[mythtv] Refresh rate reported by frontend when playing 1080i content at 1080i at 60Hz?

[Tom Dexter]

This is something that's confused me for some time.  I have a RPCRT TV
and have X setup for 1080i at 60Hz.

I was curious as to why the frontend reports a refresh rate of 33333
(30 Hz) when playing interlaced content (1080i broadcasts) rather
than 16666 (60 Hz).  When playing 720p content it reports 60 Hz.

I'm one of several on the users list who are using a hack similar to this:

http://svn.mythtv.org/trac/ticket/2903

...to change that in order to allow the use of bob de-interlacing.
(Note that the patch listed there has a '&&' that's intended to be a
bitwise '&').  When the frontend reports a 30Hz refresh rate, it
disallows the use of bob.

I keep reading that bob shouldn't be used on an interlaced display.
However, barring nVidia someday actually fixing the horribly broken
interlaced output of their Linux drivers and thus making
de-interlacing unnecessary, I've found without question that bob
de-interlacing produces by far the best playback of 1080i content I've
been able to get in MythTV.  Othres have found the same.  It also
seems to use less CPU than kerndeint.

Mind you, I'm admittedly not very knowledgeable on the technical
aspects of video..so I may not understand the answer :D.  None the
less, I'm curious as to why that reports 30Hz.

Thanks in advance.

Tom