Ffmpeg.py

#!/usr/bin/env python2
# encoding: utf-8
"""
Ffmpeg.py

Created by Ichabond on 2012-07-01.
Copyright (c) 2012 Baconseed. All rights reserved.
"""

import os
import subprocess
import sys
import re

from tempfile import mkdtemp
from hashlib import md5


class FFMpeg(object):
    def __init__(self, filepath):
        self.file = filepath
        self.ffmpeg = None
        self.duration = None
        self.tempdir = mkdtemp(prefix="pythonbits-") + os.sep

    def getDuration(self):
        try:
            self.ffmpeg = subprocess.Popen([r"ffmpeg", "-i", self.file], stdout=subprocess.PIPE,
                                           stderr=subprocess.STDOUT)
        except OSError:
            sys.stderr.write(
                "Error: Ffmpeg not installed, refer to http://www.ffmpeg.org/download.html for installation")
            exit(1)
        ffmpeg_out = self.ffmpeg.stdout.read()
        ffmpeg_duration = re.findall(r'Duration:\D(\d{2}):(\d{2}):(\d{2})', ffmpeg_out)
        if not ffmpeg_duration:
            # the odds of a filename collision on an md5 digest are very small
            out_fn = '%s.txt' % md5(ffmpeg_out).hexdigest()
            err_f = open(out_fn, 'wb')
            err_f.write(ffmpeg_out)
            err_f.close()
            err_msg = ("Expected ffmpeg to mention 'Duration' but it did not;\n" +
                       "Please copy the contents of '%s' to http://pastebin.com/\n" +
                       " and send the pastebin link to the bB forum.") % out_fn
            sys.stderr.write(err_msg)
        dur = ffmpeg_duration[0]
        dur_hh = int(dur[0])
        dur_mm = int(dur[1])
        dur_ss = int(dur[2])
        self.duration = dur_hh * 3600 + dur_mm * 60 + dur_ss

    def takeScreenshots(self, shots):
        self.getDuration()
        stops = range(20, 81, 60 / (shots - 1))
        imgs = []
        try:
            for stop in stops:
                imgs.append(self.tempdir + "screen%s.png" % stop)
                subprocess.Popen([r"ffmpeg", "-ss", str((self.duration * stop) / 100), "-i", self.file, "-vframes", "1",
                                  "-y", "-f", "image2", "-vf", """scale='max(sar,1)*iw':'max(1/sar,1)*ih'""", imgs[-1]],
                                 stdout=subprocess.PIPE, stderr=subprocess.STDOUT).communicate()
        except OSError:
            sys.stderr.write(
                "Error: Ffmpeg not installed, refer to http://www.ffmpeg.org/download.html for installation")
            exit(1)
        return imgs