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1 // Copyright 2013 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 #include "media/cast/audio_receiver/audio_decoder.h" | |
6 | |
7 #include "base/bind.h" | |
8 #include "base/bind_helpers.h" | |
9 #include "base/location.h" | |
10 #include "base/logging.h" | |
11 #include "base/memory/ref_counted.h" | |
12 #include "base/sys_byteorder.h" | |
13 #include "media/cast/cast_defines.h" | |
14 #include "third_party/opus/src/include/opus.h" | |
15 | |
16 namespace media { | |
17 namespace cast { | |
18 | |
19 // Base class that handles the common problem of detecting dropped frames, and | |
20 // then invoking the Decode() method implemented by the subclasses to convert | |
21 // the encoded payload data into usable audio data. | |
22 class AudioDecoder::ImplBase | |
23 : public base::RefCountedThreadSafe<AudioDecoder::ImplBase> { | |
24 public: | |
25 ImplBase(const scoped_refptr<CastEnvironment>& cast_environment, | |
26 transport::AudioCodec codec, | |
27 int num_channels, | |
28 int sampling_rate) | |
29 : cast_environment_(cast_environment), | |
30 codec_(codec), | |
31 num_channels_(num_channels), | |
32 cast_initialization_status_(STATUS_AUDIO_UNINITIALIZED), | |
33 seen_first_frame_(false) { | |
34 if (num_channels_ <= 0 || sampling_rate <= 0 || sampling_rate % 100 != 0) | |
35 cast_initialization_status_ = STATUS_INVALID_AUDIO_CONFIGURATION; | |
36 } | |
37 | |
38 CastInitializationStatus InitializationResult() const { | |
39 return cast_initialization_status_; | |
40 } | |
41 | |
42 void DecodeFrame(scoped_ptr<transport::EncodedFrame> encoded_frame, | |
43 const DecodeFrameCallback& callback) { | |
44 DCHECK_EQ(cast_initialization_status_, STATUS_AUDIO_INITIALIZED); | |
45 | |
46 COMPILE_ASSERT(sizeof(encoded_frame->frame_id) == sizeof(last_frame_id_), | |
47 size_of_frame_id_types_do_not_match); | |
48 bool is_continuous = true; | |
49 if (seen_first_frame_) { | |
50 const uint32 frames_ahead = encoded_frame->frame_id - last_frame_id_; | |
51 if (frames_ahead > 1) { | |
52 RecoverBecauseFramesWereDropped(); | |
53 is_continuous = false; | |
54 } | |
55 } else { | |
56 seen_first_frame_ = true; | |
57 } | |
58 last_frame_id_ = encoded_frame->frame_id; | |
59 | |
60 scoped_ptr<AudioBus> decoded_audio = Decode( | |
61 encoded_frame->mutable_bytes(), | |
62 static_cast<int>(encoded_frame->data.size())); | |
63 cast_environment_->PostTask(CastEnvironment::MAIN, | |
64 FROM_HERE, | |
65 base::Bind(callback, | |
66 base::Passed(&decoded_audio), | |
67 is_continuous)); | |
68 } | |
69 | |
70 protected: | |
71 friend class base::RefCountedThreadSafe<ImplBase>; | |
72 virtual ~ImplBase() {} | |
73 | |
74 virtual void RecoverBecauseFramesWereDropped() {} | |
75 | |
76 // Note: Implementation of Decode() is allowed to mutate |data|. | |
77 virtual scoped_ptr<AudioBus> Decode(uint8* data, int len) = 0; | |
78 | |
79 const scoped_refptr<CastEnvironment> cast_environment_; | |
80 const transport::AudioCodec codec_; | |
81 const int num_channels_; | |
82 | |
83 // Subclass' ctor is expected to set this to STATUS_AUDIO_INITIALIZED. | |
84 CastInitializationStatus cast_initialization_status_; | |
85 | |
86 private: | |
87 bool seen_first_frame_; | |
88 uint32 last_frame_id_; | |
89 | |
90 DISALLOW_COPY_AND_ASSIGN(ImplBase); | |
91 }; | |
92 | |
93 class AudioDecoder::OpusImpl : public AudioDecoder::ImplBase { | |
94 public: | |
95 OpusImpl(const scoped_refptr<CastEnvironment>& cast_environment, | |
96 int num_channels, | |
97 int sampling_rate) | |
98 : ImplBase(cast_environment, | |
99 transport::kOpus, | |
100 num_channels, | |
101 sampling_rate), | |
102 decoder_memory_(new uint8[opus_decoder_get_size(num_channels)]), | |
103 opus_decoder_(reinterpret_cast<OpusDecoder*>(decoder_memory_.get())), | |
104 max_samples_per_frame_( | |
105 kOpusMaxFrameDurationMillis * sampling_rate / 1000), | |
106 buffer_(new float[max_samples_per_frame_ * num_channels]) { | |
107 if (ImplBase::cast_initialization_status_ != STATUS_AUDIO_UNINITIALIZED) | |
108 return; | |
109 if (opus_decoder_init(opus_decoder_, sampling_rate, num_channels) != | |
110 OPUS_OK) { | |
111 ImplBase::cast_initialization_status_ = | |
112 STATUS_INVALID_AUDIO_CONFIGURATION; | |
113 return; | |
114 } | |
115 ImplBase::cast_initialization_status_ = STATUS_AUDIO_INITIALIZED; | |
116 } | |
117 | |
118 private: | |
119 virtual ~OpusImpl() {} | |
120 | |
121 virtual void RecoverBecauseFramesWereDropped() OVERRIDE { | |
122 // Passing NULL for the input data notifies the decoder of frame loss. | |
123 const opus_int32 result = | |
124 opus_decode_float( | |
125 opus_decoder_, NULL, 0, buffer_.get(), max_samples_per_frame_, 0); | |
126 DCHECK_GE(result, 0); | |
127 } | |
128 | |
129 virtual scoped_ptr<AudioBus> Decode(uint8* data, int len) OVERRIDE { | |
130 scoped_ptr<AudioBus> audio_bus; | |
131 const opus_int32 num_samples_decoded = opus_decode_float( | |
132 opus_decoder_, data, len, buffer_.get(), max_samples_per_frame_, 0); | |
133 if (num_samples_decoded <= 0) | |
134 return audio_bus.Pass(); // Decode error. | |
135 | |
136 // Copy interleaved samples from |buffer_| into a new AudioBus (where | |
137 // samples are stored in planar format, for each channel). | |
138 audio_bus = AudioBus::Create(num_channels_, num_samples_decoded).Pass(); | |
139 // TODO(miu): This should be moved into AudioBus::FromInterleaved(). | |
140 for (int ch = 0; ch < num_channels_; ++ch) { | |
141 const float* src = buffer_.get() + ch; | |
142 const float* const src_end = src + num_samples_decoded * num_channels_; | |
143 float* dest = audio_bus->channel(ch); | |
144 for (; src < src_end; src += num_channels_, ++dest) | |
145 *dest = *src; | |
146 } | |
147 return audio_bus.Pass(); | |
148 } | |
149 | |
150 const scoped_ptr<uint8[]> decoder_memory_; | |
151 OpusDecoder* const opus_decoder_; | |
152 const int max_samples_per_frame_; | |
153 const scoped_ptr<float[]> buffer_; | |
154 | |
155 // According to documentation in third_party/opus/src/include/opus.h, we must | |
156 // provide enough space in |buffer_| to contain 120ms of samples. At 48 kHz, | |
157 // then, that means 5760 samples times the number of channels. | |
158 static const int kOpusMaxFrameDurationMillis = 120; | |
159 | |
160 DISALLOW_COPY_AND_ASSIGN(OpusImpl); | |
161 }; | |
162 | |
163 class AudioDecoder::Pcm16Impl : public AudioDecoder::ImplBase { | |
164 public: | |
165 Pcm16Impl(const scoped_refptr<CastEnvironment>& cast_environment, | |
166 int num_channels, | |
167 int sampling_rate) | |
168 : ImplBase(cast_environment, | |
169 transport::kPcm16, | |
170 num_channels, | |
171 sampling_rate) { | |
172 if (ImplBase::cast_initialization_status_ != STATUS_AUDIO_UNINITIALIZED) | |
173 return; | |
174 ImplBase::cast_initialization_status_ = STATUS_AUDIO_INITIALIZED; | |
175 } | |
176 | |
177 private: | |
178 virtual ~Pcm16Impl() {} | |
179 | |
180 virtual scoped_ptr<AudioBus> Decode(uint8* data, int len) OVERRIDE { | |
181 scoped_ptr<AudioBus> audio_bus; | |
182 const int num_samples = len / sizeof(int16) / num_channels_; | |
183 if (num_samples <= 0) | |
184 return audio_bus.Pass(); | |
185 | |
186 int16* const pcm_data = reinterpret_cast<int16*>(data); | |
187 #if defined(ARCH_CPU_LITTLE_ENDIAN) | |
188 // Convert endianness. | |
189 const int num_elements = num_samples * num_channels_; | |
190 for (int i = 0; i < num_elements; ++i) | |
191 pcm_data[i] = static_cast<int16>(base::NetToHost16(pcm_data[i])); | |
192 #endif | |
193 audio_bus = AudioBus::Create(num_channels_, num_samples).Pass(); | |
194 audio_bus->FromInterleaved(pcm_data, num_samples, sizeof(int16)); | |
195 return audio_bus.Pass(); | |
196 } | |
197 | |
198 DISALLOW_COPY_AND_ASSIGN(Pcm16Impl); | |
199 }; | |
200 | |
201 AudioDecoder::AudioDecoder( | |
202 const scoped_refptr<CastEnvironment>& cast_environment, | |
203 const FrameReceiverConfig& audio_config) | |
204 : cast_environment_(cast_environment) { | |
205 switch (audio_config.codec.audio) { | |
206 case transport::kOpus: | |
207 impl_ = new OpusImpl(cast_environment, | |
208 audio_config.channels, | |
209 audio_config.frequency); | |
210 break; | |
211 case transport::kPcm16: | |
212 impl_ = new Pcm16Impl(cast_environment, | |
213 audio_config.channels, | |
214 audio_config.frequency); | |
215 break; | |
216 default: | |
217 NOTREACHED() << "Unknown or unspecified codec."; | |
218 break; | |
219 } | |
220 } | |
221 | |
222 AudioDecoder::~AudioDecoder() {} | |
223 | |
224 CastInitializationStatus AudioDecoder::InitializationResult() const { | |
225 if (impl_) | |
226 return impl_->InitializationResult(); | |
227 return STATUS_UNSUPPORTED_AUDIO_CODEC; | |
228 } | |
229 | |
230 void AudioDecoder::DecodeFrame( | |
231 scoped_ptr<transport::EncodedFrame> encoded_frame, | |
232 const DecodeFrameCallback& callback) { | |
233 DCHECK(encoded_frame.get()); | |
234 DCHECK(!callback.is_null()); | |
235 if (!impl_ || impl_->InitializationResult() != STATUS_AUDIO_INITIALIZED) { | |
236 callback.Run(make_scoped_ptr<AudioBus>(NULL), false); | |
237 return; | |
238 } | |
239 cast_environment_->PostTask(CastEnvironment::AUDIO, | |
240 FROM_HERE, | |
241 base::Bind(&AudioDecoder::ImplBase::DecodeFrame, | |
242 impl_, | |
243 base::Passed(&encoded_frame), | |
244 callback)); | |
245 } | |
246 | |
247 } // namespace cast | |
248 } // namespace media | |
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