Video processing script

repair.py

#! python3

"""Video processing script.

Video is twice as slow as audio. Here we extract sequence at 12 FPS,
then encode a new one with 24 FPS using an original audio.
"""

import os
import shutil
import subprocess
import sys

try:
    vpath = os.path.abspath(sys.argv[1])
except IndexError:
    scriptname = os.path.basename(__file__)
    raise Exception("Usage\n\t{} input.flv".format(scriptname))

try:
    workdir, _ = os.path.splitext(vpath)
    os.mkdir(workdir)
except FileExistsError:
    raise Exception("Unable to create a fresh folder at " + workdir)

# Sequence extraction command.
spath = os.path.join(workdir, r"%05d.jpg")
sexec = [
    "ffmpeg",    # ffmpeg executable.
    "-i", vpath, # Bad video input.
    "-r", "12",  # Assumed framerate.
    "-q:v", "1", # Explode in maximum quality.
    spath        # Sequence output.
]

# Audio extraction command.
apath = os.path.join(workdir, "audio.aac")
aexec = [
    "ffmpeg",
    "-i", vpath,
    "-c:a", "copy", # Audio codec (no encode).
    apath           # Audio output.
]

# Encode command.
epath = workdir + ".mp4"
eexec = [
    "ffmpeg",
    "-framerate", "24",        # Desired framerate.
    "-i", spath,               # Sequence input.
    "-i", apath,               # Audio input.
    "-c:v", "libx264",         # Video codec.
    "-c:a", "aac",             # Audio codec (aac).
    "-strict", "experimental", # Enabling the aac codec.
    epath                      # Ecoded mp4 output.
]

# Run commands.
subprocess.call(sexec)
subprocess.call(aexec)
subprocess.call(eexec)

# Cleanup and finish.
shutil.rmtree(workdir)
os.system("pause")