www.pudn.com > avi 到 mpeg 的转换程序及源代码.zip > TIMECODE.C

/************************************************************************* 
*  mplex - MPEG/SYSTEMS multiplexer					 * 
*  Copyright (C) 1994 1995 Christoph Moar				 * 
*  Siemens ZFE ST SN 11 / T SN 6					 * 
*									 * 
*  moar@informatik.tu-muenchen.de 					 * 
*       (Christoph Moar)			 			 * 
*  klee@heaven.zfe.siemens.de						 * 
*       (Christian Kleegrewe, Siemens only requests)			 * 
*									 * 
*  This program is free software; you can redistribute it and/or modify	 * 
*  it under the terms of the GNU General Public License as published by	 *	 
*  the Free Software Foundation; either version 2 of the License, or	 * 
*  (at your option) any later version.					 * 
*									 * 
*  This program is distributed in the hope that it will be useful,	 * 
*  but WITHOUT ANY WARRANTY; without even the implied warranty of	 * 
*  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the	 * 
*  GNU General Public License for more details.				 * 
*									 * 
*  You should have received a copy of the GNU General Public License	 * 
*  along with this program; if not, write to the Free Software		 * 
*  Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.		 * 
*************************************************************************/ 
/* 
 * 4/4/97 - John Schlichther 
 * 
 * extensively altered to create avi2mpg1 - avi to mpeg-1 encoder 
 * 
 * Since avi file, and the avi subsystem are platform dependant, cross 
 * platform compatibility removed, many optional features disabled or 
 * removed, code generally trimmed to a minimum. 
 * 
 * 
 */ 
#include "mplex.h" 
/************************************************************************* 
    Funktionen zu Time_Code Berechnungen im System Clock Reference Format 
 
    Functions for Time_Code computations in System Clock Reference Format 
*************************************************************************/ 
 
void empty_timecode_struc (timecode) 
Timecode_struc *timecode; 
{ 
    timecode->msb=0; 
    timecode->lsb=0; 
} 
 
void offset_timecode (time1, time2, offset) 
Timecode_struc *time1, *time2, *offset; 
{ 
    offset->msb = time2->msb - time1->msb; 
    offset->lsb = time2->lsb - time1->lsb; 
} 
 
void copy_timecode (time_original, time_copy) 
Timecode_struc *time_original, *time_copy; 
{ 
    time_copy->lsb=time_original->lsb; 
    time_copy->msb=time_original->msb; 
} 
 
void make_timecode (timestamp, pointer) 
double timestamp; 
Timecode_struc *pointer; 
{ 
    if (timestamp > MAX_FFFFFFFF) 
    { 
	pointer->msb=1; 
	timestamp -= MAX_FFFFFFFF; 
	pointer->lsb=(unsigned long)timestamp; 
    } else 
    { 
	pointer->msb=0; 
	pointer->lsb=(unsigned long)timestamp; 
    } 
} 
 
 
void add_to_timecode (add, to) 
Timecode_struc *add; 
Timecode_struc *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; 
    } 
} 
 
 
/************************************************************************* 
    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 (pointer, marker, buffer) 
 
Timecode_struc *pointer; 
unsigned char  marker; 
unsigned char **buffer; 
 
{ 
    unsigned char temp; 
 
    temp = (unsigned char)((marker << 4) | (pointer->msb <<3) | 
		((pointer->lsb >> 29) & 0x6) | 1); 
    *((*buffer)++)=temp; 
    temp = (unsigned char)((pointer->lsb & 0x3fc00000) >> 22); 
    *((*buffer)++)=temp; 
    temp = (unsigned char)(((pointer->lsb & 0x003f8000) >> 14) | 1); 
    *((*buffer)++)=temp; 
    temp = (unsigned char)((pointer->lsb & 0x7f80) >> 7); 
    *((*buffer)++)=temp; 
    temp = (unsigned char)(((pointer->lsb & 0x007f) << 1) | 1); 
    *((*buffer)++)=temp; 
 
} 
 
/****************************************************************** 
	Comp_Timecode 
	liefert TRUE zurueck, wenn TS1 <= TS2 ist. 
 
	Yields TRUE, if TS1 <= TS2. 
******************************************************************/ 
 
int comp_timecode (TS1, TS2) 
Timecode_struc *TS1; 
Timecode_struc *TS2; 
{ 
    double Time1; 
    double Time2; 
 
    Time1 = (TS1->msb * MAX_FFFFFFFF) + (TS1->lsb); 
    Time2 = (TS2->msb * MAX_FFFFFFFF) + (TS2->lsb); 
 
    return (Time1 <= Time2); 
}