1// Copyright (c) 2012 The Chromium Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style license that can be
3// found in the LICENSE file.
4
5#ifndef MEDIA_BASE_AUDIO_DECODER_CONFIG_H_
6#define MEDIA_BASE_AUDIO_DECODER_CONFIG_H_
7
8#include <string>
9#include <vector>
10
11#include "base/basictypes.h"
12#include "base/time/time.h"
13#include "media/base/channel_layout.h"
14#include "media/base/media_export.h"
15#include "media/base/sample_format.h"
16
17namespace media {
18
19enum AudioCodec {
20  // These values are histogrammed over time; do not change their ordinal
21  // values.  When deleting a codec replace it with a dummy value; when adding a
22  // codec, do so at the bottom before kAudioCodecMax, and update the value of
23  // kAudioCodecMax to equal the new codec.
24  kUnknownAudioCodec = 0,
25  kCodecAAC = 1,
26  kCodecMP3 = 2,
27  kCodecPCM = 3,
28  kCodecVorbis = 4,
29  kCodecFLAC = 5,
30  kCodecAMR_NB = 6,
31  kCodecAMR_WB = 7,
32  kCodecPCM_MULAW = 8,
33  kCodecGSM_MS = 9,
34  kCodecPCM_S16BE = 10,
35  kCodecPCM_S24BE = 11,
36  kCodecOpus = 12,
37  // kCodecEAC3 = 13,
38  kCodecPCM_ALAW = 14,
39  // DO NOT ADD RANDOM AUDIO CODECS!
40  //
41  // The only acceptable time to add a new codec is if there is production code
42  // that uses said codec in the same CL.
43
44  // Must always be equal to the largest entry ever logged.
45  kAudioCodecMax = kCodecPCM_ALAW,
46};
47
48// TODO(dalecurtis): FFmpeg API uses |bytes_per_channel| instead of
49// |bits_per_channel|, we should switch over since bits are generally confusing
50// to work with.
51class MEDIA_EXPORT AudioDecoderConfig {
52 public:
53  // Constructs an uninitialized object. Clients should call Initialize() with
54  // appropriate values before using.
55  AudioDecoderConfig();
56
57  // Constructs an initialized object. It is acceptable to pass in NULL for
58  // |extra_data|, otherwise the memory is copied.
59  AudioDecoderConfig(AudioCodec codec, SampleFormat sample_format,
60                     ChannelLayout channel_layout, int samples_per_second,
61                     const uint8* extra_data, size_t extra_data_size,
62                     bool is_encrypted);
63
64  ~AudioDecoderConfig();
65
66  // Resets the internal state of this object.  |codec_delay| is in frames.
67  void Initialize(AudioCodec codec, SampleFormat sample_format,
68                  ChannelLayout channel_layout, int samples_per_second,
69                  const uint8* extra_data, size_t extra_data_size,
70                  bool is_encrypted, bool record_stats,
71                  base::TimeDelta seek_preroll,
72                  int codec_delay);
73
74  // Returns true if this object has appropriate configuration values, false
75  // otherwise.
76  bool IsValidConfig() const;
77
78  // Returns true if all fields in |config| match this config.
79  // Note: The contents of |extra_data_| are compared not the raw pointers.
80  bool Matches(const AudioDecoderConfig& config) const;
81
82  // Returns a human-readable string describing |*this|.  For debugging & test
83  // output only.
84  std::string AsHumanReadableString() const;
85
86  AudioCodec codec() const { return codec_; }
87  int bits_per_channel() const { return bytes_per_channel_ * 8; }
88  int bytes_per_channel() const { return bytes_per_channel_; }
89  ChannelLayout channel_layout() const { return channel_layout_; }
90  int samples_per_second() const { return samples_per_second_; }
91  SampleFormat sample_format() const { return sample_format_; }
92  int bytes_per_frame() const { return bytes_per_frame_; }
93  base::TimeDelta seek_preroll() const { return seek_preroll_; }
94  int codec_delay() const { return codec_delay_; }
95
96  // Optional byte data required to initialize audio decoders such as Vorbis
97  // codebooks.
98  const uint8* extra_data() const {
99    return extra_data_.empty() ? NULL : &extra_data_[0];
100  }
101  size_t extra_data_size() const { return extra_data_.size(); }
102
103  // Whether the audio stream is potentially encrypted.
104  // Note that in a potentially encrypted audio stream, individual buffers
105  // can be encrypted or not encrypted.
106  bool is_encrypted() const { return is_encrypted_; }
107
108 private:
109  AudioCodec codec_;
110  SampleFormat sample_format_;
111  int bytes_per_channel_;
112  ChannelLayout channel_layout_;
113  int samples_per_second_;
114  int bytes_per_frame_;
115  std::vector<uint8> extra_data_;
116  bool is_encrypted_;
117
118  // |seek_preroll_| is the duration of the data that the decoder must decode
119  // before the decoded data is valid.
120  base::TimeDelta seek_preroll_;
121
122  // |codec_delay_| is the number of frames the decoder should discard before
123  // returning decoded data.  This value can include both decoder delay as well
124  // as padding added during encoding.
125  int codec_delay_;
126
127  // Not using DISALLOW_COPY_AND_ASSIGN here intentionally to allow the compiler
128  // generated copy constructor and assignment operator. Since the extra data is
129  // typically small, the performance impact is minimal.
130};
131
132}  // namespace media
133
134#endif  // MEDIA_BASE_AUDIO_DECODER_CONFIG_H_
135