1 /* 2 * Copyright (C) 2011 The Android Open Source Project 3 * 4 * Licensed under the Apache License, Version 2.0 (the "License"); 5 * you may not use this file except in compliance with the License. 6 * You may obtain a copy of the License at 7 * 8 * http://www.apache.org/licenses/LICENSE-2.0 9 * 10 * Unless required by applicable law or agreed to in writing, software 11 * distributed under the License is distributed on an "AS IS" BASIS, 12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 13 * See the License for the specific language governing permissions and 14 * limitations under the License. 15 */ 16 17 #include "sllog.h" 18 #include <utils/Log.h> 19 20 #include "android/include/AacAdtsExtractor.h" 21 #include "include/avc_utils.h" 22 23 24 namespace android { 25 26 #define ADTS_HEADER_LENGTH 7 27 // ADTS header size is 7, but frame size information ends on byte 6 (when counting from byte 1) 28 #define ADTS_HEADER_SIZE_UP_TO_FRAMESIZE 6 29 30 //////////////////////////////////////////////////////////////////////////////// 31 32 // Returns the sample rate based on the sampling frequency index 33 static uint32_t get_sample_rate(const uint8_t sf_index) 34 { 35 static const uint32_t sample_rates[] = 36 { 37 96000, 88200, 64000, 48000, 44100, 32000, 38 24000, 22050, 16000, 12000, 11025, 8000 39 }; 40 41 if (sf_index < sizeof(sample_rates) / sizeof(sample_rates[0])) { 42 return sample_rates[sf_index]; 43 } 44 45 return 0; 46 } 47 48 static size_t getFrameSize(const sp<DataSource> &source, off64_t offset) { 49 size_t frameSize = 0; 50 51 uint8_t syncHeader[ADTS_HEADER_SIZE_UP_TO_FRAMESIZE]; 52 const uint8_t *syncword = syncHeader; 53 const uint8_t *header = syncHeader + 3; 54 55 ssize_t readSize = source->readAt(offset, &syncHeader, ADTS_HEADER_SIZE_UP_TO_FRAMESIZE); 56 if (readSize == 0) { 57 // EOS is normal, not an error 58 SL_LOGV("AacAdtsExtractor::getFrameSize EOS"); 59 return 0; 60 } 61 if (readSize != ADTS_HEADER_SIZE_UP_TO_FRAMESIZE) { 62 SL_LOGE("AacAdtsExtractor:: getFrameSize() returns %d (syncword and header read error)", 63 (int) readSize); 64 return 0; 65 } 66 67 if ((syncword[0] != 0xff) || ((syncword[1] & 0xf6) != 0xf0)) { 68 SL_LOGE("AacAdtsExtractor:: getFrameSize() returns 0 (syncword pb)"); 69 return 0; 70 } 71 72 const uint8_t protectionAbsent = syncword[1] & 0x1; 73 74 frameSize = (header[0] & 0x3) << 11 | header[1] << 3 | header[2] >> 5; 75 // the frame size read already contains the size of the ADTS header, so no need to add it here 76 77 // protectionAbsent is 0 if there is CRC 78 static const size_t kAdtsHeaderLengthNoCrc = 7; 79 static const size_t kAdtsHeaderLengthWithCrc = 9; 80 size_t headSize = protectionAbsent ? kAdtsHeaderLengthNoCrc : kAdtsHeaderLengthWithCrc; 81 if (headSize > frameSize) { 82 SL_LOGE("AacAdtsExtractor:: getFrameSize() returns 0 (frameSize %u < headSize %u)", 83 frameSize, headSize); 84 return 0; 85 } 86 87 //SL_LOGV("AacAdtsExtractor:: getFrameSize() returns %u", frameSize); 88 89 return frameSize; 90 } 91 92 93 AacAdtsExtractor::AacAdtsExtractor(const sp<DataSource> &source) 94 : mDataSource(source), 95 mInitCheck(NO_INIT), 96 mFrameDurationUs(0) { 97 98 // difference with framework's AAC Extractor: we have already validated the data 99 // upon enqueueing, so no need to sniff the data: 100 // String8 mimeType; 101 // float confidence; 102 // if (!SniffAAC(mDataSource, &mimeType, &confidence, NULL)) { 103 // return; 104 // } 105 106 uint8_t profile, sf_index, channel, header[2]; 107 ssize_t readSize = mDataSource->readAt(2, &header, 2); 108 if (readSize != 2) { 109 SL_LOGE("Unable to determine sample rate"); 110 return; 111 } 112 113 profile = (header[0] >> 6) & 0x3; 114 sf_index = (header[0] >> 2) & 0xf; 115 uint32_t sr = get_sample_rate(sf_index); 116 117 if (sr == 0) { 118 SL_LOGE("Invalid sample rate"); 119 return; 120 } 121 channel = (header[0] & 0x1) << 2 | (header[1] >> 6); 122 123 SL_LOGV("AacAdtsExtractor has found sr=%d channel=%d", sr, channel); 124 125 // Never fails 126 mMeta = MakeAACCodecSpecificData(profile, sf_index, channel); 127 128 // Round up and get the duration of each frame 129 mFrameDurationUs = (1024 * 1000000ll + (sr - 1)) / sr; 130 131 off64_t streamSize; 132 if (mDataSource->getSize(&streamSize) == OK) { 133 off64_t offset = 0, numFrames = 0; 134 while (offset < streamSize) { 135 size_t frameSize; 136 if ((frameSize = getFrameSize(mDataSource, offset)) == 0) { 137 // Usually frameSize == 0 due to EOS is benign (and getFrameSize() doesn't SL_LOGE), 138 // but in this case we were told the total size of the data source and so an EOS 139 // should not happen. 140 SL_LOGE("AacAdtsExtractor() failed querying framesize at offset=%lld", offset); 141 return; 142 } 143 144 offset += frameSize; 145 if (offset > streamSize) { 146 SL_LOGE("AacAdtsExtractor() frame of size %zu at offset=%lld is beyond EOF %lld", 147 frameSize, offset, streamSize); 148 return; 149 } 150 numFrames ++; 151 } 152 153 // Compute total duration 154 int64_t duration = numFrames * mFrameDurationUs; 155 mMeta->setInt64(kKeyDuration, duration); 156 } 157 158 // Any earlier "return" would leave mInitCheck as NO_INIT, causing later methods to fail quickly 159 mInitCheck = OK; 160 161 } 162 163 164 AacAdtsExtractor::~AacAdtsExtractor() { 165 } 166 167 168 sp<MetaData> AacAdtsExtractor::getMetaData() { 169 sp<MetaData> meta = new MetaData; 170 171 if (mInitCheck != OK) { 172 return meta; 173 } 174 175 meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_AAC_ADTS); 176 177 return meta; 178 } 179 180 181 size_t AacAdtsExtractor::countTracks() { 182 return mInitCheck == OK ? 1 : 0; 183 } 184 185 186 sp<MediaSource> AacAdtsExtractor::getTrack(size_t index) { 187 if (mInitCheck != OK || index != 0) { 188 return NULL; 189 } 190 191 return new AacAdtsSource(mDataSource, mMeta, mFrameDurationUs); 192 } 193 194 195 sp<MetaData> AacAdtsExtractor::getTrackMetaData(size_t index, uint32_t flags) { 196 if (mInitCheck != OK || index != 0) { 197 return NULL; 198 } 199 200 return mMeta; 201 } 202 203 204 //////////////////////////////////////////////////////////////////////////////// 205 206 // 8192 = 2^13, 13bit AAC frame size (in bytes) 207 const size_t AacAdtsSource::kMaxFrameSize = 8192; 208 209 AacAdtsSource::AacAdtsSource( 210 const sp<DataSource> &source, const sp<MetaData> &meta, 211 int64_t frame_duration_us) 212 : mDataSource(source), 213 mMeta(meta), 214 mOffset(0), 215 mCurrentTimeUs(0), 216 mStarted(false), 217 mGroup(NULL), 218 mFrameDurationUs(frame_duration_us) { 219 } 220 221 222 AacAdtsSource::~AacAdtsSource() { 223 if (mStarted) { 224 stop(); 225 } 226 } 227 228 229 status_t AacAdtsSource::start(MetaData *params) { 230 CHECK(!mStarted); 231 232 mOffset = 0; 233 mCurrentTimeUs = 0; 234 mGroup = new MediaBufferGroup; 235 mGroup->add_buffer(new MediaBuffer(kMaxFrameSize)); 236 mStarted = true; 237 238 return OK; 239 } 240 241 242 status_t AacAdtsSource::stop() { 243 CHECK(mStarted); 244 245 delete mGroup; 246 mGroup = NULL; 247 248 mStarted = false; 249 return OK; 250 } 251 252 253 sp<MetaData> AacAdtsSource::getFormat() { 254 return mMeta; 255 } 256 257 258 status_t AacAdtsSource::read( 259 MediaBuffer **out, const ReadOptions *options) { 260 *out = NULL; 261 262 int64_t seekTimeUs; 263 ReadOptions::SeekMode mode; 264 if (options && options->getSeekTo(&seekTimeUs, &mode)) { 265 // difference with framework's AAC Extractor: no seeking 266 SL_LOGE("Can't seek in AAC ADTS buffer queue"); 267 } 268 269 size_t frameSize, frameSizeWithoutHeader; 270 SL_LOGV("AacAdtsSource::read() offset=%lld", mOffset); 271 if ((frameSize = getFrameSize(mDataSource, mOffset)) == 0) { 272 // EOS is normal, not an error 273 SL_LOGV("AacAdtsSource::read() returns EOS"); 274 return ERROR_END_OF_STREAM; 275 } 276 277 MediaBuffer *buffer; 278 status_t err = mGroup->acquire_buffer(&buffer); 279 if (err != OK) { 280 return err; 281 } 282 283 frameSizeWithoutHeader = frameSize - ADTS_HEADER_LENGTH; 284 ssize_t readSize = mDataSource->readAt(mOffset + ADTS_HEADER_LENGTH, buffer->data(), 285 frameSizeWithoutHeader); 286 //SL_LOGV("AacAdtsSource::read() readAt returned %u bytes", readSize); 287 if (readSize != (ssize_t)frameSizeWithoutHeader) { 288 SL_LOGW("AacAdtsSource::read() readSize != frameSizeWithoutHeader"); 289 buffer->release(); 290 buffer = NULL; 291 return ERROR_IO; 292 } 293 294 buffer->set_range(0, frameSizeWithoutHeader); 295 buffer->meta_data()->setInt64(kKeyTime, mCurrentTimeUs); 296 buffer->meta_data()->setInt32(kKeyIsSyncFrame, 1); 297 298 mOffset += frameSize; 299 mCurrentTimeUs += mFrameDurationUs; 300 301 *out = buffer; 302 return OK; 303 } 304 305 } // namespace android 306