SRTmove: shift all subtitles from an srt file, in order to make them appear earlier or later.

srtmove-lib.hpp

/***** SRTmove ******
Author: Ophir LOJKINE
Licence: LGPLv3
*/

#ifndef SRTMOVE_LIB_H
#define SRTMOVE_LIB_H

#include <iostream>

/** Reads subtitles in srt format from fin, and writes it to fout, with addition
milliseconds added to each subtitles. addition can be a negative number.
Returns the number of subtitles that were processed, or a negative number if anb error occured.
*/
template<typename INTYPE, typename OUTTYPE>
int srtmove (INTYPE &fin, OUTTYPE &fout, int addition);

/** Converts a value like 12:03, 2m3s, or 8s3ms to a number of milliseconds
arg2msec("1h") == 3600000
arg2msec("1h1m1s1ms") == 60*60*1000 + 60*1000 + 1*1000 + 1 == 3661001
arg2msec("-2:03") == 2*60*1000 + 3*1000 == -123000 //Removes 2 minutes and 3 seconds to every subtitles
*/
int arg2msec(const char *arg);

#include "srtmove-lib.tpp"
#endif

srtmove-lib.tpp

/***** SRTmove ******
Author: Ophir LOJKINE
Licence: LGPLv3

Adds or removes time from the subtitles inside an .srt file.

This version is easier to work with on Windows. It takes a list of subtitles as command-line
arguments, and prompts the user for a time, and outputs the resynced subtitles to files in the same
directory as the input files.

You can use Windows' "Open with" functionality with this program.

*/
#include <iostream>     // std::cin, std::cout
#include <stdio.h>

#define LINE_LEN 256

using namespace std;

int str2msec (char *line) {
	int mul[12] = {36000000, 3600000, 0, 600000, 60000, 0, 10000, 1000, 0, 100, 10, 1},
		msec = 0;
	for (int i=11; i>=0; i--) {
		msec += mul[i] * (int) (line[i]-'0');
	}
	return msec;
}

void msec2str (int msec, char *out) {
	int ms = msec%1000; msec /= 1000;
	int s  = msec%60;   msec /= 60;
	int m  = msec%60;   msec /= 60;
	int h  = msec;
	sprintf(out, "%02d:%02d:%02d,%02d", h,m,s,ms/10);
	out[11] = (char) ('0' + ms%10);
}

/**Returns true if s begins with pat, where pat is a string with a simple format 'N' matches a number, any other character matches only itself.*/
bool matchpattern(char *s, char *pat) {
	int i;
	for (i=0; pat[i] != '\0' && s[i] != '\0'; i++) {
		if (pat[i] == 'N' && s[i] <= '9' && s[i] >= '0') continue;
		if (pat[i] != s[i]) return false;
	}
	return (pat[i] == '\0');
}

int arg2msec(const char *arg) { // arg can ba "6" for 6 seconds or "3:10" for 3 minutes
	size_t len = char_traits<char>::length(arg);
	int mul = 1000;
	int res = 0;
	int sgn = (arg[0] == '-') ? -1 : 1;
	for (int i = len-1; i>=0 && arg[i] != '-' && arg[i] != '+'; i--) {
		switch (arg[i]) {
			case 's': mul=1000; break;
			case ':': mul = mul/10 * 6; break;
			case 'm':
				if(i<len-1 && arg[i+1] == 's') mul=1;//ms
				else mul = 60000;
				break;
			case 'h': mul = 3600000; break;
			default:
				if ('0' <= arg[i] && arg[i] <= '9'){
					res += mul * int(arg[i] - '0');
					mul *= 10;
				} else {
					cerr << "Malformed argument." << endl;
                    cerr << "You can type -10m3s for making your subtitles appear 10 minutes and 3 seconds earlier, for instance." <<endl;
					return 0;
				}
		}
	}
	return sgn*res;
}

template<typename INTYPE, typename OUTTYPE>
int srtmove (INTYPE &fin, OUTTYPE &fout, int addition) {
	char pattern[] = "NN:NN:NN,NNN --> NN:NN:NN,NNN";
	char line[LINE_LEN];

	if (!fin.good() || !fout.good()) return -1;

    int subcount = 0;

    while (fin.good()) {
        fin.getline (line, LINE_LEN);
        size_t size = char_traits<char>::length(line);
        if (matchpattern(line, pattern)) {
            int t1 = str2msec(line),
                t2 = str2msec(line + 17);
            t1 = (t1 > -addition) ? t1 + addition : 0;
            t2 = (t2 > -addition) ? t2 + addition : 0;
            msec2str(t1, line);
            msec2str(t2, line+17);
            subcount++;
        }
        fout.write(line, size);
        if (!fin.fail()) { //A full line was read
            fout << endl;
        }
    }
    return subcount;
}

SRTmove.md

SRTmove

Compilation

g++ -o srtmove srtmove.cpp

This small programm uses no library.

Usage

./srtmove time < input_file.srt > shifted_file.srt

Where time can be of the format XmYs with X the number of minutes and Y the number of seconds to add to the time of each subtitle. If only a number is provided, it will be interpreted as a number of seconds. time can also contain a number of hours and a number of milliseconds: XhYmZsMms

For instance, if you want to remove 2 minutes ans 30 seconds to all subtitles in the file film.srt and save the result in the file film.corrected.srt, you can run:

./srtmove -2m30s < film.srt > film.corrected.srt

srtmove_UNIX.cpp

/*    SRTmove
by Ophir LOJKINE
Adds or removes time from the subtitles inside an .srt file.

This version is UNIX friendly it reads a subtitle file from it's standard input,
takes it's parameter as a command-line argument, and outputs the new subtitles to it's standard output.

*/
#include <iostream>
#include "srtmove-lib.h"

int main (int argc, char **argv) {
	if (argc != 2) {
		cerr << "Wrong argument count.\n\tUsage: srtmove time\n\t(where time can be in format -3m2s for substracting 3 minutes and 2 seconds to all subtitles)" << endl;
		return 1;
	}

	int addition = arg2msec(argv[1]);
	int num = srtmove(std::cin, std::cout, addition);

	return (num > 0) ? 0 : 2;
}

srtmove_windows.cpp

/* SRTmove
by Ophir LOJKINE
Adds or removes time from the subtitles inside an .srt file.

This version is easier to work with on Windows. It takes a list of subtitles as command-line
arguments, and prompts the user for a time, and outputs the resynced subtitles to files in the same
directory as the input files.

You can use Windows' "Open with" functionality with this program.

*/
#include "srtmove-lib.h"

#include <fstream>     // std::ifstream, std::ofstream
#include <vector>
#include <string>

using namespace std;

struct t_outfile {
	string name;
	int subcount;
};

int main (int argc, char **argv) {
    if (argc < 2) {
        cerr << "No file to handle..." << endl;
        return 1;
    }

    string addstr;
    int addition=0;
    while (addition == 0) {
        cout << "Time to add (MM:SS): ";
        cin >> addstr;
        if (addstr.find("exit") == 0 || addstr.find("quit") == 0) return 1;
        addition = arg2msec(addstr.c_str());
    };

    vector <t_outfile*> outfiles;

    for (int numfile=1; numfile < argc; numfile++) {
        char *finname = argv[numfile];
        string foutname (finname);
        size_t pos = foutname.rfind(".srt");
        if (pos == string::npos) pos = foutname.size()-1;
        foutname.replace(pos, 4, "-resync.srt");

        ifstream fin (finname);
        if (!fin.good()) {
            cerr << "Unable to open input file: " << finname << endl;
            continue;
        }
        ofstream fout (foutname.c_str());
        if (!fout.good()) {
            cerr << "Unable to open output file: " << foutname << endl;
            continue;
        }

		int subcount = srtmove (fin, fout, addition);
		if (subcount < 0) {
			cerr << "Sorry, an error occured in srtmove." << endl;
			continue;
		} else if (subcount == 0) {
			cerr << "No subtitles found in file: " << finname << endl;
			continue;
		} else { //Everything went well
		    t_outfile* outfile = new t_outfile;
		    outfiles.push_back(outfile);

		    outfile->name = foutname;
		    outfile->subcount = subcount;
		}
    }

	cerr << "End of program. Files created:" << endl;
	for (int i=0; i<outfiles.size(); i++) {
		cerr << " - " << outfiles[i]->name;
		cerr << " (" << outfiles[i]->subcount << " subtitles)" <<endl;
		delete outfiles[i];
	}

  return 0;
}