xref: /frameworks/av/media/libstagefright/matroska/MatroskaExtractor.cpp

/*
 * Copyright (C) 2010 The Android Open Source Project
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

//#define LOG_NDEBUG 0
#define LOG_TAG "MatroskaExtractor"
#include <utils/Log.h>

#include "MatroskaExtractor.h"

#include "mkvparser.hpp"

#include <media/stagefright/foundation/ADebug.h>
#include <media/stagefright/foundation/hexdump.h>
#include <media/stagefright/DataSource.h>
#include <media/stagefright/MediaBuffer.h>
#include <media/stagefright/MediaDefs.h>
#include <media/stagefright/MediaErrors.h>
#include <media/stagefright/MediaSource.h>
#include <media/stagefright/MetaData.h>
#include <media/stagefright/Utils.h>
#include <utils/String8.h>

namespace android {

struct DataSourceReader : public mkvparser::IMkvReader {
    DataSourceReader(const sp<DataSource> &source)
        : mSource(source) {
    }

    virtual int Read(long long position, long length, unsigned char* buffer) {
        CHECK(position >= 0);
        CHECK(length >= 0);

        if (length == 0) {
            return 0;
        }

        ssize_t n = mSource->readAt(position, buffer, length);

        if (n <= 0) {
            return -1;
        }

        return 0;
    }

    virtual int Length(long long* total, long long* available) {
        off64_t size;
        if (mSource->getSize(&size) != OK) {
            *total = -1;
            *available = (long long)((1ull << 63) - 1);

            return 0;
        }

        if (total) {
            *total = size;
        }

        if (available) {
            *available = size;
        }

        return 0;
    }

private:
    sp<DataSource> mSource;

    DataSourceReader(const DataSourceReader &);
    DataSourceReader &operator=(const DataSourceReader &);
};

////////////////////////////////////////////////////////////////////////////////

struct BlockIterator {
    BlockIterator(MatroskaExtractor *extractor, unsigned long trackNum);

    bool eos() const;

    void advance();
    void reset();

    void seek(
            int64_t seekTimeUs, bool isAudio,
            int64_t *actualFrameTimeUs);

    const mkvparser::Block *block() const;
    int64_t blockTimeUs() const;

private:
    MatroskaExtractor *mExtractor;
    unsigned long mTrackNum;

    const mkvparser::Cluster *mCluster;
    const mkvparser::BlockEntry *mBlockEntry;
    long mBlockEntryIndex;

    void advance_l();

    BlockIterator(const BlockIterator &);
    BlockIterator &operator=(const BlockIterator &);
};

struct MatroskaSource : public MediaSource {
    MatroskaSource(
            const sp<MatroskaExtractor> &extractor, size_t index);

    virtual status_t start(MetaData *params);
    virtual status_t stop();

    virtual sp<MetaData> getFormat();

    virtual status_t read(
            MediaBuffer **buffer, const ReadOptions *options);

protected:
    virtual ~MatroskaSource();

private:
    enum Type {
        AVC,
        AAC,
        OTHER
    };

    sp<MatroskaExtractor> mExtractor;
    size_t mTrackIndex;
    Type mType;
    bool mIsAudio;
    BlockIterator mBlockIter;
    size_t mNALSizeLen;  // for type AVC

    List<MediaBuffer *> mPendingFrames;

    status_t advance();

    status_t readBlock();
    void clearPendingFrames();

    MatroskaSource(const MatroskaSource &);
    MatroskaSource &operator=(const MatroskaSource &);
};

MatroskaSource::MatroskaSource(
        const sp<MatroskaExtractor> &extractor, size_t index)
    : mExtractor(extractor),
      mTrackIndex(index),
      mType(OTHER),
      mIsAudio(false),
      mBlockIter(mExtractor.get(),
                 mExtractor->mTracks.itemAt(index).mTrackNum),
      mNALSizeLen(0) {
    sp<MetaData> meta = mExtractor->mTracks.itemAt(index).mMeta;

    const char *mime;
    CHECK(meta->findCString(kKeyMIMEType, &mime));

    mIsAudio = !strncasecmp("audio/", mime, 6);

    if (!strcasecmp(mime, MEDIA_MIMETYPE_VIDEO_AVC)) {
        mType = AVC;

        uint32_t dummy;
        const uint8_t *avcc;
        size_t avccSize;
        CHECK(meta->findData(
                    kKeyAVCC, &dummy, (const void **)&avcc, &avccSize));

        CHECK_GE(avccSize, 5u);

        mNALSizeLen = 1 + (avcc[4] & 3);
        ALOGV("mNALSizeLen = %d", mNALSizeLen);
    } else if (!strcasecmp(mime, MEDIA_MIMETYPE_AUDIO_AAC)) {
        mType = AAC;
    }
}

MatroskaSource::~MatroskaSource() {
    clearPendingFrames();
}

status_t MatroskaSource::start(MetaData *params) {
    mBlockIter.reset();

    return OK;
}

status_t MatroskaSource::stop() {
    clearPendingFrames();

    return OK;
}

sp<MetaData> MatroskaSource::getFormat() {
    return mExtractor->mTracks.itemAt(mTrackIndex).mMeta;
}

////////////////////////////////////////////////////////////////////////////////

BlockIterator::BlockIterator(
        MatroskaExtractor *extractor, unsigned long trackNum)
    : mExtractor(extractor),
      mTrackNum(trackNum),
      mCluster(NULL),
      mBlockEntry(NULL),
      mBlockEntryIndex(0) {
    reset();
}

bool BlockIterator::eos() const {
    return mCluster == NULL || mCluster->EOS();
}

void BlockIterator::advance() {
    Mutex::Autolock autoLock(mExtractor->mLock);
    advance_l();
}

void BlockIterator::advance_l() {
    for (;;) {
        long res = mCluster->GetEntry(mBlockEntryIndex, mBlockEntry);
        ALOGV("GetEntry returned %ld", res);

        long long pos;
        long len;
        if (res < 0) {
            // Need to parse this cluster some more

            CHECK_EQ(res, mkvparser::E_BUFFER_NOT_FULL);

            res = mCluster->Parse(pos, len);
            ALOGV("Parse returned %ld", res);

            if (res < 0) {
                // I/O error

                ALOGE("Cluster::Parse returned result %ld", res);

                mCluster = NULL;
                break;
            }

            continue;
        } else if (res == 0) {
            // We're done with this cluster

            const mkvparser::Cluster *nextCluster;
            res = mExtractor->mSegment->ParseNext(
                    mCluster, nextCluster, pos, len);
            ALOGV("ParseNext returned %ld", res);

            if (res != 0) {
                // EOF or error

                mCluster = NULL;
                break;
            }

            CHECK_EQ(res, 0);
            CHECK(nextCluster != NULL);
            CHECK(!nextCluster->EOS());

            mCluster = nextCluster;

            res = mCluster->Parse(pos, len);
            ALOGV("Parse (2) returned %ld", res);
            CHECK_GE(res, 0);

            mBlockEntryIndex = 0;
            continue;
        }

        CHECK(mBlockEntry != NULL);
        CHECK(mBlockEntry->GetBlock() != NULL);
        ++mBlockEntryIndex;

        if (mBlockEntry->GetBlock()->GetTrackNumber() == mTrackNum) {
            break;
        }
    }
}

void BlockIterator::reset() {
    Mutex::Autolock autoLock(mExtractor->mLock);

    mCluster = mExtractor->mSegment->GetFirst();
    mBlockEntry = NULL;
    mBlockEntryIndex = 0;

    do {
        advance_l();
    } while (!eos() && block()->GetTrackNumber() != mTrackNum);
}

void BlockIterator::seek(
        int64_t seekTimeUs, bool isAudio,
        int64_t *actualFrameTimeUs) {
    Mutex::Autolock autoLock(mExtractor->mLock);

    *actualFrameTimeUs = -1ll;

    const int64_t seekTimeNs = seekTimeUs * 1000ll;

    mkvparser::Segment* const pSegment = mExtractor->mSegment;

    // Special case the 0 seek to avoid loading Cues when the application
    // extraneously seeks to 0 before playing.
    if (seekTimeNs <= 0) {
        ALOGV("Seek to beginning: %lld", seekTimeUs);
        mCluster = pSegment->GetFirst();
        mBlockEntryIndex = 0;
        do {
            advance_l();
        } while (!eos() && block()->GetTrackNumber() != mTrackNum);
        return;
    }

    ALOGV("Seeking to: %lld", seekTimeUs);

    // If the Cues have not been located then find them.
    const mkvparser::Cues* pCues = pSegment->GetCues();
    const mkvparser::SeekHead* pSH = pSegment->GetSeekHead();
    if (!pCues && pSH) {
        const size_t count = pSH->GetCount();
        const mkvparser::SeekHead::Entry* pEntry;
        ALOGV("No Cues yet");

        for (size_t index = 0; index < count; index++) {
            pEntry = pSH->GetEntry(index);

            if (pEntry->id == 0x0C53BB6B) { // Cues ID
                long len; long long pos;
                pSegment->ParseCues(pEntry->pos, pos, len);
                pCues = pSegment->GetCues();
                ALOGV("Cues found");
                break;
            }
        }

        if (!pCues) {
            ALOGE("No Cues in file");
            return;
        }
    }
    else if (!pSH) {
        ALOGE("No SeekHead");
        return;
    }

    const mkvparser::CuePoint* pCP;
    while (!pCues->DoneParsing()) {
        pCues->LoadCuePoint();
        pCP = pCues->GetLast();

        if (pCP->GetTime(pSegment) >= seekTimeNs) {
            ALOGV("Parsed past relevant Cue");
            break;
        }
    }

    // The Cue index is built around video keyframes
    mkvparser::Tracks const *pTracks = pSegment->GetTracks();
    const mkvparser::Track *pTrack = NULL;
    for (size_t index = 0; index < pTracks->GetTracksCount(); ++index) {
        pTrack = pTracks->GetTrackByIndex(index);
        if (pTrack && pTrack->GetType() == 1) { // VIDEO_TRACK
            ALOGV("Video track located at %d", index);
            break;
        }
    }

    // Always *search* based on the video track, but finalize based on mTrackNum
    const mkvparser::CuePoint::TrackPosition* pTP;
    if (pTrack && pTrack->GetType() == 1) {
        pCues->Find(seekTimeNs, pTrack, pCP, pTP);
    } else {
        ALOGE("Did not locate the video track for seeking");
        return;
    }

    mCluster = pSegment->FindOrPreloadCluster(pTP->m_pos);

    CHECK(mCluster);
    CHECK(!mCluster->EOS());

    // mBlockEntryIndex starts at 0 but m_block starts at 1
    CHECK_GT(pTP->m_block, 0);
    mBlockEntryIndex = pTP->m_block - 1;

    for (;;) {
        advance_l();

        if (eos()) break;

        if (isAudio || block()->IsKey()) {
            // Accept the first key frame
            *actualFrameTimeUs = (block()->GetTime(mCluster) + 500LL) / 1000LL;
            ALOGV("Requested seek point: %lld actual: %lld",
                  seekTimeUs, actualFrameTimeUs);
            break;
        }
    }
}

const mkvparser::Block *BlockIterator::block() const {
    CHECK(!eos());

    return mBlockEntry->GetBlock();
}

int64_t BlockIterator::blockTimeUs() const {
    return (mBlockEntry->GetBlock()->GetTime(mCluster) + 500ll) / 1000ll;
}

////////////////////////////////////////////////////////////////////////////////

static unsigned U24_AT(const uint8_t *ptr) {
    return ptr[0] << 16 | ptr[1] << 8 | ptr[2];
}

static size_t clz(uint8_t x) {
    size_t numLeadingZeroes = 0;

    while (!(x & 0x80)) {
        ++numLeadingZeroes;
        x = x << 1;
    }

    return numLeadingZeroes;
}

void MatroskaSource::clearPendingFrames() {
    while (!mPendingFrames.empty()) {
        MediaBuffer *frame = *mPendingFrames.begin();
        mPendingFrames.erase(mPendingFrames.begin());

        frame->release();
        frame = NULL;
    }
}

status_t MatroskaSource::readBlock() {
    CHECK(mPendingFrames.empty());

    if (mBlockIter.eos()) {
        return ERROR_END_OF_STREAM;
    }

    const mkvparser::Block *block = mBlockIter.block();

    int64_t timeUs = mBlockIter.blockTimeUs();

    for (int i = 0; i < block->GetFrameCount(); ++i) {
        const mkvparser::Block::Frame &frame = block->GetFrame(i);

        MediaBuffer *mbuf = new MediaBuffer(frame.len);
        mbuf->meta_data()->setInt64(kKeyTime, timeUs);
        mbuf->meta_data()->setInt32(kKeyIsSyncFrame, block->IsKey());

        long n = frame.Read(mExtractor->mReader, (unsigned char *)mbuf->data());
        if (n != 0) {
            mPendingFrames.clear();

            mBlockIter.advance();
            return ERROR_IO;
        }

        mPendingFrames.push_back(mbuf);
    }

    mBlockIter.advance();

    return OK;
}

status_t MatroskaSource::read(
        MediaBuffer **out, const ReadOptions *options) {
    *out = NULL;

    int64_t targetSampleTimeUs = -1ll;

    int64_t seekTimeUs;
    ReadOptions::SeekMode mode;
    if (options && options->getSeekTo(&seekTimeUs, &mode)
            && !mExtractor->isLiveStreaming()) {
        clearPendingFrames();

        // The audio we want is located by using the Cues to seek the video
        // stream to find the target Cluster then iterating to finalize for
        // audio.
        int64_t actualFrameTimeUs;
        mBlockIter.seek(seekTimeUs, mIsAudio, &actualFrameTimeUs);

        if (mode == ReadOptions::SEEK_CLOSEST) {
            targetSampleTimeUs = actualFrameTimeUs;
        }
    }

    while (mPendingFrames.empty()) {
        status_t err = readBlock();

        if (err != OK) {
            clearPendingFrames();

            return err;
        }
    }

    MediaBuffer *frame = *mPendingFrames.begin();
    mPendingFrames.erase(mPendingFrames.begin());

    if (mType != AVC) {
        if (targetSampleTimeUs >= 0ll) {
            frame->meta_data()->setInt64(
                    kKeyTargetTime, targetSampleTimeUs);
        }

        *out = frame;

        return OK;
    }

    // Each input frame contains one or more NAL fragments, each fragment
    // is prefixed by mNALSizeLen bytes giving the fragment length,
    // followed by a corresponding number of bytes containing the fragment.
    // We output all these fragments into a single large buffer separated
    // by startcodes (0x00 0x00 0x00 0x01).

    const uint8_t *srcPtr =
        (const uint8_t *)frame->data() + frame->range_offset();

    size_t srcSize = frame->range_length();

    size_t dstSize = 0;
    MediaBuffer *buffer = NULL;
    uint8_t *dstPtr = NULL;

    for (int32_t pass = 0; pass < 2; ++pass) {
        size_t srcOffset = 0;
        size_t dstOffset = 0;
        while (srcOffset + mNALSizeLen <= srcSize) {
            size_t NALsize;
            switch (mNALSizeLen) {
                case 1: NALsize = srcPtr[srcOffset]; break;
                case 2: NALsize = U16_AT(srcPtr + srcOffset); break;
                case 3: NALsize = U24_AT(srcPtr + srcOffset); break;
                case 4: NALsize = U32_AT(srcPtr + srcOffset); break;
                default:
                    TRESPASS();
            }

            if (srcOffset + mNALSizeLen + NALsize > srcSize) {
                break;
            }

            if (pass == 1) {
                memcpy(&dstPtr[dstOffset], "\x00\x00\x00\x01", 4);

                memcpy(&dstPtr[dstOffset + 4],
                       &srcPtr[srcOffset + mNALSizeLen],
                       NALsize);
            }

            dstOffset += 4;  // 0x00 00 00 01
            dstOffset += NALsize;

            srcOffset += mNALSizeLen + NALsize;
        }

        if (srcOffset < srcSize) {
            // There were trailing bytes or not enough data to complete
            // a fragment.

            frame->release();
            frame = NULL;

            return ERROR_MALFORMED;
        }

        if (pass == 0) {
            dstSize = dstOffset;

            buffer = new MediaBuffer(dstSize);

            int64_t timeUs;
            CHECK(frame->meta_data()->findInt64(kKeyTime, &timeUs));
            int32_t isSync;
            CHECK(frame->meta_data()->findInt32(kKeyIsSyncFrame, &isSync));

            buffer->meta_data()->setInt64(kKeyTime, timeUs);
            buffer->meta_data()->setInt32(kKeyIsSyncFrame, isSync);

            dstPtr = (uint8_t *)buffer->data();
        }
    }

    frame->release();
    frame = NULL;

    if (targetSampleTimeUs >= 0ll) {
        buffer->meta_data()->setInt64(
                kKeyTargetTime, targetSampleTimeUs);
    }

    *out = buffer;

    return OK;
}

////////////////////////////////////////////////////////////////////////////////

MatroskaExtractor::MatroskaExtractor(const sp<DataSource> &source)
    : mDataSource(source),
      mReader(new DataSourceReader(mDataSource)),
      mSegment(NULL),
      mExtractedThumbnails(false),
      mIsWebm(false) {
    off64_t size;
    mIsLiveStreaming =
        (mDataSource->flags()
            & (DataSource::kWantsPrefetching
                | DataSource::kIsCachingDataSource))
        && mDataSource->getSize(&size) != OK;

    mkvparser::EBMLHeader ebmlHeader;
    long long pos;
    if (ebmlHeader.Parse(mReader, pos) < 0) {
        return;
    }

    if (ebmlHeader.m_docType && !strcmp("webm", ebmlHeader.m_docType)) {
        mIsWebm = true;
    }

    long long ret =
        mkvparser::Segment::CreateInstance(mReader, pos, mSegment);

    if (ret) {
        CHECK(mSegment == NULL);
        return;
    }

    ret = mSegment->ParseHeaders();
    CHECK_EQ(ret, 0);

    long len;
    ret = mSegment->LoadCluster(pos, len);
    CHECK_EQ(ret, 0);

    if (ret < 0) {
        delete mSegment;
        mSegment = NULL;
        return;
    }

#if 0
    const mkvparser::SegmentInfo *info = mSegment->GetInfo();
    ALOGI("muxing app: %s, writing app: %s",
         info->GetMuxingAppAsUTF8(),
         info->GetWritingAppAsUTF8());
#endif

    addTracks();
}

MatroskaExtractor::~MatroskaExtractor() {
    delete mSegment;
    mSegment = NULL;

    delete mReader;
    mReader = NULL;
}

size_t MatroskaExtractor::countTracks() {
    return mTracks.size();
}

sp<MediaSource> MatroskaExtractor::getTrack(size_t index) {
    if (index >= mTracks.size()) {
        return NULL;
    }

    return new MatroskaSource(this, index);
}

sp<MetaData> MatroskaExtractor::getTrackMetaData(
        size_t index, uint32_t flags) {
    if (index >= mTracks.size()) {
        return NULL;
    }

    if ((flags & kIncludeExtensiveMetaData) && !mExtractedThumbnails
            && !isLiveStreaming()) {
        findThumbnails();
        mExtractedThumbnails = true;
    }

    return mTracks.itemAt(index).mMeta;
}

bool MatroskaExtractor::isLiveStreaming() const {
    return mIsLiveStreaming;
}

static void addESDSFromCodecPrivate(
        const sp<MetaData> &meta,
        bool isAudio, const void *priv, size_t privSize) {
    static const uint8_t kStaticESDS[] = {
        0x03, 22,
        0x00, 0x00,     // ES_ID
        0x00,           // streamDependenceFlag, URL_Flag, OCRstreamFlag

        0x04, 17,
        0x40,           // ObjectTypeIndication
        0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00,
        0x00, 0x00, 0x00, 0x00,

        0x05,
        // CodecSpecificInfo (with size prefix) follows
    };

    // Make sure all sizes can be coded in a single byte.
    CHECK(privSize + 22 - 2 < 128);
    size_t esdsSize = sizeof(kStaticESDS) + privSize + 1;
    uint8_t *esds = new uint8_t[esdsSize];
    memcpy(esds, kStaticESDS, sizeof(kStaticESDS));
    uint8_t *ptr = esds + sizeof(kStaticESDS);
    *ptr++ = privSize;
    memcpy(ptr, priv, privSize);

    // Increment by codecPrivateSize less 2 bytes that are accounted for
    // already in lengths of 22/17
    esds[1] += privSize - 2;
    esds[6] += privSize - 2;

    // Set ObjectTypeIndication.
    esds[7] = isAudio ? 0x40   // Audio ISO/IEC 14496-3
                      : 0x20;  // Visual ISO/IEC 14496-2

    meta->setData(kKeyESDS, 0, esds, esdsSize);

    delete[] esds;
    esds = NULL;
}

status_t addVorbisCodecInfo(
        const sp<MetaData> &meta,
        const void *_codecPrivate, size_t codecPrivateSize) {
    // hexdump(_codecPrivate, codecPrivateSize);

    if (codecPrivateSize < 1) {
        return ERROR_MALFORMED;
    }

    const uint8_t *codecPrivate = (const uint8_t *)_codecPrivate;

    if (codecPrivate[0] != 0x02) {
        return ERROR_MALFORMED;
    }

    // codecInfo starts with two lengths, len1 and len2, that are
    // "Xiph-style-lacing encoded"...

    size_t offset = 1;
    size_t len1 = 0;
    while (offset < codecPrivateSize && codecPrivate[offset] == 0xff) {
        len1 += 0xff;
        ++offset;
    }
    if (offset >= codecPrivateSize) {
        return ERROR_MALFORMED;
    }
    len1 += codecPrivate[offset++];

    size_t len2 = 0;
    while (offset < codecPrivateSize && codecPrivate[offset] == 0xff) {
        len2 += 0xff;
        ++offset;
    }
    if (offset >= codecPrivateSize) {
        return ERROR_MALFORMED;
    }
    len2 += codecPrivate[offset++];

    if (codecPrivateSize < offset + len1 + len2) {
        return ERROR_MALFORMED;
    }

    if (codecPrivate[offset] != 0x01) {
        return ERROR_MALFORMED;
    }
    meta->setData(kKeyVorbisInfo, 0, &codecPrivate[offset], len1);

    offset += len1;
    if (codecPrivate[offset] != 0x03) {
        return ERROR_MALFORMED;
    }

    offset += len2;
    if (codecPrivate[offset] != 0x05) {
        return ERROR_MALFORMED;
    }

    meta->setData(
            kKeyVorbisBooks, 0, &codecPrivate[offset],
            codecPrivateSize - offset);

    return OK;
}

void MatroskaExtractor::addTracks() {
    const mkvparser::Tracks *tracks = mSegment->GetTracks();

    for (size_t index = 0; index < tracks->GetTracksCount(); ++index) {
        const mkvparser::Track *track = tracks->GetTrackByIndex(index);

        if (track == NULL) {
            // Apparently this is currently valid (if unexpected) behaviour
            // of the mkv parser lib.
            continue;
        }

        const char *const codecID = track->GetCodecId();
        ALOGV("codec id = %s", codecID);
        ALOGV("codec name = %s", track->GetCodecNameAsUTF8());

        size_t codecPrivateSize;
        const unsigned char *codecPrivate =
            track->GetCodecPrivate(codecPrivateSize);

        enum { VIDEO_TRACK = 1, AUDIO_TRACK = 2 };

        sp<MetaData> meta = new MetaData;

        status_t err = OK;

        switch (track->GetType()) {
            case VIDEO_TRACK:
            {
                const mkvparser::VideoTrack *vtrack =
                    static_cast<const mkvparser::VideoTrack *>(track);

                if (!strcmp("V_MPEG4/ISO/AVC", codecID)) {
                    meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_VIDEO_AVC);
                    meta->setData(kKeyAVCC, 0, codecPrivate, codecPrivateSize);
                } else if (!strcmp("V_MPEG4/ISO/ASP", codecID)) {
                    if (codecPrivateSize > 0) {
                        meta->setCString(
                                kKeyMIMEType, MEDIA_MIMETYPE_VIDEO_MPEG4);
                        addESDSFromCodecPrivate(
                                meta, false, codecPrivate, codecPrivateSize);
                    } else {
                        ALOGW("%s is detected, but does not have configuration.",
                                codecID);
                        continue;
                    }
                } else if (!strcmp("V_VP8", codecID)) {
                    meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_VIDEO_VPX);
                } else {
                    ALOGW("%s is not supported.", codecID);
                    continue;
                }

                meta->setInt32(kKeyWidth, vtrack->GetWidth());
                meta->setInt32(kKeyHeight, vtrack->GetHeight());
                break;
            }

            case AUDIO_TRACK:
            {
                const mkvparser::AudioTrack *atrack =
                    static_cast<const mkvparser::AudioTrack *>(track);

                if (!strcmp("A_AAC", codecID)) {
                    meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_AAC);
                    CHECK(codecPrivateSize >= 2);

                    addESDSFromCodecPrivate(
                            meta, true, codecPrivate, codecPrivateSize);
                } else if (!strcmp("A_VORBIS", codecID)) {
                    meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_VORBIS);

                    err = addVorbisCodecInfo(
                            meta, codecPrivate, codecPrivateSize);
                } else if (!strcmp("A_MPEG/L3", codecID)) {
                    meta->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_MPEG);
                } else {
                    ALOGW("%s is not supported.", codecID);
                    continue;
                }

                meta->setInt32(kKeySampleRate, atrack->GetSamplingRate());
                meta->setInt32(kKeyChannelCount, atrack->GetChannels());
                break;
            }

            default:
                continue;
        }

        if (err != OK) {
            ALOGE("skipping track, codec specific data was malformed.");
            continue;
        }

        long long durationNs = mSegment->GetDuration();
        meta->setInt64(kKeyDuration, (durationNs + 500) / 1000);

        mTracks.push();
        TrackInfo *trackInfo = &mTracks.editItemAt(mTracks.size() - 1);
        trackInfo->mTrackNum = track->GetNumber();
        trackInfo->mMeta = meta;
    }
}

void MatroskaExtractor::findThumbnails() {
    for (size_t i = 0; i < mTracks.size(); ++i) {
        TrackInfo *info = &mTracks.editItemAt(i);

        const char *mime;
        CHECK(info->mMeta->findCString(kKeyMIMEType, &mime));

        if (strncasecmp(mime, "video/", 6)) {
            continue;
        }

        BlockIterator iter(this, info->mTrackNum);
        int32_t j = 0;
        int64_t thumbnailTimeUs = 0;
        size_t maxBlockSize = 0;
        while (!iter.eos() && j < 20) {
            if (iter.block()->IsKey()) {
                ++j;

                size_t blockSize = 0;
                for (int k = 0; k < iter.block()->GetFrameCount(); ++k) {
                    blockSize += iter.block()->GetFrame(k).len;
                }

                if (blockSize > maxBlockSize) {
                    maxBlockSize = blockSize;
                    thumbnailTimeUs = iter.blockTimeUs();
                }
            }
            iter.advance();
        }
        info->mMeta->setInt64(kKeyThumbnailTime, thumbnailTimeUs);
    }
}

sp<MetaData> MatroskaExtractor::getMetaData() {
    sp<MetaData> meta = new MetaData;

    meta->setCString(
            kKeyMIMEType,
            mIsWebm ? "video/webm" : MEDIA_MIMETYPE_CONTAINER_MATROSKA);

    return meta;
}

uint32_t MatroskaExtractor::flags() const {
    uint32_t x = CAN_PAUSE;
    if (!isLiveStreaming()) {
        x |= CAN_SEEK_BACKWARD | CAN_SEEK_FORWARD | CAN_SEEK;
    }

    return x;
}

bool SniffMatroska(
        const sp<DataSource> &source, String8 *mimeType, float *confidence,
        sp<AMessage> *) {
    DataSourceReader reader(source);
    mkvparser::EBMLHeader ebmlHeader;
    long long pos;
    if (ebmlHeader.Parse(&reader, pos) < 0) {
        return false;
    }

    mimeType->setTo(MEDIA_MIMETYPE_CONTAINER_MATROSKA);
    *confidence = 0.6;

    return true;
}

}  // namespace android