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