Make the ytdl-format flag usable

[bugboy-20]

As far as I looked the only way to pass the --ytdl-format flag is write it in the /tmp/file-local-options.txt by hand and reload the video.
When mpv is started with this flag it's ignored (also if written down in the config file)
I guess the 'official' way to add it in the POST /api/v1/playlist request, but the app doesn't do this, and in my opinion it's ok: it's more likely a flag you tune once per server ...or at least this is my use case

Why this is important in my usecase?
I'm using mpv on an old PC connected to a 1080p display and the PC became very laggy when try to 4K video. Moreover some videos on the internet have multiple audio tracks (e.g. this) and makes no sense for me listen them in English while I can understand the original version.

The easiest solution could be to add ytdl-format to every file if defined in the mpv's config file. If you like the idea but you're not interested in coding it I could make a PR.

[husudosu]

Hey there,
Yeah it makes sense, if you can implement it please go ahead and raise a PR. Unfortunately I don't have time to maintain this project anymore.

[bugboy-20]

if you can implement it please go ahead and raise a PR

Ok, I will

Unfortunately I don't have time to maintain this project anymore.

It's terrible news.

Edit: reformatting