[mythtv-users] Transcoding and deinterlacing, and other transcode issues

Brad Templeton brad+myth at templetons.com
Tue Jun 13 23:20:38 UTC 2006


I'm trying to set up transode profiles for some HD needs.

a)

One thing that is surprising me is that when I attempt to transcode
a 720p program which was upsampled from SD for broadcast, and I use
a profile that does not turn on the interlace handlers (are there
some docs on what they do) the resulting recording mythtv sees as
interlaced.   It's 864x480 (with pillarbox bars) and when mythtv
starts and stops playing it says it's interlaced now and looks like
it could be.   Is there a good testing software to verify this?

b) I want transcodes that actually de-interlace.  In particular one
for 1080i to 720p or 1280x540p, which are good resolutions to
shrink 1080i for if your TV is a 720p, like most HDTVs.


c) I notice that once a recording is old, it vanishes from the 'record'
table where the 'transcoder' field would have been set for it.  The
'recorded' table does not remember this, so if you transcode an old
recording you are going to get the system default.  Or you can
manually pick one but that does not allow the use of extended ones
nor could I get it to work reliably. 


When it comes to interlace, ideally I would hope mythtranscode
might be able to tell if a recording is interlaced, and figure
out what to do, ie. whether to deinterlace, or whether to transcode
interlaced with various tricks.   On progressive recordings it would
of course not do those things.


Is there documentation for the filters that can be applied in
transcode profiles?  Which tool's filter sets are they?



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