TLS is a headache. We should avoid it if we can.
The involved mechanism is unfortunately entangled with the unfortunate
libmpv API for returning pointers to host API objects. This has to be
kept until we change the API somehow.
Practically untested out of pure laziness. I'm sure I'll get a bunch of
reports if it's broken.
The video code can deal fine with feeding software image formats to
hwdec interop drivers. In RPI's case, this is preferable for
performance, working around OpenGL bugs (see RPI firmware issue #666),
and because OpenGL rendering doesn't bring too many advantages due to
RPI supporting GLES 2.0 only.
Maybe a way to force the normal video path is needed later. But
currently, this can be tested by just not loading the hwdec interop
driver.
If you run command-line mpv and set --hwdec to something that does
not load the RPI interop layer, you'll even have to use --hwdec-preload
manually to get it enabled.
This overlay support specifically skips the OpenGL rendering chain, and
uses GL rendering only for OSD/subtitles. This is for devices which
don't have performant GL support.
hwdec_rpi.c contains code ported from vo_rpi.c. vo_rpi.c is going to be
deprecated. I left in the code for uploading sw surfaces (as it might
be slightly more efficient for rendering sw decoded video), although
it's dead code for now.
