[mythtv] DVB, HD-2000, and CRCs

Daniel Thor Kristjansson danielk at mrl.nyu.edu
Tue Mar 22 13:55:37 UTC 2005


On Tue, 22 Mar 2005, Taylor Jacob wrote:
]Quoting Doug Larrick <doug at ties.org>:
]It seems more reasonable to just drop the table to me.. Having CRC code in
]multiple places seems like a bad idea.. With the frequency of any section table
]its not worth worrying about loosing one here or there..  I figure if you are
]droping so many mal-formed tables that its actually a problem you won't be
]getting a reliable mpeg stream anyway and should fix your antenna setup..

You can use the mpegts_crc32() function in ffmpeg, see pespacket.h in 
the libs/libmythtv/mpeg directory:

    unsigned int CalcCRC() const {
        return mpegts_crc32(_pesdata+1, Length()-1);
    }
    bool VerifyCRC() const { return CalcCRC()==CRC(); }

-- Daniel


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