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 WEBRTC_MODULES_AUDIO_CODING_NETEQ_COMFORT_NOISE_H_
12#define WEBRTC_MODULES_AUDIO_CODING_NETEQ_COMFORT_NOISE_H_
13
14#include "webrtc/base/constructormagic.h"
15#include "webrtc/modules/audio_coding/neteq/audio_multi_vector.h"
16#include "webrtc/typedefs.h"
17
18namespace webrtc {
19
20// Forward declarations.
21class DecoderDatabase;
22class SyncBuffer;
23struct Packet;
24
25// This class acts as an interface to the CNG generator.
26class ComfortNoise {
27 public:
28  enum ReturnCodes {
29    kOK = 0,
30    kUnknownPayloadType,
31    kInternalError,
32    kMultiChannelNotSupported
33  };
34
35  ComfortNoise(int fs_hz, 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        internal_error_code_(0) {
43  }
44
45  // Resets the state. Should be called before each new comfort noise period.
46  void Reset();
47
48  // Update the comfort noise generator with the parameters in |packet|.
49  // Will delete the packet.
50  int UpdateParameters(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  DISALLOW_COPY_AND_ASSIGN(ComfortNoise);
70};
71
72}  // namespace webrtc
73#endif  // WEBRTC_MODULES_AUDIO_CODING_NETEQ_COMFORT_NOISE_H_
74