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MPEG2TransportStreamIndexFile.hh
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16 // "liveMedia"
17 // Copyright (c) 1996-2021 Live Networks, Inc. All rights reserved.
18 // A class that encapsulates MPEG-2 Transport Stream 'index files'/
19 // These index files are used to implement 'trick play' operations
20 // (seek-by-time, fast forward, reverse play) on Transport Stream files.
21 //
22 // C++ header
23 
24 #ifndef _MPEG2_TRANSPORT_STREAM_INDEX_FILE_HH
25 #define _MPEG2_TRANSPORT_STREAM_INDEX_FILE_HH
26 
27 #ifndef _MEDIA_HH
28 #include "Media.hh"
29 #endif
30 
31 #define INDEX_RECORD_SIZE 11
32 
34 public:
36  char const* indexFileName);
37 
39 
40  // Functions that map between a playing time and a Transport packet number
41  // in the original Transport Stream file:
42 
43  void lookupTSPacketNumFromNPT(float& npt, unsigned long& tsPacketNumber,
44  unsigned long& indexRecordNumber);
45  // Looks up the Transport Stream Packet number corresponding to "npt".
46  // (This may modify "npt" to a more exact value.)
47  // (We also return the index record number that we looked up.)
48 
49  void lookupPCRFromTSPacketNum(unsigned long& tsPacketNumber, Boolean reverseToPreviousCleanPoint,
50  float& pcr, unsigned long& indexRecordNumber);
51  // Looks up the PCR timestamp for the transport packet "tsPacketNumber".
52  // (Adjust "tsPacketNumber" only if "reverseToPreviousCleanPoint" is True.)
53  // (We also return the index record number that we looked up.)
54 
55  // Miscellaneous functions used to implement 'trick play':
56  Boolean readIndexRecordValues(unsigned long indexRecordNum,
57  unsigned long& transportPacketNum, u_int8_t& offset,
58  u_int8_t& size, float& pcr, u_int8_t& recordType);
60  void stopReading() { closeFid(); }
61 
62  int mpegVersion();
63  // returns the best guess for the version of MPEG being used for data within the underlying Transport Stream file.
64  // (1,2,4, or 5 (representing H.264). 0 means 'don't know' (usually because the index file is empty))
65 
66 private:
67  MPEG2TransportStreamIndexFile(UsageEnvironment& env, char const* indexFileName);
68 
70  Boolean seekToIndexRecord(unsigned long indexRecordNumber);
71  Boolean readIndexRecord(unsigned long indexRecordNum); // into "fBuf"
72  Boolean readOneIndexRecord(unsigned long indexRecordNum); // closes "fFid" at end
73  void closeFid();
74 
75  u_int8_t recordTypeFromBuf() { return fBuf[0]; }
76  u_int8_t offsetFromBuf() { return fBuf[1]; }
77  u_int8_t sizeFromBuf() { return fBuf[2]; }
78  float pcrFromBuf(); // after "fBuf" has been read
79  unsigned long tsPacketNumFromBuf();
80  void setMPEGVersionFromRecordType(u_int8_t recordType);
81 
82  Boolean rewindToCleanPoint(unsigned long&ixFound);
83  // used to implement "lookupTSPacketNumber()"
84 
85 private:
86  char* fFileName;
87  FILE* fFid; // used internally when reading from the file
89  unsigned long fCurrentIndexRecordNum; // within "fFid"
90  float fCachedPCR;
92  unsigned long fNumIndexRecords;
93  unsigned char fBuf[INDEX_RECORD_SIZE]; // used for reading index records from file
94 };
95 
96 #endif
unsigned char Boolean
Definition: Boolean.hh:25
#define INDEX_RECORD_SIZE
void lookupTSPacketNumFromNPT(float &npt, unsigned long &tsPacketNumber, unsigned long &indexRecordNumber)
void lookupPCRFromTSPacketNum(unsigned long &tsPacketNumber, Boolean reverseToPreviousCleanPoint, float &pcr, unsigned long &indexRecordNumber)
Boolean readOneIndexRecord(unsigned long indexRecordNum)
unsigned char fBuf[INDEX_RECORD_SIZE]
static MPEG2TransportStreamIndexFile * createNew(UsageEnvironment &env, char const *indexFileName)
unsigned long tsPacketNumFromBuf()
void setMPEGVersionFromRecordType(u_int8_t recordType)
Boolean readIndexRecordValues(unsigned long indexRecordNum, unsigned long &transportPacketNum, u_int8_t &offset, u_int8_t &size, float &pcr, u_int8_t &recordType)
MPEG2TransportStreamIndexFile(UsageEnvironment &env, char const *indexFileName)
Boolean seekToIndexRecord(unsigned long indexRecordNumber)
Boolean rewindToCleanPoint(unsigned long &ixFound)
Boolean readIndexRecord(unsigned long indexRecordNum)
Definition: Media.hh:50