comfort_noise.h - mozsearch

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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_NETEQ_COMFORT_NOISE_H_

#define MODULES_AUDIO_CODING_NETEQ_COMFORT_NOISE_H_

#include <stddef.h>

namespace webrtc {

// Forward declarations.

class AudioMultiVector;

class DecoderDatabase;

class SyncBuffer;

struct Packet;

// This class acts as an interface to the CNG generator.

class ComfortNoise {

 public:

  enum ReturnCodes {

    kOK = 0,

    kUnknownPayloadType,

    kInternalError,

    kMultiChannelNotSupported

};

  ComfortNoise(int fs_hz,

               DecoderDatabase* decoder_database,

               SyncBuffer* sync_buffer)

      : fs_hz_(fs_hz),

        first_call_(true),

        overlap_length_(5 * fs_hz_ / 8000),

        decoder_database_(decoder_database),

        sync_buffer_(sync_buffer) {}

  ComfortNoise(const ComfortNoise&) = delete;

  ComfortNoise& operator=(const ComfortNoise&) = delete;

  // Resets the state. Should be called before each new comfort noise period.

  void Reset();

  // Update the comfort noise generator with the parameters in `packet`.

  int UpdateParameters(const Packet& packet);

  // Generates `requested_length` samples of comfort noise and writes to

  // `output`. If this is the first in call after Reset (or first after creating

  // the object), it will also mix in comfort noise at the end of the

  // SyncBuffer object provided in the constructor.

  int Generate(size_t requested_length, AudioMultiVector* output);

  // Returns the last error code that was produced by the comfort noise

  // decoder. Returns 0 if no error has been encountered since the last reset.

  int internal_error_code() { return internal_error_code_; }

 private:

  int fs_hz_;

  bool first_call_;

  size_t overlap_length_;

  DecoderDatabase* decoder_database_;

  SyncBuffer* sync_buffer_;

  int internal_error_code_;

};

}  // namespace webrtc

#endif  // MODULES_AUDIO_CODING_NETEQ_COMFORT_NOISE_H_