CTIMECOD.CPP

//=========================================================================== 
// 
// THIS CODE AND INFORMATION IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY 
// KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE 
// IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A PARTICULAR 
// PURPOSE. 
// 
// Copyright (c) 1992 - 1997  Microsoft Corporation.  All Rights Reserved. 
// 
//=========================================================================== 
// 
//   filename: ctimecod.cpp 
// 
//     SMPTE Timecode support class 
// 
//--------------------------------------------------------- 
// 
//This code is provided for reference purposes only 
// 
//NOTES: 
// 1. Code is un-optimized for clarity 
// 2. Minimal error checking. 
// 3. Negative t/c values not supported 
// 4. File logging functions are here for illustrative  
//purposes but not used. 
// 
//--------------------------------------------------------- 
 
 
#include <windows.h> 
#include <stdio.h> 
#include <string.h> 
#include <stdarg.h> 
#include <vfw.h> 
#include <streams.h> 
#include "ctimecod.h"  
 
// timecode conversion tables 
#define TC_LENGTH 11*sizeof(TCHAR)// length of a t/c string 
static long lNDFTable[] = {1080000L,108000L,18000L,1800L,300L,30L,10L,1L}; 
static long lDFTable[] = {1078920L,107892L,17982L,1798L,300L,30L,10L,1L}; 
static long l25Table[] = {900000L,90000L,15000L,1500L,250L,25L,10L,1L}; 
static long l24Table[] = {864000L,86400L,14400L,1440L,240L,24L,10L,1L}; 
 
//--------------------------------------------------------- 
// 
//ConvertStringToTimecode 
// 
// Timecode sample passed in contains desired framerate for conversion 
// 
//--------------------------------------------------------- 
DWORD 
CTimecode::ConvertStringToTimecode(TCHAR *lpszTimecode,  
   PTIMECODE_SAMPLE pTimecodeSample) 
{ 
int i, j; 
long *table; 
TCHAR temp; 
 
// select conversion table 
switch (pTimecodeSample->timecode.wFrameRate) 
{ 
case AM_TIMECODE_30DROP: 
table = lDFTable; 
break; 
case AM_TIMECODE_30NONDROP: 
table = lNDFTable; 
break; 
case AM_TIMECODE_25: 
table = l25Table; 
break; 
case AM_TIMECODE_24: 
table = l24Table; 
break; 
default: 
table = lNDFTable; 
} 
pTimecodeSample->timecode.dwFrames = 0L; 
j = 0; 
for ( i = 0; lpszTimecode[i]!= 0; i++ ) 
{ 
if ( (lpszTimecode[i] > '9') || (lpszTimecode[i] < '0') ) 
continue; 
temp = (lpszTimecode[i] - '0'); 
pTimecodeSample->timecode.dwFrames += (DWORD)temp * table[j]; 
j++; 
} 
return 0L; 
} 
//--------------------------------------------------------- 
// 
//ConvertTimecodeToString 
// 
//--------------------------------------------------------- 
DWORD  
CTimecode::ConvertTimecodeToString(PTIMECODE_SAMPLE pTimecodeSample,  
   TCHAR *lpszTimecode) 
{ 
int i, j, temp; 
long timecode; 
long *table; 
WORD wFCM; 
int flag = 0; 
 
// make local copies 
wFCM = pTimecodeSample->timecode.wFrameRate; 
timecode = pTimecodeSample->timecode.dwFrames; 
 
// select conversion table 
switch (wFCM) 
{ 
case AM_TIMECODE_30DROP: 
table = lDFTable; 
break; 
case AM_TIMECODE_30NONDROP: 
table = lNDFTable; 
break; 
case AM_TIMECODE_25: 
table = l25Table; 
break; 
case AM_TIMECODE_24: 
table = l24Table; 
break; 
default: 
table = lNDFTable; 
} 
for ( i=0, j=0; j<(TC_LENGTH); i++, j++ ) 
{ 
temp = (int)( timecode / table[i]); 
lpszTimecode[j] = temp + '0';// ASCII conversion 
timecode -= temp * table[i]; 
// if minutesx10, do the drop frame test 
if ( i == 2 ) { 
if ( timecode < 2) 
flag = 1;// this means we are on a 10 minute 
// boundary and 2 frames should be  
// added later 
else 
timecode-=2L; 
} 
if ( i == 3 ) { 
// this is where the 2 frames get added in 
if ( !flag ) 
timecode+=2L; 
} 
// add punctuation 
if ( 1 == j || 4 == j || 7 == j ) 
{ 
j++; 
if ( 8 == j && wFCM == AM_TIMECODE_30DROP ) 
lpszTimecode[j] = ';'; 
else 
lpszTimecode[j] = ':'; 
} 
} 
lpszTimecode[j] = 0;// null terminate 
return 0L; 
} 
 
// eof ctimecod.c