[vdr] Aspect Ratio problems

Mike Parker vdr at msatt.freeserve.co.uk
Sat Sep 3 13:33:02 CEST 2005


----- Original Message ----- 
From: "Jon Burgess" <jburgess at uklinux.net>
To: "Klaus Schmidinger's VDR" <vdr at linuxtv.org>
Sent: Friday, September 02, 2005 8:47 PM
Subject: Re: [vdr] Aspect Ratio problems


> Mike Parker wrote:
> > Thanks for the Help Darren.
> >
> > By squashed I mean that the TV is showing a 'full' picture which is not
in
> > the correct aspect ratio, no pillar boxing.
> > When a 4:3 is being transmitted I have to switch my TV into 4:3 mode and
the
> > tv puts in its own blank sides and the picture is correct.
> > Watched bbc3 Apprentice last night, it shows pillar-boxing and no change
is
> > necessary, but surely that is 16:9 in stream (I did not check) so it
should
> > look ok anyway.
>
> I recorded that program, it was broadcast as 16:9 stream containing
> pillar-boxed 4:3 content. If you have a 16:9 TV then you are correct, it
> will look OK without VDR or the TV doing any kind of proceeing on the
video.
>
> > The problem is when a 4:3 stream is being sent and dbv is set to 16:9,
the
> > 4:3 picture is sent to my tv in 16:9 format and the tv does not
> > automatically switch.
>
> I have a 4:3 TV and use a DXR3 card for my display so I can't be certain
> about the capabilities of the FF card, but here is what I can tell you
> about what I believe should happen.
>
> A true 4:3 video stream obviously doesn't have the black borders to make
> it look right on a 16:9 TV so something needs to add them. I believe
> what is meant to happen is that the TV gets instructed to switch into
> the 4:3 mode in one of two ways:
>
> - Signalling via SCART pin 8 which probably isn't applicable since even
> if you use some s-video to scart conveter then this pin will not be
> driven by the FF card. (see this link for some information on SCART
> http://en.wikipedia.org/wiki/SCART )
>
> - Widescreen Signalling (WSS), which is a special signal embedded in one
> of the offscreen lines of the picture much like the old TeleText system.
> ( see http://en.wikipedia.org/wiki/Widescreen_signaling ). I think this
> can either be delivered inside the original video stream by the
> broadcaster or be inserted by the playback card (I'm not sure if the FF
> is in this category).
>
> > Is this a vdr / driver problem?
>
> Sorry I can't help here. Other possibilities include the video stream
> not including the WSS signal or your TV perhaps not obeying the WSS.
> Occasionally broadcasters have even been known to flag 4:3 programs as
> 16:9 by mistake.
>
> Jon
>
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>
Hi Jon

Just like to say thank you for taking the time to reply about the Aspect
Ratio problem with vdr/tv.

The TV is about 4 months old (42" LG plasma) so pretty upto date. If I watch
an analog tranmsission the tv switches correctly, or inserts blanks down
side etc.

I am using composite out of the FF card so pin 8 is not a viable solution.

So that leads us to WSS - which I assume the tv does support as it appears
to switch correctly on analogue.

It seems to me that setting 16:9 or 4:3 in vdr setup sets the output at that
and WSS does not occur. I assume vdr needs this info for handling OSD etc.

I have replied off list due to the 'noise' generated by quoting ;-)

Thanks once again - I will keep on investigating.

Mike






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