Make playlist/N/title writable

Expected behavior of the wanted feature

When playing a playlist of URLs via ytdl-hook, it would be nice if there was a way to pre-load the titles of the videos that these URLs point to and display them in playlist visualizations, e.g. F8 or other OSCs. To achieve this, playlist/N/title should be writable so that a script can pre-load the titles using ytdl itself and then set them in MPV directly.

References:

• playlistmanager.lua achieves this functionality by rendering a custom playlist instead of reading playlist/N/title.
• Mentioned as a potential feature addition in https://github.com/mpv-player/mpv/issues/9288#issuecomment-1530437813
• Required for https://github.com/tomasklaen/uosc/issues/472.
• https://github.com/tomasklaen/uosc/issues/1018 appends items to the playlist by providing them in M3U format with EXTINF for the title.

Alternative behavior of the wanted feature

ytdl_hook.lua could implement this feature natively to request and set URL titles directly on playlist load. It probably makes sense to only do this for titles that start with something that would be passed to ytdl and that does not have an explicitly set title yet, e.g. via M3U EXTINF.

This does not make the initial feature request redundant, however.

Log File

No response

Sample Files

Just copy a few random URLs from YouTube or similar to a file and open them via mpv --playlist=file.txt.

Start by tracing the playlist/N/title property and the ytdl_hook.lua entry point, then reproduce the case with mpv --playlist=file.txt using URLs whose titles are not preloaded. Compare the existing playlistmanager.lua behavior and verify that writable titles appear in playlist visualizations without replacing explicitly set titles.