SampleTable.cpp revision 23fc0dafa8e1d53343790fb576731784e8bdd3b7 
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
30/* TODO: remove after being merged into other branches */
31#ifndef UINT32_MAX
32#define UINT32_MAX       (4294967295U)
33#endif
34
35namespace android {
36
37// static
38const uint32_t SampleTable::kChunkOffsetType32 = FOURCC('s', 't', 'c', 'o');
39// static
40const uint32_t SampleTable::kChunkOffsetType64 = FOURCC('c', 'o', '6', '4');
41// static
42const uint32_t SampleTable::kSampleSizeType32 = FOURCC('s', 't', 's', 'z');
43// static
44const uint32_t SampleTable::kSampleSizeTypeCompact = FOURCC('s', 't', 'z', '2');
45
46////////////////////////////////////////////////////////////////////////////////
47
48struct SampleTable::CompositionDeltaLookup {
49    CompositionDeltaLookup();
50
51    void setEntries(
52            const int32_t *deltaEntries, size_t numDeltaEntries);
53
54    int32_t getCompositionTimeOffset(uint32_t sampleIndex);
55
56private:
57    Mutex mLock;
58
59    const int32_t *mDeltaEntries;
60    size_t mNumDeltaEntries;
61
62    size_t mCurrentDeltaEntry;
63    size_t mCurrentEntrySampleIndex;
64
65    DISALLOW_EVIL_CONSTRUCTORS(CompositionDeltaLookup);
66};
67
68SampleTable::CompositionDeltaLookup::CompositionDeltaLookup()
69    : mDeltaEntries(NULL),
70      mNumDeltaEntries(0),
71      mCurrentDeltaEntry(0),
72      mCurrentEntrySampleIndex(0) {
73}
74
75void SampleTable::CompositionDeltaLookup::setEntries(
76        const int32_t *deltaEntries, size_t numDeltaEntries) {
77    Mutex::Autolock autolock(mLock);
78
79    mDeltaEntries = deltaEntries;
80    mNumDeltaEntries = numDeltaEntries;
81    mCurrentDeltaEntry = 0;
82    mCurrentEntrySampleIndex = 0;
83}
84
85int32_t SampleTable::CompositionDeltaLookup::getCompositionTimeOffset(
86        uint32_t sampleIndex) {
87    Mutex::Autolock autolock(mLock);
88
89    if (mDeltaEntries == NULL) {
90        return 0;
91    }
92
93    if (sampleIndex < mCurrentEntrySampleIndex) {
94        mCurrentDeltaEntry = 0;
95        mCurrentEntrySampleIndex = 0;
96    }
97
98    while (mCurrentDeltaEntry < mNumDeltaEntries) {
99        uint32_t sampleCount = mDeltaEntries[2 * mCurrentDeltaEntry];
100        if (sampleIndex < mCurrentEntrySampleIndex + sampleCount) {
101            return mDeltaEntries[2 * mCurrentDeltaEntry + 1];
102        }
103
104        mCurrentEntrySampleIndex += sampleCount;
105        ++mCurrentDeltaEntry;
106    }
107
108    return 0;
109}
110
111////////////////////////////////////////////////////////////////////////////////
112
113SampleTable::SampleTable(const sp<DataSource> &source)
114    : mDataSource(source),
115      mChunkOffsetOffset(-1),
116      mChunkOffsetType(0),
117      mNumChunkOffsets(0),
118      mSampleToChunkOffset(-1),
119      mNumSampleToChunkOffsets(0),
120      mSampleSizeOffset(-1),
121      mSampleSizeFieldSize(0),
122      mDefaultSampleSize(0),
123      mNumSampleSizes(0),
124      mTimeToSampleCount(0),
125      mTimeToSample(NULL),
126      mSampleTimeEntries(NULL),
127      mCompositionTimeDeltaEntries(NULL),
128      mNumCompositionTimeDeltaEntries(0),
129      mCompositionDeltaLookup(new CompositionDeltaLookup),
130      mSyncSampleOffset(-1),
131      mNumSyncSamples(0),
132      mSyncSamples(NULL),
133      mLastSyncSampleIndex(0),
134      mSampleToChunkEntries(NULL) {
135    mSampleIterator = new SampleIterator(this);
136}
137
138SampleTable::~SampleTable() {
139    delete[] mSampleToChunkEntries;
140    mSampleToChunkEntries = NULL;
141
142    delete[] mSyncSamples;
143    mSyncSamples = NULL;
144
145    delete mCompositionDeltaLookup;
146    mCompositionDeltaLookup = NULL;
147
148    delete[] mCompositionTimeDeltaEntries;
149    mCompositionTimeDeltaEntries = NULL;
150
151    delete[] mSampleTimeEntries;
152    mSampleTimeEntries = NULL;
153
154    delete[] mTimeToSample;
155    mTimeToSample = NULL;
156
157    delete mSampleIterator;
158    mSampleIterator = NULL;
159}
160
161bool SampleTable::isValid() const {
162    return mChunkOffsetOffset >= 0
163        && mSampleToChunkOffset >= 0
164        && mSampleSizeOffset >= 0
165        && mTimeToSample != NULL;
166}
167
168status_t SampleTable::setChunkOffsetParams(
169        uint32_t type, off64_t data_offset, size_t data_size) {
170    if (mChunkOffsetOffset >= 0) {
171        return ERROR_MALFORMED;
172    }
173
174    CHECK(type == kChunkOffsetType32 || type == kChunkOffsetType64);
175
176    mChunkOffsetOffset = data_offset;
177    mChunkOffsetType = type;
178
179    if (data_size < 8) {
180        return ERROR_MALFORMED;
181    }
182
183    uint8_t header[8];
184    if (mDataSource->readAt(
185                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
186        return ERROR_IO;
187    }
188
189    if (U32_AT(header) != 0) {
190        // Expected version = 0, flags = 0.
191        return ERROR_MALFORMED;
192    }
193
194    mNumChunkOffsets = U32_AT(&header[4]);
195
196    if (mChunkOffsetType == kChunkOffsetType32) {
197      if ((data_size - 8) / 4 < mNumChunkOffsets) {
198            return ERROR_MALFORMED;
199        }
200    } else {
201      if ((data_size - 8) / 8 < mNumChunkOffsets) {
202            return ERROR_MALFORMED;
203        }
204    }
205
206    return OK;
207}
208
209status_t SampleTable::setSampleToChunkParams(
210        off64_t data_offset, size_t data_size) {
211    if (mSampleToChunkOffset >= 0) {
212        // already set
213        return ERROR_MALFORMED;
214    }
215
216    if (data_offset < 0) {
217        return ERROR_MALFORMED;
218    }
219
220    mSampleToChunkOffset = data_offset;
221
222    if (data_size < 8) {
223        return ERROR_MALFORMED;
224    }
225
226    uint8_t header[8];
227    if (mDataSource->readAt(
228                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
229        return ERROR_IO;
230    }
231
232    if (U32_AT(header) != 0) {
233        // Expected version = 0, flags = 0.
234        return ERROR_MALFORMED;
235    }
236
237    mNumSampleToChunkOffsets = U32_AT(&header[4]);
238
239    if ((data_size - 8) / 12 < mNumSampleToChunkOffsets) {
240        return ERROR_MALFORMED;
241    }
242
243    if (SIZE_MAX / sizeof(SampleToChunkEntry) <= (size_t)mNumSampleToChunkOffsets)
244        return ERROR_OUT_OF_RANGE;
245
246    mSampleToChunkEntries =
247        new (std::nothrow) SampleToChunkEntry[mNumSampleToChunkOffsets];
248    if (!mSampleToChunkEntries)
249        return ERROR_OUT_OF_RANGE;
250
251    for (uint32_t i = 0; i < mNumSampleToChunkOffsets; ++i) {
252        uint8_t buffer[12];
253
254        if ((SIZE_MAX - 8 - (i * 12)) < (size_t)mSampleToChunkOffset) {
255            return ERROR_MALFORMED;
256        }
257
258        if (mDataSource->readAt(
259                    mSampleToChunkOffset + 8 + i * 12, buffer, sizeof(buffer))
260                != (ssize_t)sizeof(buffer)) {
261            return ERROR_IO;
262        }
263        // chunk index is 1 based in the spec.
264        if (U32_AT(buffer) < 1) {
265            ALOGE("b/23534160");
266            return ERROR_OUT_OF_RANGE;
267        }
268
269        // We want the chunk index to be 0-based.
270        mSampleToChunkEntries[i].startChunk = U32_AT(buffer) - 1;
271        mSampleToChunkEntries[i].samplesPerChunk = U32_AT(&buffer[4]);
272        mSampleToChunkEntries[i].chunkDesc = U32_AT(&buffer[8]);
273    }
274
275    return OK;
276}
277
278status_t SampleTable::setSampleSizeParams(
279        uint32_t type, off64_t data_offset, size_t data_size) {
280    if (mSampleSizeOffset >= 0) {
281        return ERROR_MALFORMED;
282    }
283
284    CHECK(type == kSampleSizeType32 || type == kSampleSizeTypeCompact);
285
286    mSampleSizeOffset = data_offset;
287
288    if (data_size < 12) {
289        return ERROR_MALFORMED;
290    }
291
292    uint8_t header[12];
293    if (mDataSource->readAt(
294                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
295        return ERROR_IO;
296    }
297
298    if (U32_AT(header) != 0) {
299        // Expected version = 0, flags = 0.
300        return ERROR_MALFORMED;
301    }
302
303    mDefaultSampleSize = U32_AT(&header[4]);
304    mNumSampleSizes = U32_AT(&header[8]);
305    if (mNumSampleSizes > (UINT32_MAX - 12) / 16) {
306        return ERROR_MALFORMED;
307    }
308
309    if (type == kSampleSizeType32) {
310        mSampleSizeFieldSize = 32;
311
312        if (mDefaultSampleSize != 0) {
313            return OK;
314        }
315
316        if (data_size < 12 + mNumSampleSizes * 4) {
317            return ERROR_MALFORMED;
318        }
319    } else {
320        if ((mDefaultSampleSize & 0xffffff00) != 0) {
321            // The high 24 bits are reserved and must be 0.
322            return ERROR_MALFORMED;
323        }
324
325        mSampleSizeFieldSize = mDefaultSampleSize & 0xff;
326        mDefaultSampleSize = 0;
327
328        if (mSampleSizeFieldSize != 4 && mSampleSizeFieldSize != 8
329            && mSampleSizeFieldSize != 16) {
330            return ERROR_MALFORMED;
331        }
332
333        if (data_size < 12 + (mNumSampleSizes * mSampleSizeFieldSize + 4) / 8) {
334            return ERROR_MALFORMED;
335        }
336    }
337
338    return OK;
339}
340
341status_t SampleTable::setTimeToSampleParams(
342        off64_t data_offset, size_t data_size) {
343    if (mTimeToSample != NULL || data_size < 8) {
344        return ERROR_MALFORMED;
345    }
346
347    uint8_t header[8];
348    if (mDataSource->readAt(
349                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
350        return ERROR_IO;
351    }
352
353    if (U32_AT(header) != 0) {
354        // Expected version = 0, flags = 0.
355        return ERROR_MALFORMED;
356    }
357
358    mTimeToSampleCount = U32_AT(&header[4]);
359    uint64_t allocSize = (uint64_t)mTimeToSampleCount * 2 * sizeof(uint32_t);
360    if (allocSize > UINT32_MAX) {
361        return ERROR_OUT_OF_RANGE;
362    }
363    mTimeToSample = new (std::nothrow) uint32_t[mTimeToSampleCount * 2];
364    if (!mTimeToSample)
365        return ERROR_OUT_OF_RANGE;
366
367    size_t size = sizeof(uint32_t) * mTimeToSampleCount * 2;
368    if (mDataSource->readAt(
369                data_offset + 8, mTimeToSample, size) < (ssize_t)size) {
370        return ERROR_IO;
371    }
372
373    for (uint32_t i = 0; i < mTimeToSampleCount * 2; ++i) {
374        mTimeToSample[i] = ntohl(mTimeToSample[i]);
375    }
376
377    return OK;
378}
379
380// NOTE: per 14996-12, version 0 ctts contains unsigned values, while version 1
381// contains signed values, however some software creates version 0 files that
382// contain signed values, so we're always treating the values as signed,
383// regardless of version.
384status_t SampleTable::setCompositionTimeToSampleParams(
385        off64_t data_offset, size_t data_size) {
386    ALOGI("There are reordered frames present.");
387
388    if (mCompositionTimeDeltaEntries != NULL || data_size < 8) {
389        return ERROR_MALFORMED;
390    }
391
392    uint8_t header[8];
393    if (mDataSource->readAt(
394                data_offset, header, sizeof(header))
395            < (ssize_t)sizeof(header)) {
396        return ERROR_IO;
397    }
398
399    uint32_t flags = U32_AT(header);
400    uint32_t version = flags >> 24;
401    flags &= 0xffffff;
402
403    if ((version != 0 && version != 1) || flags != 0) {
404        // Expected version = 0 or 1, flags = 0.
405        return ERROR_MALFORMED;
406    }
407
408    size_t numEntries = U32_AT(&header[4]);
409
410    if (((SIZE_MAX / 8) - 1 < numEntries) || (data_size != (numEntries + 1) * 8)) {
411        return ERROR_MALFORMED;
412    }
413
414    mNumCompositionTimeDeltaEntries = numEntries;
415    uint64_t allocSize = (uint64_t)numEntries * 2 * sizeof(uint32_t);
416    if (allocSize > UINT32_MAX) {
417        return ERROR_OUT_OF_RANGE;
418    }
419
420    mCompositionTimeDeltaEntries = new (std::nothrow) int32_t[2 * numEntries];
421    if (!mCompositionTimeDeltaEntries)
422        return ERROR_OUT_OF_RANGE;
423
424    if (mDataSource->readAt(
425                data_offset + 8, mCompositionTimeDeltaEntries, numEntries * 8)
426            < (ssize_t)numEntries * 8) {
427        delete[] mCompositionTimeDeltaEntries;
428        mCompositionTimeDeltaEntries = NULL;
429
430        return ERROR_IO;
431    }
432
433    for (size_t i = 0; i < 2 * numEntries; ++i) {
434        mCompositionTimeDeltaEntries[i] = ntohl(mCompositionTimeDeltaEntries[i]);
435    }
436
437    mCompositionDeltaLookup->setEntries(
438            mCompositionTimeDeltaEntries, mNumCompositionTimeDeltaEntries);
439
440    return OK;
441}
442
443status_t SampleTable::setSyncSampleParams(off64_t data_offset, size_t data_size) {
444    if (mSyncSampleOffset >= 0 || data_size < 8) {
445        return ERROR_MALFORMED;
446    }
447
448    mSyncSampleOffset = data_offset;
449
450    uint8_t header[8];
451    if (mDataSource->readAt(
452                data_offset, header, sizeof(header)) < (ssize_t)sizeof(header)) {
453        return ERROR_IO;
454    }
455
456    if (U32_AT(header) != 0) {
457        // Expected version = 0, flags = 0.
458        return ERROR_MALFORMED;
459    }
460
461    mNumSyncSamples = U32_AT(&header[4]);
462
463    if (mNumSyncSamples < 2) {
464        ALOGV("Table of sync samples is empty or has only a single entry!");
465    }
466
467    uint64_t allocSize = mNumSyncSamples * (uint64_t)sizeof(uint32_t);
468    if (allocSize > SIZE_MAX) {
469        return ERROR_OUT_OF_RANGE;
470    }
471
472    mSyncSamples = new (std::nothrow) uint32_t[mNumSyncSamples];
473    if (!mSyncSamples)
474        return ERROR_OUT_OF_RANGE;
475
476    size_t size = mNumSyncSamples * sizeof(uint32_t);
477    if (mDataSource->readAt(mSyncSampleOffset + 8, mSyncSamples, size)
478            != (ssize_t)size) {
479        return ERROR_IO;
480    }
481
482    for (size_t i = 0; i < mNumSyncSamples; ++i) {
483        mSyncSamples[i] = ntohl(mSyncSamples[i]) - 1;
484    }
485
486    return OK;
487}
488
489uint32_t SampleTable::countChunkOffsets() const {
490    return mNumChunkOffsets;
491}
492
493uint32_t SampleTable::countSamples() const {
494    return mNumSampleSizes;
495}
496
497status_t SampleTable::getMaxSampleSize(size_t *max_size) {
498    Mutex::Autolock autoLock(mLock);
499
500    *max_size = 0;
501
502    for (uint32_t i = 0; i < mNumSampleSizes; ++i) {
503        size_t sample_size;
504        status_t err = getSampleSize_l(i, &sample_size);
505
506        if (err != OK) {
507            return err;
508        }
509
510        if (sample_size > *max_size) {
511            *max_size = sample_size;
512        }
513    }
514
515    return OK;
516}
517
518uint32_t abs_difference(uint32_t time1, uint32_t time2) {
519    return time1 > time2 ? time1 - time2 : time2 - time1;
520}
521
522// static
523int SampleTable::CompareIncreasingTime(const void *_a, const void *_b) {
524    const SampleTimeEntry *a = (const SampleTimeEntry *)_a;
525    const SampleTimeEntry *b = (const SampleTimeEntry *)_b;
526
527    if (a->mCompositionTime < b->mCompositionTime) {
528        return -1;
529    } else if (a->mCompositionTime > b->mCompositionTime) {
530        return 1;
531    }
532
533    return 0;
534}
535
536void SampleTable::buildSampleEntriesTable() {
537    Mutex::Autolock autoLock(mLock);
538
539    if (mSampleTimeEntries != NULL || mNumSampleSizes == 0) {
540        return;
541    }
542
543    mSampleTimeEntries = new (std::nothrow) SampleTimeEntry[mNumSampleSizes];
544    if (!mSampleTimeEntries)
545        return;
546
547    uint32_t sampleIndex = 0;
548    uint32_t sampleTime = 0;
549
550    for (uint32_t i = 0; i < mTimeToSampleCount; ++i) {
551        uint32_t n = mTimeToSample[2 * i];
552        uint32_t delta = mTimeToSample[2 * i + 1];
553
554        for (uint32_t j = 0; j < n; ++j) {
555            if (sampleIndex < mNumSampleSizes) {
556                // Technically this should always be the case if the file
557                // is well-formed, but you know... there's (gasp) malformed
558                // content out there.
559
560                mSampleTimeEntries[sampleIndex].mSampleIndex = sampleIndex;
561
562                int32_t compTimeDelta =
563                    mCompositionDeltaLookup->getCompositionTimeOffset(
564                            sampleIndex);
565
566                if ((compTimeDelta < 0 && sampleTime <
567                        (compTimeDelta == INT32_MIN ?
568                                INT32_MAX : uint32_t(-compTimeDelta)))
569                        || (compTimeDelta > 0 &&
570                                sampleTime > UINT32_MAX - compTimeDelta)) {
571                    ALOGE("%u + %d would overflow, clamping",
572                            sampleTime, compTimeDelta);
573                    if (compTimeDelta < 0) {
574                        sampleTime = 0;
575                    } else {
576                        sampleTime = UINT32_MAX;
577                    }
578                    compTimeDelta = 0;
579                }
580
581                mSampleTimeEntries[sampleIndex].mCompositionTime =
582                        compTimeDelta > 0 ? sampleTime + compTimeDelta:
583                                sampleTime - (-compTimeDelta);
584            }
585
586            ++sampleIndex;
587            sampleTime += delta;
588        }
589    }
590
591    qsort(mSampleTimeEntries, mNumSampleSizes, sizeof(SampleTimeEntry),
592          CompareIncreasingTime);
593}
594
595status_t SampleTable::findSampleAtTime(
596        uint64_t req_time, uint64_t scale_num, uint64_t scale_den,
597        uint32_t *sample_index, uint32_t flags) {
598    buildSampleEntriesTable();
599
600    if (mSampleTimeEntries == NULL) {
601        return ERROR_OUT_OF_RANGE;
602    }
603
604    uint32_t left = 0;
605    uint32_t right_plus_one = mNumSampleSizes;
606    while (left < right_plus_one) {
607        uint32_t center = left + (right_plus_one - left) / 2;
608        uint64_t centerTime =
609            getSampleTime(center, scale_num, scale_den);
610
611        if (req_time < centerTime) {
612            right_plus_one = center;
613        } else if (req_time > centerTime) {
614            left = center + 1;
615        } else {
616            *sample_index = mSampleTimeEntries[center].mSampleIndex;
617            return OK;
618        }
619    }
620
621    uint32_t closestIndex = left;
622
623    if (closestIndex == mNumSampleSizes) {
624        if (flags == kFlagAfter) {
625            return ERROR_OUT_OF_RANGE;
626        }
627        flags = kFlagBefore;
628    } else if (closestIndex == 0) {
629        if (flags == kFlagBefore) {
630            // normally we should return out of range, but that is
631            // treated as end-of-stream.  instead return first sample
632            //
633            // return ERROR_OUT_OF_RANGE;
634        }
635        flags = kFlagAfter;
636    }
637
638    switch (flags) {
639        case kFlagBefore:
640        {
641            --closestIndex;
642            break;
643        }
644
645        case kFlagAfter:
646        {
647            // nothing to do
648            break;
649        }
650
651        default:
652        {
653            CHECK(flags == kFlagClosest);
654            // pick closest based on timestamp. use abs_difference for safety
655            if (abs_difference(
656                    getSampleTime(closestIndex, scale_num, scale_den), req_time) >
657                abs_difference(
658                    req_time, getSampleTime(closestIndex - 1, scale_num, scale_den))) {
659                --closestIndex;
660            }
661            break;
662        }
663    }
664
665    *sample_index = mSampleTimeEntries[closestIndex].mSampleIndex;
666    return OK;
667}
668
669status_t SampleTable::findSyncSampleNear(
670        uint32_t start_sample_index, uint32_t *sample_index, uint32_t flags) {
671    Mutex::Autolock autoLock(mLock);
672
673    *sample_index = 0;
674
675    if (mSyncSampleOffset < 0) {
676        // All samples are sync-samples.
677        *sample_index = start_sample_index;
678        return OK;
679    }
680
681    if (mNumSyncSamples == 0) {
682        *sample_index = 0;
683        return OK;
684    }
685
686    uint32_t left = 0;
687    uint32_t right_plus_one = mNumSyncSamples;
688    while (left < right_plus_one) {
689        uint32_t center = left + (right_plus_one - left) / 2;
690        uint32_t x = mSyncSamples[center];
691
692        if (start_sample_index < x) {
693            right_plus_one = center;
694        } else if (start_sample_index > x) {
695            left = center + 1;
696        } else {
697            *sample_index = x;
698            return OK;
699        }
700    }
701
702    if (left == mNumSyncSamples) {
703        if (flags == kFlagAfter) {
704            ALOGE("tried to find a sync frame after the last one: %d", left);
705            return ERROR_OUT_OF_RANGE;
706        }
707        flags = kFlagBefore;
708    }
709    else if (left == 0) {
710        if (flags == kFlagBefore) {
711            ALOGE("tried to find a sync frame before the first one: %d", left);
712
713            // normally we should return out of range, but that is
714            // treated as end-of-stream.  instead seek to first sync
715            //
716            // return ERROR_OUT_OF_RANGE;
717        }
718        flags = kFlagAfter;
719    }
720
721    // Now ssi[left - 1] <(=) start_sample_index <= ssi[left]
722    switch (flags) {
723        case kFlagBefore:
724        {
725            --left;
726            break;
727        }
728        case kFlagAfter:
729        {
730            // nothing to do
731            break;
732        }
733        default:
734        {
735            // this route is not used, but implement it nonetheless
736            CHECK(flags == kFlagClosest);
737
738            status_t err = mSampleIterator->seekTo(start_sample_index);
739            if (err != OK) {
740                return err;
741            }
742            uint32_t sample_time = mSampleIterator->getSampleTime();
743
744            err = mSampleIterator->seekTo(mSyncSamples[left]);
745            if (err != OK) {
746                return err;
747            }
748            uint32_t upper_time = mSampleIterator->getSampleTime();
749
750            err = mSampleIterator->seekTo(mSyncSamples[left - 1]);
751            if (err != OK) {
752                return err;
753            }
754            uint32_t lower_time = mSampleIterator->getSampleTime();
755
756            // use abs_difference for safety
757            if (abs_difference(upper_time, sample_time) >
758                abs_difference(sample_time, lower_time)) {
759                --left;
760            }
761            break;
762        }
763    }
764
765    *sample_index = mSyncSamples[left];
766    return OK;
767}
768
769status_t SampleTable::findThumbnailSample(uint32_t *sample_index) {
770    Mutex::Autolock autoLock(mLock);
771
772    if (mSyncSampleOffset < 0) {
773        // All samples are sync-samples.
774        *sample_index = 0;
775        return OK;
776    }
777
778    uint32_t bestSampleIndex = 0;
779    size_t maxSampleSize = 0;
780
781    static const size_t kMaxNumSyncSamplesToScan = 20;
782
783    // Consider the first kMaxNumSyncSamplesToScan sync samples and
784    // pick the one with the largest (compressed) size as the thumbnail.
785
786    size_t numSamplesToScan = mNumSyncSamples;
787    if (numSamplesToScan > kMaxNumSyncSamplesToScan) {
788        numSamplesToScan = kMaxNumSyncSamplesToScan;
789    }
790
791    for (size_t i = 0; i < numSamplesToScan; ++i) {
792        uint32_t x = mSyncSamples[i];
793
794        // Now x is a sample index.
795        size_t sampleSize;
796        status_t err = getSampleSize_l(x, &sampleSize);
797        if (err != OK) {
798            return err;
799        }
800
801        if (i == 0 || sampleSize > maxSampleSize) {
802            bestSampleIndex = x;
803            maxSampleSize = sampleSize;
804        }
805    }
806
807    *sample_index = bestSampleIndex;
808
809    return OK;
810}
811
812status_t SampleTable::getSampleSize_l(
813        uint32_t sampleIndex, size_t *sampleSize) {
814    return mSampleIterator->getSampleSizeDirect(
815            sampleIndex, sampleSize);
816}
817
818status_t SampleTable::getMetaDataForSample(
819        uint32_t sampleIndex,
820        off64_t *offset,
821        size_t *size,
822        uint32_t *compositionTime,
823        bool *isSyncSample,
824        uint32_t *sampleDuration) {
825    Mutex::Autolock autoLock(mLock);
826
827    status_t err;
828    if ((err = mSampleIterator->seekTo(sampleIndex)) != OK) {
829        return err;
830    }
831
832    if (offset) {
833        *offset = mSampleIterator->getSampleOffset();
834    }
835
836    if (size) {
837        *size = mSampleIterator->getSampleSize();
838    }
839
840    if (compositionTime) {
841        *compositionTime = mSampleIterator->getSampleTime();
842    }
843
844    if (isSyncSample) {
845        *isSyncSample = false;
846        if (mSyncSampleOffset < 0) {
847            // Every sample is a sync sample.
848            *isSyncSample = true;
849        } else {
850            size_t i = (mLastSyncSampleIndex < mNumSyncSamples)
851                    && (mSyncSamples[mLastSyncSampleIndex] <= sampleIndex)
852                ? mLastSyncSampleIndex : 0;
853
854            while (i < mNumSyncSamples && mSyncSamples[i] < sampleIndex) {
855                ++i;
856            }
857
858            if (i < mNumSyncSamples && mSyncSamples[i] == sampleIndex) {
859                *isSyncSample = true;
860            }
861
862            mLastSyncSampleIndex = i;
863        }
864    }
865
866    if (sampleDuration) {
867        *sampleDuration = mSampleIterator->getSampleDuration();
868    }
869
870    return OK;
871}
872
873int32_t SampleTable::getCompositionTimeOffset(uint32_t sampleIndex) {
874    return mCompositionDeltaLookup->getCompositionTimeOffset(sampleIndex);
875}
876
877}  // namespace android
878
879