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/*
* 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 MODULES_AUDIO_CODING_CODECS_CNG_WEBRTC_CNG_H_
#define MODULES_AUDIO_CODING_CODECS_CNG_WEBRTC_CNG_H_
#include <stdint.h>
#include <cstddef>
#include "api/array_view.h"
#include "rtc_base/buffer.h"
#define WEBRTC_CNG_MAX_LPC_ORDER 12
namespace webrtc {
class ComfortNoiseDecoder {
public:
ComfortNoiseDecoder();
~ComfortNoiseDecoder() = default;
ComfortNoiseDecoder(const ComfortNoiseDecoder&) = delete;
ComfortNoiseDecoder& operator=(const ComfortNoiseDecoder&) = delete;
void Reset();
// Updates the CN state when a new SID packet arrives.
// `sid` is a view of the SID packet without the headers.
void UpdateSid(rtc::ArrayView<const uint8_t> sid);
// Generates comfort noise.
// `out_data` will be filled with samples - its size determines the number of
// samples generated. When `new_period` is true, CNG history will be reset
// before any audio is generated. Returns `false` if outData is too large -
// currently 640 bytes (equalling 10ms at 64kHz).
// TODO(ossu): Specify better limits for the size of out_data. Either let it
// be unbounded or limit to 10ms in the current sample rate.
bool Generate(rtc::ArrayView<int16_t> out_data, bool new_period);
private:
uint32_t dec_seed_;
int32_t dec_target_energy_;
int32_t dec_used_energy_;
int16_t dec_target_reflCoefs_[WEBRTC_CNG_MAX_LPC_ORDER + 1];
int16_t dec_used_reflCoefs_[WEBRTC_CNG_MAX_LPC_ORDER + 1];
int16_t dec_filtstate_[WEBRTC_CNG_MAX_LPC_ORDER + 1];
int16_t dec_filtstateLow_[WEBRTC_CNG_MAX_LPC_ORDER + 1];
uint16_t dec_order_;
int16_t dec_target_scale_factor_; /* Q29 */
int16_t dec_used_scale_factor_; /* Q29 */
};
class ComfortNoiseEncoder {
public:
// Creates a comfort noise encoder.
// `fs` selects sample rate: 8000 for narrowband or 16000 for wideband.
// `interval` sets the interval at which to generate SID data (in ms).
// `quality` selects the number of refl. coeffs. Maximum allowed is 12.
ComfortNoiseEncoder(int fs, int interval, int quality);
~ComfortNoiseEncoder() = default;
ComfortNoiseEncoder(const ComfortNoiseEncoder&) = delete;
ComfortNoiseEncoder& operator=(const ComfortNoiseEncoder&) = delete;
// Resets the comfort noise encoder to its initial state.
// Parameters are set as during construction.
void Reset(int fs, int interval, int quality);
// Analyzes background noise from `speech` and appends coefficients to
// `output`. Returns the number of coefficients generated. If `force_sid` is
// true, a SID frame is forced and the internal sid interval counter is reset.
// Will fail if the input size is too large (> 640 samples, see
// ComfortNoiseDecoder::Generate).
size_t Encode(rtc::ArrayView<const int16_t> speech,
bool force_sid,
rtc::Buffer* output);
private:
size_t enc_nrOfCoefs_;
int enc_sampfreq_;
int16_t enc_interval_;
int16_t enc_msSinceSid_;
int32_t enc_Energy_;
int16_t enc_reflCoefs_[WEBRTC_CNG_MAX_LPC_ORDER + 1];
int32_t enc_corrVector_[WEBRTC_CNG_MAX_LPC_ORDER + 1];
uint32_t enc_seed_;
};
} // namespace webrtc
#endif // MODULES_AUDIO_CODING_CODECS_CNG_WEBRTC_CNG_H_
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