97 lines
3.9 KiB
C++
97 lines
3.9 KiB
C++
/**********
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This library is free software; you can redistribute it and/or modify it under
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the terms of the GNU Lesser General Public License as published by the
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Free Software Foundation; either version 3 of the License, or (at your
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option) any later version. (See <http://www.gnu.org/copyleft/lesser.html>.)
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This library is distributed in the hope that it will be useful, but WITHOUT
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for
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more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this library; if not, write to the Free Software Foundation, Inc.,
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51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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**********/
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// "liveMedia"
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// Copyright (c) 1996-2024 Live Networks, Inc. All rights reserved.
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// A class that encapsulates MPEG-2 Transport Stream 'index files'/
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// These index files are used to implement 'trick play' operations
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// (seek-by-time, fast forward, reverse play) on Transport Stream files.
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//
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// C++ header
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#ifndef _MPEG2_TRANSPORT_STREAM_INDEX_FILE_HH
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#define _MPEG2_TRANSPORT_STREAM_INDEX_FILE_HH
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#ifndef _MEDIA_HH
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#include "Media.hh"
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#endif
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#define INDEX_RECORD_SIZE 11
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class LIVEMEDIA_API MPEG2TransportStreamIndexFile: public Medium {
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public:
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static MPEG2TransportStreamIndexFile* createNew(UsageEnvironment& env,
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char const* indexFileName);
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virtual ~MPEG2TransportStreamIndexFile();
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// Functions that map between a playing time and a Transport packet number
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// in the original Transport Stream file:
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void lookupTSPacketNumFromNPT(float& npt, unsigned long& tsPacketNumber,
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unsigned long& indexRecordNumber);
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// Looks up the Transport Stream Packet number corresponding to "npt".
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// (This may modify "npt" to a more exact value.)
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// (We also return the index record number that we looked up.)
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void lookupPCRFromTSPacketNum(unsigned long& tsPacketNumber, Boolean reverseToPreviousCleanPoint,
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float& pcr, unsigned long& indexRecordNumber);
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// Looks up the PCR timestamp for the transport packet "tsPacketNumber".
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// (Adjust "tsPacketNumber" only if "reverseToPreviousCleanPoint" is True.)
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// (We also return the index record number that we looked up.)
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// Miscellaneous functions used to implement 'trick play':
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Boolean readIndexRecordValues(unsigned long indexRecordNum,
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unsigned long& transportPacketNum, u_int8_t& offset,
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u_int8_t& size, float& pcr, u_int8_t& recordType);
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float getPlayingDuration();
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void stopReading() { closeFid(); }
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int mpegVersion();
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// returns the best guess for the version of MPEG being used for data within the underlying Transport Stream file.
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// (1,2,4, or 5 (representing H.264). 0 means 'don't know' (usually because the index file is empty))
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private:
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MPEG2TransportStreamIndexFile(UsageEnvironment& env, char const* indexFileName);
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Boolean openFid();
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Boolean seekToIndexRecord(unsigned long indexRecordNumber);
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Boolean readIndexRecord(unsigned long indexRecordNum); // into "fBuf"
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Boolean readOneIndexRecord(unsigned long indexRecordNum); // closes "fFid" at end
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void closeFid();
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u_int8_t recordTypeFromBuf() { return fBuf[0]; }
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u_int8_t offsetFromBuf() { return fBuf[1]; }
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u_int8_t sizeFromBuf() { return fBuf[2]; }
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float pcrFromBuf(); // after "fBuf" has been read
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unsigned long tsPacketNumFromBuf();
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void setMPEGVersionFromRecordType(u_int8_t recordType);
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Boolean rewindToCleanPoint(unsigned long&ixFound);
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// used to implement "lookupTSPacketNumber()"
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private:
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char* fFileName;
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FILE* fFid; // used internally when reading from the file
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int fMPEGVersion;
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unsigned long fCurrentIndexRecordNum; // within "fFid"
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float fCachedPCR;
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unsigned long fCachedTSPacketNumber, fCachedIndexRecordNumber;
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unsigned long fNumIndexRecords;
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unsigned char fBuf[INDEX_RECORD_SIZE]; // used for reading index records from file
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};
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#endif
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