| /* |
| * 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. |
| */ |
| |
| #include "webrtc/common_audio/blocker.h" |
| |
| #include <string.h> |
| |
| #include "webrtc/base/checks.h" |
| |
| namespace { |
| |
| // Adds |a| and |b| frame by frame into |result| (basically matrix addition). |
| void AddFrames(const float* const* a, |
| size_t a_start_index, |
| const float* const* b, |
| int b_start_index, |
| size_t num_frames, |
| int num_channels, |
| float* const* result, |
| size_t result_start_index) { |
| for (int i = 0; i < num_channels; ++i) { |
| for (size_t j = 0; j < num_frames; ++j) { |
| result[i][j + result_start_index] = |
| a[i][j + a_start_index] + b[i][j + b_start_index]; |
| } |
| } |
| } |
| |
| // Copies |src| into |dst| channel by channel. |
| void CopyFrames(const float* const* src, |
| size_t src_start_index, |
| size_t num_frames, |
| int num_channels, |
| float* const* dst, |
| size_t dst_start_index) { |
| for (int i = 0; i < num_channels; ++i) { |
| memcpy(&dst[i][dst_start_index], |
| &src[i][src_start_index], |
| num_frames * sizeof(dst[i][dst_start_index])); |
| } |
| } |
| |
| // Moves |src| into |dst| channel by channel. |
| void MoveFrames(const float* const* src, |
| size_t src_start_index, |
| size_t num_frames, |
| int num_channels, |
| float* const* dst, |
| size_t dst_start_index) { |
| for (int i = 0; i < num_channels; ++i) { |
| memmove(&dst[i][dst_start_index], |
| &src[i][src_start_index], |
| num_frames * sizeof(dst[i][dst_start_index])); |
| } |
| } |
| |
| void ZeroOut(float* const* buffer, |
| size_t starting_idx, |
| size_t num_frames, |
| int num_channels) { |
| for (int i = 0; i < num_channels; ++i) { |
| memset(&buffer[i][starting_idx], 0, |
| num_frames * sizeof(buffer[i][starting_idx])); |
| } |
| } |
| |
| // Pointwise multiplies each channel of |frames| with |window|. Results are |
| // stored in |frames|. |
| void ApplyWindow(const float* window, |
| size_t num_frames, |
| int num_channels, |
| float* const* frames) { |
| for (int i = 0; i < num_channels; ++i) { |
| for (size_t j = 0; j < num_frames; ++j) { |
| frames[i][j] = frames[i][j] * window[j]; |
| } |
| } |
| } |
| |
| size_t gcd(size_t a, size_t b) { |
| size_t tmp; |
| while (b) { |
| tmp = a; |
| a = b; |
| b = tmp % b; |
| } |
| return a; |
| } |
| |
| } // namespace |
| |
| namespace webrtc { |
| |
| Blocker::Blocker(size_t chunk_size, |
| size_t block_size, |
| int num_input_channels, |
| int num_output_channels, |
| const float* window, |
| size_t shift_amount, |
| BlockerCallback* callback) |
| : chunk_size_(chunk_size), |
| block_size_(block_size), |
| num_input_channels_(num_input_channels), |
| num_output_channels_(num_output_channels), |
| initial_delay_(block_size_ - gcd(chunk_size, shift_amount)), |
| frame_offset_(0), |
| input_buffer_(num_input_channels_, chunk_size_ + initial_delay_), |
| output_buffer_(chunk_size_ + initial_delay_, num_output_channels_), |
| input_block_(block_size_, num_input_channels_), |
| output_block_(block_size_, num_output_channels_), |
| window_(new float[block_size_]), |
| shift_amount_(shift_amount), |
| callback_(callback) { |
| RTC_CHECK_LE(num_output_channels_, num_input_channels_); |
| RTC_CHECK_LE(shift_amount_, block_size_); |
| |
| memcpy(window_.get(), window, block_size_ * sizeof(*window_.get())); |
| input_buffer_.MoveReadPositionBackward(initial_delay_); |
| } |
| |
| // When block_size < chunk_size the input and output buffers look like this: |
| // |
| // delay* chunk_size chunk_size + delay* |
| // buffer: <-------------|---------------------|---------------|> |
| // _a_ _b_ _c_ |
| // |
| // On each call to ProcessChunk(): |
| // 1. New input gets read into sections _b_ and _c_ of the input buffer. |
| // 2. We block starting from frame_offset. |
| // 3. We block until we reach a block |bl| that doesn't contain any frames |
| // from sections _a_ or _b_ of the input buffer. |
| // 4. We window the current block, fire the callback for processing, window |
| // again, and overlap/add to the output buffer. |
| // 5. We copy sections _a_ and _b_ of the output buffer into output. |
| // 6. For both the input and the output buffers, we copy section _c_ into |
| // section _a_. |
| // 7. We set the new frame_offset to be the difference between the first frame |
| // of |bl| and the border between sections _b_ and _c_. |
| // |
| // When block_size > chunk_size the input and output buffers look like this: |
| // |
| // chunk_size delay* chunk_size + delay* |
| // buffer: <-------------|---------------------|---------------|> |
| // _a_ _b_ _c_ |
| // |
| // On each call to ProcessChunk(): |
| // The procedure is the same as above, except for: |
| // 1. New input gets read into section _c_ of the input buffer. |
| // 3. We block until we reach a block |bl| that doesn't contain any frames |
| // from section _a_ of the input buffer. |
| // 5. We copy section _a_ of the output buffer into output. |
| // 6. For both the input and the output buffers, we copy sections _b_ and _c_ |
| // into section _a_ and _b_. |
| // 7. We set the new frame_offset to be the difference between the first frame |
| // of |bl| and the border between sections _a_ and _b_. |
| // |
| // * delay here refers to inintial_delay_ |
| // |
| // TODO(claguna): Look at using ring buffers to eliminate some copies. |
| void Blocker::ProcessChunk(const float* const* input, |
| size_t chunk_size, |
| int num_input_channels, |
| int num_output_channels, |
| float* const* output) { |
| RTC_CHECK_EQ(chunk_size, chunk_size_); |
| RTC_CHECK_EQ(num_input_channels, num_input_channels_); |
| RTC_CHECK_EQ(num_output_channels, num_output_channels_); |
| |
| input_buffer_.Write(input, num_input_channels, chunk_size_); |
| size_t first_frame_in_block = frame_offset_; |
| |
| // Loop through blocks. |
| while (first_frame_in_block < chunk_size_) { |
| input_buffer_.Read(input_block_.channels(), num_input_channels, |
| block_size_); |
| input_buffer_.MoveReadPositionBackward(block_size_ - shift_amount_); |
| |
| ApplyWindow(window_.get(), |
| block_size_, |
| num_input_channels_, |
| input_block_.channels()); |
| callback_->ProcessBlock(input_block_.channels(), |
| block_size_, |
| num_input_channels_, |
| num_output_channels_, |
| output_block_.channels()); |
| ApplyWindow(window_.get(), |
| block_size_, |
| num_output_channels_, |
| output_block_.channels()); |
| |
| AddFrames(output_buffer_.channels(), |
| first_frame_in_block, |
| output_block_.channels(), |
| 0, |
| block_size_, |
| num_output_channels_, |
| output_buffer_.channels(), |
| first_frame_in_block); |
| |
| first_frame_in_block += shift_amount_; |
| } |
| |
| // Copy output buffer to output |
| CopyFrames(output_buffer_.channels(), |
| 0, |
| chunk_size_, |
| num_output_channels_, |
| output, |
| 0); |
| |
| // Copy output buffer [chunk_size_, chunk_size_ + initial_delay] |
| // to output buffer [0, initial_delay], zero the rest. |
| MoveFrames(output_buffer_.channels(), |
| chunk_size, |
| initial_delay_, |
| num_output_channels_, |
| output_buffer_.channels(), |
| 0); |
| ZeroOut(output_buffer_.channels(), |
| initial_delay_, |
| chunk_size_, |
| num_output_channels_); |
| |
| // Calculate new starting frames. |
| frame_offset_ = first_frame_in_block - chunk_size_; |
| } |
| |
| } // namespace webrtc |