[mythtv-users] Loosen auto-swap from interlaced to progressive, but not vice versa?

Steven Adeff adeffs.mythtv at gmail.com
Wed Feb 25 00:47:05 UTC 2009

On Tue, Feb 24, 2009 at 6:49 PM, Yeechang Lee <ylee at pobox.com> wrote:
> I'd like to revisit an issue that has come up several times over the
> years.[1] The issue is video streams with both interlaced and
> (allegedly) progressive frames, and the problems such mixing causes.
> As Daniel Kristjansson points out while closing ticket #2429, the real
> solution is for broadcasters to not send out such abominations in the
> first place. In my experience, though, the problem isn't so much that
> mythfrontend doesn't deinterlace frames mistakenly marked as
> progressive. It is that in many cases interlaced and progressive
> frames alternate so quickly that mythfrontend is constantly jumping
> between interlacing and not.[2] This is where the real problem with
> playback comes from. As far as I know no one out there puts interlaced
> frames in otherwise progressive streams but the other way around is,
> again, far too common.


I remember a few years back, the WB in Boston (probably in its last
year in broadcasting) had some really random pattern they used for all
their shows. It played havoc with trying to re-encode for archival.
anyway, in trying to figure out what was going on with their original
encode I noticed that the same issue manifested itself when watching
through the cable box and the TV's internal tuner as well as through
the PC. None of the devices were able to properly handle it. It looked
a little funny watching too, but I guess not enough people were
complaining to make them fix it.

point being: this may just be an issue where users need to complain to
the broadcasters that their broadcast looks like carp because their
TV/cable box/etc can't properly render the image.

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