create a series of FFMPEG commands to 1) trim video/audio from a source 2) add audio/video fade in, fade out

create_ffmpeg_commands.py

#!/bin/env python3

import os

current_dir = os.path.dirname(os.path.realpath(__file__))
source = 'my_ProRes.mov'

ffmpeg_command_template = ( 'ffmpeg \\\n'
'-loop 1 -r {fps} -t 5 -i black.jpg \\\n'
'-ss {start} -r {fps} \\\n'
'-i $SOURCE -t 00:00:{duration}.000 \\\n'
'-vcodec libx264 -pix_fmt yuv420p \\\n'
'-movflags +faststart -preset slower \\\n'
'-color_primaries bt709 -color_trc bt709 -colorspace bt709 \\\n'
'-tune animation \\\n'
'-filter_complex \\\n'
'"[1]fade=t=in:st=0:d=2,fade=t=out:st={dissolve_start}:d={dissolve_length}" \\\n'
'-filter_complex \\\n'
'"afade=in:st=0:d=2,afade=out:st={dissolve_start}:d={dissolve_length}" \\\n'
'-y \\\n'
'minicuts/{name}.mp4'
)

def main():
    with open(os.path.join(current_dir, "cut_list.txt"), "r") as f:
        lines = f.readlines()

    dissolve_length = 2

    commands = []
    for i, line in enumerate(lines):
        if "#" in line:
            continue
        name, start, duration = line.replace("\n", "").split(",")
        num = str(i + 1).zfill(2)
        dissolve_start = int(duration) - dissolve_length
        commands.append(f"echo 'encoding cut {num}..'")
        commands.append(
                ffmpeg_command_template.format(start=start,
                                               duration=duration,
                                               dissolve_start=dissolve_start,
                                               dissolve_length=dissolve_length,
                                               fps=25,
                                               name=name))

    with open(os.path.join(current_dir, "ffmpeg_cut.sh"), "w") as f:
        f.write("#!/bin/bash\n")
        f.write(f"export SOURCE={source}\n")
        f.write("\n".join(commands))
        f.write("\n")

if __name__ == "__main__":
    main()

cut_list.txt

longcut01,00:00:35.000,47
longcut02,00:02:06.000,25