123 : // The buffer is primed once at the very beginning of processing.
124 : bool buffer_primed_;
125 :
126 : // Source of data for resampling.
127 : SincResamplerCallback* read_cb_;
128 :
129 : // The size (in samples) to request from each |read_cb_| execution.
130 : const size_t request_frames_;
131 :
132 : // The number of source frames processed per pass.
133 : size_t block_size_;
134 :
135 : // The size (in samples) of the internal buffer used by the resampler.
136 : const size_t input_buffer_size_;
137 :
138 : // Contains kKernelOffsetCount kernels back-to-back, each of size kKernelSize.
139 : // The kernel offsets are sub-sample shifts of a windowed sinc shifted from
140 : // 0.0 to 1.0 sample.
141 : std::unique_ptr<float[], AlignedFreeDeleter> kernel_storage_;
142 : std::unique_ptr<float[], AlignedFreeDeleter> kernel_pre_sinc_storage_;
143 : std::unique_ptr<float[], AlignedFreeDeleter> kernel_window_storage_;
144 :
145 : // Data from the source is copied into this buffer for each processing pass.
146 : std::unique_ptr<float[], AlignedFreeDeleter> input_buffer_;
147 :
148 : // Stores the runtime selection of which Convolve function to use.
149 : // TODO(ajm): Move to using a global static which must only be initialized
150 : // once by the user. We're not doing this initially, because we don't have
151 : // e.g. a LazyInstance helper in webrtc.
152 : #if defined(WEBRTC_CPU_DETECTION)
153 : typedef float (*ConvolveProc)(const float*, const float*, const float*,
154 : double);
155 : ConvolveProc convolve_proc_;
156 : #endif
157 :
158 : // Pointers to the various regions inside |input_buffer_|. See the diagram at
159 : // the top of the .cc file for more information.
160 : float* r0_;
161 : float* const r1_;
162 : float* const r2_;
163 : float* r3_;
164 : float* r4_;
165 :
166 : RTC_DISALLOW_COPY_AND_ASSIGN(SincResampler);
167 : };
168 :
169 : } // namespace webrtc
170 :
171 : #endif // WEBRTC_COMMON_AUDIO_RESAMPLER_SINC_RESAMPLER_H_
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