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 ssize_t count = source->readAt(offset, &header, 1);
104 if (count == 0) {
105 return ERROR_END_OF_STREAM;
106 } else if (count < 0) {
107 return ERROR_IO;
108 }
109
110 unsigned FT = (header >> 3) & 0x0f;
111
112 *frameSize = getFrameSize(isWide, FT);
113 if (*frameSize == 0) {
114 return ERROR_MALFORMED;
115 }
116 return OK;
117 }
118
AMRExtractor(const sp<DataSource> & source)119 AMRExtractor::AMRExtractor(const sp<DataSource> &source)
120 : mDataSource(source),
121 mInitCheck(NO_INIT),
122 mOffsetTableLength(0) {
123 String8 mimeType;
124 float confidence;
125 if (!SniffAMR(mDataSource, &mimeType, &confidence, NULL)) {
126 return;
127 }
128
129 mIsWide = (mimeType == MEDIA_MIMETYPE_AUDIO_AMR_WB);
130
131 mMeta = new MetaData;
132 mMeta->setCString(
133 kKeyMIMEType, mIsWide ? MEDIA_MIMETYPE_AUDIO_AMR_WB
134 : MEDIA_MIMETYPE_AUDIO_AMR_NB);
135
136 mMeta->setInt32(kKeyChannelCount, 1);
137 mMeta->setInt32(kKeySampleRate, mIsWide ? 16000 : 8000);
138
139 off64_t offset = mIsWide ? 9 : 6;
140 off64_t streamSize;
141 size_t frameSize, numFrames = 0;
142 int64_t duration = 0;
143
144 if (mDataSource->getSize(&streamSize) == OK) {
145 while (offset < streamSize) {
146 status_t status = getFrameSizeByOffset(source, offset, mIsWide, &frameSize);
147 if (status == ERROR_END_OF_STREAM) {
148 break;
149 } else if (status != OK) {
150 return;
151 }
152
153 if ((numFrames % 50 == 0) && (numFrames / 50 < OFFSET_TABLE_LEN)) {
154 CHECK_EQ(mOffsetTableLength, numFrames / 50);
155 mOffsetTable[mOffsetTableLength] = offset - (mIsWide ? 9: 6);
156 mOffsetTableLength ++;
157 }
158
159 offset += frameSize;
160 duration += 20000; // Each frame is 20ms
161 numFrames ++;
162 }
163
164 mMeta->setInt64(kKeyDuration, duration);
165 }
166
167 mInitCheck = OK;
168 }
169
~AMRExtractor()170 AMRExtractor::~AMRExtractor() {
171 }
172
getMetaData()173 sp<MetaData> AMRExtractor::getMetaData() {
174 sp<MetaData> meta = new MetaData;
175
176 if (mInitCheck != OK) {
177 return meta;
178 }
179
180 meta->setCString(kKeyMIMEType, mIsWide ? "audio/amr-wb" : "audio/amr");
181
182 return meta;
183 }
184
countTracks()185 size_t AMRExtractor::countTracks() {
186 return mInitCheck == OK ? 1 : 0;
187 }
188
getTrack(size_t index)189 sp<IMediaSource> AMRExtractor::getTrack(size_t index) {
190 if (mInitCheck != OK || index != 0) {
191 return NULL;
192 }
193
194 return new AMRSource(mDataSource, mMeta, mIsWide,
195 mOffsetTable, mOffsetTableLength);
196 }
197
getTrackMetaData(size_t index,uint32_t)198 sp<MetaData> AMRExtractor::getTrackMetaData(size_t index, uint32_t /* flags */) {
199 if (mInitCheck != OK || index != 0) {
200 return NULL;
201 }
202
203 return mMeta;
204 }
205
206 ////////////////////////////////////////////////////////////////////////////////
207
AMRSource(const sp<DataSource> & source,const sp<MetaData> & meta,bool isWide,const off64_t * offset_table,size_t offset_table_length)208 AMRSource::AMRSource(
209 const sp<DataSource> &source, const sp<MetaData> &meta,
210 bool isWide, const off64_t *offset_table, size_t offset_table_length)
211 : mDataSource(source),
212 mMeta(meta),
213 mIsWide(isWide),
214 mOffset(mIsWide ? 9 : 6),
215 mCurrentTimeUs(0),
216 mStarted(false),
217 mGroup(NULL),
218 mOffsetTableLength(offset_table_length) {
219 if (mOffsetTableLength > 0 && mOffsetTableLength <= OFFSET_TABLE_LEN) {
220 memcpy ((char*)mOffsetTable, (char*)offset_table, sizeof(off64_t) * mOffsetTableLength);
221 }
222 }
223
~AMRSource()224 AMRSource::~AMRSource() {
225 if (mStarted) {
226 stop();
227 }
228 }
229
start(MetaData *)230 status_t AMRSource::start(MetaData * /* params */) {
231 CHECK(!mStarted);
232
233 mOffset = mIsWide ? 9 : 6;
234 mCurrentTimeUs = 0;
235 mGroup = new MediaBufferGroup;
236 mGroup->add_buffer(new MediaBuffer(128));
237 mStarted = true;
238
239 return OK;
240 }
241
stop()242 status_t AMRSource::stop() {
243 CHECK(mStarted);
244
245 delete mGroup;
246 mGroup = NULL;
247
248 mStarted = false;
249 return OK;
250 }
251
getFormat()252 sp<MetaData> AMRSource::getFormat() {
253 return mMeta;
254 }
255
read(MediaBuffer ** out,const ReadOptions * options)256 status_t AMRSource::read(
257 MediaBuffer **out, const ReadOptions *options) {
258 *out = NULL;
259
260 int64_t seekTimeUs;
261 ReadOptions::SeekMode mode;
262 if (options && options->getSeekTo(&seekTimeUs, &mode)) {
263 size_t size;
264 int64_t seekFrame = seekTimeUs / 20000ll; // 20ms per frame.
265 mCurrentTimeUs = seekFrame * 20000ll;
266
267 size_t index = seekFrame < 0 ? 0 : seekFrame / 50;
268 if (index >= mOffsetTableLength) {
269 index = mOffsetTableLength - 1;
270 }
271
272 mOffset = mOffsetTable[index] + (mIsWide ? 9 : 6);
273
274 for (size_t i = 0; i< seekFrame - index * 50; i++) {
275 status_t err;
276 if ((err = getFrameSizeByOffset(mDataSource, mOffset,
277 mIsWide, &size)) != OK) {
278 return err;
279 }
280 mOffset += size;
281 }
282 }
283
284 uint8_t header;
285 ssize_t n = mDataSource->readAt(mOffset, &header, 1);
286
287 if (n < 1) {
288 return ERROR_END_OF_STREAM;
289 }
290
291 if (header & 0x83) {
292 // Padding bits must be 0.
293
294 ALOGE("padding bits must be 0, header is 0x%02x", header);
295
296 return ERROR_MALFORMED;
297 }
298
299 unsigned FT = (header >> 3) & 0x0f;
300
301 size_t frameSize = getFrameSize(mIsWide, FT);
302 if (frameSize == 0) {
303 return ERROR_MALFORMED;
304 }
305
306 MediaBuffer *buffer;
307 status_t err = mGroup->acquire_buffer(&buffer);
308 if (err != OK) {
309 return err;
310 }
311
312 n = mDataSource->readAt(mOffset, buffer->data(), frameSize);
313
314 if (n != (ssize_t)frameSize) {
315 buffer->release();
316 buffer = NULL;
317
318 if (n < 0) {
319 return ERROR_IO;
320 } else {
321 // only partial frame is available, treat it as EOS.
322 mOffset += n;
323 return ERROR_END_OF_STREAM;
324 }
325 }
326
327 buffer->set_range(0, frameSize);
328 buffer->meta_data()->setInt64(kKeyTime, mCurrentTimeUs);
329 buffer->meta_data()->setInt32(kKeyIsSyncFrame, 1);
330
331 mOffset += frameSize;
332 mCurrentTimeUs += 20000; // Each frame is 20ms
333
334 *out = buffer;
335
336 return OK;
337 }
338
339 ////////////////////////////////////////////////////////////////////////////////
340
SniffAMR(const sp<DataSource> & source,String8 * mimeType,float * confidence,sp<AMessage> *)341 bool SniffAMR(
342 const sp<DataSource> &source, String8 *mimeType, float *confidence,
343 sp<AMessage> *) {
344 char header[9];
345
346 if (source->readAt(0, header, sizeof(header)) != sizeof(header)) {
347 return false;
348 }
349
350 if (!memcmp(header, "#!AMR\n", 6)) {
351 *mimeType = MEDIA_MIMETYPE_AUDIO_AMR_NB;
352 *confidence = 0.5;
353
354 return true;
355 } else if (!memcmp(header, "#!AMR-WB\n", 9)) {
356 *mimeType = MEDIA_MIMETYPE_AUDIO_AMR_WB;
357 *confidence = 0.5;
358
359 return true;
360 }
361
362 return false;
363 }
364
365 } // namespace android
366