[mythtv-users] pvr-350, freeview and letterbox mode - how?

Graeme Wilford gwilford at gmail.com
Tue Aug 30 14:44:53 UTC 2005


On 29/08/05, John Risby <john at enville.demon.co.uk> wrote:
> hi all,
> having finally got my mythbox somewhere near replacing my tivo, one of
> the few things I need to fix is the aspect ratio. I want the tv to be
> displayed in letterbox mode. the source signal is a DVB (freeview) card.
> I also have a sky digibox on another input.

This is essentially what I'm doing although I have a cable box feeding
the 350 and my DVB-T card doesn't have an adequate aerial yet.
> I'm outputting via the tv out on the pvr-350 and the w key to change the
> aspect ratio does nothing at all.

For the record, are you using PS or TS as DVB stream? If I use TS,
then the output has to go via X (Xv in my case, using the 350 YUV
decoder) rather than using the 350's lovely mpeg2 decoder.

I'm wondering if the dropping of PS support in future MythTV versions
(it's already deprecated in SVN) will screw everyone with a 350 output
> is there anyway to get this working?

If you're outputting via the 350's mpeg2 decocer (ie. the DVB streams
are full-height with no de-interlace artifacts), then you can use
vbi-inserts to fix the aspect ratio.

You need to issue 'ivtvctl -w wss' and then you can manually change
the aspect ratio using the wss utility bundled with the ivtv driver
source. This utility will embed widescreen vbi in the 350's output
stream and force your TV into a widescreen mode.

However, the wss utility as shipped switches between 4:3 and "16:9
centred" mode which is effectively a zoom. I've changed this to switch
between 4:3 and "16:9 anamorphic" and have it tied to a remote button
press. Change line 53 of wss.c from:

        wss = 8 + (atol(argv[1]) ? 3 : 0);
        wss = 8 + (atol(argv[1]) ? 7 : 0);

Unfortunately, every time you ff/rw or jump out/in a recording, the
mode reverts back to 4:3. This is really annoying and I was working
with one of the ivtv devs on this for a while but we came to the
conclusion that MythTV is controlling the vbi/wss signals internally
as it doesn't happen when testing outside of Myth...

This issue also affects emedded vbi/wss signals recorded directly via
the 350's video input. You can turn on recording and embedding of wss
via 'ivtvctl -w wss -x 1 -b wss'. Playback of recordings send correct
aspect signals to the TV *until* you ff/rw or set a bookmark. After
that, playback for that recording defaults to 4:3 until you restart it
from the beginning again.

NB. I'm using ivtv 0.3.7g. The latest is 0.3.7k.
Me at google

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