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/*
Copyright 2018 Google Inc. All Rights Reserved.
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS-IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
#ifndef RESONANCE_AUDIO_UTILS_BUFFER_PARTITIONER_H_
#define RESONANCE_AUDIO_UTILS_BUFFER_PARTITIONER_H_
#include <functional>
#include <memory>
#include "base/audio_buffer.h"
#include "base/logging.h"
namespace vraudio {
// Packages input buffers of arbitrary sizes into fixed size |AudioBuffer|s.
class BufferPartitioner {
public:
// Callback to receive processed and assign empty |AudioBuffer|s while
// processing input buffers.
//
// @param output Pointer to partitioned |AudioBuffer| with input audio data.
// @return Pointer to the next |AudioBuffer| to be filled.
typedef std::function<AudioBuffer*(AudioBuffer* output)> NewBufferCallback;
// Constructor.
//
// @param num_channels Number of audio channels in input and output buffers.
// @param frames_per_buffer Number of frames in output |AudioBuffer|s.
// @param buffer_callback Callback to receive output |AudioBuffer|s.
BufferPartitioner(size_t num_channels, size_t frames_per_buffer,
NewBufferCallback buffer_callback);
// Predicts the number of generated buffers for a given number of input frames
// and based on the current fill state of the internal |temp_buffer_|.
//
// @param num_input_frames Number of input frames.
// @return Number of generated output buffers.
size_t GetNumGeneratedBuffersForNumInputFrames(size_t num_input_frames) const;
// Returns the number of buffered frames in internal |temp_buffer_|.
size_t GetNumBufferedFrames() const;
// Adds an interleaved int16 input buffer. This method triggers
// |NewBufferCallback| whenever a new |AudioBuffer| has been generated.
//
// @param interleaved_buffer Interleaved input buffer.
// @param num_channels Number of channels in input buffer.
// @param num_frames Number of frames in input buffer.
void AddBuffer(const int16* interleaved_buffer, size_t num_channels,
size_t num_frames);
// Adds an interleaved float input buffer. This method triggers
// |NewBufferCallback| whenever a new |AudioBuffer| has been generated.
//
// @param interleaved_buffer Interleaved input buffer.
// @param num_channels Number of channels in input buffer.
// @param num_frames Number of frames in input buffer.
void AddBuffer(const float* interleaved_buffer, size_t num_channels,
size_t num_frames);
// Adds a planar float input buffer. This method triggers
// |NewBufferCallback| whenever a new |AudioBuffer| has been generated.
//
// @param planar_buffer Pointer to array of pointers for each audio channel.
// @param num_channels Number of channels in input buffer.
// @param num_frames Number of frames in input buffer.
void AddBuffer(const float* const* planar_buffer, size_t num_channels,
size_t num_frames);
// Adds a planar int16 input buffer. This method triggers
// |NewBufferCallback| whenever a new |AudioBuffer| has been generated.
//
// @param planar_buffer Pointer to array of pointers for each audio channel.
// @param num_channels Number of channels in input buffer.
// @param num_frames Number of frames in input buffer.
void AddBuffer(const int16* const* planar_buffer, size_t num_channels,
size_t num_frames);
// Adds an |AudioBuffer|. This method triggers |NewBufferCallback| whenever a
// new |AudioBuffer| has been generated.
//
// @param audio_buffer Planar |AudioBuffer| input.
void AddBuffer(const AudioBuffer& audio_buffer);
// Adds an |AudioBuffer| and specifies how many of that audio buffers frames
// are valid. This method triggers |NewBufferCallback| whenever a new
// |AudioBuffer| has been generated.
//
// @param num_valid_frames Indicates the number of frames which are actually
// valid in the audio buffer passed. Frames after this will be ignored.
// @param audio_buffer Planar |AudioBuffer| input.
void AddBuffer(size_t num_valid_frames, const AudioBuffer& audio_buffer);
// Flushes the internal temporary |AudioBuffer| by filling the remaining
// audio frames with silence.
//
// @return Number of zero padded audio frames. Zero if the internal buffer
// is empty.
size_t Flush();
// Clears internal temporary buffer that holds remaining audio frames.
void Clear();
private:
// Adds an interleaved and planar float and int16 input buffer as well as
// planar |AudioBuffer| input. This method triggers |NewBufferCallback|
// whenever a new |AudioBuffer| has been generated.
//
// @tparam BufferType Input buffer type.
// @param buffer Input buffer.
// @param num_channels Number of channels in input buffer.
// @param num_frames Number of frames in input buffer.
template <typename BufferType>
void AddBufferTemplated(BufferType buffer, size_t num_channels,
size_t num_frames);
// Number of channels in input buffers.
const size_t num_channels_;
// Number of frames per buffer in output buffers.
const size_t frames_per_buffer_;
// Callback to output generated |AudioBuffer|s.
const NewBufferCallback buffer_callback_;
// Temporary buffer to remaining samples from input buffers.
AudioBuffer* current_buffer_ptr_; // Not owned.
// Current write position in frames in temporary buffer.
size_t current_buffer_write_position_frames_;
// Helper vector to obtain an array of planar channel pointers from an
// |AudioBuffer|.
std::vector<const float*> planar_channel_ptrs_;
};
} // namespace vraudio
#endif // RESONANCE_AUDIO_UTILS_BUFFER_PARTITIONER_H_