convert.py

#! python3

"""Video processing script.

Call repair.py for all .flv videos in working directory. Three months of
processing later, concatenate videos in working directory by name.
(inb4: traceback at the middle of the night.)
"""

import itertools
import os
import subprocess
import sys

workdir = os.path.dirname(__file__)

# Convert videos to mp4.
files = [os.path.abspath(f) for f in os.listdir(workdir)]
vids =  [f for f in files if os.path.splitext(f)[1] == ".flv"]
for vid in vids:
    script = os.path.abspath("repair.py")
    subprocess.call([script, vid], shell=True)

# Concatenate output by weeks.
files = [os.path.abspath(f) for f in os.listdir(workdir)]
vids =  [f for f in files if os.path.splitext(f)[1] == ".mp4"]

def sorter(path):
    """Sort lectures ans critiques vids by week."""
    path = os.path.basename(path)
    return path[:11] if "Critiques" in path else path[0]

vids = sorted(vids, key=sorter)
groups = itertools.groupby(vids, sorter)

for group, vids in groups:
    vids = list(vids)

    # Generate a list file containing all videos to concatenate.
    listfile = os.path.join(workdir, group)
    with open(listfile, "w") as f:
        for vid in vids:
            line = "file '{}'".format(vid)
            print(line, file=f)

    output = group + ".mp4"
    cexec = [
        "ffmpeg",
        "-f", "concat",
        "-i", listfile,
        "-c", "copy",
        output
    ]

    subprocess.call(cexec)
    os.remove(listfile)

# Finish script and wait when I wake up.
os.system("pause")

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)