frames-to-spans.py

#!/usr/bin/env python

import sys
from os.path import splitext

def write_range(start, end, handle):
    if start == end:
        handle.write("{0}\n".format(start))
    elif end < 0:
        pass
    else:
        handle.write("{0},{1}\n".format(start, end))

try:
    file_in = sys.argv[1]
except IndexError:
    print("Usage: {0} [file with list of combed frames]".format(sys.argv[0]))
    raise SystemExit

last = -9
start = 0

fparts = splitext(file_in)
file_out = "{0}-range{1}".format(fparts[0], fparts[1])

try:
    with open(file_in) as in_f:
        try:
            with open(file_out, 'w') as o:
                for line in in_f:
                    curr = int(line)
                    if curr - last > 4:
                        write_range(start, last, o)
                        start = curr
                    last = curr
                write_range(start, last, o)
        except IOError:
            print("Cannot open {0} for writing.".format(file_out))
            raise SystemExit
except IOError:
    print("Cannot open: {0}".format(file_in))
    raise SystemExit