Question

I’m having trouble extracting the timings from a .srt (subtitle) file and writing it to another file called output.srt. When i run the following i get some funky stuff written onto the output file.

// where hr=hours,mn=minutes,sc=seconds,ms=mili seconds

#include <stdio.h>
#define LINES 50
#define CHARAC 80
int main(void){
    FILE *in;
    FILE *out;
    char text[LINES][CHARAC];
    char timings[LINES][CHARAC];
    int i=0,lines=0,items=0;
    int hr=0,mn=0,sc=0,ms=0,hr2=0,mn2=0,sc2=0,ms2=0;

    in=fopen("file2.srt","r");
    out=fopen("output.srt","w");

    while (!feof(in)){
        fgets(text[i],80,in);
        items=sscanf(text[i],"%d:%d:%d,%d --> %d:%d:%d,%d ",&hr,&mn,&sc,&ms,&hr2,&mn2,&sc2,&ms2);
        //------------------------------------->edited<----------------------------------
        switch (items)
        {   
            case 1: break;
            case 8: 
                sprintf(timings[i],"%d:%d:%d,%d --> %d:%d:%d,%d",hr,mn,sc,ms,hr2,mn2,sc2,ms2);
                break;
            case 0: break;

        }
        //------------------------------------->edited<----------------------------------
        ++i;
    }
    lines=i;

    for (int i=0;i<lines;i++){
        fprintf(out,"%s\n",timings[i]);
    }

    fclose(in);
    fclose(out);

    return 0;
}

how do I go about extracting those first 10 timings?

Answer 1

If this is on windows (or MSDOS) the open modes need to be text:

in =  fopen ("file2.srt", "rt");
out = fopen ("output.srt", "wt");

Secondly, the code isn’t doing anything to react to the differently formatted lines. The first few data lines are:

1
00:00:30,909--> 00:00:32,775
Take a look at yourself.

2
00:00:34,066--> 00:00:37,681
Disconnect you from the seats,
lift yourself and take a look in the mirror.

So, naturally, the first sscanf isn’t going to fill in most of the fields. Here’s the output I got (for the corresponding lines):

1:0:0,0 --> 0:0:0,0
0:0:30,909 --> 0:0:32,775
0:0:30,909 --> 0:0:32,775
0:0:30,909 --> 0:0:32,775
2:0:30,909 --> 0:0:32,775

To fix this, you’ll have to add logic which expects the proper number of elements, or at least reacts to them:

itms = sscanf(text[i],"%d:%d:%d,%d --> %d:%d:%d,%d ",&hr,&mn,&sc,&ms,&hr2,&mn2,&sc2,&ms2);
switch (itms)
{
case 1:  // the first line
case 8:  // the lines with the times
case 0:  // the text lines
}

Edited to add a fixed version of your last edit:

#include <stdio.h>
#define LINES 50
#define CHARAC 80
int main(void){
    FILE *in;
    FILE *out;
    char text[LINES][CHARAC];
    char timings[LINES][CHARAC];
    int i=0,lines=0,items=0;
    int hr=0,mn=0,sc=0,ms=0,hr2=0,mn2=0,sc2=0,ms2=0;

    in=fopen("file2.srt","rt");
    out=fopen("output.srt","wt");

    while (!feof(in))
    {
        if (!fgets(text[i],80,in))
            break;
        items = sscanf(text[i], "%d:%d:%d,%d --> %d:%d:%d,%d ", &hr,&mn,&sc,&ms,&hr2,&mn2,&sc2,&ms2);
        switch (items)
        {       
        case 1: break;
        case 8: 
                sprintf(timings[i],"%d:%d:%d,%d --> %d:%d:%d,%d",hr,mn,sc,ms,hr2,mn2,sc2,ms2);
                ++i;  // advance only when a valid line is seen
                break;
        case 0: break;
        }
    }
    lines=i;

    for (i=0; i<lines; i++){
        fprintf(out,"%s\n",timings[i]);
    }

    fclose(in);
    fclose(out);

    return 0;
}