Should vlc_preparser_t and vlc_thumbnailer_t share the same input_thread_t ?

Hello, while working on !3503, I just realized that parser and thumbnailer could share the same context, but it's not done in the core.

Do you think it's worth it to share the same input_thread_t for thumbnailing and preparsing ? Are there some known limitations by using one single instance for both ?

If so, we could easily merge both Core API into one.

As an alternative, we can use one single API for libVLC and take care of the Core later.