README.md

• The script will write the tag to a new file with the same name, which will be created in 'jd\tmp' folder.
• If the tag is added successfully, the orignal file will be deleted and replaced with the temp file.
• 'youtube.com' is excluded, since JD adds the metadata to that host by default.
• Currently the script only processes 'mp4' files. Other filetypes which support the 'comment' tag can be whitelisted in the script.
• Periodically, check the 'jd\tmp' folder for any temp files which may have not be copied/deleted by the script and left behind.
• Please use the comment section below for feedback/queries.

script.js

/*
    add metadata to media files
    trigger : a download finished
*/

var hosts = ["youtubee.com"]; //exclude hosts
var exts = ["mp4"]; //include filetypes
var ext = link.name.split(".").reverse()[0];

if (
    link.finished &&
    hosts.indexOf(hosts) == -1 &&
    exts.indexOf(ext) > -1
) {
    var url = link.contentURL;
    var input = getPath(link.downloadPath);
    var output = getPath(JD_HOME + "/tmp/" + link.name);
    var ffmpeg = callAPI("config", "get", "org.jdownloader.controlling.ffmpeg.FFmpegSetup", null, "BinaryPath");

    callAsync(function(n) {
        if (n === 0) {
            input.delete();
            output.moveTo(link.package.downloadFolder);
        } else {
            output.delete();
        }
    }, ffmpeg, "-i", input, "-metadata", "comment=" + url, "-codec", "copy", output);
}