Simple python script to encode videos using ffmpeg

encode.py

"""
This python script encodes all files that have the extension mkv in the current
working directory.

Sources:
    http://ffmpeg.org/trac/ffmpeg/wiki/x264EncodingGuide
"""
import subprocess, os

#-------------------------------------------------------------------------------
# CONFIGURABLE SETTINGS
#-------------------------------------------------------------------------------

# controls the quality of the encode
CRF_VALUE = '21'

# h.264 profile
PROFILE = 'high'

# encoding speed:compression ratio
PRESET = 'fast'

# path to ffmpeg bin
FFMPEG_PATH = '/usr/local/bin/ffmpeg'

# font dir
FONT_DIR = '/var/www/.fonts'

#-------------------------------------------------------------------------------
# encoding script
#-------------------------------------------------------------------------------

def process():
    cwd = os.getcwd()

    # get a list of files that have the extension mkv
    filelist = filter(lambda f: f.split('.')[-1] == 'mkv', os.listdir(cwd))
    filelist = sorted(filelist)

    # encode each file
    for file in filelist:
        encode(file)


def encode(file):
    name = ''.join(file.split('.')[:-1])
    subtitles = 'temp.ass'.format(name)
    output = '{}.mp4'.format(name)

    try:
        command = [
            FFMPEG_PATH, '-i', file,
            '-c:v', 'libx264', '-tune', 'animation', '-preset', PRESET, '-profile:v', PROFILE, '-crf', CRF_VALUE,
        ]

        # create a folder called attachments and symlink it to FONT_DIR
        # extract attachments
        subprocess.call(['mkdir', 'attachments'])
        subprocess.call(['rm', '-f', FONT_DIR])
        subprocess.call(['ln', '-s', '{}/attachments'.format(os.getcwd()), FONT_DIR])

        os.chdir('attachments')

        subprocess.call([FFMPEG_PATH, '-dump_attachment:t', '', '-i', '../{}'.format(file)])

        os.chdir('..')

        # extract ass subtitles and and subtitle into command
        subprocess.call([FFMPEG_PATH, '-i', file, subtitles])
        if os.path.getsize(subtitles) > 0:
            command += ['-vf', 'ass={}'.format(subtitles)]

        command += ['-c:a', 'copy']             # if audio is using AAC copy it - else encode it
        command += ['-threads', '8', output]    # add threads and output
        subprocess.call(command)                # encode the video!

    finally:
        # always cleanup even if there are errors
        subprocess.call(['rm', '-fr', 'attachments'])
        subprocess.call(['rm', '-f', FONT_DIR])
        subprocess.call(['rm', '-f', subtitles])


if __name__ == "__main__":
    process()

Thanks for the script.

Can it be modified to look for a keyword string in the first part of the file name? I want to decode only files that have "x265" in the name (e.g. "The.Invisible.Man.x265.DD5.1.mkv").

I assume the modification would center around this line in the script:
filelist = filter(lambda f: f.split('.')[-1] == 'mkv', os.listdir(cwd))

I looked on the web and couldn't find much, and trial and error resulted in only errors. Any help you can offer would be appreciated!

Can it be modified to look for a keyword string in the first part of the file name? I want to decode only files that have "x265" in the name (e.g. "The.Invisible.Man.x265.DD5.1.mkv").
I assume the modification would center around this line in the script:
filelist = filter(lambda f: f.split('.')[-1] == 'mkv', os.listdir(cwd))

for future reference, this would be filter(lambda f: 'x265' in f and f.split('.')[-1] == 'mkv', os.listdir(cwd))
or, using list comprehension, filelist = [f for f in os.listdir(cwd) if 'x265' in f and f.split('.')[-1] == 'mkv']