/*
 * 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 "ESQueue"
#include <media/stagefright/foundation/ADebug.h>

#include "ESQueue.h"

#include <media/stagefright/foundation/hexdump.h>
#include <media/stagefright/foundation/ABitReader.h>
#include <media/stagefright/foundation/ABuffer.h>
#include <media/stagefright/foundation/AMessage.h>
#include <media/stagefright/foundation/ByteUtils.h>
#include <media/stagefright/foundation/avc_utils.h>
#include <media/stagefright/MediaErrors.h>
#include <media/stagefright/MediaDefs.h>
#include <media/stagefright/MetaData.h>
#include <media/stagefright/MetaDataUtils.h>
#include <media/cas/DescramblerAPI.h>
#include <media/hardware/CryptoAPI.h>

#include <inttypes.h>
#include <netinet/in.h>

#ifdef ENABLE_CRYPTO
#include "HlsSampleDecryptor.h"
#endif

namespace android {

ElementaryStreamQueue::ElementaryStreamQueue(Mode mode, uint32_t flags)
    : mMode(mode),
      mFlags(flags),
      mEOSReached(false),
      mCASystemId(0),
      mAUIndex(0) {

    ALOGV("ElementaryStreamQueue(%p) mode %x  flags %x  isScrambled %d  isSampleEncrypted %d",
            this, mode, flags, isScrambled(), isSampleEncrypted());

    // Create the decryptor anyway since we don't know the use-case unless key is provided
    // Won't decrypt if key info not available (e.g., scanner/extractor just parsing ts files)
    mSampleDecryptor = isSampleEncrypted() ?
#ifdef ENABLE_CRYPTO
        new HlsSampleDecryptor
#else
        new SampleDecryptor
#endif
        : NULL;
}

sp<MetaData> ElementaryStreamQueue::getFormat() {
    return mFormat;
}

void ElementaryStreamQueue::clear(bool clearFormat) {
    if (mBuffer != NULL) {
        mBuffer->setRange(0, 0);
    }

    mRangeInfos.clear();

    if (mScrambledBuffer != NULL) {
        mScrambledBuffer->setRange(0, 0);
    }
    mScrambledRangeInfos.clear();

    if (clearFormat) {
        mFormat.clear();
    }

    mEOSReached = false;
}

bool ElementaryStreamQueue::isScrambled() const {
    return (mFlags & kFlag_ScrambledData) != 0;
}

void ElementaryStreamQueue::setCasInfo(
        int32_t systemId, const std::vector<uint8_t> &sessionId) {
    mCASystemId = systemId;
    mCasSessionId = sessionId;
}

static int32_t readVariableBits(ABitReader &bits, int32_t nbits) {
    int32_t value = 0;
    int32_t more_bits = 1;

    while (more_bits) {
        value += bits.getBits(nbits);
        more_bits = bits.getBits(1);
        if (!more_bits)
            break;
        value++;
        value <<= nbits;
    }
    return value;
}

// Parse AC3 header assuming the current ptr is start position of syncframe,
// update metadata only applicable, and return the payload size
static unsigned parseAC3SyncFrame(
        const uint8_t *ptr, size_t size, sp<MetaData> *metaData) {
    static const unsigned channelCountTable[] = {2, 1, 2, 3, 3, 4, 4, 5};
    static const unsigned samplingRateTable[] = {48000, 44100, 32000};

    static const unsigned frameSizeTable[19][3] = {
        { 64, 69, 96 },
        { 80, 87, 120 },
        { 96, 104, 144 },
        { 112, 121, 168 },
        { 128, 139, 192 },
        { 160, 174, 240 },
        { 192, 208, 288 },
        { 224, 243, 336 },
        { 256, 278, 384 },
        { 320, 348, 480 },
        { 384, 417, 576 },
        { 448, 487, 672 },
        { 512, 557, 768 },
        { 640, 696, 960 },
        { 768, 835, 1152 },
        { 896, 975, 1344 },
        { 1024, 1114, 1536 },
        { 1152, 1253, 1728 },
        { 1280, 1393, 1920 },
    };

    ABitReader bits(ptr, size);
    if (bits.numBitsLeft() < 16) {
        return 0;
    }
    if (bits.getBits(16) != 0x0B77) {
        return 0;
    }

    if (bits.numBitsLeft() < 16 + 2 + 6 + 5 + 3 + 3) {
        ALOGV("Not enough bits left for further parsing");
        return 0;
    }
    bits.skipBits(16);  // crc1

    unsigned fscod = bits.getBits(2);
    if (fscod == 3) {
        ALOGW("Incorrect fscod in AC3 header");
        return 0;
    }

    unsigned frmsizecod = bits.getBits(6);
    if (frmsizecod > 37) {
        ALOGW("Incorrect frmsizecod in AC3 header");
        return 0;
    }

    unsigned bsid = bits.getBits(5);
    if (bsid > 8) {
        ALOGW("Incorrect bsid in AC3 header. Possibly E-AC-3?");
        return 0;
    }

    bits.skipBits(3); // bsmod
    unsigned acmod = bits.getBits(3);

    if ((acmod & 1) > 0 && acmod != 1) {
        if (bits.numBitsLeft() < 2) {
            return 0;
        }
        bits.skipBits(2); //cmixlev
    }
    if ((acmod & 4) > 0) {
        if (bits.numBitsLeft() < 2) {
            return 0;
        }
        bits.skipBits(2); //surmixlev
    }
    if (acmod == 2) {
        if (bits.numBitsLeft() < 2) {
            return 0;
        }
        bits.skipBits(2); //dsurmod
    }

    if (bits.numBitsLeft() < 1) {
        return 0;
    }
    unsigned lfeon = bits.getBits(1);

    unsigned samplingRate = samplingRateTable[fscod];
    unsigned payloadSize = frameSizeTable[frmsizecod >> 1][fscod];
    if (fscod == 1) {
        payloadSize += frmsizecod & 1;
    }
    payloadSize <<= 1;  // convert from 16-bit words to bytes

    unsigned channelCount = channelCountTable[acmod] + lfeon;

    if (metaData != NULL) {
        (*metaData)->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_AC3);
        (*metaData)->setInt32(kKeyChannelCount, channelCount);
        (*metaData)->setInt32(kKeySampleRate, samplingRate);
    }

    return payloadSize;
}

// Parse EAC3 header assuming the current ptr is start position of syncframe,
// update metadata only applicable, and return the payload size
// ATSC A/52:2012 E2.3.1
static unsigned parseEAC3SyncFrame(
    const uint8_t *ptr, size_t size, sp<MetaData> *metaData) {
    static const unsigned channelCountTable[] = {2, 1, 2, 3, 3, 4, 4, 5};
    static const unsigned samplingRateTable[] = {48000, 44100, 32000};
    static const unsigned samplingRateTable2[] = {24000, 22050, 16000};

    ABitReader bits(ptr, size);
    if (bits.numBitsLeft() < 16) {
        ALOGE("Not enough bits left for further parsing");
        return 0;
    }
    if (bits.getBits(16) != 0x0B77) {
        ALOGE("No valid sync word in EAC3 header");
        return 0;
    }

    // we parse up to bsid so there needs to be at least that many bits
    if (bits.numBitsLeft() < 2 + 3 + 11 + 2 + 2 + 3 + 1 + 5) {
        ALOGE("Not enough bits left for further parsing");
        return 0;
    }

    unsigned strmtyp = bits.getBits(2);
    if (strmtyp == 3) {
        ALOGE("Incorrect strmtyp in EAC3 header");
        return 0;
    }

    unsigned substreamid = bits.getBits(3);
    // only the first independent stream is supported
    if ((strmtyp == 0 || strmtyp == 2) && substreamid != 0)
        return 0;

    unsigned frmsiz = bits.getBits(11);
    unsigned fscod = bits.getBits(2);

    unsigned samplingRate = 0;
    if (fscod == 0x3) {
        unsigned fscod2 = bits.getBits(2);
        if (fscod2 == 3) {
            ALOGW("Incorrect fscod2 in EAC3 header");
            return 0;
        }
        samplingRate = samplingRateTable2[fscod2];
    } else {
        samplingRate = samplingRateTable[fscod];
        bits.skipBits(2); // numblkscod
    }

    unsigned acmod = bits.getBits(3);
    unsigned lfeon = bits.getBits(1);
    unsigned bsid = bits.getBits(5);
    if (bsid < 11 || bsid > 16) {
        ALOGW("Incorrect bsid in EAC3 header. Could be AC-3 or some unknown EAC3 format");
        return 0;
    }

    // we currently only support the first independant stream
    if (metaData != NULL && (strmtyp == 0 || strmtyp == 2)) {
        unsigned channelCount = channelCountTable[acmod] + lfeon;
        ALOGV("EAC3 channelCount = %d", channelCount);
        ALOGV("EAC3 samplingRate = %d", samplingRate);
        (*metaData)->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_EAC3);
        (*metaData)->setInt32(kKeyChannelCount, channelCount);
        (*metaData)->setInt32(kKeySampleRate, samplingRate);
        (*metaData)->setInt32(kKeyIsSyncFrame, 1);
    }

    unsigned payloadSize = frmsiz + 1;
    payloadSize <<= 1;  // convert from 16-bit words to bytes

    return payloadSize;
}

// Parse AC4 header assuming the current ptr is start position of syncframe
// and update frameSize and metadata.
static status_t parseAC4SyncFrame(
        const uint8_t *ptr, size_t size, unsigned &frameSize, sp<MetaData> *metaData) {
    // ETSI TS 103 190-2 V1.1.1 (2015-09), Annex C
    // The sync_word can be either 0xAC40 or 0xAC41.
    static const int kSyncWordAC40 = 0xAC40;
    static const int kSyncWordAC41 = 0xAC41;

    size_t headerSize = 0;
    ABitReader bits(ptr, size);
    int32_t syncWord = bits.getBits(16);
    if ((syncWord != kSyncWordAC40) && (syncWord != kSyncWordAC41)) {
        ALOGE("Invalid syncword in AC4 header");
        return ERROR_MALFORMED;
    }
    headerSize += 2;

    frameSize = bits.getBits(16);
    headerSize += 2;
    if (frameSize == 0xFFFF) {
        frameSize = bits.getBits(24);
        headerSize += 3;
    }

    if (frameSize == 0) {
        ALOGE("Invalid frame size in AC4 header");
        return ERROR_MALFORMED;
    }
    frameSize += headerSize;
    // If the sync_word is 0xAC41, a crc_word is also transmitted.
    if (syncWord == kSyncWordAC41) {
        frameSize += 2; // crc_word
    }
    ALOGV("AC4 frameSize = %u", frameSize);

    // ETSI TS 103 190-2 V1.1.1 6.2.1.1
    uint32_t bitstreamVersion = bits.getBits(2);
    if (bitstreamVersion == 3) {
        bitstreamVersion += readVariableBits(bits, 2);
    }

    bits.skipBits(10); // Sequence Counter

    uint32_t bWaitFrames = bits.getBits(1);
    if (bWaitFrames) {
        uint32_t waitFrames = bits.getBits(3);
        if (waitFrames > 0) {
            bits.skipBits(2); // br_code;
        }
    }

    // ETSI TS 103 190 V1.1.1 Table 82
    bool fsIndex = bits.getBits(1);
    uint32_t samplingRate = fsIndex ? 48000 : 44100;

    if (metaData != NULL) {
        ALOGV("dequeueAccessUnitAC4 Setting mFormat");
        (*metaData)->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_AC4);
        (*metaData)->setInt32(kKeyIsSyncFrame, 1);
        // [FIXME] AC4 channel count is defined per presentation. Provide a default channel count
        // as stereo for the entire stream.
        (*metaData)->setInt32(kKeyChannelCount, 2);
        (*metaData)->setInt32(kKeySampleRate, samplingRate);
    }
    return OK;
}

static status_t IsSeeminglyValidAC4Header(const uint8_t *ptr, size_t size, unsigned &frameSize) {
    return parseAC4SyncFrame(ptr, size, frameSize, NULL);
}

static bool IsSeeminglyValidADTSHeader(
        const uint8_t *ptr, size_t size, size_t *frameLength) {
    if (size < 7) {
        // Not enough data to verify header.
        return false;
    }

    if (ptr[0] != 0xff || (ptr[1] >> 4) != 0x0f) {
        return false;
    }

    unsigned layer = (ptr[1] >> 1) & 3;

    if (layer != 0) {
        return false;
    }

    unsigned ID = (ptr[1] >> 3) & 1;
    unsigned profile_ObjectType = ptr[2] >> 6;

    if (ID == 1 && profile_ObjectType == 3) {
        // MPEG-2 profile 3 is reserved.
        return false;
    }

    size_t frameLengthInHeader =
            ((ptr[3] & 3) << 11) + (ptr[4] << 3) + ((ptr[5] >> 5) & 7);
    if (frameLengthInHeader > size) {
        return false;
    }

    *frameLength = frameLengthInHeader;
    return true;
}

static bool IsSeeminglyValidMPEGAudioHeader(const uint8_t *ptr, size_t size) {
    if (size < 3) {
        // Not enough data to verify header.
        return false;
    }

    if (ptr[0] != 0xff || (ptr[1] >> 5) != 0x07) {
        return false;
    }

    unsigned ID = (ptr[1] >> 3) & 3;

    if (ID == 1) {
        return false;  // reserved
    }

    unsigned layer = (ptr[1] >> 1) & 3;

    if (layer == 0) {
        return false;  // reserved
    }

    unsigned bitrateIndex = (ptr[2] >> 4);

    if (bitrateIndex == 0x0f) {
        return false;  // reserved
    }

    unsigned samplingRateIndex = (ptr[2] >> 2) & 3;

    if (samplingRateIndex == 3) {
        return false;  // reserved
    }

    return true;
}

status_t ElementaryStreamQueue::appendData(
        const void *data, size_t size, int64_t timeUs,
        int32_t payloadOffset, uint32_t pesScramblingControl) {

    if (mEOSReached) {
        ALOGE("appending data after EOS");
        return ERROR_MALFORMED;
    }

    if (!isScrambled() && (mBuffer == NULL || mBuffer->size() == 0)) {
        switch (mMode) {
            case H264:
            case MPEG_VIDEO:
            {
#if 0
                if (size < 4 || memcmp("\x00\x00\x00\x01", data, 4)) {
                    return ERROR_MALFORMED;
                }
#else
                uint8_t *ptr = (uint8_t *)data;

                ssize_t startOffset = -1;
                for (size_t i = 0; i + 2 < size; ++i) {
                    if (!memcmp("\x00\x00\x01", &ptr[i], 3)) {
                        startOffset = i;
                        break;
                    }
                }

                if (startOffset < 0) {
                    return ERROR_MALFORMED;
                }

                if (mFormat == NULL && startOffset > 0) {
                    ALOGI("found something resembling an H.264/MPEG syncword "
                          "at offset %zd",
                          startOffset);
                }

                data = &ptr[startOffset];
                size -= startOffset;
#endif
                break;
            }

            case MPEG4_VIDEO:
            {
#if 0
                if (size < 3 || memcmp("\x00\x00\x01", data, 3)) {
                    return ERROR_MALFORMED;
                }
#else
                uint8_t *ptr = (uint8_t *)data;

                ssize_t startOffset = -1;
                for (size_t i = 0; i + 2 < size; ++i) {
                    if (!memcmp("\x00\x00\x01", &ptr[i], 3)) {
                        startOffset = i;
                        break;
                    }
                }

                if (startOffset < 0) {
                    return ERROR_MALFORMED;
                }

                if (startOffset > 0) {
                    ALOGI("found something resembling an H.264/MPEG syncword "
                          "at offset %zd",
                          startOffset);
                }

                data = &ptr[startOffset];
                size -= startOffset;
#endif
                break;
            }

            case AAC:
            {
                uint8_t *ptr = (uint8_t *)data;

#if 0
                if (size < 2 || ptr[0] != 0xff || (ptr[1] >> 4) != 0x0f) {
                    return ERROR_MALFORMED;
                }
#else
                ssize_t startOffset = -1;
                size_t frameLength;
                for (size_t i = 0; i < size; ++i) {
                    if (IsSeeminglyValidADTSHeader(
                            &ptr[i], size - i, &frameLength)) {
                        startOffset = i;
                        break;
                    }
                }

                if (startOffset < 0) {
                    return ERROR_MALFORMED;
                }

                if (startOffset > 0) {
                    ALOGI("found something resembling an AAC syncword at "
                          "offset %zd",
                          startOffset);
                }

                if (frameLength != size - startOffset) {
                    ALOGV("First ADTS AAC frame length is %zd bytes, "
                          "while the buffer size is %zd bytes.",
                          frameLength, size - startOffset);
                }

                data = &ptr[startOffset];
                size -= startOffset;
#endif
                break;
            }

            case AC3:
            case EAC3:
            {
                uint8_t *ptr = (uint8_t *)data;

                ssize_t startOffset = -1;
                for (size_t i = 0; i < size; ++i) {
                    unsigned payloadSize = 0;
                    if (mMode == AC3) {
                        payloadSize = parseAC3SyncFrame(&ptr[i], size - i, NULL);
                    } else if (mMode == EAC3) {
                        payloadSize = parseEAC3SyncFrame(&ptr[i], size - i, NULL);
                    }
                    if (payloadSize > 0) {
                        startOffset = i;
                        break;
                    }
                }

                if (startOffset < 0) {
                    return ERROR_MALFORMED;
                }

                if (startOffset > 0) {
                    ALOGI("found something resembling an (E)AC3 syncword at "
                          "offset %zd",
                          startOffset);
                }

                data = &ptr[startOffset];
                size -= startOffset;
                break;
            }

            case AC4:
            {
                uint8_t *ptr = (uint8_t *)data;
                unsigned frameSize = 0;
                ssize_t startOffset = -1;

                // A valid AC4 stream should have minimum of 7 bytes in its buffer.
                // (Sync header 4 bytes + AC4 toc 3 bytes)
                if (size < 7) {
                    return ERROR_MALFORMED;
                }
                for (size_t i = 0; i < size; ++i) {
                    if (IsSeeminglyValidAC4Header(&ptr[i], size - i, frameSize) == OK) {
                        startOffset = i;
                        break;
                    }
                }

                if (startOffset < 0) {
                    return ERROR_MALFORMED;
                }

                if (startOffset > 0) {
                    ALOGI("found something resembling an AC4 syncword at "
                          "offset %zd",
                          startOffset);
                }
                if (frameSize != size - startOffset) {
                    ALOGV("AC4 frame size is %u bytes, while the buffer size is %zd bytes.",
                          frameSize, size - startOffset);
                }

                data = &ptr[startOffset];
                size -= startOffset;
                break;
            }

            case MPEG_AUDIO:
            {
                uint8_t *ptr = (uint8_t *)data;

                ssize_t startOffset = -1;
                for (size_t i = 0; i < size; ++i) {
                    if (IsSeeminglyValidMPEGAudioHeader(&ptr[i], size - i)) {
                        startOffset = i;
                        break;
                    }
                }

                if (startOffset < 0) {
                    return ERROR_MALFORMED;
                }

                if (startOffset > 0) {
                    ALOGI("found something resembling an MPEG audio "
                          "syncword at offset %zd",
                          startOffset);
                }

                data = &ptr[startOffset];
                size -= startOffset;
                break;
            }

            case PCM_AUDIO:
            case METADATA:
            {
                break;
            }

            default:
                ALOGE("Unknown mode: %d", mMode);
                return ERROR_MALFORMED;
        }
    }

    size_t neededSize = (mBuffer == NULL ? 0 : mBuffer->size()) + size;
    if (mBuffer == NULL || neededSize > mBuffer->capacity()) {
        neededSize = (neededSize + 65535) & ~65535;

        ALOGV("resizing buffer to size %zu", neededSize);

        sp<ABuffer> buffer = new ABuffer(neededSize);
        if (mBuffer != NULL) {
            memcpy(buffer->data(), mBuffer->data(), mBuffer->size());
            buffer->setRange(0, mBuffer->size());
        } else {
            buffer->setRange(0, 0);
        }

        mBuffer = buffer;
    }

    memcpy(mBuffer->data() + mBuffer->size(), data, size);
    mBuffer->setRange(0, mBuffer->size() + size);

    RangeInfo info;
    info.mLength = size;
    info.mTimestampUs = timeUs;
    info.mPesOffset = payloadOffset;
    info.mPesScramblingControl = pesScramblingControl;
    mRangeInfos.push_back(info);

#if 0
    if (mMode == AAC) {
        ALOGI("size = %zu, timeUs = %.2f secs", size, timeUs / 1E6);
        hexdump(data, size);
    }
#endif

    return OK;
}

void ElementaryStreamQueue::appendScrambledData(
        const void *data, size_t size,
        size_t leadingClearBytes,
        int32_t keyId, bool isSync,
        sp<ABuffer> clearSizes, sp<ABuffer> encSizes) {
    if (!isScrambled()) {
        return;
    }

    size_t neededSize = (mScrambledBuffer == NULL ? 0 : mScrambledBuffer->size()) + size;
    if (mScrambledBuffer == NULL || neededSize > mScrambledBuffer->capacity()) {
        neededSize = (neededSize + 65535) & ~65535;

        ALOGI("resizing scrambled buffer to size %zu", neededSize);

        sp<ABuffer> buffer = new ABuffer(neededSize);
        if (mScrambledBuffer != NULL) {
            memcpy(buffer->data(), mScrambledBuffer->data(), mScrambledBuffer->size());
            buffer->setRange(0, mScrambledBuffer->size());
        } else {
            buffer->setRange(0, 0);
        }

        mScrambledBuffer = buffer;
    }
    memcpy(mScrambledBuffer->data() + mScrambledBuffer->size(), data, size);
    mScrambledBuffer->setRange(0, mScrambledBuffer->size() + size);

    ScrambledRangeInfo scrambledInfo;
    scrambledInfo.mLength = size;
    scrambledInfo.mLeadingClearBytes = leadingClearBytes;
    scrambledInfo.mKeyId = keyId;
    scrambledInfo.mIsSync = isSync;
    scrambledInfo.mClearSizes = clearSizes;
    scrambledInfo.mEncSizes = encSizes;

    ALOGV("[stream %d] appending scrambled range: size=%zu", mMode, size);

    mScrambledRangeInfos.push_back(scrambledInfo);
}

sp<ABuffer> ElementaryStreamQueue::dequeueScrambledAccessUnit() {
    size_t nextScan = mBuffer->size();
    int32_t pesOffset = 0, pesScramblingControl = 0;
    int64_t timeUs = fetchTimestamp(nextScan, &pesOffset, &pesScramblingControl);
    if (timeUs < 0ll) {
        ALOGE("Negative timeUs");
        return NULL;
    }

    // return scrambled unit
    int32_t keyId = pesScramblingControl, isSync = 0, scrambledLength = 0;
    sp<ABuffer> clearSizes, encSizes;
    size_t leadingClearBytes;
    while (mScrambledRangeInfos.size() > mRangeInfos.size()) {
        auto it = mScrambledRangeInfos.begin();
        ALOGV("[stream %d] fetching scrambled range: size=%zu", mMode, it->mLength);

        if (scrambledLength > 0) {
            // This shouldn't happen since we always dequeue the entire PES.
            ALOGW("Discarding srambled length %d", scrambledLength);
        }
        scrambledLength = it->mLength;

        // TODO: handle key id change, use first non-zero keyId for now
        if (keyId == 0) {
            keyId = it->mKeyId;
        }
        clearSizes = it->mClearSizes;
        encSizes = it->mEncSizes;
        isSync = it->mIsSync;
        leadingClearBytes = it->mLeadingClearBytes;
        mScrambledRangeInfos.erase(it);
    }
    if (scrambledLength == 0) {
        ALOGE("[stream %d] empty scrambled unit!", mMode);
        return NULL;
    }

    // Retrieve the leading clear bytes info, and use it to set the clear
    // range on mBuffer. Note that the leading clear bytes includes the
    // PES header portion, while mBuffer doesn't.
    if ((int32_t)leadingClearBytes > pesOffset) {
        mBuffer->setRange(0, leadingClearBytes - pesOffset);
    } else {
        mBuffer->setRange(0, 0);
    }

    // Try to parse formats, and if unavailable set up a dummy format.
    // Only support the following modes for scrambled content for now.
    // (will be expanded later).
    if (mFormat == NULL) {
        mFormat = new MetaData;
        switch (mMode) {
            case H264:
            {
                if (!MakeAVCCodecSpecificData(
                        *mFormat, mBuffer->data(), mBuffer->size())) {
                    ALOGI("Creating dummy AVC format for scrambled content");

                    mFormat->setCString(kKeyMIMEType, MEDIA_MIMETYPE_VIDEO_AVC);
                    mFormat->setInt32(kKeyWidth, 1280);
                    mFormat->setInt32(kKeyHeight, 720);
                }
                break;
            }
            case AAC:
            {
                if (!MakeAACCodecSpecificData(
                        *mFormat, mBuffer->data(), mBuffer->size())) {
                    ALOGI("Creating dummy AAC format for scrambled content");

                    MakeAACCodecSpecificData(*mFormat,
                            1 /*profile*/, 7 /*sampling_freq_index*/, 1 /*channel_config*/);
                    mFormat->setInt32(kKeyIsADTS, true);
                }

                break;
            }
            case MPEG_VIDEO:
            {
                ALOGI("Creating dummy MPEG format for scrambled content");

                mFormat->setCString(kKeyMIMEType, MEDIA_MIMETYPE_VIDEO_MPEG2);
                mFormat->setInt32(kKeyWidth, 1280);
                mFormat->setInt32(kKeyHeight, 720);
                break;
            }
            default:
            {
                ALOGE("Unknown mode for scrambled content");
                return NULL;
            }
        }

        // for MediaExtractor.CasInfo
        mFormat->setInt32(kKeyCASystemID, mCASystemId);
        mFormat->setData(kKeyCASessionID,
                0, mCasSessionId.data(), mCasSessionId.size());
    }

    mBuffer->setRange(0, 0);

    // copy into scrambled access unit
    sp<ABuffer> scrambledAccessUnit = ABuffer::CreateAsCopy(
            mScrambledBuffer->data(), scrambledLength);

    scrambledAccessUnit->meta()->setInt64("timeUs", timeUs);
    if (isSync) {
        scrambledAccessUnit->meta()->setInt32("isSync", 1);
    }

    // fill in CryptoInfo fields for AnotherPacketSource::read()
    // MediaCas doesn't use cryptoMode, but set to non-zero value here.
    scrambledAccessUnit->meta()->setInt32(
            "cryptoMode", CryptoPlugin::kMode_AES_CTR);
    scrambledAccessUnit->meta()->setInt32("cryptoKey", keyId);
    scrambledAccessUnit->meta()->setBuffer("clearBytes", clearSizes);
    scrambledAccessUnit->meta()->setBuffer("encBytes", encSizes);
    scrambledAccessUnit->meta()->setInt32("pesOffset", pesOffset);

    memmove(mScrambledBuffer->data(),
            mScrambledBuffer->data() + scrambledLength,
            mScrambledBuffer->size() - scrambledLength);

    mScrambledBuffer->setRange(0, mScrambledBuffer->size() - scrambledLength);

    ALOGV("[stream %d] dequeued scrambled AU: timeUs=%lld, size=%zu",
            mMode, (long long)timeUs, scrambledAccessUnit->size());

    return scrambledAccessUnit;
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnit() {
    if (isScrambled()) {
        return dequeueScrambledAccessUnit();
    }

    if ((mFlags & kFlag_AlignedData) && mMode == H264) {
        if (mRangeInfos.empty()) {
            return NULL;
        }

        RangeInfo info = *mRangeInfos.begin();
        mRangeInfos.erase(mRangeInfos.begin());

        sp<ABuffer> accessUnit = new ABuffer(info.mLength);
        memcpy(accessUnit->data(), mBuffer->data(), info.mLength);
        accessUnit->meta()->setInt64("timeUs", info.mTimestampUs);

        memmove(mBuffer->data(),
                mBuffer->data() + info.mLength,
                mBuffer->size() - info.mLength);

        mBuffer->setRange(0, mBuffer->size() - info.mLength);

        if (mFormat == NULL) {
            mFormat = new MetaData;
            if (!MakeAVCCodecSpecificData(*mFormat, accessUnit->data(), accessUnit->size())) {
                mFormat.clear();
            }
        }

        return accessUnit;
    }

    switch (mMode) {
        case H264:
            return dequeueAccessUnitH264();
        case AAC:
            return dequeueAccessUnitAAC();
        case AC3:
        case EAC3:
            return dequeueAccessUnitEAC3();
        case AC4:
            return dequeueAccessUnitAC4();
        case MPEG_VIDEO:
            return dequeueAccessUnitMPEGVideo();
        case MPEG4_VIDEO:
            return dequeueAccessUnitMPEG4Video();
        case PCM_AUDIO:
            return dequeueAccessUnitPCMAudio();
        case METADATA:
            return dequeueAccessUnitMetadata();
        default:
            if (mMode != MPEG_AUDIO) {
                ALOGE("Unknown mode");
                return NULL;
            }
            return dequeueAccessUnitMPEGAudio();
    }
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitEAC3() {
    unsigned syncStartPos = 0;  // in bytes
    unsigned payloadSize = 0;
    sp<MetaData> format = new MetaData;

    ALOGV("dequeueAccessUnitEAC3[%d]: mBuffer %p(%zu)", mAUIndex,
            mBuffer->data(), mBuffer->size());

    while (true) {
        if (syncStartPos + 2 >= mBuffer->size()) {
            return NULL;
        }

        uint8_t *ptr = mBuffer->data() + syncStartPos;
        size_t size = mBuffer->size() - syncStartPos;
        if (mMode == AC3) {
            payloadSize = parseAC3SyncFrame(ptr, size, &format);
        } else if (mMode == EAC3) {
            payloadSize = parseEAC3SyncFrame(ptr, size, &format);
        }
        if (payloadSize > 0) {
            break;
        }

        ALOGV("dequeueAccessUnitEAC3[%d]: syncStartPos %u payloadSize %u",
                mAUIndex, syncStartPos, payloadSize);

        ++syncStartPos;
    }

    if (mBuffer->size() < syncStartPos + payloadSize) {
        ALOGV("Not enough buffer size for E/AC3");
        return NULL;
    }

    if (mFormat == NULL) {
        mFormat = format;
    }

    int64_t timeUs = fetchTimestamp(syncStartPos + payloadSize);
    if (timeUs < 0ll) {
        ALOGE("negative timeUs");
        return NULL;
    }

    // Not decrypting if key info not available (e.g., scanner/extractor parsing ts files)
    if (mSampleDecryptor != NULL) {
        if (mMode == AC3) {
            mSampleDecryptor->processAC3(mBuffer->data() + syncStartPos, payloadSize);
        } else if (mMode == EAC3) {
            ALOGE("EAC3 AU is encrypted and decryption is not supported");
            return NULL;
        }
    }
    mAUIndex++;

    sp<ABuffer> accessUnit = new ABuffer(syncStartPos + payloadSize);
    memcpy(accessUnit->data(), mBuffer->data(), syncStartPos + payloadSize);

    accessUnit->meta()->setInt64("timeUs", timeUs);
    accessUnit->meta()->setInt32("isSync", 1);

    memmove(
            mBuffer->data(),
            mBuffer->data() + syncStartPos + payloadSize,
            mBuffer->size() - syncStartPos - payloadSize);

    mBuffer->setRange(0, mBuffer->size() - syncStartPos - payloadSize);

    return accessUnit;
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitAC4() {
    unsigned syncStartPos = 0;
    unsigned payloadSize = 0;
    sp<MetaData> format = new MetaData;
    ALOGV("dequeueAccessUnit_AC4[%d]: mBuffer %p(%zu)", mAUIndex, mBuffer->data(), mBuffer->size());

    // A valid AC4 stream should have minimum of 7 bytes in its buffer.
    // (Sync header 4 bytes + AC4 toc 3 bytes)
    if (mBuffer->size() < 7) {
        return NULL;
    }

    while (true) {
        if (syncStartPos + 2 >= mBuffer->size()) {
            return NULL;
        }

        status_t status = parseAC4SyncFrame(
                    mBuffer->data() + syncStartPos,
                    mBuffer->size() - syncStartPos,
                    payloadSize,
                    &format);
        if (status == OK) {
            break;
        }

        ALOGV("dequeueAccessUnit_AC4[%d]: syncStartPos %u payloadSize %u",
                mAUIndex, syncStartPos, payloadSize);

        ++syncStartPos;
    }

    if (mBuffer->size() < syncStartPos + payloadSize) {
        ALOGV("Not enough buffer size for AC4");
        return NULL;
    }

    if (mFormat == NULL) {
        mFormat = format;
    }

    int64_t timeUs = fetchTimestamp(syncStartPos + payloadSize);
    if (timeUs < 0ll) {
        ALOGE("negative timeUs");
        return NULL;
    }
    mAUIndex++;

    sp<ABuffer> accessUnit = new ABuffer(syncStartPos + payloadSize);
    memcpy(accessUnit->data(), mBuffer->data(), syncStartPos + payloadSize);

    accessUnit->meta()->setInt64("timeUs", timeUs);
    accessUnit->meta()->setInt32("isSync", 1);

    memmove(
            mBuffer->data(),
            mBuffer->data() + syncStartPos + payloadSize,
            mBuffer->size() - syncStartPos - payloadSize);

    mBuffer->setRange(0, mBuffer->size() - syncStartPos - payloadSize);
    return accessUnit;
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitPCMAudio() {
    if (mBuffer->size() < 4) {
        return NULL;
    }

    ABitReader bits(mBuffer->data(), 4);
    if (bits.getBits(8) != 0xa0) {
        ALOGE("Unexpected bit values");
        return NULL;
    }
    unsigned numAUs = bits.getBits(8);
    bits.skipBits(8);
    bits.skipBits(2); // quantization_word_length
    unsigned audio_sampling_frequency = bits.getBits(3);
    unsigned num_channels = bits.getBits(3);

    if (audio_sampling_frequency != 2) {
        ALOGE("Wrong sampling freq");
        return NULL;
    }
    if (num_channels != 1u) {
        ALOGE("Wrong channel #");
        return NULL;
    }

    if (mFormat == NULL) {
        mFormat = new MetaData;
        mFormat->setCString(kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_RAW);
        mFormat->setInt32(kKeyChannelCount, 2);
        mFormat->setInt32(kKeySampleRate, 48000);
        mFormat->setInt32(kKeyPcmEncoding, kAudioEncodingPcm16bit);
    }

    static const size_t kFramesPerAU = 80;
    size_t frameSize = 2 /* numChannels */ * sizeof(int16_t);

    size_t payloadSize = numAUs * frameSize * kFramesPerAU;

    if (mBuffer->size() < 4 + payloadSize) {
        return NULL;
    }

    sp<ABuffer> accessUnit = new ABuffer(payloadSize);
    memcpy(accessUnit->data(), mBuffer->data() + 4, payloadSize);

    int64_t timeUs = fetchTimestamp(payloadSize + 4);
    if (timeUs < 0LL) {
        ALOGE("Negative timeUs");
        return NULL;
    }
    accessUnit->meta()->setInt64("timeUs", timeUs);
    accessUnit->meta()->setInt32("isSync", 1);

    int16_t *ptr = (int16_t *)accessUnit->data();
    for (size_t i = 0; i < payloadSize / sizeof(int16_t); ++i) {
        ptr[i] = ntohs(ptr[i]);
    }

    memmove(
            mBuffer->data(),
            mBuffer->data() + 4 + payloadSize,
            mBuffer->size() - 4 - payloadSize);

    mBuffer->setRange(0, mBuffer->size() - 4 - payloadSize);

    return accessUnit;
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitAAC() {
    if (mBuffer->size() == 0) {
        return NULL;
    }

    if (mRangeInfos.empty()) {
        return NULL;
    }

    const RangeInfo &info = *mRangeInfos.begin();
    if (info.mLength == 0 || mBuffer->size() < info.mLength) {
        return NULL;
    }

    if (info.mTimestampUs < 0LL) {
        ALOGE("Negative info.mTimestampUs");
        return NULL;
    }

    ALOGV("dequeueAccessUnit_AAC[%d]: mBuffer %zu info.mLength %zu",
            mAUIndex, mBuffer->size(), info.mLength);

    struct ADTSPosition {
        size_t offset;
        size_t headerSize;
        size_t length;
    };

    Vector<ADTSPosition> frames;

    // The idea here is consume all AAC frames starting at offsets before
    // info.mLength so we can assign a meaningful timestamp without
    // having to interpolate.
    // The final AAC frame may well extend into the next RangeInfo but
    // that's ok.
    size_t offset = 0;
    while (offset < info.mLength) {
        if (offset + 7 > mBuffer->size()) {
            return NULL;
        }

        ABitReader bits(mBuffer->data() + offset, mBuffer->size() - offset);

        // adts_fixed_header

        if (bits.getBits(12) != 0xfffu) {
            ALOGE("Wrong atds_fixed_header");
            return NULL;
        }
        bits.skipBits(3);  // ID, layer
        bool protection_absent = bits.getBits(1) != 0;

        if (mFormat == NULL) {
            mFormat = new MetaData;
            if (!MakeAACCodecSpecificData(
                    *mFormat, mBuffer->data() + offset, mBuffer->size() - offset)) {
                return NULL;
            }

            int32_t sampleRate;
            int32_t numChannels;
            if (!mFormat->findInt32(kKeySampleRate, &sampleRate)) {
                ALOGE("SampleRate not found");
                return NULL;
            }
            if (!mFormat->findInt32(kKeyChannelCount, &numChannels)) {
                ALOGE("ChannelCount not found");
                return NULL;
            }

            ALOGI("found AAC codec config (%d Hz, %d channels)",
                 sampleRate, numChannels);
        }

        // profile_ObjectType, sampling_frequency_index, private_bits,
        // channel_configuration, original_copy, home
        bits.skipBits(12);

        // adts_variable_header

        // copyright_identification_bit, copyright_identification_start
        bits.skipBits(2);

        unsigned aac_frame_length = bits.getBits(13);
        if (aac_frame_length == 0){
            ALOGE("b/62673179, Invalid AAC frame length!");
            android_errorWriteLog(0x534e4554, "62673179");
            return NULL;
        }

        bits.skipBits(11);  // adts_buffer_fullness

        unsigned number_of_raw_data_blocks_in_frame = bits.getBits(2);

        if (number_of_raw_data_blocks_in_frame != 0) {
            // To be implemented.
            ALOGE("Should not reach here.");
            return NULL;
        }

        if (offset + aac_frame_length > mBuffer->size()) {
            return NULL;
        }

        size_t headerSize = protection_absent ? 7 : 9;

        // tracking the frame positions first then decrypt only if an accessUnit to be generated
        if (mSampleDecryptor != NULL) {
            ADTSPosition frame = {
                .offset     = offset,
                .headerSize = headerSize,
                .length     = aac_frame_length
            };

            frames.push(frame);
        }

        offset += aac_frame_length;
    }

    // Decrypting only if the loop didn't exit early and an accessUnit is about to be generated
    // Not decrypting if key info not available (e.g., scanner/extractor parsing ts files)
    if (mSampleDecryptor != NULL) {
        for (size_t frameId = 0; frameId < frames.size(); frameId++) {
            const ADTSPosition &frame = frames.itemAt(frameId);

            mSampleDecryptor->processAAC(frame.headerSize,
                    mBuffer->data() + frame.offset, frame.length);
//            ALOGV("dequeueAccessUnitAAC[%zu]: while offset %zu headerSize %zu frame_len %zu",
//                    frameId, frame.offset, frame.headerSize, frame.length);
        }
    }
    mAUIndex++;

    int64_t timeUs = fetchTimestamp(offset);

    sp<ABuffer> accessUnit = new ABuffer(offset);
    memcpy(accessUnit->data(), mBuffer->data(), offset);

    memmove(mBuffer->data(), mBuffer->data() + offset,
            mBuffer->size() - offset);
    mBuffer->setRange(0, mBuffer->size() - offset);

    accessUnit->meta()->setInt64("timeUs", timeUs);
    accessUnit->meta()->setInt32("isSync", 1);

    return accessUnit;
}

int64_t ElementaryStreamQueue::fetchTimestamp(
        size_t size, int32_t *pesOffset, int32_t *pesScramblingControl) {
    int64_t timeUs = -1;
    bool first = true;

    while (size > 0) {
        if (mRangeInfos.empty()) {
            return timeUs;
        }

        RangeInfo *info = &*mRangeInfos.begin();

        if (first) {
            timeUs = info->mTimestampUs;
            if (pesOffset != NULL) {
                *pesOffset = info->mPesOffset;
            }
            if (pesScramblingControl != NULL) {
                *pesScramblingControl = info->mPesScramblingControl;
            }
            first = false;
        }

        if (info->mLength > size) {
            info->mLength -= size;
            size = 0;
        } else {
            size -= info->mLength;

            mRangeInfos.erase(mRangeInfos.begin());
            info = NULL;
        }

    }

    if (timeUs == 0LL) {
        ALOGV("Returning 0 timestamp");
    }

    return timeUs;
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitH264() {
    const uint8_t *data = mBuffer->data();

    size_t size = mBuffer->size();
    Vector<NALPosition> nals;

    size_t totalSize = 0;
    size_t seiCount = 0;

    status_t err;
    const uint8_t *nalStart;
    size_t nalSize;
    bool foundSlice = false;
    bool foundIDR = false;

    ALOGV("dequeueAccessUnit_H264[%d] %p/%zu", mAUIndex, data, size);

    while ((err = getNextNALUnit(&data, &size, &nalStart, &nalSize)) == OK) {
        if (nalSize == 0) continue;

        unsigned nalType = nalStart[0] & 0x1f;
        bool flush = false;

        if (nalType == 1 || nalType == 5) {
            if (nalType == 5) {
                foundIDR = true;
            }
            if (foundSlice) {
                //TODO: Shouldn't this have been called with nalSize-1?
                ABitReader br(nalStart + 1, nalSize);
                unsigned first_mb_in_slice = parseUE(&br);

                if (first_mb_in_slice == 0) {
                    // This slice starts a new frame.

                    flush = true;
                }
            }

            foundSlice = true;
        } else if ((nalType == 9 || nalType == 7) && foundSlice) {
            // Access unit delimiter and SPS will be associated with the
            // next frame.

            flush = true;
        } else if (nalType == 6 && nalSize > 0) {
            // found non-zero sized SEI
            ++seiCount;
        }

        if (flush) {
            // The access unit will contain all nal units up to, but excluding
            // the current one, separated by 0x00 0x00 0x00 0x01 startcodes.

            size_t auSize = 4 * nals.size() + totalSize;
            sp<ABuffer> accessUnit = new ABuffer(auSize);
            sp<ABuffer> sei;

            if (seiCount > 0) {
                sei = new ABuffer(seiCount * sizeof(NALPosition));
                accessUnit->meta()->setBuffer("sei", sei);
            }

#if !LOG_NDEBUG
            AString out;
#endif

            size_t dstOffset = 0;
            size_t seiIndex = 0;
            size_t shrunkBytes = 0;
            for (size_t i = 0; i < nals.size(); ++i) {
                const NALPosition &pos = nals.itemAt(i);

                unsigned nalType = mBuffer->data()[pos.nalOffset] & 0x1f;

                if (nalType == 6 && pos.nalSize > 0) {
                    if (seiIndex >= sei->size() / sizeof(NALPosition)) {
                        ALOGE("Wrong seiIndex");
                        return NULL;
                    }
                    NALPosition &seiPos = ((NALPosition *)sei->data())[seiIndex++];
                    seiPos.nalOffset = dstOffset + 4;
                    seiPos.nalSize = pos.nalSize;
                }

#if !LOG_NDEBUG
                char tmp[128];
                sprintf(tmp, "0x%02x", nalType);
                if (i > 0) {
                    out.append(", ");
                }
                out.append(tmp);
#endif

                memcpy(accessUnit->data() + dstOffset, "\x00\x00\x00\x01", 4);

                if (mSampleDecryptor != NULL && (nalType == 1 || nalType == 5)) {
                    uint8_t *nalData = mBuffer->data() + pos.nalOffset;
                    size_t newSize = mSampleDecryptor->processNal(nalData, pos.nalSize);
                    // Note: the data can shrink due to unescaping, but it can never grow
                    if (newSize > pos.nalSize) {
                        // don't log unless verbose, since this can get called a lot if
                        // the caller is trying to resynchronize
                        ALOGV("expected sample size < %u, got %zu", pos.nalSize, newSize);
                        return NULL;
                    }
                    memcpy(accessUnit->data() + dstOffset + 4,
                            nalData,
                            newSize);
                    dstOffset += newSize + 4;

                    size_t thisShrunkBytes = pos.nalSize - newSize;
                    //ALOGV("dequeueAccessUnitH264[%d]: nalType: %d -> %zu (%zu)",
                    //        nalType, (int)pos.nalSize, newSize, thisShrunkBytes);

                    shrunkBytes += thisShrunkBytes;
                }
                else {
                    memcpy(accessUnit->data() + dstOffset + 4,
                            mBuffer->data() + pos.nalOffset,
                            pos.nalSize);

                    dstOffset += pos.nalSize + 4;
                    //ALOGV("dequeueAccessUnitH264 [%d] %d @%d",
                    //        nalType, (int)pos.nalSize, (int)pos.nalOffset);
                }
            }

#if !LOG_NDEBUG
            ALOGV("accessUnit contains nal types %s", out.c_str());
#endif

            const NALPosition &pos = nals.itemAt(nals.size() - 1);
            size_t nextScan = pos.nalOffset + pos.nalSize;

            memmove(mBuffer->data(),
                    mBuffer->data() + nextScan,
                    mBuffer->size() - nextScan);

            mBuffer->setRange(0, mBuffer->size() - nextScan);

            int64_t timeUs = fetchTimestamp(nextScan);
            if (timeUs < 0LL) {
                ALOGE("Negative timeUs");
                return NULL;
            }

            accessUnit->meta()->setInt64("timeUs", timeUs);
            if (foundIDR) {
                accessUnit->meta()->setInt32("isSync", 1);
            }

            if (mFormat == NULL) {
                mFormat = new MetaData;
                if (!MakeAVCCodecSpecificData(*mFormat,
                        accessUnit->data(),
                        accessUnit->size())) {
                    mFormat.clear();
                }
            }

            if (mSampleDecryptor != NULL && shrunkBytes > 0) {
                size_t adjustedSize = accessUnit->size() - shrunkBytes;
                ALOGV("dequeueAccessUnitH264[%d]: AU size adjusted %zu -> %zu",
                        mAUIndex, accessUnit->size(), adjustedSize);
                accessUnit->setRange(0, adjustedSize);
            }

            ALOGV("dequeueAccessUnitH264[%d]: AU %p(%zu) dstOffset:%zu, nals:%zu, totalSize:%zu ",
                    mAUIndex, accessUnit->data(), accessUnit->size(),
                    dstOffset, nals.size(), totalSize);
            mAUIndex++;

            return accessUnit;
        }

        NALPosition pos;
        pos.nalOffset = nalStart - mBuffer->data();
        pos.nalSize = nalSize;

        nals.push(pos);

        totalSize += nalSize;
    }
    if (err != (status_t)-EAGAIN) {
        ALOGE("Unexpeted err");
        return NULL;
    }

    return NULL;
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitMPEGAudio() {
    const uint8_t *data = mBuffer->data();
    size_t size = mBuffer->size();

    if (size < 4) {
        return NULL;
    }

    uint32_t header = U32_AT(data);

    size_t frameSize;
    int samplingRate, numChannels, bitrate, numSamples;
    if (!GetMPEGAudioFrameSize(
                header, &frameSize, &samplingRate, &numChannels,
                &bitrate, &numSamples)) {
        ALOGE("Failed to get audio frame size");
        mBuffer->setRange(0, 0);
        return NULL;
    }

    if (size < frameSize) {
        return NULL;
    }

    unsigned layer = 4 - ((header >> 17) & 3);

    sp<ABuffer> accessUnit = new ABuffer(frameSize);
    memcpy(accessUnit->data(), data, frameSize);

    memmove(mBuffer->data(),
            mBuffer->data() + frameSize,
            mBuffer->size() - frameSize);

    mBuffer->setRange(0, mBuffer->size() - frameSize);

    int64_t timeUs = fetchTimestamp(frameSize);
    if (timeUs < 0LL) {
        ALOGE("Negative timeUs");
        return NULL;
    }

    if (mFormat != NULL) {
        const char *mime;
        if (mFormat->findCString(kKeyMIMEType, &mime)) {
            if ((layer == 1) && strcmp (mime, MEDIA_MIMETYPE_AUDIO_MPEG_LAYER_I)) {
                ALOGE("Audio layer is not MPEG_LAYER_I");
                return NULL;
            } else if ((layer == 2) && strcmp (mime, MEDIA_MIMETYPE_AUDIO_MPEG_LAYER_II)) {
                ALOGE("Audio layer is not MPEG_LAYER_II");
                return NULL;
            } else if ((layer == 3) && strcmp (mime, MEDIA_MIMETYPE_AUDIO_MPEG)) {
                ALOGE("Audio layer is not AUDIO_MPEG");
                return NULL;
            }
        }
    }

    accessUnit->meta()->setInt64("timeUs", timeUs);
    accessUnit->meta()->setInt32("isSync", 1);

    if (mFormat == NULL) {
        mFormat = new MetaData;

        switch (layer) {
            case 1:
                mFormat->setCString(
                        kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_MPEG_LAYER_I);
                break;
            case 2:
                mFormat->setCString(
                        kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_MPEG_LAYER_II);
                break;
            case 3:
                mFormat->setCString(
                        kKeyMIMEType, MEDIA_MIMETYPE_AUDIO_MPEG);
                break;
            default:
                return NULL;
        }

        mFormat->setInt32(kKeySampleRate, samplingRate);
        mFormat->setInt32(kKeyChannelCount, numChannels);
    }

    return accessUnit;
}

static void EncodeSize14(uint8_t **_ptr, size_t size) {
    if (size > 0x3fff) {
        ALOGE("Wrong size");
        return;
    }

    uint8_t *ptr = *_ptr;

    *ptr++ = 0x80 | (size >> 7);
    *ptr++ = size & 0x7f;

    *_ptr = ptr;
}

static sp<ABuffer> MakeMPEGVideoESDS(const sp<ABuffer> &csd) {
    sp<ABuffer> esds = new ABuffer(csd->size() + 25);

    uint8_t *ptr = esds->data();
    *ptr++ = 0x03;
    EncodeSize14(&ptr, 22 + csd->size());

    *ptr++ = 0x00;  // ES_ID
    *ptr++ = 0x00;

    *ptr++ = 0x00;  // streamDependenceFlag, URL_Flag, OCRstreamFlag

    *ptr++ = 0x04;
    EncodeSize14(&ptr, 16 + csd->size());

    *ptr++ = 0x40;  // Audio ISO/IEC 14496-3

    for (size_t i = 0; i < 12; ++i) {
        *ptr++ = 0x00;
    }

    *ptr++ = 0x05;
    EncodeSize14(&ptr, csd->size());

    memcpy(ptr, csd->data(), csd->size());

    return esds;
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitMPEGVideo() {
    const uint8_t *data = mBuffer->data();
    size_t size = mBuffer->size();

    Vector<size_t> userDataPositions;

    bool sawPictureStart = false;
    int pprevStartCode = -1;
    int prevStartCode = -1;
    int currentStartCode = -1;
    bool gopFound = false;
    bool isClosedGop = false;
    bool brokenLink = false;

    size_t offset = 0;
    while (offset + 3 < size) {
        if (memcmp(&data[offset], "\x00\x00\x01", 3)) {
            ++offset;
            continue;
        }

        pprevStartCode = prevStartCode;
        prevStartCode = currentStartCode;
        currentStartCode = data[offset + 3];

        if (currentStartCode == 0xb3 && mFormat == NULL) {
            memmove(mBuffer->data(), mBuffer->data() + offset, size - offset);
            size -= offset;
            (void)fetchTimestamp(offset);
            offset = 0;
            mBuffer->setRange(0, size);
        }

        if ((prevStartCode == 0xb3 && currentStartCode != 0xb5)
                || (pprevStartCode == 0xb3 && prevStartCode == 0xb5)) {
            // seqHeader without/with extension

            if (mFormat == NULL) {
                if (size < 7u) {
                    ALOGE("Size too small");
                    return NULL;
                }

                unsigned width =
                    (data[4] << 4) | data[5] >> 4;

                unsigned height =
                    ((data[5] & 0x0f) << 8) | data[6];

                mFormat = new MetaData;
                mFormat->setCString(kKeyMIMEType, MEDIA_MIMETYPE_VIDEO_MPEG2);
                mFormat->setInt32(kKeyWidth, width);
                mFormat->setInt32(kKeyHeight, height);

                ALOGI("found MPEG2 video codec config (%d x %d)", width, height);

                sp<ABuffer> csd = new ABuffer(offset);
                memcpy(csd->data(), data, offset);

                memmove(mBuffer->data(),
                        mBuffer->data() + offset,
                        mBuffer->size() - offset);

                mBuffer->setRange(0, mBuffer->size() - offset);
                size -= offset;
                (void)fetchTimestamp(offset);
                offset = 0;

                // hexdump(csd->data(), csd->size());

                sp<ABuffer> esds = MakeMPEGVideoESDS(csd);
                mFormat->setData(
                        kKeyESDS, kTypeESDS, esds->data(), esds->size());

                return NULL;
            }
        }

        if (mFormat != NULL && currentStartCode == 0xb8) {
            // GOP layer
            if (offset + 7 >= size) {
                ALOGE("Size too small");
                return NULL;
            }
            gopFound = true;
            isClosedGop = (data[offset + 7] & 0x40) != 0;
            brokenLink = (data[offset + 7] & 0x20) != 0;
        }

        if (mFormat != NULL && currentStartCode == 0xb2) {
            userDataPositions.add(offset);
        }

        if (mFormat != NULL && currentStartCode == 0x00) {
            // Picture start

            if (!sawPictureStart) {
                sawPictureStart = true;
            } else {
                sp<ABuffer> accessUnit = new ABuffer(offset);
                memcpy(accessUnit->data(), data, offset);

                memmove(mBuffer->data(),
                        mBuffer->data() + offset,
                        mBuffer->size() - offset);

                mBuffer->setRange(0, mBuffer->size() - offset);

                int64_t timeUs = fetchTimestamp(offset);
                if (timeUs < 0LL) {
                    ALOGE("Negative timeUs");
                    return NULL;
                }

                offset = 0;

                accessUnit->meta()->setInt64("timeUs", timeUs);
                if (gopFound && (!brokenLink || isClosedGop)) {
                    accessUnit->meta()->setInt32("isSync", 1);
                }

                ALOGV("returning MPEG video access unit at time %" PRId64 " us",
                      timeUs);

                // hexdump(accessUnit->data(), accessUnit->size());

                if (userDataPositions.size() > 0) {
                    sp<ABuffer> mpegUserData =
                        new ABuffer(userDataPositions.size() * sizeof(size_t));
                    if (mpegUserData != NULL && mpegUserData->data() != NULL) {
                        for (size_t i = 0; i < userDataPositions.size(); ++i) {
                            memcpy(
                                    mpegUserData->data() + i * sizeof(size_t),
                                    &userDataPositions[i], sizeof(size_t));
                        }
                        accessUnit->meta()->setBuffer("mpeg-user-data", mpegUserData);
                    }
                }

                return accessUnit;
            }
        }

        ++offset;
    }

    return NULL;
}

static ssize_t getNextChunkSize(
        const uint8_t *data, size_t size) {
    static const char kStartCode[] = "\x00\x00\x01";

    // per ISO/IEC 14496-2 6.2.1, a chunk has a 3-byte prefix + 1-byte start code
    // we need at least <prefix><start><next prefix> to successfully scan
    if (size < 3 + 1 + 3) {
        return -EAGAIN;
    }

    if (memcmp(kStartCode, data, 3)) {
        return -EAGAIN;
    }

    size_t offset = 4;
    while (offset + 2 < size) {
        if (!memcmp(&data[offset], kStartCode, 3)) {
            return offset;
        }

        ++offset;
    }

    return -EAGAIN;
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitMPEG4Video() {
    uint8_t *data = mBuffer->data();
    size_t size = mBuffer->size();

    enum {
        SKIP_TO_VISUAL_OBJECT_SEQ_START,
        EXPECT_VISUAL_OBJECT_START,
        EXPECT_VO_START,
        EXPECT_VOL_START,
        WAIT_FOR_VOP_START,
        SKIP_TO_VOP_START,

    } state;

    if (mFormat == NULL) {
        state = SKIP_TO_VISUAL_OBJECT_SEQ_START;
    } else {
        state = SKIP_TO_VOP_START;
    }

    int32_t width = -1, height = -1;

    size_t offset = 0;
    ssize_t chunkSize;
    while ((chunkSize = getNextChunkSize(
                    &data[offset], size - offset)) > 0) {
        bool discard = false;

        unsigned chunkType = data[offset + 3];

        switch (state) {
            case SKIP_TO_VISUAL_OBJECT_SEQ_START:
            {
                if (chunkType == 0xb0) {
                    // Discard anything before this marker.

                    state = EXPECT_VISUAL_OBJECT_START;
                } else {
                    discard = true;
                    offset += chunkSize;
                    ALOGW("b/74114680, advance to next chunk");
                    android_errorWriteLog(0x534e4554, "74114680");
                }
                break;
            }

            case EXPECT_VISUAL_OBJECT_START:
            {
                if (chunkType != 0xb5) {
                    ALOGE("Unexpected chunkType");
                    return NULL;
                }
                state = EXPECT_VO_START;
                break;
            }

            case EXPECT_VO_START:
            {
                if (chunkType > 0x1f) {
                    ALOGE("Unexpected chunkType");
                    return NULL;
                }
                state = EXPECT_VOL_START;
                break;
            }

            case EXPECT_VOL_START:
            {
                if ((chunkType & 0xf0) != 0x20) {
                    ALOGE("Wrong chunkType");
                    return NULL;
                }

                if (!ExtractDimensionsFromVOLHeader(
                            &data[offset], chunkSize,
                            &width, &height)) {
                    ALOGE("Failed to get dimension");
                    return NULL;
                }

                state = WAIT_FOR_VOP_START;
                break;
            }

            case WAIT_FOR_VOP_START:
            {
                if (chunkType == 0xb3 || chunkType == 0xb6) {
                    // group of VOP or VOP start.

                    mFormat = new MetaData;
                    mFormat->setCString(
                            kKeyMIMEType, MEDIA_MIMETYPE_VIDEO_MPEG4);

                    mFormat->setInt32(kKeyWidth, width);
                    mFormat->setInt32(kKeyHeight, height);

                    ALOGI("found MPEG4 video codec config (%d x %d)",
                         width, height);

                    sp<ABuffer> csd = new ABuffer(offset);
                    memcpy(csd->data(), data, offset);

                    // hexdump(csd->data(), csd->size());

                    sp<ABuffer> esds = MakeMPEGVideoESDS(csd);
                    mFormat->setData(
                            kKeyESDS, kTypeESDS,
                            esds->data(), esds->size());

                    discard = true;
                    state = SKIP_TO_VOP_START;
                }

                break;
            }

            case SKIP_TO_VOP_START:
            {
                if (chunkType == 0xb6) {
                    int vopCodingType = (data[offset + 4] & 0xc0) >> 6;

                    offset += chunkSize;

                    sp<ABuffer> accessUnit = new ABuffer(offset);
                    memcpy(accessUnit->data(), data, offset);

                    memmove(data, &data[offset], size - offset);
                    size -= offset;
                    mBuffer->setRange(0, size);

                    int64_t timeUs = fetchTimestamp(offset);
                    if (timeUs < 0LL) {
                        ALOGE("Negative timeus");
                        return NULL;
                    }

                    offset = 0;

                    accessUnit->meta()->setInt64("timeUs", timeUs);
                    if (vopCodingType == 0) {  // intra-coded VOP
                        accessUnit->meta()->setInt32("isSync", 1);
                    }

                    ALOGV("returning MPEG4 video access unit at time %" PRId64 " us",
                         timeUs);

                    // hexdump(accessUnit->data(), accessUnit->size());

                    return accessUnit;
                } else if (chunkType != 0xb3) {
                    offset += chunkSize;
                    discard = true;
                }

                break;
            }

            default:
                ALOGE("Unknown state: %d", state);
                return NULL;
        }

        if (discard) {
            (void)fetchTimestamp(offset);
            memmove(data, &data[offset], size - offset);
            size -= offset;
            offset = 0;
            mBuffer->setRange(0, size);
        } else {
            offset += chunkSize;
        }
    }

    return NULL;
}

void ElementaryStreamQueue::signalEOS() {
    if (!mEOSReached) {
        if (mMode == MPEG_VIDEO) {
            const char *theEnd = "\x00\x00\x01\x00";
            appendData(theEnd, 4, 0);
        }
        mEOSReached = true;
    } else {
        ALOGW("EOS already signaled");
    }
}

sp<ABuffer> ElementaryStreamQueue::dequeueAccessUnitMetadata() {
    size_t size = mBuffer->size();
    if (!size) {
        return NULL;
    }

    sp<ABuffer> accessUnit = new ABuffer(size);
    int64_t timeUs = fetchTimestamp(size);
    accessUnit->meta()->setInt64("timeUs", timeUs);

    memcpy(accessUnit->data(), mBuffer->data(), size);
    mBuffer->setRange(0, 0);

    if (mFormat == NULL) {
        mFormat = new MetaData;
        mFormat->setCString(kKeyMIMEType, MEDIA_MIMETYPE_DATA_TIMED_ID3);
    }

    return accessUnit;
}

void ElementaryStreamQueue::signalNewSampleAesKey(const sp<AMessage> &keyItem) {
    if (mSampleDecryptor == NULL) {
        ALOGE("signalNewSampleAesKey: Stream %x is not encrypted; keyItem: %p",
                mMode, keyItem.get());
        return;
    }

    mSampleDecryptor->signalNewSampleAesKey(keyItem);
}


}  // namespace android