leansdr::randomizer Struct Reference

#include <dvb.h>

Inheritance diagram for leansdr::randomizer:

Collaboration diagram for leansdr::randomizer:

Public Member Functions
	randomizer (scheduler *sch, pipebuf< tspacket > &_in, pipebuf< tspacket > &_out)
void	precompute_pattern ()
void	run ()
Public Member Functions inherited from leansdr::runnable
	runnable (scheduler *_sch, const char *name)
Public Member Functions inherited from leansdr::runnable_common
	runnable_common (const char *_name)
virtual	~runnable_common ()
virtual void	shutdown ()

Private Attributes
u8	pattern [188 *8]
u8 *	pattern_end
u8 *	pos
pipereader< tspacket >	in
pipewriter< tspacket >	out

Additional Inherited Members
Public Attributes inherited from leansdr::runnable_common
const char *	name
Protected Attributes inherited from leansdr::runnable
scheduler *	sch

Detailed Description

Definition at line 1311 of file dvb.h.

Constructor & Destructor Documentation

randomizer()

leansdr::randomizer::randomizer ( scheduler *  sch, pipebuf< tspacket > &  _in, pipebuf< tspacket > &  _out  )

inline

Definition at line 1313 of file dvb.h.

                                        : runnable(sch, "derandomizer"),
                                          in(_in),
                                          out(_out)
    {
        precompute_pattern();
        pos = pattern;
        pattern_end = pattern + sizeof(pattern) / sizeof(pattern[0]);
    }

Member Function Documentation

precompute_pattern()

void leansdr::randomizer::precompute_pattern ( )

inline

Definition at line 1324 of file dvb.h.

References i, and leansdr::deconvol_sync< Tbyte, BYTE_ERASED >::sync_t::out.

    {
        // EN 300 421, section 4.4.1 Transport multiplex adaptation
        pattern[0] = 0xff;          // Invert one in eight sync bytes
        unsigned short st = 000251; // 0b 000 000 010 101 001 (Fig 2 reversed)

        for (int i = 1; i < 188 * 8; ++i)
        {
            u8 out = 0;

            for (int n = 8; n--;)
            {
                int bit = ((st >> 13) ^ (st >> 14)) & 1; // Taps
                out = (out << 1) | bit;                  // MSB first
                st = (st << 1) | bit;                    // Feedback
            }

            pattern[i] = (i % 188) ? out : 0; // Inhibit on sync bytes
        }
    }

run()

void leansdr::randomizer::run ( )

inlinevirtual

Reimplemented from leansdr::runnable_common.

Definition at line 1345 of file dvb.h.

References leansdr::deconvol_sync< Tbyte, BYTE_ERASED >::sync_t::in, and leansdr::deconvol_sync< Tbyte, BYTE_ERASED >::sync_t::out.

    {
        while (in.readable() >= 1 && out.writable() >= 1)
        {
            u8 *pin = in.rd()->data, *pend = pin + SIZE_TSPACKET;
            u8 *pout = out.wr()->data;
            if (pin[0] != MPEG_SYNC)
                fprintf(stderr, "randomizer: bad MPEG sync %02x\n", pin[0]);
            for (; pin < pend; ++pin, ++pout, ++pos)
                *pout = *pin ^ *pos;
            if (pos == pattern_end)
                pos = pattern;
            in.read(1);
            out.written(1);
        }
    }

Member Data Documentation

in

pipereader<tspacket> leansdr::randomizer::in

private

Definition at line 1364 of file dvb.h.

out

pipewriter<tspacket> leansdr::randomizer::out

private

Definition at line 1365 of file dvb.h.

pattern

u8 leansdr::randomizer::pattern[188 *8]

private

Definition at line 1363 of file dvb.h.

pattern_end

u8 * leansdr::randomizer::pattern_end

private

Definition at line 1363 of file dvb.h.

pos

u8 * leansdr::randomizer::pos

private

Definition at line 1363 of file dvb.h.

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The documentation for this struct was generated from the following file:

• plugins/channelrx/demoddatv/leansdr/dvb.h