mirror of
https://github.com/oxen-io/session-android.git
synced 2024-11-24 18:45:19 +00:00
111 lines
4.4 KiB
C++
111 lines
4.4 KiB
C++
/*
|
|
* Copyright (c) 2012 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 WEBRTC_MODULES_AUDIO_CODING_NETEQ_MERGE_H_
|
|
#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_MERGE_H_
|
|
|
|
#include <assert.h>
|
|
|
|
#include "webrtc/base/constructormagic.h"
|
|
#include "webrtc/modules/audio_coding/neteq/audio_multi_vector.h"
|
|
#include "webrtc/typedefs.h"
|
|
|
|
namespace webrtc {
|
|
|
|
// Forward declarations.
|
|
class Expand;
|
|
class SyncBuffer;
|
|
|
|
// This class handles the transition from expansion to normal operation.
|
|
// When a packet is not available for decoding when needed, the expand operation
|
|
// is called to generate extrapolation data. If the missing packet arrives,
|
|
// i.e., it was just delayed, it can be decoded and appended directly to the
|
|
// end of the expanded data (thanks to how the Expand class operates). However,
|
|
// if a later packet arrives instead, the loss is a fact, and the new data must
|
|
// be stitched together with the end of the expanded data. This stitching is
|
|
// what the Merge class does.
|
|
class Merge {
|
|
public:
|
|
Merge(int fs_hz, size_t num_channels, Expand* expand, SyncBuffer* sync_buffer)
|
|
: fs_hz_(fs_hz),
|
|
num_channels_(num_channels),
|
|
fs_mult_(fs_hz_ / 8000),
|
|
timestamps_per_call_(fs_hz_ / 100),
|
|
expand_(expand),
|
|
sync_buffer_(sync_buffer),
|
|
expanded_(num_channels_) {
|
|
assert(num_channels_ > 0);
|
|
}
|
|
|
|
virtual ~Merge() {}
|
|
|
|
// The main method to produce the audio data. The decoded data is supplied in
|
|
// |input|, having |input_length| samples in total for all channels
|
|
// (interleaved). The result is written to |output|. The number of channels
|
|
// allocated in |output| defines the number of channels that will be used when
|
|
// de-interleaving |input|. The values in |external_mute_factor_array| (Q14)
|
|
// will be used to scale the audio, and is updated in the process. The array
|
|
// must have |num_channels_| elements.
|
|
virtual int Process(int16_t* input, size_t input_length,
|
|
int16_t* external_mute_factor_array,
|
|
AudioMultiVector* output);
|
|
|
|
virtual int RequiredFutureSamples();
|
|
|
|
protected:
|
|
const int fs_hz_;
|
|
const size_t num_channels_;
|
|
|
|
private:
|
|
static const int kMaxSampleRate = 48000;
|
|
static const int kExpandDownsampLength = 100;
|
|
static const int kInputDownsampLength = 40;
|
|
static const int kMaxCorrelationLength = 60;
|
|
|
|
// Calls |expand_| to get more expansion data to merge with. The data is
|
|
// written to |expanded_signal_|. Returns the length of the expanded data,
|
|
// while |expand_period| will be the number of samples in one expansion period
|
|
// (typically one pitch period). The value of |old_length| will be the number
|
|
// of samples that were taken from the |sync_buffer_|.
|
|
int GetExpandedSignal(int* old_length, int* expand_period);
|
|
|
|
// Analyzes |input| and |expanded_signal| to find maximum values. Returns
|
|
// a muting factor (Q14) to be used on the new data.
|
|
int16_t SignalScaling(const int16_t* input, int input_length,
|
|
const int16_t* expanded_signal,
|
|
int16_t* expanded_max, int16_t* input_max) const;
|
|
|
|
// Downsamples |input| (|input_length| samples) and |expanded_signal| to
|
|
// 4 kHz sample rate. The downsampled signals are written to
|
|
// |input_downsampled_| and |expanded_downsampled_|, respectively.
|
|
void Downsample(const int16_t* input, int input_length,
|
|
const int16_t* expanded_signal, int expanded_length);
|
|
|
|
// Calculates cross-correlation between |input_downsampled_| and
|
|
// |expanded_downsampled_|, and finds the correlation maximum. The maximizing
|
|
// lag is returned.
|
|
int16_t CorrelateAndPeakSearch(int16_t expanded_max, int16_t input_max,
|
|
int start_position, int input_length,
|
|
int expand_period) const;
|
|
|
|
const int fs_mult_; // fs_hz_ / 8000.
|
|
const int timestamps_per_call_;
|
|
Expand* expand_;
|
|
SyncBuffer* sync_buffer_;
|
|
int16_t expanded_downsampled_[kExpandDownsampLength];
|
|
int16_t input_downsampled_[kInputDownsampLength];
|
|
AudioMultiVector expanded_;
|
|
|
|
DISALLOW_COPY_AND_ASSIGN(Merge);
|
|
};
|
|
|
|
} // namespace webrtc
|
|
#endif // WEBRTC_MODULES_AUDIO_CODING_NETEQ_MERGE_H_
|