Support rotating subtitles along with video

[petzku]

Expected behavior of the wanted feature

Somewhat related to #6400, but I believe this is a separate concern.

Rotating video currently does not rotate subtitles. This is generally desirable for dialogue text, but for on-screen text rendered diegetically ("Typesetting" or "TS"), it would be more desirable to follow the video. Images below taken from (at time of writing, unreleased) [Kaleido-subs] Blue Archive episode 10.

Normal display

With video-rotate=180

Enabling this for all rendering schemes is probably not a good idea. However, libass has been working towards a "split rendering" system, where TS and dialogue could be rendered in different passes. This could be a good fit as a solution of sorts.

Alternative behavior of the wanted feature

No response

Log File

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Sample Files

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