New add-subtitle command for inserting individual subtitle lines in memory

Expected behavior of the wanted feature

Coming from: https://github.com/ripose-jp/Memento/issues/176

I wanted to know it if possible to create a new add-subtitle command for inserting subtitles into tracks.

With current use of Auto-Speech-Recognition (ASR) systems and their improvements there are many mpv-based (and not mpv-based) programs that add some ability to do ASR on-the-fly with either local models or API services.

e.g. LLPlayer and whisper-subs, and the issue I've linked.

whisper-mpv and current memento's approach rely on writing subtitles into a file, and repeatedly using the sub-reload command. to update the subtitle list.

This isn't a bad solution, but having subtitles already in-memory means it would be simpler if you could insert them into a subtitle track directly.

Additionally, similar commands could include:

• remove-subtitle for removing a subtitle line
• edit-subtitle for editing a subtitle line
• clear-subtitles to empty clear an entire subtitle track contents

The benefit would be that mpv-based clients could implement ASR solutions in-memory without invoking I/O read/write.

I couldn't find it it either in the feature or the scripts in the wiki.
So sorry if I'm asking for an existing/requested feature.

Alternative behavior of the wanted feature

No response

Log File

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Sample Files

No response

Start by reading the existing sub-reload command and the feature or scripts documentation referenced in the issue. Define the behavior and scope of add-subtitle, including how an in-memory subtitle line is selected and inserted, before considering the related remove, edit, and clear commands. Done means the requested command is implemented and its behavior is documented and verifiable.