Examples/docs request: subtitle processing

[DaniGuardiola]

I'd like to implement processing of subtitles, and it seems like this library provides many excellent primitives for it! However, it's a bit hard for a newcomer to tell how to properly handle them for purposes such as converting into VTT cues and similar use cases. The demo code is very old and hard to parse, and the documentation is scarce.

I'd specifically love examples and documentation around:

• Extracting cue text and other metadata from samples.
• Converting into VTT, potentially including other data like styles (if that's even possible?).
• Extracting subtitle metadata such as language, labels, etc.
• Clear streaming, seeking, etc examples/docs.

Thank you for your time and for the excellent library!