tor-browser

The Tor Browser
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comfort_noise.h (2283B)

      1 /*
      2 *  Copyright (c) 2012 The WebRTC project authors. All Rights Reserved.
      3 *
      4 *  Use of this source code is governed by a BSD-style license
      5 *  that can be found in the LICENSE file in the root of the source
      6 *  tree. An additional intellectual property rights grant can be found
      7 *  in the file PATENTS.  All contributing project authors may
      8 *  be found in the AUTHORS file in the root of the source tree.
      9 */
     10 
     11 #ifndef MODULES_AUDIO_CODING_NETEQ_COMFORT_NOISE_H_
     12 #define MODULES_AUDIO_CODING_NETEQ_COMFORT_NOISE_H_
     13 
     14 #include <stddef.h>
     15 
     16 namespace webrtc {
     17 
     18 // Forward declarations.
     19 class AudioMultiVector;
     20 class DecoderDatabase;
     21 class SyncBuffer;
     22 struct Packet;
     23 
     24 // This class acts as an interface to the CNG generator.
     25 class ComfortNoise {
     26 public:
     27  enum ReturnCodes {
     28    kOK = 0,
     29    kUnknownPayloadType,
     30    kInternalError,
     31    kMultiChannelNotSupported
     32  };
     33 
     34  ComfortNoise(int fs_hz,
     35               DecoderDatabase* decoder_database,
     36               SyncBuffer* sync_buffer)
     37      : fs_hz_(fs_hz),
     38        first_call_(true),
     39        overlap_length_(5 * fs_hz_ / 8000),
     40        decoder_database_(decoder_database),
     41        sync_buffer_(sync_buffer) {}
     42 
     43  ComfortNoise(const ComfortNoise&) = delete;
     44  ComfortNoise& operator=(const ComfortNoise&) = delete;
     45 
     46  // Resets the state. Should be called before each new comfort noise period.
     47  void Reset();
     48 
     49  // Update the comfort noise generator with the parameters in `packet`.
     50  int UpdateParameters(const Packet& packet);
     51 
     52  // Generates `requested_length` samples of comfort noise and writes to
     53  // `output`. If this is the first in call after Reset (or first after creating
     54  // the object), it will also mix in comfort noise at the end of the
     55  // SyncBuffer object provided in the constructor.
     56  int Generate(size_t requested_length, AudioMultiVector* output);
     57 
     58  // Returns the last error code that was produced by the comfort noise
     59  // decoder. Returns 0 if no error has been encountered since the last reset.
     60  int internal_error_code() { return internal_error_code_; }
     61 
     62 private:
     63  int fs_hz_;
     64  bool first_call_;
     65  size_t overlap_length_;
     66  DecoderDatabase* decoder_database_;
     67  SyncBuffer* sync_buffer_;
     68  int internal_error_code_;
     69 };
     70 
     71 }  // namespace webrtc
     72 #endif  // MODULES_AUDIO_CODING_NETEQ_COMFORT_NOISE_H_