/* * Copyright (c) 2013 The WebRTC project authors. All Rights Reserved. * * Use of this source code is governed by a BSD-style license * that can be found in the LICENSE file in the root of the source * tree. An additional intellectual property rights grant can be found * in the file PATENTS. All contributing project authors may * be found in the AUTHORS file in the root of the source tree. */ // Modified from the Chromium original here: // src/media/base/sinc_resampler.h #ifndef COMMON_AUDIO_RESAMPLER_SINC_RESAMPLER_H_ #define COMMON_AUDIO_RESAMPLER_SINC_RESAMPLER_H_ #include #include #include "rtc_base/constructor_magic.h" #include "rtc_base/gtest_prod_util.h" #include "rtc_base/memory/aligned_malloc.h" #include "rtc_base/system/arch.h" namespace webrtc { // Callback class for providing more data into the resampler. Expects |frames| // of data to be rendered into |destination|; zero padded if not enough frames // are available to satisfy the request. class SincResamplerCallback { public: virtual ~SincResamplerCallback() {} virtual void Run(size_t frames, float* destination) = 0; }; // SincResampler is a high-quality single-channel sample-rate converter. class SincResampler { public: // The kernel size can be adjusted for quality (higher is better) at the // expense of performance. Must be a multiple of 32. // TODO(dalecurtis): Test performance to see if we can jack this up to 64+. static const size_t kKernelSize = 32; // Default request size. Affects how often and for how much SincResampler // calls back for input. Must be greater than kKernelSize. static const size_t kDefaultRequestSize = 512; // The kernel offset count is used for interpolation and is the number of // sub-sample kernel shifts. Can be adjusted for quality (higher is better) // at the expense of allocating more memory. static const size_t kKernelOffsetCount = 32; static const size_t kKernelStorageSize = kKernelSize * (kKernelOffsetCount + 1); // Constructs a SincResampler with the specified |read_cb|, which is used to // acquire audio data for resampling. |io_sample_rate_ratio| is the ratio // of input / output sample rates. |request_frames| controls the size in // frames of the buffer requested by each |read_cb| call. The value must be // greater than kKernelSize. Specify kDefaultRequestSize if there are no // request size constraints. SincResampler(double io_sample_rate_ratio, size_t request_frames, SincResamplerCallback* read_cb); virtual ~SincResampler(); // Resample |frames| of data from |read_cb_| into |destination|. void Resample(size_t frames, float* destination); // The maximum size in frames that guarantees Resample() will only make a // single call to |read_cb_| for more data. size_t ChunkSize() const; size_t request_frames() const { return request_frames_; } // Flush all buffered data and reset internal indices. Not thread safe, do // not call while Resample() is in progress. void Flush(); // Update |io_sample_rate_ratio_|. SetRatio() will cause a reconstruction of // the kernels used for resampling. Not thread safe, do not call while // Resample() is in progress. // // TODO(ajm): Use this in PushSincResampler rather than reconstructing // SincResampler. We would also need a way to update |request_frames_|. void SetRatio(double io_sample_rate_ratio); float* get_kernel_for_testing() { return kernel_storage_.get(); } private: FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, Convolve); FRIEND_TEST_ALL_PREFIXES(SincResamplerTest, ConvolveBenchmark); void InitializeKernel(); void UpdateRegions(bool second_load); // Selects runtime specific CPU features like SSE. Must be called before // using SincResampler. // TODO(ajm): Currently managed by the class internally. See the note with // |convolve_proc_| below. void InitializeCPUSpecificFeatures(); // Compute convolution of |k1| and |k2| over |input_ptr|, resultant sums are // linearly interpolated using |kernel_interpolation_factor|. On x86 and ARM // the underlying implementation is chosen at run time. static float Convolve_C(const float* input_ptr, const float* k1, const float* k2, double kernel_interpolation_factor); #if defined(WEBRTC_ARCH_X86_FAMILY) static float Convolve_SSE(const float* input_ptr, const float* k1, const float* k2, double kernel_interpolation_factor); static float Convolve_AVX2(const float* input_ptr, const float* k1, const float* k2, double kernel_interpolation_factor); #elif defined(WEBRTC_HAS_NEON) static float Convolve_NEON(const float* input_ptr, const float* k1, const float* k2, double kernel_interpolation_factor); #endif // The ratio of input / output sample rates. double io_sample_rate_ratio_; // An index on the source input buffer with sub-sample precision. It must be // double precision to avoid drift. double virtual_source_idx_; // The buffer is primed once at the very beginning of processing. bool buffer_primed_; // Source of data for resampling. SincResamplerCallback* read_cb_; // The size (in samples) to request from each |read_cb_| execution. const size_t request_frames_; // The number of source frames processed per pass. size_t block_size_; // The size (in samples) of the internal buffer used by the resampler. const size_t input_buffer_size_; // Contains kKernelOffsetCount kernels back-to-back, each of size kKernelSize. // The kernel offsets are sub-sample shifts of a windowed sinc shifted from // 0.0 to 1.0 sample. std::unique_ptr kernel_storage_; std::unique_ptr kernel_pre_sinc_storage_; std::unique_ptr kernel_window_storage_; // Data from the source is copied into this buffer for each processing pass. std::unique_ptr input_buffer_; // Stores the runtime selection of which Convolve function to use. // TODO(ajm): Move to using a global static which must only be initialized // once by the user. We're not doing this initially, because we don't have // e.g. a LazyInstance helper in webrtc. typedef float (*ConvolveProc)(const float*, const float*, const float*, double); ConvolveProc convolve_proc_; // Pointers to the various regions inside |input_buffer_|. See the diagram at // the top of the .cc file for more information. float* r0_; float* const r1_; float* const r2_; float* r3_; float* r4_; RTC_DISALLOW_COPY_AND_ASSIGN(SincResampler); }; } // namespace webrtc #endif // COMMON_AUDIO_RESAMPLER_SINC_RESAMPLER_H_