NAME¶

Subtitles - handle video subtitles in various text formats

DESCRIPTION¶

Video files (avi mpeg etc) are sometimes accompanied with subtitles, which are currently very popular as text files. "Subtitles" provides means for simple loading, re-timing, and storing these subtitle files. A command-line tool subs for the same purpose and using "Subtitles" interface is included in the distribution. The module supports "srt", "sub", "smi", and "mdvd" subtitle formats. Time values are floats, in seconds with millisecond precision.

SYNOPSIS¶

        use Subtitles;
        
        my $sub = Subtitles->new();
        open F, 'Ichi The Killer.sub' or die "Cannot read:$!";
        die "Cannot load:$@\n" unless $sub-> load(\*F);
        close F;
        # back two minutes
        $sub-> shift( $sub-> parse_time('-02:00')); 
        # re-frame from 25 fps
        $sub-> scale( 23.976 / 25 );
        # or both
        $sub-> transform( -120, 0.96);
        $sub-> transform( -120, 0.96, 0, $sub-> length - 60);
        # split in 2
        my ( $part1, $part2) = $sub-> split( $self-> length / 2);
        # join back with 5-second gap 
        $part1-> join( $part2, 5);
        # save
        open F, "> out.sub" or die "Cannot write:$!\n";
        $part1-> save( \*F);
        close F;
        # report
        print "sub is ", time2str( $sub-> length);

API¶

Package methods¶

codecs

Returns array of installed codecs.

hms2time HOURS, MINUTES, SECONDS, MILLISECONDS

Combines four parameters into float time in seconds.

time2hms TIME

Splits time into four integers, - hours, minutes, seconds, and milliseconds. If time is less than zero, zero times are returned.

time2shms

Splits time into five integers, - time sign, hours, minutes, seconds, and milliseconds.

time2str TIME

Converts time to a human-readable string.

Object methods¶

clear

Removes all content

codec [ STRING ]

If STRING is not defined, returns currently associated codec. Otherwise, sets the new codec in association. The STRING is the codec's package name, such as "Subtitles::Codec::srt".

dup [ CLEAR ]

Duplicates object instance in deep-copy fashion. If CLEAR flag is set, timeframes are not copied.

join GUEST, GAP

Adds content of object GUEST at the end of the list of subtitles with GAP in seconds.

length

Returns length of subtitle span.

load FH [ CODEC ]

Reads subtitle content into object. If successful, returns 1; otherwise undef is returned and $@ contains the error.

 

By default, tries to deduce which codec to use; to point the selection explicitly CODEC string is to be used.

lines

Returns number of subtitle cues.

new

Creates a new instance. To force a particular codec, supply "codec" string here.

parse_time STRING

Parses STRING which is either a "[[HH:]MM:]SS[,MSEC]" string or string in a format specific to a codec, for example, number of a frame.

rate FPS

Forces a particluar frame-per-second rate, if a codec can make use of it.

save FH

Writes content of instance into FH file handle, using the associated codec.

scale A

Changes time-scale. If A is 2, the subtitles go off 2 times slower, if 0.5 - two times faster, etc.

shift B

Shifts timings by B seconds. B can be negative.

split TIME

Splits the content of the instance between two newly created instances of the same class, by TIME, and returns these. The both resulting subtitles begin at time 0.

transform A, B [FROM, TO]

Applies linear transformation to the time-scale, such as "u = At + B" where "t" is the original time and "u" is the result. If FROM and TO brackets are set, the changes are applied only to the lines in the timeframe between these.

BUGS¶

This is alpha code, more a proof-of-concept rather that anything else, so most surely bugs are lurking. Anyway: not all subtitle types are recognized. The modules doesn't handle multi-language subtitles.

SEE ALSO¶

subs - command-line wrapper for this module

THANKS¶

<http://dvd.box.sk/>, <http://subs.2ya.com>.

AUTHOR¶

Dmitry Karasik, <dmitry@karasik.eu.org>.