MPEG2TSExtractor.cpp revision 0075debd2c559904ee8a2a4e4706ed5af0abaeb9 
1/*
2 * Copyright (C) 2010 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 "MPEG2TSExtractor"
19#include <utils/Log.h>
20
21#include "include/MPEG2TSExtractor.h"
22#include "include/NuCachedSource2.h"
23
24#include <media/stagefright/foundation/ABuffer.h>
25#include <media/stagefright/foundation/ADebug.h>
26#include <media/stagefright/foundation/ALooper.h>
27#include <media/stagefright/DataSource.h>
28#include <media/stagefright/MediaDefs.h>
29#include <media/stagefright/MediaErrors.h>
30#include <media/stagefright/MediaSource.h>
31#include <media/stagefright/MetaData.h>
32#include <media/IStreamSource.h>
33#include <utils/String8.h>
34
35#include "AnotherPacketSource.h"
36#include "ATSParser.h"
37
38namespace android {
39
40static const size_t kTSPacketSize = 188;
41
42struct MPEG2TSSource : public MediaSource {
43    MPEG2TSSource(
44            const sp<MPEG2TSExtractor> &extractor,
45            const sp<AnotherPacketSource> &impl,
46            bool doesSeek);
47
48    virtual status_t start(MetaData *params = NULL);
49    virtual status_t stop();
50    virtual sp<MetaData> getFormat();
51
52    virtual status_t read(
53            MediaBuffer **buffer, const ReadOptions *options = NULL);
54
55private:
56    sp<MPEG2TSExtractor> mExtractor;
57    sp<AnotherPacketSource> mImpl;
58
59    // If there are both audio and video streams, only the video stream
60    // will signal seek on the extractor; otherwise the single stream will seek.
61    bool mDoesSeek;
62
63    DISALLOW_EVIL_CONSTRUCTORS(MPEG2TSSource);
64};
65
66MPEG2TSSource::MPEG2TSSource(
67        const sp<MPEG2TSExtractor> &extractor,
68        const sp<AnotherPacketSource> &impl,
69        bool doesSeek)
70    : mExtractor(extractor),
71      mImpl(impl),
72      mDoesSeek(doesSeek) {
73}
74
75status_t MPEG2TSSource::start(MetaData *params) {
76    return mImpl->start(params);
77}
78
79status_t MPEG2TSSource::stop() {
80    return mImpl->stop();
81}
82
83sp<MetaData> MPEG2TSSource::getFormat() {
84    return mImpl->getFormat();
85}
86
87status_t MPEG2TSSource::read(
88        MediaBuffer **out, const ReadOptions *options) {
89    *out = NULL;
90
91    int64_t seekTimeUs;
92    ReadOptions::SeekMode seekMode;
93    if (mDoesSeek && options && options->getSeekTo(&seekTimeUs, &seekMode)) {
94        // seek is needed
95        status_t err = mExtractor->seek(seekTimeUs, seekMode);
96        if (err != OK) {
97            return err;
98        }
99    }
100
101    if (mExtractor->feedUntilBufferAvailable(mImpl) != OK) {
102        return ERROR_END_OF_STREAM;
103    }
104
105    return mImpl->read(out, options);
106}
107
108////////////////////////////////////////////////////////////////////////////////
109
110MPEG2TSExtractor::MPEG2TSExtractor(const sp<DataSource> &source)
111    : mDataSource(source),
112      mParser(new ATSParser),
113      mOffset(0) {
114    init();
115}
116
117size_t MPEG2TSExtractor::countTracks() {
118    return mSourceImpls.size();
119}
120
121sp<MediaSource> MPEG2TSExtractor::getTrack(size_t index) {
122    if (index >= mSourceImpls.size()) {
123        return NULL;
124    }
125
126    // The seek reference track (video if present; audio otherwise) performs
127    // seek requests, while other tracks ignore requests.
128    return new MPEG2TSSource(this, mSourceImpls.editItemAt(index),
129            (mSeekSyncPoints == &mSyncPoints.editItemAt(index)));
130}
131
132sp<MetaData> MPEG2TSExtractor::getTrackMetaData(
133        size_t index, uint32_t /* flags */) {
134    return index < mSourceImpls.size()
135        ? mSourceImpls.editItemAt(index)->getFormat() : NULL;
136}
137
138sp<MetaData> MPEG2TSExtractor::getMetaData() {
139    sp<MetaData> meta = new MetaData;
140    meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_CONTAINER_MPEG2TS);
141
142    return meta;
143}
144
145void MPEG2TSExtractor::init() {
146    bool haveAudio = false;
147    bool haveVideo = false;
148    int64_t startTime = ALooper::GetNowUs();
149
150    while (feedMore() == OK) {
151        if (haveAudio && haveVideo) {
152            break;
153        }
154        if (!haveVideo) {
155            sp<AnotherPacketSource> impl =
156                (AnotherPacketSource *)mParser->getSource(
157                        ATSParser::VIDEO).get();
158
159            if (impl != NULL) {
160                haveVideo = true;
161                mSourceImpls.push(impl);
162                mSyncPoints.push();
163                mSeekSyncPoints = &mSyncPoints.editTop();
164            }
165        }
166
167        if (!haveAudio) {
168            sp<AnotherPacketSource> impl =
169                (AnotherPacketSource *)mParser->getSource(
170                        ATSParser::AUDIO).get();
171
172            if (impl != NULL) {
173                haveAudio = true;
174                mSourceImpls.push(impl);
175                mSyncPoints.push();
176                if (!haveVideo) {
177                    mSeekSyncPoints = &mSyncPoints.editTop();
178                }
179            }
180        }
181
182        // Wait only for 2 seconds to detect audio/video streams.
183        if (ALooper::GetNowUs() - startTime > 2000000ll) {
184            break;
185        }
186    }
187
188    off64_t size;
189    if (mDataSource->getSize(&size) == OK && (haveAudio || haveVideo)) {
190        sp<AnotherPacketSource> impl = haveVideo
191                ? (AnotherPacketSource *)mParser->getSource(
192                        ATSParser::VIDEO).get()
193                : (AnotherPacketSource *)mParser->getSource(
194                        ATSParser::AUDIO).get();
195        int64_t prevBufferedDurationUs = 0;
196        int64_t durationUs = -1;
197        List<int64_t> durations;
198        // Estimate duration --- stabilize until you get <500ms deviation.
199        while (feedMore() == OK && ALooper::GetNowUs() - startTime <= 2000000ll) {
200            status_t err;
201            int64_t bufferedDurationUs = impl->getBufferedDurationUs(&err);
202            if (err != OK) {
203                break;
204            }
205            if (bufferedDurationUs != prevBufferedDurationUs) {
206                durationUs = size * bufferedDurationUs / mOffset;
207                durations.push_back(durationUs);
208                if (durations.size() > 5) {
209                    durations.erase(durations.begin());
210                    int64_t min = *durations.begin();
211                    int64_t max = *durations.begin();
212                    for (List<int64_t>::iterator i = durations.begin();
213                            i != durations.end();
214                            ++i) {
215                        if (min > *i) {
216                            min = *i;
217                        }
218                        if (max < *i) {
219                            max = *i;
220                        }
221                    }
222                    if (max - min < 500 * 1000) {
223                        break;
224                    }
225                }
226                prevBufferedDurationUs = bufferedDurationUs;
227            }
228        }
229        if (durationUs > 0) {
230            const sp<MetaData> meta = impl->getFormat();
231            meta->setInt64(kKeyDuration, durationUs);
232            impl->setFormat(meta);
233        }
234    }
235
236    ALOGI("haveAudio=%d, haveVideo=%d, elaspedTime=%lld",
237            haveAudio, haveVideo, ALooper::GetNowUs() - startTime);
238}
239
240status_t MPEG2TSExtractor::feedMore() {
241    Mutex::Autolock autoLock(mLock);
242
243    uint8_t packet[kTSPacketSize];
244    ssize_t n = mDataSource->readAt(mOffset, packet, kTSPacketSize);
245
246    if (n < (ssize_t)kTSPacketSize) {
247        if (n >= 0) {
248            mParser->signalEOS(ERROR_END_OF_STREAM);
249        }
250        return (n < 0) ? (status_t)n : ERROR_END_OF_STREAM;
251    }
252
253    ATSParser::SyncEvent event(mOffset);
254    mOffset += n;
255    status_t err = mParser->feedTSPacket(packet, kTSPacketSize, &event);
256    if (event.isInit()) {
257        for (size_t i = 0; i < mSourceImpls.size(); ++i) {
258            if (mSourceImpls[i].get() == event.getMediaSource().get()) {
259                mSyncPoints.editItemAt(i).add(
260                        event.getTimeUs(), event.getOffset());
261                break;
262            }
263        }
264    }
265    return err;
266}
267
268uint32_t MPEG2TSExtractor::flags() const {
269    return CAN_PAUSE | CAN_SEEK_BACKWARD | CAN_SEEK_FORWARD;
270}
271
272status_t MPEG2TSExtractor::seek(int64_t seekTimeUs,
273        const MediaSource::ReadOptions::SeekMode &seekMode) {
274    if (mSeekSyncPoints == NULL || mSeekSyncPoints->isEmpty()) {
275        ALOGW("No sync point to seek to.");
276        // ... and therefore we have nothing useful to do here.
277        return OK;
278    }
279
280    // Determine whether we're seeking beyond the known area.
281    bool shouldSeekBeyond =
282            (seekTimeUs > mSeekSyncPoints->keyAt(mSeekSyncPoints->size() - 1));
283
284    // Determine the sync point to seek.
285    size_t index = 0;
286    for (; index < mSeekSyncPoints->size(); ++index) {
287        int64_t timeUs = mSeekSyncPoints->keyAt(index);
288        if (timeUs > seekTimeUs) {
289            break;
290        }
291    }
292
293    switch (seekMode) {
294        case MediaSource::ReadOptions::SEEK_NEXT_SYNC:
295            if (index == mSeekSyncPoints->size()) {
296                ALOGW("Next sync not found; starting from the latest sync.");
297                --index;
298            }
299            break;
300        case MediaSource::ReadOptions::SEEK_CLOSEST_SYNC:
301        case MediaSource::ReadOptions::SEEK_CLOSEST:
302            ALOGW("seekMode not supported: %d; falling back to PREVIOUS_SYNC",
303                    seekMode);
304            // fall-through
305        case MediaSource::ReadOptions::SEEK_PREVIOUS_SYNC:
306            if (index == 0) {
307                ALOGW("Previous sync not found; starting from the earliest "
308                        "sync.");
309            } else {
310                --index;
311            }
312            break;
313    }
314    if (!shouldSeekBeyond || mOffset <= mSeekSyncPoints->valueAt(index)) {
315        int64_t actualSeekTimeUs = mSeekSyncPoints->keyAt(index);
316        mOffset = mSeekSyncPoints->valueAt(index);
317        status_t err = queueDiscontinuityForSeek(actualSeekTimeUs);
318        if (err != OK) {
319            return err;
320        }
321    }
322
323    if (shouldSeekBeyond) {
324        status_t err = seekBeyond(seekTimeUs);
325        if (err != OK) {
326            return err;
327        }
328    }
329
330    // Fast-forward to sync frame.
331    for (size_t i = 0; i < mSourceImpls.size(); ++i) {
332        const sp<AnotherPacketSource> &impl = mSourceImpls[i];
333        status_t err;
334        feedUntilBufferAvailable(impl);
335        while (impl->hasBufferAvailable(&err)) {
336            sp<AMessage> meta = impl->getMetaAfterLastDequeued(0);
337            sp<ABuffer> buffer;
338            if (meta == NULL) {
339                return UNKNOWN_ERROR;
340            }
341            int32_t sync;
342            if (meta->findInt32("isSync", &sync) && sync) {
343                break;
344            }
345            err = impl->dequeueAccessUnit(&buffer);
346            if (err != OK) {
347                return err;
348            }
349            feedUntilBufferAvailable(impl);
350        }
351    }
352
353    return OK;
354}
355
356status_t MPEG2TSExtractor::queueDiscontinuityForSeek(int64_t actualSeekTimeUs) {
357    // Signal discontinuity
358    sp<AMessage> extra(new AMessage);
359    extra->setInt64(IStreamListener::kKeyMediaTimeUs, actualSeekTimeUs);
360    mParser->signalDiscontinuity(ATSParser::DISCONTINUITY_TIME, extra);
361
362    // After discontinuity, impl should only have discontinuities
363    // with the last being what we queued. Dequeue them all here.
364    for (size_t i = 0; i < mSourceImpls.size(); ++i) {
365        const sp<AnotherPacketSource> &impl = mSourceImpls.itemAt(i);
366        sp<ABuffer> buffer;
367        status_t err;
368        while (impl->hasBufferAvailable(&err)) {
369            if (err != OK) {
370                return err;
371            }
372            err = impl->dequeueAccessUnit(&buffer);
373            // If the source contains anything but discontinuity, that's
374            // a programming mistake.
375            CHECK(err == INFO_DISCONTINUITY);
376        }
377    }
378
379    // Feed until we have a buffer for each source.
380    for (size_t i = 0; i < mSourceImpls.size(); ++i) {
381        const sp<AnotherPacketSource> &impl = mSourceImpls.itemAt(i);
382        sp<ABuffer> buffer;
383        status_t err = feedUntilBufferAvailable(impl);
384        if (err != OK) {
385            return err;
386        }
387    }
388
389    return OK;
390}
391
392status_t MPEG2TSExtractor::seekBeyond(int64_t seekTimeUs) {
393    // If we're seeking beyond where we know --- read until we reach there.
394    size_t syncPointsSize = mSeekSyncPoints->size();
395
396    while (seekTimeUs > mSeekSyncPoints->keyAt(
397            mSeekSyncPoints->size() - 1)) {
398        status_t err;
399        if (syncPointsSize < mSeekSyncPoints->size()) {
400            syncPointsSize = mSeekSyncPoints->size();
401            int64_t syncTimeUs = mSeekSyncPoints->keyAt(syncPointsSize - 1);
402            // Dequeue buffers before sync point in order to avoid too much
403            // cache building up.
404            sp<ABuffer> buffer;
405            for (size_t i = 0; i < mSourceImpls.size(); ++i) {
406                const sp<AnotherPacketSource> &impl = mSourceImpls[i];
407                int64_t timeUs;
408                while ((err = impl->nextBufferTime(&timeUs)) == OK) {
409                    if (timeUs < syncTimeUs) {
410                        impl->dequeueAccessUnit(&buffer);
411                    } else {
412                        break;
413                    }
414                }
415                if (err != OK && err != -EWOULDBLOCK) {
416                    return err;
417                }
418            }
419        }
420        if (feedMore() != OK) {
421            return ERROR_END_OF_STREAM;
422        }
423    }
424
425    return OK;
426}
427
428status_t MPEG2TSExtractor::feedUntilBufferAvailable(
429        const sp<AnotherPacketSource> &impl) {
430    status_t finalResult;
431    while (!impl->hasBufferAvailable(&finalResult)) {
432        if (finalResult != OK) {
433            return finalResult;
434        }
435
436        status_t err = feedMore();
437        if (err != OK) {
438            impl->signalEOS(err);
439        }
440    }
441    return OK;
442}
443
444////////////////////////////////////////////////////////////////////////////////
445
446bool SniffMPEG2TS(
447        const sp<DataSource> &source, String8 *mimeType, float *confidence,
448        sp<AMessage> *) {
449    for (int i = 0; i < 5; ++i) {
450        char header;
451        if (source->readAt(kTSPacketSize * i, &header, 1) != 1
452                || header != 0x47) {
453            return false;
454        }
455    }
456
457    *confidence = 0.1f;
458    mimeType->setTo(MEDIA_MIMETYPE_CONTAINER_MPEG2TS);
459
460    return true;
461}
462
463}  // namespace android
464