SampleTable.cpp revision 599950efbb03b1672561d4cf2272504b879525e8 
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_TAG "SampleTable"
18//#define LOG_NDEBUG 0
19#include <utils/Log.h>
20
21#include "include/SampleTable.h"
22#include "include/SampleIterator.h"
23
24#include <arpa/inet.h>
25
26#include <media/stagefright/foundation/ADebug.h>
27#include <media/stagefright/DataSource.h>
28#include <media/stagefright/Utils.h>
29
30namespace android {
31
32// static
33const uint32_t SampleTable::kChunkOffsetType32 = FOURCC('s', 't', 'c', 'o');
34// static
35const uint32_t SampleTable::kChunkOffsetType64 = FOURCC('c', 'o', '6', '4');
36// static
37const uint32_t SampleTable::kSampleSizeType32 = FOURCC('s', 't', 's', 'z');
38// static
39const uint32_t SampleTable::kSampleSizeTypeCompact = FOURCC('s', 't', 'z', '2');
40
41////////////////////////////////////////////////////////////////////////////////
42
43struct SampleTable::CompositionDeltaLookup {
44    CompositionDeltaLookup();
45
46    void setEntries(
47            const uint32_t *deltaEntries, size_t numDeltaEntries);
48
49    uint32_t getCompositionTimeOffset(uint32_t sampleIndex);
50
51private:
52    Mutex mLock;
53
54    const uint32_t *mDeltaEntries;
55    size_t mNumDeltaEntries;
56
57    size_t mCurrentDeltaEntry;
58    size_t mCurrentEntrySampleIndex;
59
60    DISALLOW_EVIL_CONSTRUCTORS(CompositionDeltaLookup);
61};
62
63SampleTable::CompositionDeltaLookup::CompositionDeltaLookup()
64    : mDeltaEntries(NULL),
65      mNumDeltaEntries(0),
66      mCurrentDeltaEntry(0),
67      mCurrentEntrySampleIndex(0) {
68}
69
70void SampleTable::CompositionDeltaLookup::setEntries(
71        const uint32_t *deltaEntries, size_t numDeltaEntries) {
72    Mutex::Autolock autolock(mLock);
73
74    mDeltaEntries = deltaEntries;
75    mNumDeltaEntries = numDeltaEntries;
76    mCurrentDeltaEntry = 0;
77    mCurrentEntrySampleIndex = 0;
78}
79
80uint32_t SampleTable::CompositionDeltaLookup::getCompositionTimeOffset(
81        uint32_t sampleIndex) {
82    Mutex::Autolock autolock(mLock);
83
84    if (mDeltaEntries == NULL) {
85        return 0;
86    }
87
88    if (sampleIndex < mCurrentEntrySampleIndex) {
89        mCurrentDeltaEntry = 0;
90        mCurrentEntrySampleIndex = 0;
91    }
92
93    while (mCurrentDeltaEntry < mNumDeltaEntries) {
94        uint32_t sampleCount = mDeltaEntries[2 * mCurrentDeltaEntry];
95        if (sampleIndex < mCurrentEntrySampleIndex + sampleCount) {
96            return mDeltaEntries[2 * mCurrentDeltaEntry + 1];
97        }
98
99        mCurrentEntrySampleIndex += sampleCount;
100        ++mCurrentDeltaEntry;
101    }
102
103    return 0;
104}
105
106////////////////////////////////////////////////////////////////////////////////
107
108SampleTable::SampleTable(const sp<DataSource> &source)
109    : mDataSource(source),
110      mChunkOffsetOffset(-1),
111      mChunkOffsetType(0),
112      mNumChunkOffsets(0),
113      mSampleToChunkOffset(-1),
114      mNumSampleToChunkOffsets(0),
115      mSampleSizeOffset(-1),
116      mSampleSizeFieldSize(0),
117      mDefaultSampleSize(0),
118      mNumSampleSizes(0),
119      mTimeToSampleCount(0),
120      mTimeToSample(NULL),
121      mSampleTimeEntries(NULL),
122      mCompositionTimeDeltaEntries(NULL),
123      mNumCompositionTimeDeltaEntries(0),
124      mCompositionDeltaLookup(new CompositionDeltaLookup),
125      mSyncSampleOffset(-1),
126      mNumSyncSamples(0),
127      mSyncSamples(NULL),
128      mLastSyncSampleIndex(0),
129      mSampleToChunkEntries(NULL) {
130    mSampleIterator = new SampleIterator(this);
131}
132
133SampleTable::~SampleTable() {
134    delete[] mSampleToChunkEntries;
135    mSampleToChunkEntries = NULL;
136
137    delete[] mSyncSamples;
138    mSyncSamples = NULL;
139
140    delete mCompositionDeltaLookup;
141    mCompositionDeltaLookup = NULL;
142
143    delete[] mCompositionTimeDeltaEntries;
144    mCompositionTimeDeltaEntries = NULL;
145
146    delete[] mSampleTimeEntries;
147    mSampleTimeEntries = NULL;
148
149    delete[] mTimeToSample;
150    mTimeToSample = NULL;
151
152    delete mSampleIterator;
153    mSampleIterator = NULL;
154}
155
156bool SampleTable::isValid() const {
157    return mChunkOffsetOffset >= 0
158        && mSampleToChunkOffset >= 0
159        && mSampleSizeOffset >= 0
160        && mTimeToSample != NULL;
161}
162
163status_t SampleTable::setChunkOffsetParams(
164        uint32_t type, off64_t data_offset, size_t data_size) {
165    if (mChunkOffsetOffset >= 0) {
166        return ERROR_MALFORMED;
167    }
168
169    CHECK(type == kChunkOffsetType32 || type == kChunkOffsetType64);
170
171    mChunkOffsetOffset = data_offset;
172    mChunkOffsetType = type;
173
174    if (data_size < 8) {
175        return ERROR_MALFORMED;
176    }
177
178    uint8_t header[8];
179    if (mDataSource->readAt(
180                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
181        return ERROR_IO;
182    }
183
184    if (U32_AT(header) != 0) {
185        // Expected version = 0, flags = 0.
186        return ERROR_MALFORMED;
187    }
188
189    mNumChunkOffsets = U32_AT(&header[4]);
190
191    if (mChunkOffsetType == kChunkOffsetType32) {
192        if (data_size < 8 + mNumChunkOffsets * 4) {
193            return ERROR_MALFORMED;
194        }
195    } else {
196        if (data_size < 8 + mNumChunkOffsets * 8) {
197            return ERROR_MALFORMED;
198        }
199    }
200
201    return OK;
202}
203
204status_t SampleTable::setSampleToChunkParams(
205        off64_t data_offset, size_t data_size) {
206    if (mSampleToChunkOffset >= 0) {
207        return ERROR_MALFORMED;
208    }
209
210    mSampleToChunkOffset = data_offset;
211
212    if (data_size < 8) {
213        return ERROR_MALFORMED;
214    }
215
216    uint8_t header[8];
217    if (mDataSource->readAt(
218                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
219        return ERROR_IO;
220    }
221
222    if (U32_AT(header) != 0) {
223        // Expected version = 0, flags = 0.
224        return ERROR_MALFORMED;
225    }
226
227    mNumSampleToChunkOffsets = U32_AT(&header[4]);
228
229    if (data_size < 8 + mNumSampleToChunkOffsets * 12) {
230        return ERROR_MALFORMED;
231    }
232
233    mSampleToChunkEntries =
234        new SampleToChunkEntry[mNumSampleToChunkOffsets];
235
236    for (uint32_t i = 0; i < mNumSampleToChunkOffsets; ++i) {
237        uint8_t buffer[12];
238        if (mDataSource->readAt(
239                    mSampleToChunkOffset + 8 + i * 12, buffer, sizeof(buffer))
240                != (ssize_t)sizeof(buffer)) {
241            return ERROR_IO;
242        }
243
244        CHECK(U32_AT(buffer) >= 1);  // chunk index is 1 based in the spec.
245
246        // We want the chunk index to be 0-based.
247        mSampleToChunkEntries[i].startChunk = U32_AT(buffer) - 1;
248        mSampleToChunkEntries[i].samplesPerChunk = U32_AT(&buffer[4]);
249        mSampleToChunkEntries[i].chunkDesc = U32_AT(&buffer[8]);
250    }
251
252    return OK;
253}
254
255status_t SampleTable::setSampleSizeParams(
256        uint32_t type, off64_t data_offset, size_t data_size) {
257    if (mSampleSizeOffset >= 0) {
258        return ERROR_MALFORMED;
259    }
260
261    CHECK(type == kSampleSizeType32 || type == kSampleSizeTypeCompact);
262
263    mSampleSizeOffset = data_offset;
264
265    if (data_size < 12) {
266        return ERROR_MALFORMED;
267    }
268
269    uint8_t header[12];
270    if (mDataSource->readAt(
271                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
272        return ERROR_IO;
273    }
274
275    if (U32_AT(header) != 0) {
276        // Expected version = 0, flags = 0.
277        return ERROR_MALFORMED;
278    }
279
280    mDefaultSampleSize = U32_AT(&header[4]);
281    mNumSampleSizes = U32_AT(&header[8]);
282
283    if (type == kSampleSizeType32) {
284        mSampleSizeFieldSize = 32;
285
286        if (mDefaultSampleSize != 0) {
287            return OK;
288        }
289
290        if (data_size < 12 + mNumSampleSizes * 4) {
291            return ERROR_MALFORMED;
292        }
293    } else {
294        if ((mDefaultSampleSize & 0xffffff00) != 0) {
295            // The high 24 bits are reserved and must be 0.
296            return ERROR_MALFORMED;
297        }
298
299        mSampleSizeFieldSize = mDefaultSampleSize & 0xff;
300        mDefaultSampleSize = 0;
301
302        if (mSampleSizeFieldSize != 4 && mSampleSizeFieldSize != 8
303            && mSampleSizeFieldSize != 16) {
304            return ERROR_MALFORMED;
305        }
306
307        if (data_size < 12 + (mNumSampleSizes * mSampleSizeFieldSize + 4) / 8) {
308            return ERROR_MALFORMED;
309        }
310    }
311
312    return OK;
313}
314
315status_t SampleTable::setTimeToSampleParams(
316        off64_t data_offset, size_t data_size) {
317    if (mTimeToSample != NULL || data_size < 8) {
318        return ERROR_MALFORMED;
319    }
320
321    uint8_t header[8];
322    if (mDataSource->readAt(
323                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
324        return ERROR_IO;
325    }
326
327    if (U32_AT(header) != 0) {
328        // Expected version = 0, flags = 0.
329        return ERROR_MALFORMED;
330    }
331
332    mTimeToSampleCount = U32_AT(&header[4]);
333    mTimeToSample = new uint32_t[mTimeToSampleCount * 2];
334
335    size_t size = sizeof(uint32_t) * mTimeToSampleCount * 2;
336    if (mDataSource->readAt(
337                data_offset + 8, mTimeToSample, size) < (ssize_t)size) {
338        return ERROR_IO;
339    }
340
341    for (uint32_t i = 0; i < mTimeToSampleCount * 2; ++i) {
342        mTimeToSample[i] = ntohl(mTimeToSample[i]);
343    }
344
345    return OK;
346}
347
348status_t SampleTable::setCompositionTimeToSampleParams(
349        off64_t data_offset, size_t data_size) {
350    ALOGI("There are reordered frames present.");
351
352    if (mCompositionTimeDeltaEntries != NULL || data_size < 8) {
353        return ERROR_MALFORMED;
354    }
355
356    uint8_t header[8];
357    if (mDataSource->readAt(
358                data_offset, header, sizeof(header))
359            < (ssize_t)sizeof(header)) {
360        return ERROR_IO;
361    }
362
363    if (U32_AT(header) != 0) {
364        // Expected version = 0, flags = 0.
365        return ERROR_MALFORMED;
366    }
367
368    size_t numEntries = U32_AT(&header[4]);
369
370    if (data_size != (numEntries + 1) * 8) {
371        return ERROR_MALFORMED;
372    }
373
374    mNumCompositionTimeDeltaEntries = numEntries;
375    mCompositionTimeDeltaEntries = new uint32_t[2 * numEntries];
376
377    if (mDataSource->readAt(
378                data_offset + 8, mCompositionTimeDeltaEntries, numEntries * 8)
379            < (ssize_t)numEntries * 8) {
380        delete[] mCompositionTimeDeltaEntries;
381        mCompositionTimeDeltaEntries = NULL;
382
383        return ERROR_IO;
384    }
385
386    for (size_t i = 0; i < 2 * numEntries; ++i) {
387        mCompositionTimeDeltaEntries[i] = ntohl(mCompositionTimeDeltaEntries[i]);
388    }
389
390    mCompositionDeltaLookup->setEntries(
391            mCompositionTimeDeltaEntries, mNumCompositionTimeDeltaEntries);
392
393    return OK;
394}
395
396status_t SampleTable::setSyncSampleParams(off64_t data_offset, size_t data_size) {
397    if (mSyncSampleOffset >= 0 || data_size < 8) {
398        return ERROR_MALFORMED;
399    }
400
401    mSyncSampleOffset = data_offset;
402
403    uint8_t header[8];
404    if (mDataSource->readAt(
405                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
406        return ERROR_IO;
407    }
408
409    if (U32_AT(header) != 0) {
410        // Expected version = 0, flags = 0.
411        return ERROR_MALFORMED;
412    }
413
414    mNumSyncSamples = U32_AT(&header[4]);
415
416    if (mNumSyncSamples < 2) {
417        ALOGV("Table of sync samples is empty or has only a single entry!");
418    }
419
420    mSyncSamples = new uint32_t[mNumSyncSamples];
421    size_t size = mNumSyncSamples * sizeof(uint32_t);
422    if (mDataSource->readAt(mSyncSampleOffset + 8, mSyncSamples, size)
423            != (ssize_t)size) {
424        return ERROR_IO;
425    }
426
427    for (size_t i = 0; i < mNumSyncSamples; ++i) {
428        mSyncSamples[i] = ntohl(mSyncSamples[i]) - 1;
429    }
430
431    return OK;
432}
433
434uint32_t SampleTable::countChunkOffsets() const {
435    return mNumChunkOffsets;
436}
437
438uint32_t SampleTable::countSamples() const {
439    return mNumSampleSizes;
440}
441
442status_t SampleTable::getMaxSampleSize(size_t *max_size) {
443    Mutex::Autolock autoLock(mLock);
444
445    *max_size = 0;
446
447    for (uint32_t i = 0; i < mNumSampleSizes; ++i) {
448        size_t sample_size;
449        status_t err = getSampleSize_l(i, &sample_size);
450
451        if (err != OK) {
452            return err;
453        }
454
455        if (sample_size > *max_size) {
456            *max_size = sample_size;
457        }
458    }
459
460    return OK;
461}
462
463uint32_t abs_difference(uint32_t time1, uint32_t time2) {
464    return time1 > time2 ? time1 - time2 : time2 - time1;
465}
466
467// static
468int SampleTable::CompareIncreasingTime(const void *_a, const void *_b) {
469    const SampleTimeEntry *a = (const SampleTimeEntry *)_a;
470    const SampleTimeEntry *b = (const SampleTimeEntry *)_b;
471
472    if (a->mCompositionTime < b->mCompositionTime) {
473        return -1;
474    } else if (a->mCompositionTime > b->mCompositionTime) {
475        return 1;
476    }
477
478    return 0;
479}
480
481void SampleTable::buildSampleEntriesTable() {
482    Mutex::Autolock autoLock(mLock);
483
484    if (mSampleTimeEntries != NULL) {
485        return;
486    }
487
488    mSampleTimeEntries = new SampleTimeEntry[mNumSampleSizes];
489
490    uint32_t sampleIndex = 0;
491    uint32_t sampleTime = 0;
492
493    for (uint32_t i = 0; i < mTimeToSampleCount; ++i) {
494        uint32_t n = mTimeToSample[2 * i];
495        uint32_t delta = mTimeToSample[2 * i + 1];
496
497        for (uint32_t j = 0; j < n; ++j) {
498            if (sampleIndex < mNumSampleSizes) {
499                // Technically this should always be the case if the file
500                // is well-formed, but you know... there's (gasp) malformed
501                // content out there.
502
503                mSampleTimeEntries[sampleIndex].mSampleIndex = sampleIndex;
504
505                uint32_t compTimeDelta =
506                    mCompositionDeltaLookup->getCompositionTimeOffset(
507                            sampleIndex);
508
509                mSampleTimeEntries[sampleIndex].mCompositionTime =
510                    sampleTime + compTimeDelta;
511            }
512
513            ++sampleIndex;
514            sampleTime += delta;
515        }
516    }
517
518    qsort(mSampleTimeEntries, mNumSampleSizes, sizeof(SampleTimeEntry),
519          CompareIncreasingTime);
520}
521
522status_t SampleTable::findSampleAtTime(
523        uint64_t req_time, uint64_t scale_num, uint64_t scale_den,
524        uint32_t *sample_index, uint32_t flags) {
525    buildSampleEntriesTable();
526
527    uint32_t left = 0;
528    uint32_t right = mNumSampleSizes - 1;
529    while (left <= right) {
530        uint32_t center = left + (right - left) / 2;
531        uint64_t centerTime =
532            getSampleTime(center, scale_num, scale_den);
533
534        if (req_time < centerTime) {
535            right = center - 1;
536        } else if (req_time > centerTime) {
537            left = center + 1;
538        } else {
539            *sample_index = mSampleTimeEntries[center].mSampleIndex;
540            return OK;
541        }
542    }
543
544    uint32_t closestIndex = left;
545
546    if (closestIndex == mNumSampleSizes) {
547        if (flags == kFlagAfter) {
548            return ERROR_OUT_OF_RANGE;
549        }
550        flags = kFlagBefore;
551    } else if (closestIndex == 0) {
552        if (flags == kFlagBefore) {
553            // normally we should return out of range, but that is
554            // treated as end-of-stream.  instead return first sample
555            //
556            // return ERROR_OUT_OF_RANGE;
557        }
558        flags = kFlagAfter;
559    }
560
561    switch (flags) {
562        case kFlagBefore:
563        {
564            --closestIndex;
565            break;
566        }
567
568        case kFlagAfter:
569        {
570            // nothing to do
571            break;
572        }
573
574        default:
575        {
576            CHECK(flags == kFlagClosest);
577            // pick closest based on timestamp. use abs_difference for safety
578            if (abs_difference(
579                    getSampleTime(closestIndex, scale_num, scale_den), req_time) >
580                abs_difference(
581                    req_time, getSampleTime(closestIndex - 1, scale_num, scale_den))) {
582                --closestIndex;
583            }
584            break;
585        }
586    }
587
588    *sample_index = mSampleTimeEntries[closestIndex].mSampleIndex;
589    return OK;
590}
591
592status_t SampleTable::findSyncSampleNear(
593        uint32_t start_sample_index, uint32_t *sample_index, uint32_t flags) {
594    Mutex::Autolock autoLock(mLock);
595
596    *sample_index = 0;
597
598    if (mSyncSampleOffset < 0) {
599        // All samples are sync-samples.
600        *sample_index = start_sample_index;
601        return OK;
602    }
603
604    if (mNumSyncSamples == 0) {
605        *sample_index = 0;
606        return OK;
607    }
608
609    uint32_t left = 0;
610    uint32_t right = mNumSyncSamples - 1;
611    while (left <= right) {
612        uint32_t center = left + (right - left) / 2;
613        uint32_t x = mSyncSamples[center];
614
615        if (start_sample_index < x) {
616            right = center - 1;
617        } else if (start_sample_index > x) {
618            left = center + 1;
619        } else {
620            *sample_index = x;
621            return OK;
622        }
623    }
624
625    if (left == mNumSyncSamples) {
626        if (flags == kFlagAfter) {
627            ALOGE("tried to find a sync frame after the last one: %d", left);
628            return ERROR_OUT_OF_RANGE;
629        }
630        flags = kFlagBefore;
631    }
632    else if (left == 0) {
633        if (flags == kFlagBefore) {
634            ALOGE("tried to find a sync frame before the first one: %d", left);
635
636            // normally we should return out of range, but that is
637            // treated as end-of-stream.  instead seek to first sync
638            //
639            // return ERROR_OUT_OF_RANGE;
640        }
641        flags = kFlagAfter;
642    }
643
644    // Now ssi[left - 1] <(=) start_sample_index <= ssi[left]
645    switch (flags) {
646        case kFlagBefore:
647        {
648            --left;
649            break;
650        }
651        case kFlagAfter:
652        {
653            // nothing to do
654            break;
655        }
656        default:
657        {
658            // this route is not used, but implement it nonetheless
659            CHECK(flags == kFlagClosest);
660
661            status_t err = mSampleIterator->seekTo(start_sample_index);
662            if (err != OK) {
663                return err;
664            }
665            uint32_t sample_time = mSampleIterator->getSampleTime();
666
667            err = mSampleIterator->seekTo(mSyncSamples[left]);
668            if (err != OK) {
669                return err;
670            }
671            uint32_t upper_time = mSampleIterator->getSampleTime();
672
673            err = mSampleIterator->seekTo(mSyncSamples[left - 1]);
674            if (err != OK) {
675                return err;
676            }
677            uint32_t lower_time = mSampleIterator->getSampleTime();
678
679            // use abs_difference for safety
680            if (abs_difference(upper_time, sample_time) >
681                abs_difference(sample_time, lower_time)) {
682                --left;
683            }
684            break;
685        }
686    }
687
688    *sample_index = mSyncSamples[left];
689    return OK;
690}
691
692status_t SampleTable::findThumbnailSample(uint32_t *sample_index) {
693    Mutex::Autolock autoLock(mLock);
694
695    if (mSyncSampleOffset < 0) {
696        // All samples are sync-samples.
697        *sample_index = 0;
698        return OK;
699    }
700
701    uint32_t bestSampleIndex = 0;
702    size_t maxSampleSize = 0;
703
704    static const size_t kMaxNumSyncSamplesToScan = 20;
705
706    // Consider the first kMaxNumSyncSamplesToScan sync samples and
707    // pick the one with the largest (compressed) size as the thumbnail.
708
709    size_t numSamplesToScan = mNumSyncSamples;
710    if (numSamplesToScan > kMaxNumSyncSamplesToScan) {
711        numSamplesToScan = kMaxNumSyncSamplesToScan;
712    }
713
714    for (size_t i = 0; i < numSamplesToScan; ++i) {
715        uint32_t x = mSyncSamples[i];
716
717        // Now x is a sample index.
718        size_t sampleSize;
719        status_t err = getSampleSize_l(x, &sampleSize);
720        if (err != OK) {
721            return err;
722        }
723
724        if (i == 0 || sampleSize > maxSampleSize) {
725            bestSampleIndex = x;
726            maxSampleSize = sampleSize;
727        }
728    }
729
730    *sample_index = bestSampleIndex;
731
732    return OK;
733}
734
735status_t SampleTable::getSampleSize_l(
736        uint32_t sampleIndex, size_t *sampleSize) {
737    return mSampleIterator->getSampleSizeDirect(
738            sampleIndex, sampleSize);
739}
740
741status_t SampleTable::getMetaDataForSample(
742        uint32_t sampleIndex,
743        off64_t *offset,
744        size_t *size,
745        uint32_t *compositionTime,
746        bool *isSyncSample,
747        uint32_t *sampleDuration) {
748    Mutex::Autolock autoLock(mLock);
749
750    status_t err;
751    if ((err = mSampleIterator->seekTo(sampleIndex)) != OK) {
752        return err;
753    }
754
755    if (offset) {
756        *offset = mSampleIterator->getSampleOffset();
757    }
758
759    if (size) {
760        *size = mSampleIterator->getSampleSize();
761    }
762
763    if (compositionTime) {
764        *compositionTime = mSampleIterator->getSampleTime();
765    }
766
767    if (isSyncSample) {
768        *isSyncSample = false;
769        if (mSyncSampleOffset < 0) {
770            // Every sample is a sync sample.
771            *isSyncSample = true;
772        } else {
773            size_t i = (mLastSyncSampleIndex < mNumSyncSamples)
774                    && (mSyncSamples[mLastSyncSampleIndex] <= sampleIndex)
775                ? mLastSyncSampleIndex : 0;
776
777            while (i < mNumSyncSamples && mSyncSamples[i] < sampleIndex) {
778                ++i;
779            }
780
781            if (i < mNumSyncSamples && mSyncSamples[i] == sampleIndex) {
782                *isSyncSample = true;
783            }
784
785            mLastSyncSampleIndex = i;
786        }
787    }
788
789    if (sampleDuration) {
790        *sampleDuration = mSampleIterator->getSampleDuration();
791    }
792
793    return OK;
794}
795
796uint32_t SampleTable::getCompositionTimeOffset(uint32_t sampleIndex) {
797    return mCompositionDeltaLookup->getCompositionTimeOffset(sampleIndex);
798}
799
800}  // namespace android
801
802