| /********** |
| This library is free software; you can redistribute it and/or modify it under |
| the terms of the GNU Lesser General Public License as published by the |
| Free Software Foundation; either version 3 of the License, or (at your |
| option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.) |
| |
| This library is distributed in the hope that it will be useful, but WITHOUT |
| ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS |
| FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for |
| more details. |
| |
| You should have received a copy of the GNU Lesser General Public License |
| along with this library; if not, write to the Free Software Foundation, Inc., |
| 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA |
| **********/ |
| // "liveMedia" |
| // Copyright (c) 1996-2020 Live Networks, Inc. All rights reserved. |
| // A class that encapsulates MPEG-2 Transport Stream 'index files'/ |
| // These index files are used to implement 'trick play' operations |
| // (seek-by-time, fast forward, reverse play) on Transport Stream files. |
| // |
| // C++ header |
| |
| #ifndef _MPEG2_TRANSPORT_STREAM_INDEX_FILE_HH |
| #define _MPEG2_TRANSPORT_STREAM_INDEX_FILE_HH |
| |
| #ifndef _MEDIA_HH |
| #include "Media.hh" |
| #endif |
| |
| #define INDEX_RECORD_SIZE 11 |
| |
| class MPEG2TransportStreamIndexFile: public Medium { |
| public: |
| static MPEG2TransportStreamIndexFile* createNew(UsageEnvironment& env, |
| char const* indexFileName); |
| |
| virtual ~MPEG2TransportStreamIndexFile(); |
| |
| // Functions that map between a playing time and a Transport packet number |
| // in the original Transport Stream file: |
| |
| void lookupTSPacketNumFromNPT(float& npt, unsigned long& tsPacketNumber, |
| unsigned long& indexRecordNumber); |
| // Looks up the Transport Stream Packet number corresponding to "npt". |
| // (This may modify "npt" to a more exact value.) |
| // (We also return the index record number that we looked up.) |
| |
| void lookupPCRFromTSPacketNum(unsigned long& tsPacketNumber, Boolean reverseToPreviousCleanPoint, |
| float& pcr, unsigned long& indexRecordNumber); |
| // Looks up the PCR timestamp for the transport packet "tsPacketNumber". |
| // (Adjust "tsPacketNumber" only if "reverseToPreviousCleanPoint" is True.) |
| // (We also return the index record number that we looked up.) |
| |
| // Miscellaneous functions used to implement 'trick play': |
| Boolean readIndexRecordValues(unsigned long indexRecordNum, |
| unsigned long& transportPacketNum, u_int8_t& offset, |
| u_int8_t& size, float& pcr, u_int8_t& recordType); |
| float getPlayingDuration(); |
| void stopReading() { closeFid(); } |
| |
| int mpegVersion(); |
| // returns the best guess for the version of MPEG being used for data within the underlying Transport Stream file. |
| // (1,2,4, or 5 (representing H.264). 0 means 'don't know' (usually because the index file is empty)) |
| |
| private: |
| MPEG2TransportStreamIndexFile(UsageEnvironment& env, char const* indexFileName); |
| |
| Boolean openFid(); |
| Boolean seekToIndexRecord(unsigned long indexRecordNumber); |
| Boolean readIndexRecord(unsigned long indexRecordNum); // into "fBuf" |
| Boolean readOneIndexRecord(unsigned long indexRecordNum); // closes "fFid" at end |
| void closeFid(); |
| |
| u_int8_t recordTypeFromBuf() { return fBuf[0]; } |
| u_int8_t offsetFromBuf() { return fBuf[1]; } |
| u_int8_t sizeFromBuf() { return fBuf[2]; } |
| float pcrFromBuf(); // after "fBuf" has been read |
| unsigned long tsPacketNumFromBuf(); |
| void setMPEGVersionFromRecordType(u_int8_t recordType); |
| |
| Boolean rewindToCleanPoint(unsigned long&ixFound); |
| // used to implement "lookupTSPacketNumber()" |
| |
| private: |
| char* fFileName; |
| FILE* fFid; // used internally when reading from the file |
| int fMPEGVersion; |
| unsigned long fCurrentIndexRecordNum; // within "fFid" |
| float fCachedPCR; |
| unsigned long fCachedTSPacketNumber, fCachedIndexRecordNumber; |
| unsigned long fNumIndexRecords; |
| unsigned char fBuf[INDEX_RECORD_SIZE]; // used for reading index records from file |
| }; |
| |
| #endif |