timecode.cpp

传输流分析

#include "main.h"
/*************************************************************************
    Functions for Time_Code computations in System Clock Reference Format
*************************************************************************/

double get_timecode(Timecode_struc *timestamp)
{
        double temp_ts;

        if (timestamp->msb)
                temp_ts = MSB_TIMECODE;
        else
                temp_ts = 0.0;
        temp_ts += timestamp->lsb * 300.0 + timestamp->reference_ext;
        return temp_ts;
}


void empty_timecode_struc (
        Timecode_struc *timecode)
{
        timecode->msb=0;
        timecode->lsb=0;
        timecode->reference_ext=0;
}

void offset_timecode (
        Timecode_struc *time1, Timecode_struc *time2, Timecode_struc *offset)
{
        double timestamp = get_timecode(time2) - get_timecode(time2);

        make_timecode(timestamp, offset);

        //    offset->msb = time2->msb - time1->msb;
        //    offset->lsb = time2->lsb - time1->lsb;
        //    offset->reference_ext = 0;
}

void copy_timecode (
        Timecode_struc *time_original, Timecode_struc *time_copy)
{
        time_copy->lsb=time_original->lsb;
        time_copy->msb=time_original->msb;
        time_copy->reference_ext=time_original->reference_ext;
}

void make_timecode (
        double timestamp,
        Timecode_struc *pointer)
{
        double temp_ts;

        temp_ts = floor(timestamp / 300.0);
        if (temp_ts > MAX_FFFFFFFF) {
                pointer->msb=1;
                temp_ts -= MAX_FFFFFFFF;
                pointer->lsb=(unsigned long)temp_ts;
        } else {
                pointer->msb=0;
                pointer->lsb=(unsigned long)temp_ts;
        }
        if (mplex_type > MPEG_VCD) {
                temp_ts = floor(timestamp / 1.0);
                pointer->reference_ext = ((unsigned long) temp_ts) % 300;
        } else
                pointer->reference_ext = 0;
}


void add_to_timecode (
        Timecode_struc *add
        ,
        Timecode_struc *to)
{
        double timestamp = get_timecode(to) + get_timecode(add
                                                          );

        make_timecode(timestamp, to);

        //    to->msb = (add->msb ^ to->msb);

        /* oberstes bit in beiden Feldern gesetzt */
        /* high bit set in both fields */

        //    if (((add->lsb & 0x80000000) & (to->lsb & 0x80000000))>>31)
        //    {
        //	to->msb = to->msb ^ 1;
        //	to->lsb = (to->lsb & 0x7fffffff)+(add->lsb & 0x7fffffff);
        //    }

        /* oberstes bit in einem der beiden gesetzt */
        /* high bit set in one of both fields */

        //    else if (((add->lsb & 0x80000000) | (to->lsb & 0x80000000))>>31)
        //    {
        //	to->msb = to->msb ^
        //	  ((((add->lsb & 0x7fffffff)+(to->lsb & 0x7fffffff)) & 0x80000000)>>31);
        //	to->lsb = ((to->lsb & 0x7fffffff)+(add->lsb & 0x7fffffff)^0x80000000);
        //    }

        /* kein Ueberlauf moeglich */
        /* no overflow possible */

        //    else
        //    {
        //	to->lsb = to->lsb + add->lsb;
        //    }
        //   to->reference_ext = 0;
}


/*************************************************************************
    Kopiert einen TimeCode in einen Bytebuffer. Dabei wird er nach
    MPEG-Verfahren in bits aufgesplittet.
 
    Makes a Copy of a TimeCode in a Buffer, splitting it into bitfields
    according to MPEG-System
*************************************************************************/

void buffer_timecode (
        Timecode_struc *pointer,
        unsigned char  marker,
        unsigned char **buffer)

{
        unsigned char temp;
        if (mplex_type > MPEG_VCD) {
                if (marker == MPEG2_MARKER_SCR) {
                        temp = (marker << 6) | (pointer->msb << 5) |
                               ((pointer->lsb >> 27) & 0x18) | 0x4 | ((pointer->lsb >> 28) & 0x3);
                        *((*buffer)++)=temp;
                        temp = (pointer->lsb & 0x0ff00000) >> 20;
                        *((*buffer)++)=temp;
                        temp = ((pointer->lsb & 0x000f8000) >> 12) | 0x4 |
                               ((pointer->lsb & 0x00006000) >> 13);
                        *((*buffer)++)=temp;
                        temp = (pointer->lsb & 0x00001fe0) >> 5;
                        *((*buffer)++)=temp;
                        temp = ((pointer->lsb & 0x0000001f) << 3) | 0x4 |
                               ((pointer->reference_ext & 0x00000180) >> 7);
                        *((*buffer)++)=temp;
                        temp = ((pointer->reference_ext & 0x0000007F) << 1) | 1;
                        *((*buffer)++)=temp;
                } else {
                        if (marker == MPEG2_MARKER_DTS)
                                marker = 1;

                        temp = (marker << 4) | (pointer->msb <<3) |
                               ((pointer->lsb >> 29) & 0x6) | 1;
                        *((*buffer)++)=temp;
                        temp = (pointer->lsb & 0x3fc00000) >> 22;
                        *((*buffer)++)=temp;
                        temp = ((pointer->lsb & 0x003f8000) >> 14) | 1;
                        *((*buffer)++)=temp;
                        temp = (pointer->lsb & 0x7f80) >> 7;
                        *((*buffer)++)=temp;
                        temp = ((pointer->lsb & 0x007f) << 1) | 1;
                        *((*buffer)++)=temp;
                }
        } else {
                temp = (marker << 4) | (pointer->msb << 3) |
                       ((pointer->lsb >> 29) & 0x6) | 1;
                *((*buffer)++) = temp;
                temp = (pointer->lsb & 0x3fc00000) >> 22;
                *((*buffer)++) = temp;
                temp = ((pointer->lsb & 0x003f8000) >> 14) | 1;
                *((*buffer)++) = temp;
                temp = (pointer->lsb & 0x7f80) >> 7;
                *((*buffer)++) = temp;
                temp = ((pointer->lsb & 0x007f) << 1) | 1;
                *((*buffer)++) = temp;
        }
}

/******************************************************************
	Comp_Timecode
	liefert TRUE zurueck, wenn TS1 <= TS2 ist.
 
	Yields TRUE, if TS1 <= TS2.
******************************************************************/

int comp_timecode (
        Timecode_struc *TS1,
        Timecode_struc *TS2)
{
        return (get_timecode(TS1) <= get_timecode(TS2));

        //    double Time1;
        //    double Time2;

        //    Time1 = (TS1->msb * MAX_FFFFFFFF) + (TS1->lsb);
        //    Time2 = (TS2->msb * MAX_FFFFFFFF) + (TS2->lsb);

        //   return (Time1 <= Time2);
}