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Diffstat (limited to 'third_party/libwebrtc/modules/audio_coding/codecs/opus/test/lapped_transform.h')
-rw-r--r-- | third_party/libwebrtc/modules/audio_coding/codecs/opus/test/lapped_transform.h | 175 |
1 files changed, 175 insertions, 0 deletions
diff --git a/third_party/libwebrtc/modules/audio_coding/codecs/opus/test/lapped_transform.h b/third_party/libwebrtc/modules/audio_coding/codecs/opus/test/lapped_transform.h new file mode 100644 index 0000000000..bb25c34a9e --- /dev/null +++ b/third_party/libwebrtc/modules/audio_coding/codecs/opus/test/lapped_transform.h @@ -0,0 +1,175 @@ +/* + * Copyright (c) 2014 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. + */ + +#ifndef MODULES_AUDIO_CODING_CODECS_OPUS_TEST_LAPPED_TRANSFORM_H_ +#define MODULES_AUDIO_CODING_CODECS_OPUS_TEST_LAPPED_TRANSFORM_H_ + +#include <complex> +#include <memory> + +#include "common_audio/real_fourier.h" +#include "modules/audio_coding/codecs/opus/test/blocker.h" +#include "rtc_base/memory/aligned_malloc.h" + +namespace webrtc { + +// Wrapper class for aligned arrays. Every row (and the first dimension) are +// aligned to the given byte alignment. +template <typename T> +class AlignedArray { + public: + AlignedArray(size_t rows, size_t cols, size_t alignment) + : rows_(rows), cols_(cols) { + RTC_CHECK_GT(alignment, 0); + head_row_ = + static_cast<T**>(AlignedMalloc(rows_ * sizeof(*head_row_), alignment)); + for (size_t i = 0; i < rows_; ++i) { + head_row_[i] = static_cast<T*>( + AlignedMalloc(cols_ * sizeof(**head_row_), alignment)); + } + } + + ~AlignedArray() { + for (size_t i = 0; i < rows_; ++i) { + AlignedFree(head_row_[i]); + } + AlignedFree(head_row_); + } + + T* const* Array() { return head_row_; } + + const T* const* Array() const { return head_row_; } + + T* Row(size_t row) { + RTC_CHECK_LE(row, rows_); + return head_row_[row]; + } + + const T* Row(size_t row) const { + RTC_CHECK_LE(row, rows_); + return head_row_[row]; + } + + private: + size_t rows_; + size_t cols_; + T** head_row_; +}; + +// Helper class for audio processing modules which operate on frequency domain +// input derived from the windowed time domain audio stream. +// +// The input audio chunk is sliced into possibly overlapping blocks, multiplied +// by a window and transformed with an FFT implementation. The transformed data +// is supplied to the given callback for processing. The processed output is +// then inverse transformed into the time domain and spliced back into a chunk +// which constitutes the final output of this processing module. +class LappedTransform { + public: + class Callback { + public: + virtual ~Callback() {} + + virtual void ProcessAudioBlock(const std::complex<float>* const* in_block, + size_t num_in_channels, + size_t frames, + size_t num_out_channels, + std::complex<float>* const* out_block) = 0; + }; + + // Construct a transform instance. `chunk_length` is the number of samples in + // each channel. `window` defines the window, owned by the caller (a copy is + // made internally); `window` should have length equal to `block_length`. + // `block_length` defines the length of a block, in samples. + // `shift_amount` is in samples. `callback` is the caller-owned audio + // processing function called for each block of the input chunk. + LappedTransform(size_t num_in_channels, + size_t num_out_channels, + size_t chunk_length, + const float* window, + size_t block_length, + size_t shift_amount, + Callback* callback); + ~LappedTransform(); + + // Main audio processing helper method. Internally slices `in_chunk` into + // blocks, transforms them to frequency domain, calls the callback for each + // block and returns a de-blocked time domain chunk of audio through + // `out_chunk`. Both buffers are caller-owned. + void ProcessChunk(const float* const* in_chunk, float* const* out_chunk); + + // Get the chunk length. + // + // The chunk length is the number of samples per channel that must be passed + // to ProcessChunk via the parameter in_chunk. + // + // Returns the same chunk_length passed to the LappedTransform constructor. + size_t chunk_length() const { return chunk_length_; } + + // Get the number of input channels. + // + // This is the number of arrays that must be passed to ProcessChunk via + // in_chunk. + // + // Returns the same num_in_channels passed to the LappedTransform constructor. + size_t num_in_channels() const { return num_in_channels_; } + + // Get the number of output channels. + // + // This is the number of arrays that must be passed to ProcessChunk via + // out_chunk. + // + // Returns the same num_out_channels passed to the LappedTransform + // constructor. + size_t num_out_channels() const { return num_out_channels_; } + + // Returns the initial delay. + // + // This is the delay introduced by the `blocker_` to be able to get and return + // chunks of `chunk_length`, but process blocks of `block_length`. + size_t initial_delay() const { return blocker_.initial_delay(); } + + private: + // Internal middleware callback, given to the blocker. Transforms each block + // and hands it over to the processing method given at construction time. + class BlockThunk : public BlockerCallback { + public: + explicit BlockThunk(LappedTransform* parent) : parent_(parent) {} + + void ProcessBlock(const float* const* input, + size_t num_frames, + size_t num_input_channels, + size_t num_output_channels, + float* const* output) override; + + private: + LappedTransform* const parent_; + } blocker_callback_; + + const size_t num_in_channels_; + const size_t num_out_channels_; + + const size_t block_length_; + const size_t chunk_length_; + + Callback* const block_processor_; + Blocker blocker_; + + // TODO(alessiob): Replace RealFourier with a different FFT library. + std::unique_ptr<RealFourier> fft_; + const size_t cplx_length_; + AlignedArray<float> real_buf_; + AlignedArray<std::complex<float> > cplx_pre_; + AlignedArray<std::complex<float> > cplx_post_; +}; + +} // namespace webrtc + +#endif // MODULES_AUDIO_CODING_CODECS_OPUS_TEST_LAPPED_TRANSFORM_H_ |