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 //#define LOG_NDEBUG 0
18 #define LOG_TAG "AACExtractor"
19 #include <utils/Log.h>
20
21 #include <inttypes.h>
22
23 #include "AACExtractor.h"
24 #include <media/MediaExtractorPluginApi.h>
25 #include <media/stagefright/foundation/ABuffer.h>
26 #include <media/stagefright/foundation/AMessage.h>
27 #include <media/stagefright/foundation/ADebug.h>
28 #include <media/stagefright/MediaBufferGroup.h>
29 #include <media/stagefright/MediaDefs.h>
30 #include <media/stagefright/MediaErrors.h>
31 #include <media/stagefright/MetaDataUtils.h>
32 #include <utils/String8.h>
33
34 namespace android {
35
36 class AACSource : public MediaTrackHelper {
37 public:
38 AACSource(
39 DataSourceHelper *source,
40 AMediaFormat *meta,
41 const Vector<uint64_t> &offset_vector,
42 int64_t frame_duration_us);
43
44 virtual media_status_t start();
45 virtual media_status_t stop();
46
47 virtual media_status_t getFormat(AMediaFormat*);
48
49 virtual media_status_t read(
50 MediaBufferHelper **buffer, const ReadOptions *options = NULL);
51
52 protected:
53 virtual ~AACSource();
54
55 private:
56 static const size_t kMaxFrameSize;
57 DataSourceHelper *mDataSource;
58 AMediaFormat *mMeta;
59
60 off64_t mOffset;
61 int64_t mCurrentTimeUs;
62 bool mStarted;
63
64 Vector<uint64_t> mOffsetVector;
65 int64_t mFrameDurationUs;
66
67 AACSource(const AACSource &);
68 AACSource &operator=(const AACSource &);
69 };
70
71 ////////////////////////////////////////////////////////////////////////////////
72
73 // Returns the sample rate based on the sampling frequency index
get_sample_rate(const uint8_t sf_index)74 uint32_t get_sample_rate(const uint8_t sf_index)
75 {
76 static const uint32_t sample_rates[] =
77 {
78 96000, 88200, 64000, 48000, 44100, 32000,
79 24000, 22050, 16000, 12000, 11025, 8000
80 };
81
82 if (sf_index < sizeof(sample_rates) / sizeof(sample_rates[0])) {
83 return sample_rates[sf_index];
84 }
85
86 return 0;
87 }
88
89 // Returns the frame length in bytes as described in an ADTS header starting at the given offset,
90 // or 0 if the size can't be read due to an error in the header or a read failure.
91 // The returned value is the AAC frame size with the ADTS header length (regardless of
92 // the presence of the CRC).
93 // If headerSize is non-NULL, it will be used to return the size of the header of this ADTS frame.
getAdtsFrameLength(DataSourceHelper * source,off64_t offset,size_t * headerSize)94 static size_t getAdtsFrameLength(DataSourceHelper *source, off64_t offset, size_t* headerSize) {
95
96 const size_t kAdtsHeaderLengthNoCrc = 7;
97 const size_t kAdtsHeaderLengthWithCrc = 9;
98
99 size_t frameSize = 0;
100
101 uint8_t syncword[2];
102 if (source->readAt(offset, &syncword, 2) != 2) {
103 return 0;
104 }
105 if ((syncword[0] != 0xff) || ((syncword[1] & 0xf6) != 0xf0)) {
106 return 0;
107 }
108
109 uint8_t protectionAbsent;
110 if (source->readAt(offset + 1, &protectionAbsent, 1) < 1) {
111 return 0;
112 }
113 protectionAbsent &= 0x1;
114
115 uint8_t header[3];
116 if (source->readAt(offset + 3, &header, 3) < 3) {
117 return 0;
118 }
119
120 frameSize = (header[0] & 0x3) << 11 | header[1] << 3 | header[2] >> 5;
121
122 // protectionAbsent is 0 if there is CRC
123 size_t headSize = protectionAbsent ? kAdtsHeaderLengthNoCrc : kAdtsHeaderLengthWithCrc;
124 if (headSize > frameSize) {
125 return 0;
126 }
127 if (headerSize != NULL) {
128 *headerSize = headSize;
129 }
130
131 return frameSize;
132 }
133
AACExtractor(DataSourceHelper * source,off64_t offset)134 AACExtractor::AACExtractor(
135 DataSourceHelper *source, off64_t offset)
136 : mDataSource(source),
137 mMeta(nullptr),
138 mInitCheck(NO_INIT),
139 mFrameDurationUs(0) {
140
141 uint8_t profile, sf_index, channel, header[2];
142 if (mDataSource->readAt(offset + 2, &header, 2) < 2) {
143 return;
144 }
145
146 profile = (header[0] >> 6) & 0x3;
147 sf_index = (header[0] >> 2) & 0xf;
148 uint32_t sr = get_sample_rate(sf_index);
149 if (sr == 0) {
150 return;
151 }
152 channel = (header[0] & 0x1) << 2 | (header[1] >> 6);
153
154 mMeta = AMediaFormat_new();
155 MakeAACCodecSpecificData(mMeta, profile, sf_index, channel);
156 AMediaFormat_setInt32(mMeta, AMEDIAFORMAT_KEY_AAC_PROFILE, profile + 1);
157
158 off64_t streamSize, numFrames = 0;
159 size_t frameSize = 0;
160 int64_t duration = 0;
161
162 if (mDataSource->getSize(&streamSize) == OK) {
163 while (offset < streamSize) {
164 if ((frameSize = getAdtsFrameLength(source, offset, NULL)) == 0) {
165 ALOGW("prematured AAC stream (%lld vs %lld)",
166 (long long)offset, (long long)streamSize);
167 break;
168 }
169
170 mOffsetVector.push(offset);
171
172 offset += frameSize;
173 numFrames ++;
174 }
175
176 // Round up and get the duration
177 mFrameDurationUs = (1024 * 1000000ll + (sr - 1)) / sr;
178 duration = numFrames * mFrameDurationUs;
179 AMediaFormat_setInt64(mMeta, AMEDIAFORMAT_KEY_DURATION, duration);
180 }
181
182 mInitCheck = OK;
183 }
184
~AACExtractor()185 AACExtractor::~AACExtractor() {
186 mOffsetVector.clear();
187 delete mDataSource;
188 if (mMeta != nullptr) {
189 AMediaFormat_delete(mMeta);
190 }
191 }
192
getMetaData(AMediaFormat * meta)193 media_status_t AACExtractor::getMetaData(AMediaFormat *meta) {
194 AMediaFormat_clear(meta);
195 if (mInitCheck == OK) {
196 AMediaFormat_setString(meta, AMEDIAFORMAT_KEY_MIME, MEDIA_MIMETYPE_AUDIO_AAC_ADTS);
197 }
198
199 return AMEDIA_OK;
200 }
201
countTracks()202 size_t AACExtractor::countTracks() {
203 return mInitCheck == OK ? 1 : 0;
204 }
205
getTrack(size_t index)206 MediaTrackHelper *AACExtractor::getTrack(size_t index) {
207 if (mInitCheck != OK || index != 0) {
208 return NULL;
209 }
210
211 return new AACSource(mDataSource, mMeta, mOffsetVector, mFrameDurationUs);
212 }
213
getTrackMetaData(AMediaFormat * meta,size_t index,uint32_t)214 media_status_t AACExtractor::getTrackMetaData(AMediaFormat *meta, size_t index, uint32_t /* flags */) {
215 if (mInitCheck != OK || index != 0) {
216 return AMEDIA_ERROR_UNKNOWN;
217 }
218
219 return AMediaFormat_copy(meta, mMeta);
220 }
221
222 ////////////////////////////////////////////////////////////////////////////////
223
224 // 8192 = 2^13, 13bit AAC frame size (in bytes)
225 const size_t AACSource::kMaxFrameSize = 8192;
226
AACSource(DataSourceHelper * source,AMediaFormat * meta,const Vector<uint64_t> & offset_vector,int64_t frame_duration_us)227 AACSource::AACSource(
228 DataSourceHelper *source,
229 AMediaFormat *meta,
230 const Vector<uint64_t> &offset_vector,
231 int64_t frame_duration_us)
232 : mDataSource(source),
233 mMeta(meta),
234 mOffset(0),
235 mCurrentTimeUs(0),
236 mStarted(false),
237 mOffsetVector(offset_vector),
238 mFrameDurationUs(frame_duration_us) {
239 }
240
~AACSource()241 AACSource::~AACSource() {
242 if (mStarted) {
243 stop();
244 }
245 }
246
start()247 media_status_t AACSource::start() {
248 CHECK(!mStarted);
249
250 if (mOffsetVector.empty()) {
251 mOffset = 0;
252 } else {
253 mOffset = mOffsetVector.itemAt(0);
254 }
255
256 mCurrentTimeUs = 0;
257 mBufferGroup->add_buffer(kMaxFrameSize);
258 mStarted = true;
259
260 return AMEDIA_OK;
261 }
262
stop()263 media_status_t AACSource::stop() {
264 CHECK(mStarted);
265
266 mStarted = false;
267 return AMEDIA_OK;
268 }
269
getFormat(AMediaFormat * meta)270 media_status_t AACSource::getFormat(AMediaFormat *meta) {
271 return AMediaFormat_copy(meta, mMeta);
272 }
273
read(MediaBufferHelper ** out,const ReadOptions * options)274 media_status_t AACSource::read(
275 MediaBufferHelper **out, const ReadOptions *options) {
276 *out = NULL;
277
278 int64_t seekTimeUs;
279 ReadOptions::SeekMode mode;
280 if (options && options->getSeekTo(&seekTimeUs, &mode)) {
281 if (mFrameDurationUs > 0) {
282 int64_t seekFrame = 0;
283 switch(mode & 0x7) {
284 case ReadOptions::SEEK_NEXT_SYNC:
285 // "at or after"
286 seekFrame = (seekTimeUs + mFrameDurationUs - 1) / mFrameDurationUs;
287 break;
288 case ReadOptions::SEEK_CLOSEST_SYNC:
289 case ReadOptions::SEEK_CLOSEST:
290 seekFrame = (seekTimeUs + mFrameDurationUs/2) / mFrameDurationUs;
291 break;
292 case ReadOptions::SEEK_PREVIOUS_SYNC:
293 default:
294 // 'at or before'
295 seekFrame = seekTimeUs / mFrameDurationUs;
296 break;
297 }
298 if (seekFrame < 0 || seekFrame >= (int64_t)mOffsetVector.size()) {
299 android_errorWriteLog(0x534e4554, "70239507");
300 return AMEDIA_ERROR_MALFORMED;
301 }
302 mCurrentTimeUs = seekFrame * mFrameDurationUs;
303
304 mOffset = mOffsetVector.itemAt(seekFrame);
305 }
306 }
307
308 size_t frameSize, frameSizeWithoutHeader, headerSize;
309 if ((frameSize = getAdtsFrameLength(mDataSource, mOffset, &headerSize)) == 0) {
310 return AMEDIA_ERROR_END_OF_STREAM;
311 }
312
313 MediaBufferHelper *buffer;
314 status_t err = mBufferGroup->acquire_buffer(&buffer);
315 if (err != OK) {
316 return AMEDIA_ERROR_UNKNOWN;
317 }
318
319 frameSizeWithoutHeader = frameSize - headerSize;
320 if (mDataSource->readAt(mOffset + headerSize, buffer->data(),
321 frameSizeWithoutHeader) != (ssize_t)frameSizeWithoutHeader) {
322 buffer->release();
323 buffer = NULL;
324
325 return AMEDIA_ERROR_IO;
326 }
327
328 buffer->set_range(0, frameSizeWithoutHeader);
329 AMediaFormat *meta = buffer->meta_data();
330 AMediaFormat_setInt64(meta, AMEDIAFORMAT_KEY_TIME_US, mCurrentTimeUs);
331 AMediaFormat_setInt32(meta, AMEDIAFORMAT_KEY_IS_SYNC_FRAME, 1);
332
333 mOffset += frameSize;
334 mCurrentTimeUs += mFrameDurationUs;
335
336 *out = buffer;
337 return AMEDIA_OK;
338 }
339
340 ////////////////////////////////////////////////////////////////////////////////
341
CreateExtractor(CDataSource * source,void * meta)342 static CMediaExtractor* CreateExtractor(
343 CDataSource *source,
344 void *meta) {
345 off64_t offset = *static_cast<off64_t*>(meta);
346 return wrap(new AACExtractor(new DataSourceHelper(source), offset));
347 }
348
Sniff(CDataSource * source,float * confidence,void ** meta,FreeMetaFunc * freeMeta)349 static CreatorFunc Sniff(
350 CDataSource *source, float *confidence, void **meta,
351 FreeMetaFunc *freeMeta) {
352 off64_t pos = 0;
353
354 DataSourceHelper helper(source);
355 for (;;) {
356 uint8_t id3header[10];
357 if (helper.readAt(pos, id3header, sizeof(id3header))
358 < (ssize_t)sizeof(id3header)) {
359 return NULL;
360 }
361
362 if (memcmp("ID3", id3header, 3)) {
363 break;
364 }
365
366 // Skip the ID3v2 header.
367
368 size_t len =
369 ((id3header[6] & 0x7f) << 21)
370 | ((id3header[7] & 0x7f) << 14)
371 | ((id3header[8] & 0x7f) << 7)
372 | (id3header[9] & 0x7f);
373
374 len += 10;
375
376 pos += len;
377
378 ALOGV("skipped ID3 tag, new starting offset is %lld (0x%016llx)",
379 (long long)pos, (long long)pos);
380 }
381
382 uint8_t header[2];
383
384 if (helper.readAt(pos, &header, 2) != 2) {
385 return NULL;
386 }
387
388 // ADTS syncword
389 if ((header[0] == 0xff) && ((header[1] & 0xf6) == 0xf0)) {
390 *confidence = 0.2;
391
392 off64_t *offPtr = (off64_t*) malloc(sizeof(off64_t));
393 *offPtr = pos;
394 *meta = offPtr;
395 *freeMeta = ::free;
396
397 return CreateExtractor;
398 }
399
400 return NULL;
401 }
402
403 static const char *extensions[] = {
404 "aac",
405 NULL
406 };
407
408 extern "C" {
409 // This is the only symbol that needs to be exported
410 __attribute__ ((visibility ("default")))
GETEXTRACTORDEF()411 ExtractorDef GETEXTRACTORDEF() {
412 return {
413 EXTRACTORDEF_VERSION,
414 UUID("4fd80eae-03d2-4d72-9eb9-48fa6bb54613"),
415 1, // version
416 "AAC Extractor",
417 { .v3 = {Sniff, extensions} },
418 };
419 }
420
421 } // extern "C"
422
423 } // namespace android
424