autohighlights/basicclips.py

#!/bin/python3
""" basicclips.py -- generate video of clips from another video
    uses ffprobe, ffmpeg and MELT

"""

DEFAULT_CLIPS = 9
DEFAULT_DURATION = 15
DEFAULT_MIXER_DURATION = 2
FRAMERATE = 60


def get_video_duration(videofile=None):
    """Get video duration in seconds using ffprobe"""
    import subprocess

    if videofile is not None:
        ffprobe_args = ["ffprobe", "-v", "error", "-show_entries",
                        "format=duration", "-of",
                        "default=noprint_wrappers=1:nokey=1",
                        videofile]
        seconds = subprocess.run(ffprobe_args, capture_output=True)
        if seconds:
            try:
                seconds = int(float(seconds.stdout))
                return seconds
            except ValueError as e:
                print("Error getting seconds for ", videofile)
                print(e)


if __name__ == "__main__":
    import sys
    import os
    import tempfile
    import subprocess

    # Check/set settings using env vars

    if os.environ.get("HIGHLIGHT_CLIPS"):
        clips = os.environ.get("HIGHLIGHT_CLIPS")
    else:
        clips = DEFAULT_CLIPS

    if os.environ.get("HIGHLIGHT_DURATION"):
        duration = os.environ.get("HIGHLIGHT_DURATION")
    else:
        duration = DEFAULT_DURATION

    # TODO: argv sanity checks

    videofile = sys.argv[1]
    outputfile = sys.argv[2]

    video_duration = get_video_duration(videofile)
    mixer_duration = FRAMERATE * DEFAULT_MIXER_DURATION

    ffmpeg_common_args = ["ffmpeg", "-hide_banner",
                          "-loglevel", "quiet"]
    melt_args = []

    with tempfile.TemporaryDirectory() as tmpdir:
        tempclip_length = duration - 3

        for i in range(1, clips+1):
            print("Processing clip", i)
            seek = int(float(video_duration * i / float(clips+1)))

            if i == 1:
                # no intro mixer on first clip
                melt_args.extend(["melt",
                                  os.path.join(tmpdir, "hi{}.mkv".format(i))])
            else:
                melt_args.extend([os.path.join(tmpdir, "hi{}.mkv".format(i)),
                                  "-mix", str(mixer_duration),
                                  "-mixer", "luma"])
            ffmpeg_args = ffmpeg_common_args + [
                "-ss", str(seek),
                "-i", videofile, "-t", str(tempclip_length),
                "-c", "copy", os.path.join(tmpdir, "hi{}.mkv".format(i))
            ]
            print(ffmpeg_args)
            subprocess.run(ffmpeg_args)

        # MELT output format
        melt_args.extend(["-consumer", "avformat:{}".format(outputfile),
                          "crf=20"])
        print(melt_args)
        subprocess.run(melt_args)

    print("Done!")