Feature Request: Add metadata without encode

[tazlord]

Thank you for creating this wonderful tool.

I was unable to find any options that would allow you to modify/add metadata to a video file without encoding it. This type of feature would be very useful.

Maybe allowing a "copy" video codec and specifying the metadata as usual would be the easiest method? Specifying "copy" codec ignores any video encoding specific options.

Example for HDR HEVC: --codec copy --colormatrix <string> --colorprim <string> --transfer <string> --master-display <string> -i <input_file> -o <output_file>

Above options will disable encoding and produce a new file with metadata tags added/modified.

[villos]

parse hdr info to json with hdr10plus_parser and generate file again with hdr10plus_gen