[mythtv] Resync to ffmpeg 4.0

[David Engel]

On Thu, May 31, 2018 at 05:07:20PM +1200, OpenMedia Support wrote:
> Will we be able to enable some new features like NVDEC via this sync?
> 
> It would be great to see some better deinterlace support for VAAPI as well

The reason for the resync to ffmpeg 4.0 is for Android MediaCodec
support.  I know of no other specific plans beyond that at this time.
However, updating our VAAPI support to get the better deinterlacers
would be nice.  We don't currently use ffmpeg for VAAPI, so that would
likely require a complete rewrite.  I haven't seen any demand yet for
NVDEC support, but then, I haven't looked for it either.

As always, patches and pontential, new developers are welcome.

David
-- 
David Engel
david at istwok.net