/* * 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 "ATSParser" #include #include "ATSParser.h" #include "AnotherPacketSource.h" #include "ESQueue.h" #include "include/avc_utils.h" #include #include #include #include #include #include #include #include #include #include #include #include #include namespace android { // I want the expression "y" evaluated even if verbose logging is off. #define MY_LOGV(x, y) \ do { unsigned tmp = y; ALOGV(x, tmp); } while (0) static const size_t kTSPacketSize = 188; struct ATSParser::Program : public RefBase { Program(ATSParser *parser, unsigned programNumber, unsigned programMapPID, int64_t lastRecoveredPTS); bool parsePSISection( unsigned pid, ABitReader *br, status_t *err); // Pass to appropriate stream according to pid, and set event if it's a PES // with a sync frame. // Note that the method itself does not touch event. bool parsePID( unsigned pid, unsigned continuity_counter, unsigned payload_unit_start_indicator, ABitReader *br, status_t *err, SyncEvent *event); void signalDiscontinuity( DiscontinuityType type, const sp &extra); void signalEOS(status_t finalResult); sp getSource(SourceType type); bool hasSource(SourceType type) const; int64_t convertPTSToTimestamp(uint64_t PTS); bool PTSTimeDeltaEstablished() const { return mFirstPTSValid; } unsigned number() const { return mProgramNumber; } void updateProgramMapPID(unsigned programMapPID) { mProgramMapPID = programMapPID; } unsigned programMapPID() const { return mProgramMapPID; } uint32_t parserFlags() const { return mParser->mFlags; } private: struct StreamInfo { unsigned mType; unsigned mPID; }; ATSParser *mParser; unsigned mProgramNumber; unsigned mProgramMapPID; KeyedVector > mStreams; bool mFirstPTSValid; uint64_t mFirstPTS; int64_t mLastRecoveredPTS; status_t parseProgramMap(ABitReader *br); int64_t recoverPTS(uint64_t PTS_33bit); bool switchPIDs(const Vector &infos); DISALLOW_EVIL_CONSTRUCTORS(Program); }; struct ATSParser::Stream : public RefBase { Stream(Program *program, unsigned elementaryPID, unsigned streamType, unsigned PCR_PID); unsigned type() const { return mStreamType; } unsigned pid() const { return mElementaryPID; } void setPID(unsigned pid) { mElementaryPID = pid; } // Parse the payload and set event when PES with a sync frame is detected. // This method knows when a PES starts; so record mPesStartOffset in that // case. status_t parse( unsigned continuity_counter, unsigned payload_unit_start_indicator, ABitReader *br, SyncEvent *event); void signalDiscontinuity( DiscontinuityType type, const sp &extra); void signalEOS(status_t finalResult); sp getSource(SourceType type); bool isAudio() const; bool isVideo() const; bool isMeta() const; protected: virtual ~Stream(); private: Program *mProgram; unsigned mElementaryPID; unsigned mStreamType; unsigned mPCR_PID; int32_t mExpectedContinuityCounter; sp mBuffer; sp mSource; bool mPayloadStarted; bool mEOSReached; uint64_t mPrevPTS; off64_t mPesStartOffset; ElementaryStreamQueue *mQueue; // Flush accumulated payload if necessary --- i.e. at EOS or at the start of // another payload. event is set if the flushed payload is PES with a sync // frame. status_t flush(SyncEvent *event); // Strip and parse PES headers and pass remaining payload into onPayload // with parsed metadata. event is set if the PES contains a sync frame. status_t parsePES(ABitReader *br, SyncEvent *event); // Feed the payload into mQueue and if a packet is identified, queue it // into mSource. If the packet is a sync frame. set event with start offset // and timestamp of the packet. void onPayloadData( unsigned PTS_DTS_flags, uint64_t PTS, uint64_t DTS, const uint8_t *data, size_t size, SyncEvent *event); DISALLOW_EVIL_CONSTRUCTORS(Stream); }; struct ATSParser::PSISection : public RefBase { PSISection(); status_t append(const void *data, size_t size); void setSkipBytes(uint8_t skip); void clear(); bool isComplete() const; bool isEmpty() const; bool isCRCOkay() const; const uint8_t *data() const; size_t size() const; protected: virtual ~PSISection(); private: sp mBuffer; uint8_t mSkipBytes; static uint32_t CRC_TABLE[]; DISALLOW_EVIL_CONSTRUCTORS(PSISection); }; ATSParser::SyncEvent::SyncEvent(off64_t offset) : mInit(false), mOffset(offset), mTimeUs(0) {} void ATSParser::SyncEvent::init(off64_t offset, const sp &source, int64_t timeUs) { mInit = true; mOffset = offset; mMediaSource = source; mTimeUs = timeUs; } //////////////////////////////////////////////////////////////////////////////// ATSParser::Program::Program( ATSParser *parser, unsigned programNumber, unsigned programMapPID, int64_t lastRecoveredPTS) : mParser(parser), mProgramNumber(programNumber), mProgramMapPID(programMapPID), mFirstPTSValid(false), mFirstPTS(0), mLastRecoveredPTS(lastRecoveredPTS) { ALOGV("new program number %u", programNumber); } bool ATSParser::Program::parsePSISection( unsigned pid, ABitReader *br, status_t *err) { *err = OK; if (pid != mProgramMapPID) { return false; } *err = parseProgramMap(br); return true; } bool ATSParser::Program::parsePID( unsigned pid, unsigned continuity_counter, unsigned payload_unit_start_indicator, ABitReader *br, status_t *err, SyncEvent *event) { *err = OK; ssize_t index = mStreams.indexOfKey(pid); if (index < 0) { return false; } *err = mStreams.editValueAt(index)->parse( continuity_counter, payload_unit_start_indicator, br, event); return true; } void ATSParser::Program::signalDiscontinuity( DiscontinuityType type, const sp &extra) { int64_t mediaTimeUs; if ((type & DISCONTINUITY_TIME) && extra != NULL && extra->findInt64( IStreamListener::kKeyMediaTimeUs, &mediaTimeUs)) { mFirstPTSValid = false; } for (size_t i = 0; i < mStreams.size(); ++i) { mStreams.editValueAt(i)->signalDiscontinuity(type, extra); } } void ATSParser::Program::signalEOS(status_t finalResult) { for (size_t i = 0; i < mStreams.size(); ++i) { mStreams.editValueAt(i)->signalEOS(finalResult); } } bool ATSParser::Program::switchPIDs(const Vector &infos) { bool success = false; if (mStreams.size() == infos.size()) { // build type->PIDs map for old and new mapping size_t i; KeyedVector > oldType2PIDs, newType2PIDs; for (i = 0; i < mStreams.size(); ++i) { ssize_t index = oldType2PIDs.indexOfKey(mStreams[i]->type()); if (index < 0) { oldType2PIDs.add(mStreams[i]->type(), Vector()); } oldType2PIDs.editValueFor(mStreams[i]->type()).push_back(mStreams[i]->pid()); } for (i = 0; i < infos.size(); ++i) { ssize_t index = newType2PIDs.indexOfKey(infos[i].mType); if (index < 0) { newType2PIDs.add(infos[i].mType, Vector()); } newType2PIDs.editValueFor(infos[i].mType).push_back(infos[i].mPID); } // we can recover if the number of streams for each type hasn't changed if (oldType2PIDs.size() == newType2PIDs.size()) { success = true; for (i = 0; i < oldType2PIDs.size(); ++i) { // KeyedVector is sorted, we just compare key and size of each index if (oldType2PIDs.keyAt(i) != newType2PIDs.keyAt(i) || oldType2PIDs[i].size() != newType2PIDs[i].size()) { success = false; break; } } } if (success) { // save current streams to temp KeyedVector > temp; for (i = 0; i < mStreams.size(); ++i) { temp.add(mStreams.keyAt(i), mStreams.editValueAt(i)); } mStreams.clear(); for (i = 0; i < temp.size(); ++i) { // The two checks below shouldn't happen, // we already checked above the stream count matches ssize_t index = newType2PIDs.indexOfKey(temp[i]->type()); if (index < 0) { return false; } Vector &newPIDs = newType2PIDs.editValueAt(index); if (newPIDs.isEmpty()) { return false; } // get the next PID for temp[i]->type() in the new PID map Vector::iterator it = newPIDs.begin(); // change the PID of the stream, and add it back temp.editValueAt(i)->setPID(*it); mStreams.add(temp[i]->pid(), temp.editValueAt(i)); // removed the used PID newPIDs.erase(it); } } } return success; } status_t ATSParser::Program::parseProgramMap(ABitReader *br) { unsigned table_id = br->getBits(8); ALOGV(" table_id = %u", table_id); if (table_id != 0x02u) { ALOGE("PMT data error!"); return ERROR_MALFORMED; } unsigned section_syntax_indicator = br->getBits(1); ALOGV(" section_syntax_indicator = %u", section_syntax_indicator); if (section_syntax_indicator != 1u) { ALOGE("PMT data error!"); return ERROR_MALFORMED; } br->skipBits(1); // '0' MY_LOGV(" reserved = %u", br->getBits(2)); unsigned section_length = br->getBits(12); ALOGV(" section_length = %u", section_length); MY_LOGV(" program_number = %u", br->getBits(16)); MY_LOGV(" reserved = %u", br->getBits(2)); MY_LOGV(" version_number = %u", br->getBits(5)); MY_LOGV(" current_next_indicator = %u", br->getBits(1)); MY_LOGV(" section_number = %u", br->getBits(8)); MY_LOGV(" last_section_number = %u", br->getBits(8)); MY_LOGV(" reserved = %u", br->getBits(3)); unsigned PCR_PID = br->getBits(13); ALOGV(" PCR_PID = 0x%04x", PCR_PID); MY_LOGV(" reserved = %u", br->getBits(4)); unsigned program_info_length = br->getBits(12); ALOGV(" program_info_length = %u", program_info_length); br->skipBits(program_info_length * 8); // skip descriptors Vector infos; // infoBytesRemaining is the number of bytes that make up the // variable length section of ES_infos. It does not include the // final CRC. size_t infoBytesRemaining = section_length - 9 - program_info_length - 4; while (infoBytesRemaining >= 5) { unsigned streamType = br->getBits(8); ALOGV(" stream_type = 0x%02x", streamType); MY_LOGV(" reserved = %u", br->getBits(3)); unsigned elementaryPID = br->getBits(13); ALOGV(" elementary_PID = 0x%04x", elementaryPID); MY_LOGV(" reserved = %u", br->getBits(4)); unsigned ES_info_length = br->getBits(12); ALOGV(" ES_info_length = %u", ES_info_length); #if 0 br->skipBits(ES_info_length * 8); // skip descriptors #else unsigned info_bytes_remaining = ES_info_length; while (info_bytes_remaining >= 2) { MY_LOGV(" tag = 0x%02x", br->getBits(8)); unsigned descLength = br->getBits(8); ALOGV(" len = %u", descLength); if (info_bytes_remaining < descLength) { return ERROR_MALFORMED; } br->skipBits(descLength * 8); info_bytes_remaining -= descLength + 2; } #endif StreamInfo info; info.mType = streamType; info.mPID = elementaryPID; infos.push(info); infoBytesRemaining -= 5 + ES_info_length; } if (infoBytesRemaining != 0) { ALOGW("Section data remains unconsumed"); } MY_LOGV(" CRC = 0x%08x", br->getBits(32)); bool PIDsChanged = false; for (size_t i = 0; i < infos.size(); ++i) { StreamInfo &info = infos.editItemAt(i); ssize_t index = mStreams.indexOfKey(info.mPID); if (index >= 0 && mStreams.editValueAt(index)->type() != info.mType) { ALOGI("uh oh. stream PIDs have changed."); PIDsChanged = true; break; } } if (PIDsChanged) { #if 0 ALOGI("before:"); for (size_t i = 0; i < mStreams.size(); ++i) { sp stream = mStreams.editValueAt(i); ALOGI("PID 0x%08x => type 0x%02x", stream->pid(), stream->type()); } ALOGI("after:"); for (size_t i = 0; i < infos.size(); ++i) { StreamInfo &info = infos.editItemAt(i); ALOGI("PID 0x%08x => type 0x%02x", info.mPID, info.mType); } #endif // we can recover if number of streams for each type remain the same bool success = switchPIDs(infos); if (!success) { ALOGI("Stream PIDs changed and we cannot recover."); return ERROR_MALFORMED; } } for (size_t i = 0; i < infos.size(); ++i) { StreamInfo &info = infos.editItemAt(i); ssize_t index = mStreams.indexOfKey(info.mPID); if (index < 0) { sp stream = new Stream( this, info.mPID, info.mType, PCR_PID); mStreams.add(info.mPID, stream); } } return OK; } int64_t ATSParser::Program::recoverPTS(uint64_t PTS_33bit) { // We only have the lower 33-bit of the PTS. It could overflow within a // reasonable amount of time. To handle the wrap-around, use fancy math // to get an extended PTS that is within [-0xffffffff, 0xffffffff] // of the latest recovered PTS. if (mLastRecoveredPTS < 0ll) { // Use the original 33bit number for 1st frame, the reason is that // if 1st frame wraps to negative that's far away from 0, we could // never start. Only start wrapping around from 2nd frame. mLastRecoveredPTS = static_cast(PTS_33bit); } else { mLastRecoveredPTS = static_cast( ((mLastRecoveredPTS - static_cast(PTS_33bit) + 0x100000000ll) & 0xfffffffe00000000ull) | PTS_33bit); // We start from 0, but recovered PTS could be slightly below 0. // Clamp it to 0 as rest of the pipeline doesn't take negative pts. // (eg. video is read first and starts at 0, but audio starts at 0xfffffff0) if (mLastRecoveredPTS < 0ll) { ALOGI("Clamping negative recovered PTS (%" PRId64 ") to 0", mLastRecoveredPTS); mLastRecoveredPTS = 0ll; } } return mLastRecoveredPTS; } sp ATSParser::Program::getSource(SourceType type) { size_t index = (type == AUDIO) ? 0 : 0; for (size_t i = 0; i < mStreams.size(); ++i) { sp source = mStreams.editValueAt(i)->getSource(type); if (source != NULL) { if (index == 0) { return source; } --index; } } return NULL; } bool ATSParser::Program::hasSource(SourceType type) const { for (size_t i = 0; i < mStreams.size(); ++i) { const sp &stream = mStreams.valueAt(i); if (type == AUDIO && stream->isAudio()) { return true; } else if (type == VIDEO && stream->isVideo()) { return true; } } return false; } int64_t ATSParser::Program::convertPTSToTimestamp(uint64_t PTS) { PTS = recoverPTS(PTS); if (!(mParser->mFlags & TS_TIMESTAMPS_ARE_ABSOLUTE)) { if (!mFirstPTSValid) { mFirstPTSValid = true; mFirstPTS = PTS; PTS = 0; } else if (PTS < mFirstPTS) { PTS = 0; } else { PTS -= mFirstPTS; } } int64_t timeUs = (PTS * 100) / 9; if (mParser->mAbsoluteTimeAnchorUs >= 0ll) { timeUs += mParser->mAbsoluteTimeAnchorUs; } if (mParser->mTimeOffsetValid) { timeUs += mParser->mTimeOffsetUs; } return timeUs; } //////////////////////////////////////////////////////////////////////////////// ATSParser::Stream::Stream( Program *program, unsigned elementaryPID, unsigned streamType, unsigned PCR_PID) : mProgram(program), mElementaryPID(elementaryPID), mStreamType(streamType), mPCR_PID(PCR_PID), mExpectedContinuityCounter(-1), mPayloadStarted(false), mEOSReached(false), mPrevPTS(0), mQueue(NULL) { switch (mStreamType) { case STREAMTYPE_H264: mQueue = new ElementaryStreamQueue( ElementaryStreamQueue::H264, (mProgram->parserFlags() & ALIGNED_VIDEO_DATA) ? ElementaryStreamQueue::kFlag_AlignedData : 0); break; case STREAMTYPE_MPEG2_AUDIO_ADTS: mQueue = new ElementaryStreamQueue(ElementaryStreamQueue::AAC); break; case STREAMTYPE_MPEG1_AUDIO: case STREAMTYPE_MPEG2_AUDIO: mQueue = new ElementaryStreamQueue( ElementaryStreamQueue::MPEG_AUDIO); break; case STREAMTYPE_MPEG1_VIDEO: case STREAMTYPE_MPEG2_VIDEO: mQueue = new ElementaryStreamQueue( ElementaryStreamQueue::MPEG_VIDEO); break; case STREAMTYPE_MPEG4_VIDEO: mQueue = new ElementaryStreamQueue( ElementaryStreamQueue::MPEG4_VIDEO); break; case STREAMTYPE_LPCM_AC3: case STREAMTYPE_AC3: mQueue = new ElementaryStreamQueue( ElementaryStreamQueue::AC3); break; case STREAMTYPE_METADATA: mQueue = new ElementaryStreamQueue( ElementaryStreamQueue::METADATA); break; default: break; } ALOGV("new stream PID 0x%02x, type 0x%02x", elementaryPID, streamType); if (mQueue != NULL) { mBuffer = new ABuffer(192 * 1024); mBuffer->setRange(0, 0); } } ATSParser::Stream::~Stream() { delete mQueue; mQueue = NULL; } status_t ATSParser::Stream::parse( unsigned continuity_counter, unsigned payload_unit_start_indicator, ABitReader *br, SyncEvent *event) { if (mQueue == NULL) { return OK; } if (mExpectedContinuityCounter >= 0 && (unsigned)mExpectedContinuityCounter != continuity_counter) { ALOGI("discontinuity on stream pid 0x%04x", mElementaryPID); mPayloadStarted = false; mBuffer->setRange(0, 0); mExpectedContinuityCounter = -1; #if 0 // Uncomment this if you'd rather see no corruption whatsoever on // screen and suspend updates until we come across another IDR frame. if (mStreamType == STREAMTYPE_H264) { ALOGI("clearing video queue"); mQueue->clear(true /* clearFormat */); } #endif if (!payload_unit_start_indicator) { return OK; } } mExpectedContinuityCounter = (continuity_counter + 1) & 0x0f; if (payload_unit_start_indicator) { off64_t offset = (event != NULL) ? event->getOffset() : 0; if (mPayloadStarted) { // Otherwise we run the danger of receiving the trailing bytes // of a PES packet that we never saw the start of and assuming // we have a a complete PES packet. status_t err = flush(event); if (err != OK) { ALOGW("Error (%08x) happened while flushing; we simply discard " "the PES packet and continue.", err); } } mPayloadStarted = true; mPesStartOffset = offset; } if (!mPayloadStarted) { return OK; } size_t payloadSizeBits = br->numBitsLeft(); if (payloadSizeBits % 8 != 0u) { ALOGE("Wrong value"); return BAD_VALUE; } size_t neededSize = mBuffer->size() + payloadSizeBits / 8; if (mBuffer->capacity() < neededSize) { // Increment in multiples of 64K. neededSize = (neededSize + 65535) & ~65535; ALOGI("resizing buffer to %zu bytes", neededSize); sp newBuffer = new ABuffer(neededSize); memcpy(newBuffer->data(), mBuffer->data(), mBuffer->size()); newBuffer->setRange(0, mBuffer->size()); mBuffer = newBuffer; } memcpy(mBuffer->data() + mBuffer->size(), br->data(), payloadSizeBits / 8); mBuffer->setRange(0, mBuffer->size() + payloadSizeBits / 8); return OK; } bool ATSParser::Stream::isVideo() const { switch (mStreamType) { case STREAMTYPE_H264: case STREAMTYPE_MPEG1_VIDEO: case STREAMTYPE_MPEG2_VIDEO: case STREAMTYPE_MPEG4_VIDEO: return true; default: return false; } } bool ATSParser::Stream::isAudio() const { switch (mStreamType) { case STREAMTYPE_MPEG1_AUDIO: case STREAMTYPE_MPEG2_AUDIO: case STREAMTYPE_MPEG2_AUDIO_ADTS: case STREAMTYPE_LPCM_AC3: case STREAMTYPE_AC3: return true; default: return false; } } bool ATSParser::Stream::isMeta() const { if (mStreamType == STREAMTYPE_METADATA) { return true; } return false; } void ATSParser::Stream::signalDiscontinuity( DiscontinuityType type, const sp &extra) { mExpectedContinuityCounter = -1; if (mQueue == NULL) { return; } mPayloadStarted = false; mEOSReached = false; mBuffer->setRange(0, 0); bool clearFormat = false; if (isAudio()) { if (type & DISCONTINUITY_AUDIO_FORMAT) { clearFormat = true; } } else { if (type & DISCONTINUITY_VIDEO_FORMAT) { clearFormat = true; } } mQueue->clear(clearFormat); if (type & DISCONTINUITY_TIME) { uint64_t resumeAtPTS; if (extra != NULL && extra->findInt64( IStreamListener::kKeyResumeAtPTS, (int64_t *)&resumeAtPTS)) { int64_t resumeAtMediaTimeUs = mProgram->convertPTSToTimestamp(resumeAtPTS); extra->setInt64("resume-at-mediaTimeUs", resumeAtMediaTimeUs); } } if (mSource != NULL) { mSource->queueDiscontinuity(type, extra, true); } } void ATSParser::Stream::signalEOS(status_t finalResult) { if (mSource != NULL) { mSource->signalEOS(finalResult); } mEOSReached = true; flush(NULL); } status_t ATSParser::Stream::parsePES(ABitReader *br, SyncEvent *event) { unsigned packet_startcode_prefix = br->getBits(24); ALOGV("packet_startcode_prefix = 0x%08x", packet_startcode_prefix); if (packet_startcode_prefix != 1) { ALOGV("Supposedly payload_unit_start=1 unit does not start " "with startcode."); return ERROR_MALFORMED; } unsigned stream_id = br->getBits(8); ALOGV("stream_id = 0x%02x", stream_id); unsigned PES_packet_length = br->getBits(16); ALOGV("PES_packet_length = %u", PES_packet_length); if (stream_id != 0xbc // program_stream_map && stream_id != 0xbe // padding_stream && stream_id != 0xbf // private_stream_2 && stream_id != 0xf0 // ECM && stream_id != 0xf1 // EMM && stream_id != 0xff // program_stream_directory && stream_id != 0xf2 // DSMCC && stream_id != 0xf8) { // H.222.1 type E if (br->getBits(2) != 2u) { return ERROR_MALFORMED; } MY_LOGV("PES_scrambling_control = %u", br->getBits(2)); MY_LOGV("PES_priority = %u", br->getBits(1)); MY_LOGV("data_alignment_indicator = %u", br->getBits(1)); MY_LOGV("copyright = %u", br->getBits(1)); MY_LOGV("original_or_copy = %u", br->getBits(1)); unsigned PTS_DTS_flags = br->getBits(2); ALOGV("PTS_DTS_flags = %u", PTS_DTS_flags); unsigned ESCR_flag = br->getBits(1); ALOGV("ESCR_flag = %u", ESCR_flag); unsigned ES_rate_flag = br->getBits(1); ALOGV("ES_rate_flag = %u", ES_rate_flag); unsigned DSM_trick_mode_flag = br->getBits(1); ALOGV("DSM_trick_mode_flag = %u", DSM_trick_mode_flag); unsigned additional_copy_info_flag = br->getBits(1); ALOGV("additional_copy_info_flag = %u", additional_copy_info_flag); MY_LOGV("PES_CRC_flag = %u", br->getBits(1)); MY_LOGV("PES_extension_flag = %u", br->getBits(1)); unsigned PES_header_data_length = br->getBits(8); ALOGV("PES_header_data_length = %u", PES_header_data_length); unsigned optional_bytes_remaining = PES_header_data_length; uint64_t PTS = 0, DTS = 0; if (PTS_DTS_flags == 2 || PTS_DTS_flags == 3) { if (optional_bytes_remaining < 5u) { return ERROR_MALFORMED; } if (br->getBits(4) != PTS_DTS_flags) { return ERROR_MALFORMED; } PTS = ((uint64_t)br->getBits(3)) << 30; if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } PTS |= ((uint64_t)br->getBits(15)) << 15; if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } PTS |= br->getBits(15); if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } ALOGV("PTS = 0x%016" PRIx64 " (%.2f)", PTS, PTS / 90000.0); optional_bytes_remaining -= 5; if (PTS_DTS_flags == 3) { if (optional_bytes_remaining < 5u) { return ERROR_MALFORMED; } if (br->getBits(4) != 1u) { return ERROR_MALFORMED; } DTS = ((uint64_t)br->getBits(3)) << 30; if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } DTS |= ((uint64_t)br->getBits(15)) << 15; if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } DTS |= br->getBits(15); if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } ALOGV("DTS = %" PRIu64, DTS); optional_bytes_remaining -= 5; } } if (ESCR_flag) { if (optional_bytes_remaining < 6u) { return ERROR_MALFORMED; } br->getBits(2); uint64_t ESCR = ((uint64_t)br->getBits(3)) << 30; if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } ESCR |= ((uint64_t)br->getBits(15)) << 15; if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } ESCR |= br->getBits(15); if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } ALOGV("ESCR = %" PRIu64, ESCR); MY_LOGV("ESCR_extension = %u", br->getBits(9)); if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } optional_bytes_remaining -= 6; } if (ES_rate_flag) { if (optional_bytes_remaining < 3u) { return ERROR_MALFORMED; } if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } MY_LOGV("ES_rate = %u", br->getBits(22)); if (br->getBits(1) != 1u) { return ERROR_MALFORMED; } optional_bytes_remaining -= 3; } br->skipBits(optional_bytes_remaining * 8); // ES data follows. if (PES_packet_length != 0) { if (PES_packet_length < PES_header_data_length + 3) { return ERROR_MALFORMED; } unsigned dataLength = PES_packet_length - 3 - PES_header_data_length; if (br->numBitsLeft() < dataLength * 8) { ALOGE("PES packet does not carry enough data to contain " "payload. (numBitsLeft = %zu, required = %u)", br->numBitsLeft(), dataLength * 8); return ERROR_MALFORMED; } onPayloadData( PTS_DTS_flags, PTS, DTS, br->data(), dataLength, event); br->skipBits(dataLength * 8); } else { onPayloadData( PTS_DTS_flags, PTS, DTS, br->data(), br->numBitsLeft() / 8, event); size_t payloadSizeBits = br->numBitsLeft(); if (payloadSizeBits % 8 != 0u) { return ERROR_MALFORMED; } ALOGV("There's %zu bytes of payload.", payloadSizeBits / 8); } } else if (stream_id == 0xbe) { // padding_stream if (PES_packet_length == 0u) { return ERROR_MALFORMED; } br->skipBits(PES_packet_length * 8); } else { if (PES_packet_length == 0u) { return ERROR_MALFORMED; } br->skipBits(PES_packet_length * 8); } return OK; } status_t ATSParser::Stream::flush(SyncEvent *event) { if (mBuffer == NULL || mBuffer->size() == 0) { return OK; } ALOGV("flushing stream 0x%04x size = %zu", mElementaryPID, mBuffer->size()); ABitReader br(mBuffer->data(), mBuffer->size()); status_t err = parsePES(&br, event); mBuffer->setRange(0, 0); return err; } void ATSParser::Stream::onPayloadData( unsigned PTS_DTS_flags, uint64_t PTS, uint64_t /* DTS */, const uint8_t *data, size_t size, SyncEvent *event) { #if 0 ALOGI("payload streamType 0x%02x, PTS = 0x%016llx, dPTS = %lld", mStreamType, PTS, (int64_t)PTS - mPrevPTS); mPrevPTS = PTS; #endif ALOGV("onPayloadData mStreamType=0x%02x", mStreamType); int64_t timeUs = 0ll; // no presentation timestamp available. if (PTS_DTS_flags == 2 || PTS_DTS_flags == 3) { timeUs = mProgram->convertPTSToTimestamp(PTS); } status_t err = mQueue->appendData(data, size, timeUs); if (mEOSReached) { mQueue->signalEOS(); } if (err != OK) { return; } sp accessUnit; bool found = false; while ((accessUnit = mQueue->dequeueAccessUnit()) != NULL) { if (mSource == NULL) { sp meta = mQueue->getFormat(); if (meta != NULL) { ALOGV("Stream PID 0x%08x of type 0x%02x now has data.", mElementaryPID, mStreamType); const char *mime; if (meta->findCString(kKeyMIMEType, &mime) && !strcasecmp(mime, MEDIA_MIMETYPE_VIDEO_AVC) && !IsIDR(accessUnit)) { continue; } mSource = new AnotherPacketSource(meta); mSource->queueAccessUnit(accessUnit); } } else if (mQueue->getFormat() != NULL) { // After a discontinuity we invalidate the queue's format // and won't enqueue any access units to the source until // the queue has reestablished the new format. if (mSource->getFormat() == NULL) { mSource->setFormat(mQueue->getFormat()); } mSource->queueAccessUnit(accessUnit); } if ((event != NULL) && !found && mQueue->getFormat() != NULL) { int32_t sync = 0; if (accessUnit->meta()->findInt32("isSync", &sync) && sync) { int64_t timeUs; if (accessUnit->meta()->findInt64("timeUs", &timeUs)) { found = true; event->init(mPesStartOffset, mSource, timeUs); } } } } } sp ATSParser::Stream::getSource(SourceType type) { switch (type) { case VIDEO: { if (isVideo()) { return mSource; } break; } case AUDIO: { if (isAudio()) { return mSource; } break; } case META: { if (isMeta()) { return mSource; } break; } default: break; } return NULL; } //////////////////////////////////////////////////////////////////////////////// ATSParser::ATSParser(uint32_t flags) : mFlags(flags), mAbsoluteTimeAnchorUs(-1ll), mTimeOffsetValid(false), mTimeOffsetUs(0ll), mLastRecoveredPTS(-1ll), mNumTSPacketsParsed(0), mNumPCRs(0) { mPSISections.add(0 /* PID */, new PSISection); } ATSParser::~ATSParser() { } status_t ATSParser::feedTSPacket(const void *data, size_t size, SyncEvent *event) { if (size != kTSPacketSize) { ALOGE("Wrong TS packet size"); return BAD_VALUE; } ABitReader br((const uint8_t *)data, kTSPacketSize); return parseTS(&br, event); } void ATSParser::signalDiscontinuity( DiscontinuityType type, const sp &extra) { int64_t mediaTimeUs; if ((type & DISCONTINUITY_TIME) && extra != NULL) { if (extra->findInt64(IStreamListener::kKeyMediaTimeUs, &mediaTimeUs)) { mAbsoluteTimeAnchorUs = mediaTimeUs; } if ((mFlags & TS_TIMESTAMPS_ARE_ABSOLUTE) && extra->findInt64( IStreamListener::kKeyRecentMediaTimeUs, &mediaTimeUs)) { if (mAbsoluteTimeAnchorUs >= 0ll) { mediaTimeUs -= mAbsoluteTimeAnchorUs; } if (mTimeOffsetValid) { mediaTimeUs -= mTimeOffsetUs; } mLastRecoveredPTS = (mediaTimeUs * 9) / 100; } } else if (type == DISCONTINUITY_ABSOLUTE_TIME) { int64_t timeUs; if (!extra->findInt64("timeUs", &timeUs)) { ALOGE("timeUs not found"); return; } if (!mPrograms.empty()) { ALOGE("mPrograms is not empty"); return; } mAbsoluteTimeAnchorUs = timeUs; return; } else if (type == DISCONTINUITY_TIME_OFFSET) { int64_t offset; if (!extra->findInt64("offset", &offset)) { ALOGE("offset not found"); return; } mTimeOffsetValid = true; mTimeOffsetUs = offset; return; } for (size_t i = 0; i < mPrograms.size(); ++i) { mPrograms.editItemAt(i)->signalDiscontinuity(type, extra); } } void ATSParser::signalEOS(status_t finalResult) { if (finalResult == (status_t) OK) { ALOGE("finalResult not OK"); return; } for (size_t i = 0; i < mPrograms.size(); ++i) { mPrograms.editItemAt(i)->signalEOS(finalResult); } } void ATSParser::parseProgramAssociationTable(ABitReader *br) { unsigned table_id = br->getBits(8); ALOGV(" table_id = %u", table_id); if (table_id != 0x00u) { ALOGE("PAT data error!"); return ; } unsigned section_syntax_indictor = br->getBits(1); ALOGV(" section_syntax_indictor = %u", section_syntax_indictor); br->skipBits(1); // '0' MY_LOGV(" reserved = %u", br->getBits(2)); unsigned section_length = br->getBits(12); ALOGV(" section_length = %u", section_length); MY_LOGV(" transport_stream_id = %u", br->getBits(16)); MY_LOGV(" reserved = %u", br->getBits(2)); MY_LOGV(" version_number = %u", br->getBits(5)); MY_LOGV(" current_next_indicator = %u", br->getBits(1)); MY_LOGV(" section_number = %u", br->getBits(8)); MY_LOGV(" last_section_number = %u", br->getBits(8)); size_t numProgramBytes = (section_length - 5 /* header */ - 4 /* crc */); for (size_t i = 0; i < numProgramBytes / 4; ++i) { unsigned program_number = br->getBits(16); ALOGV(" program_number = %u", program_number); MY_LOGV(" reserved = %u", br->getBits(3)); if (program_number == 0) { MY_LOGV(" network_PID = 0x%04x", br->getBits(13)); } else { unsigned programMapPID = br->getBits(13); ALOGV(" program_map_PID = 0x%04x", programMapPID); bool found = false; for (size_t index = 0; index < mPrograms.size(); ++index) { const sp &program = mPrograms.itemAt(index); if (program->number() == program_number) { program->updateProgramMapPID(programMapPID); found = true; break; } } if (!found) { mPrograms.push( new Program(this, program_number, programMapPID, mLastRecoveredPTS)); } if (mPSISections.indexOfKey(programMapPID) < 0) { mPSISections.add(programMapPID, new PSISection); } } } MY_LOGV(" CRC = 0x%08x", br->getBits(32)); } status_t ATSParser::parsePID( ABitReader *br, unsigned PID, unsigned continuity_counter, unsigned payload_unit_start_indicator, SyncEvent *event) { ssize_t sectionIndex = mPSISections.indexOfKey(PID); if (sectionIndex >= 0) { sp section = mPSISections.valueAt(sectionIndex); if (payload_unit_start_indicator) { if (!section->isEmpty()) { ALOGW("parsePID encounters payload_unit_start_indicator when section is not empty"); section->clear(); } unsigned skip = br->getBits(8); section->setSkipBytes(skip + 1); // skip filler bytes + pointer field itself br->skipBits(skip * 8); } if (br->numBitsLeft() % 8 != 0) { return ERROR_MALFORMED; } status_t err = section->append(br->data(), br->numBitsLeft() / 8); if (err != OK) { return err; } if (!section->isComplete()) { return OK; } if (!section->isCRCOkay()) { return BAD_VALUE; } ABitReader sectionBits(section->data(), section->size()); if (PID == 0) { parseProgramAssociationTable(§ionBits); } else { bool handled = false; for (size_t i = 0; i < mPrograms.size(); ++i) { status_t err; if (!mPrograms.editItemAt(i)->parsePSISection( PID, §ionBits, &err)) { continue; } if (err != OK) { return err; } handled = true; break; } if (!handled) { mPSISections.removeItem(PID); section.clear(); } } if (section != NULL) { section->clear(); } return OK; } bool handled = false; for (size_t i = 0; i < mPrograms.size(); ++i) { status_t err; if (mPrograms.editItemAt(i)->parsePID( PID, continuity_counter, payload_unit_start_indicator, br, &err, event)) { if (err != OK) { return err; } handled = true; break; } } if (!handled) { ALOGV("PID 0x%04x not handled.", PID); } return OK; } status_t ATSParser::parseAdaptationField(ABitReader *br, unsigned PID) { unsigned adaptation_field_length = br->getBits(8); if (adaptation_field_length > 0) { if (adaptation_field_length * 8 > br->numBitsLeft()) { ALOGV("Adaptation field should be included in a single TS packet."); return ERROR_MALFORMED; } unsigned discontinuity_indicator = br->getBits(1); if (discontinuity_indicator) { ALOGV("PID 0x%04x: discontinuity_indicator = 1 (!!!)", PID); } br->skipBits(2); unsigned PCR_flag = br->getBits(1); size_t numBitsRead = 4; if (PCR_flag) { if (adaptation_field_length * 8 < 52) { return ERROR_MALFORMED; } br->skipBits(4); uint64_t PCR_base = br->getBits(32); PCR_base = (PCR_base << 1) | br->getBits(1); br->skipBits(6); unsigned PCR_ext = br->getBits(9); // The number of bytes from the start of the current // MPEG2 transport stream packet up and including // the final byte of this PCR_ext field. size_t byteOffsetFromStartOfTSPacket = (188 - br->numBitsLeft() / 8); uint64_t PCR = PCR_base * 300 + PCR_ext; ALOGV("PID 0x%04x: PCR = 0x%016" PRIx64 " (%.2f)", PID, PCR, PCR / 27E6); // The number of bytes received by this parser up to and // including the final byte of this PCR_ext field. size_t byteOffsetFromStart = mNumTSPacketsParsed * 188 + byteOffsetFromStartOfTSPacket; for (size_t i = 0; i < mPrograms.size(); ++i) { updatePCR(PID, PCR, byteOffsetFromStart); } numBitsRead += 52; } br->skipBits(adaptation_field_length * 8 - numBitsRead); } return OK; } status_t ATSParser::parseTS(ABitReader *br, SyncEvent *event) { ALOGV("---"); unsigned sync_byte = br->getBits(8); if (sync_byte != 0x47u) { ALOGE("[error] parseTS: return error as sync_byte=0x%x", sync_byte); return BAD_VALUE; } if (br->getBits(1)) { // transport_error_indicator // silently ignore. return OK; } unsigned payload_unit_start_indicator = br->getBits(1); ALOGV("payload_unit_start_indicator = %u", payload_unit_start_indicator); MY_LOGV("transport_priority = %u", br->getBits(1)); unsigned PID = br->getBits(13); ALOGV("PID = 0x%04x", PID); MY_LOGV("transport_scrambling_control = %u", br->getBits(2)); unsigned adaptation_field_control = br->getBits(2); ALOGV("adaptation_field_control = %u", adaptation_field_control); unsigned continuity_counter = br->getBits(4); ALOGV("PID = 0x%04x, continuity_counter = %u", PID, continuity_counter); // ALOGI("PID = 0x%04x, continuity_counter = %u", PID, continuity_counter); status_t err = OK; if (adaptation_field_control == 2 || adaptation_field_control == 3) { err = parseAdaptationField(br, PID); } if (err == OK) { if (adaptation_field_control == 1 || adaptation_field_control == 3) { err = parsePID(br, PID, continuity_counter, payload_unit_start_indicator, event); } } ++mNumTSPacketsParsed; return err; } sp ATSParser::getSource(SourceType type) { int which = -1; // any for (size_t i = 0; i < mPrograms.size(); ++i) { const sp &program = mPrograms.editItemAt(i); if (which >= 0 && (int)program->number() != which) { continue; } sp source = program->getSource(type); if (source != NULL) { return source; } } return NULL; } bool ATSParser::hasSource(SourceType type) const { for (size_t i = 0; i < mPrograms.size(); ++i) { const sp &program = mPrograms.itemAt(i); if (program->hasSource(type)) { return true; } } return false; } bool ATSParser::PTSTimeDeltaEstablished() { if (mPrograms.isEmpty()) { return false; } return mPrograms.editItemAt(0)->PTSTimeDeltaEstablished(); } void ATSParser::updatePCR( unsigned /* PID */, uint64_t PCR, size_t byteOffsetFromStart) { ALOGV("PCR 0x%016" PRIx64 " @ %zu", PCR, byteOffsetFromStart); if (mNumPCRs == 2) { mPCR[0] = mPCR[1]; mPCRBytes[0] = mPCRBytes[1]; mSystemTimeUs[0] = mSystemTimeUs[1]; mNumPCRs = 1; } mPCR[mNumPCRs] = PCR; mPCRBytes[mNumPCRs] = byteOffsetFromStart; mSystemTimeUs[mNumPCRs] = ALooper::GetNowUs(); ++mNumPCRs; if (mNumPCRs == 2) { double transportRate = (mPCRBytes[1] - mPCRBytes[0]) * 27E6 / (mPCR[1] - mPCR[0]); ALOGV("transportRate = %.2f bytes/sec", transportRate); } } //////////////////////////////////////////////////////////////////////////////// // CRC32 used for PSI section. The table was generated by following command: // $ python pycrc.py --model crc-32-mpeg --algorithm table-driven --generate c // Visit http://www.tty1.net/pycrc/index_en.html for more details. uint32_t ATSParser::PSISection::CRC_TABLE[] = { 0x00000000, 0x04c11db7, 0x09823b6e, 0x0d4326d9, 0x130476dc, 0x17c56b6b, 0x1a864db2, 0x1e475005, 0x2608edb8, 0x22c9f00f, 0x2f8ad6d6, 0x2b4bcb61, 0x350c9b64, 0x31cd86d3, 0x3c8ea00a, 0x384fbdbd, 0x4c11db70, 0x48d0c6c7, 0x4593e01e, 0x4152fda9, 0x5f15adac, 0x5bd4b01b, 0x569796c2, 0x52568b75, 0x6a1936c8, 0x6ed82b7f, 0x639b0da6, 0x675a1011, 0x791d4014, 0x7ddc5da3, 0x709f7b7a, 0x745e66cd, 0x9823b6e0, 0x9ce2ab57, 0x91a18d8e, 0x95609039, 0x8b27c03c, 0x8fe6dd8b, 0x82a5fb52, 0x8664e6e5, 0xbe2b5b58, 0xbaea46ef, 0xb7a96036, 0xb3687d81, 0xad2f2d84, 0xa9ee3033, 0xa4ad16ea, 0xa06c0b5d, 0xd4326d90, 0xd0f37027, 0xddb056fe, 0xd9714b49, 0xc7361b4c, 0xc3f706fb, 0xceb42022, 0xca753d95, 0xf23a8028, 0xf6fb9d9f, 0xfbb8bb46, 0xff79a6f1, 0xe13ef6f4, 0xe5ffeb43, 0xe8bccd9a, 0xec7dd02d, 0x34867077, 0x30476dc0, 0x3d044b19, 0x39c556ae, 0x278206ab, 0x23431b1c, 0x2e003dc5, 0x2ac12072, 0x128e9dcf, 0x164f8078, 0x1b0ca6a1, 0x1fcdbb16, 0x018aeb13, 0x054bf6a4, 0x0808d07d, 0x0cc9cdca, 0x7897ab07, 0x7c56b6b0, 0x71159069, 0x75d48dde, 0x6b93dddb, 0x6f52c06c, 0x6211e6b5, 0x66d0fb02, 0x5e9f46bf, 0x5a5e5b08, 0x571d7dd1, 0x53dc6066, 0x4d9b3063, 0x495a2dd4, 0x44190b0d, 0x40d816ba, 0xaca5c697, 0xa864db20, 0xa527fdf9, 0xa1e6e04e, 0xbfa1b04b, 0xbb60adfc, 0xb6238b25, 0xb2e29692, 0x8aad2b2f, 0x8e6c3698, 0x832f1041, 0x87ee0df6, 0x99a95df3, 0x9d684044, 0x902b669d, 0x94ea7b2a, 0xe0b41de7, 0xe4750050, 0xe9362689, 0xedf73b3e, 0xf3b06b3b, 0xf771768c, 0xfa325055, 0xfef34de2, 0xc6bcf05f, 0xc27dede8, 0xcf3ecb31, 0xcbffd686, 0xd5b88683, 0xd1799b34, 0xdc3abded, 0xd8fba05a, 0x690ce0ee, 0x6dcdfd59, 0x608edb80, 0x644fc637, 0x7a089632, 0x7ec98b85, 0x738aad5c, 0x774bb0eb, 0x4f040d56, 0x4bc510e1, 0x46863638, 0x42472b8f, 0x5c007b8a, 0x58c1663d, 0x558240e4, 0x51435d53, 0x251d3b9e, 0x21dc2629, 0x2c9f00f0, 0x285e1d47, 0x36194d42, 0x32d850f5, 0x3f9b762c, 0x3b5a6b9b, 0x0315d626, 0x07d4cb91, 0x0a97ed48, 0x0e56f0ff, 0x1011a0fa, 0x14d0bd4d, 0x19939b94, 0x1d528623, 0xf12f560e, 0xf5ee4bb9, 0xf8ad6d60, 0xfc6c70d7, 0xe22b20d2, 0xe6ea3d65, 0xeba91bbc, 0xef68060b, 0xd727bbb6, 0xd3e6a601, 0xdea580d8, 0xda649d6f, 0xc423cd6a, 0xc0e2d0dd, 0xcda1f604, 0xc960ebb3, 0xbd3e8d7e, 0xb9ff90c9, 0xb4bcb610, 0xb07daba7, 0xae3afba2, 0xaafbe615, 0xa7b8c0cc, 0xa379dd7b, 0x9b3660c6, 0x9ff77d71, 0x92b45ba8, 0x9675461f, 0x8832161a, 0x8cf30bad, 0x81b02d74, 0x857130c3, 0x5d8a9099, 0x594b8d2e, 0x5408abf7, 0x50c9b640, 0x4e8ee645, 0x4a4ffbf2, 0x470cdd2b, 0x43cdc09c, 0x7b827d21, 0x7f436096, 0x7200464f, 0x76c15bf8, 0x68860bfd, 0x6c47164a, 0x61043093, 0x65c52d24, 0x119b4be9, 0x155a565e, 0x18197087, 0x1cd86d30, 0x029f3d35, 0x065e2082, 0x0b1d065b, 0x0fdc1bec, 0x3793a651, 0x3352bbe6, 0x3e119d3f, 0x3ad08088, 0x2497d08d, 0x2056cd3a, 0x2d15ebe3, 0x29d4f654, 0xc5a92679, 0xc1683bce, 0xcc2b1d17, 0xc8ea00a0, 0xd6ad50a5, 0xd26c4d12, 0xdf2f6bcb, 0xdbee767c, 0xe3a1cbc1, 0xe760d676, 0xea23f0af, 0xeee2ed18, 0xf0a5bd1d, 0xf464a0aa, 0xf9278673, 0xfde69bc4, 0x89b8fd09, 0x8d79e0be, 0x803ac667, 0x84fbdbd0, 0x9abc8bd5, 0x9e7d9662, 0x933eb0bb, 0x97ffad0c, 0xafb010b1, 0xab710d06, 0xa6322bdf, 0xa2f33668, 0xbcb4666d, 0xb8757bda, 0xb5365d03, 0xb1f740b4 }; ATSParser::PSISection::PSISection() : mSkipBytes(0) { } ATSParser::PSISection::~PSISection() { } status_t ATSParser::PSISection::append(const void *data, size_t size) { if (mBuffer == NULL || mBuffer->size() + size > mBuffer->capacity()) { size_t newCapacity = (mBuffer == NULL) ? size : mBuffer->capacity() + size; newCapacity = (newCapacity + 1023) & ~1023; sp newBuffer = new ABuffer(newCapacity); if (mBuffer != NULL) { memcpy(newBuffer->data(), mBuffer->data(), mBuffer->size()); newBuffer->setRange(0, mBuffer->size()); } else { newBuffer->setRange(0, 0); } mBuffer = newBuffer; } memcpy(mBuffer->data() + mBuffer->size(), data, size); mBuffer->setRange(0, mBuffer->size() + size); return OK; } void ATSParser::PSISection::setSkipBytes(uint8_t skip) { mSkipBytes = skip; } void ATSParser::PSISection::clear() { if (mBuffer != NULL) { mBuffer->setRange(0, 0); } mSkipBytes = 0; } bool ATSParser::PSISection::isComplete() const { if (mBuffer == NULL || mBuffer->size() < 3) { return false; } unsigned sectionLength = U16_AT(mBuffer->data() + 1) & 0xfff; return mBuffer->size() >= sectionLength + 3; } bool ATSParser::PSISection::isEmpty() const { return mBuffer == NULL || mBuffer->size() == 0; } const uint8_t *ATSParser::PSISection::data() const { return mBuffer == NULL ? NULL : mBuffer->data(); } size_t ATSParser::PSISection::size() const { return mBuffer == NULL ? 0 : mBuffer->size(); } bool ATSParser::PSISection::isCRCOkay() const { if (!isComplete()) { return false; } uint8_t* data = mBuffer->data(); // Return true if section_syntax_indicator says no section follows the field section_length. if ((data[1] & 0x80) == 0) { return true; } unsigned sectionLength = U16_AT(data + 1) & 0xfff; ALOGV("sectionLength %u, skip %u", sectionLength, mSkipBytes); if(sectionLength < mSkipBytes) { ALOGE("b/28333006"); android_errorWriteLog(0x534e4554, "28333006"); return false; } // Skip the preceding field present when payload start indicator is on. sectionLength -= mSkipBytes; uint32_t crc = 0xffffffff; for(unsigned i = 0; i < sectionLength + 4 /* crc */; i++) { uint8_t b = data[i]; int index = ((crc >> 24) ^ (b & 0xff)) & 0xff; crc = CRC_TABLE[index] ^ (crc << 8); } ALOGV("crc: %08x\n", crc); return (crc == 0); } } // namespace android