| /* |
| * 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 <stddef.h> |
| |
| #include <memory> |
| |
| #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); |
| #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<float[], AlignedFreeDeleter> kernel_storage_; |
| std::unique_ptr<float[], AlignedFreeDeleter> kernel_pre_sinc_storage_; |
| std::unique_ptr<float[], AlignedFreeDeleter> kernel_window_storage_; |
| |
| // Data from the source is copied into this buffer for each processing pass. |
| std::unique_ptr<float[], AlignedFreeDeleter> 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. |
| #if defined(WEBRTC_ARCH_X86_FAMILY) && !defined(__SSE2__) |
| typedef float (*ConvolveProc)(const float*, |
| const float*, |
| const float*, |
| double); |
| ConvolveProc convolve_proc_; |
| #endif |
| |
| // 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_ |