1 /*
2 * Copyright (C) 2009 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 "AMRExtractor"
19 #include <utils/Log.h>
20
21 #include "include/AMRExtractor.h"
22
23 #include <media/stagefright/foundation/ADebug.h>
24 #include <media/stagefright/DataSource.h>
25 #include <media/stagefright/MediaBufferGroup.h>
26 #include <media/stagefright/MediaDefs.h>
27 #include <media/stagefright/MediaErrors.h>
28 #include <media/stagefright/MediaSource.h>
29 #include <media/stagefright/MetaData.h>
30 #include <utils/String8.h>
31
32 namespace android {
33
34 class AMRSource : public MediaSource {
35 public:
36 AMRSource(const sp<DataSource> &source,
37 const sp<MetaData> &meta,
38 bool isWide,
39 const off64_t *offset_table,
40 size_t offset_table_length);
41
42 virtual status_t start(MetaData *params = NULL);
43 virtual status_t stop();
44
45 virtual sp<MetaData> getFormat();
46
47 virtual status_t read(
48 MediaBuffer **buffer, const ReadOptions *options = NULL);
49
50 protected:
51 virtual ~AMRSource();
52
53 private:
54 sp<DataSource> mDataSource;
55 sp<MetaData> mMeta;
56 bool mIsWide;
57
58 off64_t mOffset;
59 int64_t mCurrentTimeUs;
60 bool mStarted;
61 MediaBufferGroup *mGroup;
62
63 off64_t mOffsetTable[OFFSET_TABLE_LEN];
64 size_t mOffsetTableLength;
65
66 AMRSource(const AMRSource &);
67 AMRSource &operator=(const AMRSource &);
68 };
69
70 ////////////////////////////////////////////////////////////////////////////////
71
getFrameSize(bool isWide,unsigned FT)72 static size_t getFrameSize(bool isWide, unsigned FT) {
73 static const size_t kFrameSizeNB[16] = {
74 95, 103, 118, 134, 148, 159, 204, 244,
75 39, 43, 38, 37, // SID
76 0, 0, 0, // future use
77 0 // no data
78 };
79 static const size_t kFrameSizeWB[16] = {
80 132, 177, 253, 285, 317, 365, 397, 461, 477,
81 40, // SID
82 0, 0, 0, 0, // future use
83 0, // speech lost
84 0 // no data
85 };
86
87 if (FT > 15 || (isWide && FT > 9 && FT < 14) || (!isWide && FT > 11 && FT < 15)) {
88 ALOGE("illegal AMR frame type %d", FT);
89 return 0;
90 }
91
92 size_t frameSize = isWide ? kFrameSizeWB[FT] : kFrameSizeNB[FT];
93
94 // Round up bits to bytes and add 1 for the header byte.
95 frameSize = (frameSize + 7) / 8 + 1;
96
97 return frameSize;
98 }
99
getFrameSizeByOffset(const sp<DataSource> & source,off64_t offset,bool isWide,size_t * frameSize)100 static status_t getFrameSizeByOffset(const sp<DataSource> &source,
101 off64_t offset, bool isWide, size_t *frameSize) {
102 uint8_t header;
103 if (source->readAt(offset, &header, 1) < 1) {
104 return ERROR_IO;
105 }
106
107 unsigned FT = (header >> 3) & 0x0f;
108
109 *frameSize = getFrameSize(isWide, FT);
110 if (*frameSize == 0) {
111 return ERROR_MALFORMED;
112 }
113 return OK;
114 }
115
AMRExtractor(const sp<DataSource> & source)116 AMRExtractor::AMRExtractor(const sp<DataSource> &source)
117 : mDataSource(source),
118 mInitCheck(NO_INIT),
119 mOffsetTableLength(0) {
120 String8 mimeType;
121 float confidence;
122 if (!SniffAMR(mDataSource, &mimeType, &confidence, NULL)) {
123 return;
124 }
125
126 mIsWide = (mimeType == MEDIA_MIMETYPE_AUDIO_AMR_WB);
127
128 mMeta = new MetaData;
129 mMeta->setCString(
130 kKeyMIMEType, mIsWide ? MEDIA_MIMETYPE_AUDIO_AMR_WB
131 : MEDIA_MIMETYPE_AUDIO_AMR_NB);
132
133 mMeta->setInt32(kKeyChannelCount, 1);
134 mMeta->setInt32(kKeySampleRate, mIsWide ? 16000 : 8000);
135
136 off64_t offset = mIsWide ? 9 : 6;
137 off64_t streamSize;
138 size_t frameSize, numFrames = 0;
139 int64_t duration = 0;
140
141 if (mDataSource->getSize(&streamSize) == OK) {
142 while (offset < streamSize) {
143 if (getFrameSizeByOffset(source, offset, mIsWide, &frameSize) != OK) {
144 return;
145 }
146
147 if ((numFrames % 50 == 0) && (numFrames / 50 < OFFSET_TABLE_LEN)) {
148 CHECK_EQ(mOffsetTableLength, numFrames / 50);
149 mOffsetTable[mOffsetTableLength] = offset - (mIsWide ? 9: 6);
150 mOffsetTableLength ++;
151 }
152
153 offset += frameSize;
154 duration += 20000; // Each frame is 20ms
155 numFrames ++;
156 }
157
158 mMeta->setInt64(kKeyDuration, duration);
159 }
160
161 mInitCheck = OK;
162 }
163
~AMRExtractor()164 AMRExtractor::~AMRExtractor() {
165 }
166
getMetaData()167 sp<MetaData> AMRExtractor::getMetaData() {
168 sp<MetaData> meta = new MetaData;
169
170 if (mInitCheck != OK) {
171 return meta;
172 }
173
174 meta->setCString(kKeyMIMEType, mIsWide ? "audio/amr-wb" : "audio/amr");
175
176 return meta;
177 }
178
countTracks()179 size_t AMRExtractor::countTracks() {
180 return mInitCheck == OK ? 1 : 0;
181 }
182
getTrack(size_t index)183 sp<MediaSource> AMRExtractor::getTrack(size_t index) {
184 if (mInitCheck != OK || index != 0) {
185 return NULL;
186 }
187
188 return new AMRSource(mDataSource, mMeta, mIsWide,
189 mOffsetTable, mOffsetTableLength);
190 }
191
getTrackMetaData(size_t index,uint32_t)192 sp<MetaData> AMRExtractor::getTrackMetaData(size_t index, uint32_t /* flags */) {
193 if (mInitCheck != OK || index != 0) {
194 return NULL;
195 }
196
197 return mMeta;
198 }
199
200 ////////////////////////////////////////////////////////////////////////////////
201
AMRSource(const sp<DataSource> & source,const sp<MetaData> & meta,bool isWide,const off64_t * offset_table,size_t offset_table_length)202 AMRSource::AMRSource(
203 const sp<DataSource> &source, const sp<MetaData> &meta,
204 bool isWide, const off64_t *offset_table, size_t offset_table_length)
205 : mDataSource(source),
206 mMeta(meta),
207 mIsWide(isWide),
208 mOffset(mIsWide ? 9 : 6),
209 mCurrentTimeUs(0),
210 mStarted(false),
211 mGroup(NULL),
212 mOffsetTableLength(offset_table_length) {
213 if (mOffsetTableLength > 0 && mOffsetTableLength <= OFFSET_TABLE_LEN) {
214 memcpy ((char*)mOffsetTable, (char*)offset_table, sizeof(off64_t) * mOffsetTableLength);
215 }
216 }
217
~AMRSource()218 AMRSource::~AMRSource() {
219 if (mStarted) {
220 stop();
221 }
222 }
223
start(MetaData *)224 status_t AMRSource::start(MetaData * /* params */) {
225 CHECK(!mStarted);
226
227 mOffset = mIsWide ? 9 : 6;
228 mCurrentTimeUs = 0;
229 mGroup = new MediaBufferGroup;
230 mGroup->add_buffer(new MediaBuffer(128));
231 mStarted = true;
232
233 return OK;
234 }
235
stop()236 status_t AMRSource::stop() {
237 CHECK(mStarted);
238
239 delete mGroup;
240 mGroup = NULL;
241
242 mStarted = false;
243 return OK;
244 }
245
getFormat()246 sp<MetaData> AMRSource::getFormat() {
247 return mMeta;
248 }
249
read(MediaBuffer ** out,const ReadOptions * options)250 status_t AMRSource::read(
251 MediaBuffer **out, const ReadOptions *options) {
252 *out = NULL;
253
254 int64_t seekTimeUs;
255 ReadOptions::SeekMode mode;
256 if (options && options->getSeekTo(&seekTimeUs, &mode)) {
257 size_t size;
258 int64_t seekFrame = seekTimeUs / 20000ll; // 20ms per frame.
259 mCurrentTimeUs = seekFrame * 20000ll;
260
261 size_t index = seekFrame < 0 ? 0 : seekFrame / 50;
262 if (index >= mOffsetTableLength) {
263 index = mOffsetTableLength - 1;
264 }
265
266 mOffset = mOffsetTable[index] + (mIsWide ? 9 : 6);
267
268 for (size_t i = 0; i< seekFrame - index * 50; i++) {
269 status_t err;
270 if ((err = getFrameSizeByOffset(mDataSource, mOffset,
271 mIsWide, &size)) != OK) {
272 return err;
273 }
274 mOffset += size;
275 }
276 }
277
278 uint8_t header;
279 ssize_t n = mDataSource->readAt(mOffset, &header, 1);
280
281 if (n < 1) {
282 return ERROR_END_OF_STREAM;
283 }
284
285 if (header & 0x83) {
286 // Padding bits must be 0.
287
288 ALOGE("padding bits must be 0, header is 0x%02x", header);
289
290 return ERROR_MALFORMED;
291 }
292
293 unsigned FT = (header >> 3) & 0x0f;
294
295 size_t frameSize = getFrameSize(mIsWide, FT);
296 if (frameSize == 0) {
297 return ERROR_MALFORMED;
298 }
299
300 MediaBuffer *buffer;
301 status_t err = mGroup->acquire_buffer(&buffer);
302 if (err != OK) {
303 return err;
304 }
305
306 n = mDataSource->readAt(mOffset, buffer->data(), frameSize);
307
308 if (n != (ssize_t)frameSize) {
309 buffer->release();
310 buffer = NULL;
311
312 return ERROR_IO;
313 }
314
315 buffer->set_range(0, frameSize);
316 buffer->meta_data()->setInt64(kKeyTime, mCurrentTimeUs);
317 buffer->meta_data()->setInt32(kKeyIsSyncFrame, 1);
318
319 mOffset += frameSize;
320 mCurrentTimeUs += 20000; // Each frame is 20ms
321
322 *out = buffer;
323
324 return OK;
325 }
326
327 ////////////////////////////////////////////////////////////////////////////////
328
SniffAMR(const sp<DataSource> & source,String8 * mimeType,float * confidence,sp<AMessage> *)329 bool SniffAMR(
330 const sp<DataSource> &source, String8 *mimeType, float *confidence,
331 sp<AMessage> *) {
332 char header[9];
333
334 if (source->readAt(0, header, sizeof(header)) != sizeof(header)) {
335 return false;
336 }
337
338 if (!memcmp(header, "#!AMR\n", 6)) {
339 *mimeType = MEDIA_MIMETYPE_AUDIO_AMR_NB;
340 *confidence = 0.5;
341
342 return true;
343 } else if (!memcmp(header, "#!AMR-WB\n", 9)) {
344 *mimeType = MEDIA_MIMETYPE_AUDIO_AMR_WB;
345 *confidence = 0.5;
346
347 return true;
348 }
349
350 return false;
351 }
352
353 } // namespace android
354