[mythtv] Stretching to 16:9 ?

Mark J. Titorenko mythtv-dev at titorenko.net
Tue Sep 30 16:35:43 EDT 2003

On Mon, Sep 29, 2003 at 12:54:41PM +0100, Edward Wildgoose wrote:
> > > Hello Kristof,
> > > 
> > > Have  you  tried  the  strange widescreen mode thingie that's a fix for BBCs DVB
> > > broadcasts?  Check keys.txt, and I guess you need the CVS, think it got in after
> > > 0.11.
> > > 
> > 
> > Does this fix broadcasts that are what me and my flat-mates would call
> > "4:3 broadcast in widescreen", i.e. when you have black bars all round a
> > picture?
> Sadly not.  I'm not quite sure what the point of the new mode in CVS
> is?  It appears (at least on my system) to only offer a mode to
> stretch the picture to full height, but without altering the width.

I added the 16:9/4:3 toggle patch to cope with the following case:

I have my digital STB set to "show widescreen picture as 16:9"
(ie. anamorphic widescreen).  This is as opposed to "show widescreen
picture as 4:3 letterbox" (ie. letterbox widescreen). This causes the
picture to be displayed as a 16:9 image whether the destination is a
4:3 TV, 4:3 capture card (DC10+) or 16:9 TV.

4:3 devices display a vertically squashed picture, 16:9 devices
display a widescreen picture.

When myth is playing back a 16:9 video captured on my 4:3 capture
device to be displayed on a 16:9 device all is well and good because I
can set the device to 16:9 mode (eg. my widescreen TV).  However when
displaying the picture on a 4:3 device (eg. my monitor) I get a
vertically squashed picture.

In short: I added the mode so that I can squash the picture vertically
from 4:3 to 16:9 and display the widescreen picture on my 4:3 display
device with black bars at the top and bottom.

There's some excellent information about letter-box and anamorphic
widescreen at

> So for the funny PAL DVB broadcasts I now see black bars left and
> right, and everyone is stretched tall and thin...  The code doesn't
> seem to change the width and effectively zoom into the center of the
> black rectangle.  Is this intended behaviour?  Happy to try and dig
> in and add a third mode, but I wasn't sure if this other mode was
> being used by someone else at the moment?

A third mode, such as "zoom to 4:3" sounds like a good plan to me.



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