[mythtv] Stretching to 16:9 ?

[Kristof Pelckmans]

Hello everyone,

I got up to the point where I have MythTV properly configured. The only
annoyance that I still have is the support of Pal plus. This is a 16/9
format squeezed in a 4:3 PAL signal. The signal is encoded so that original 4:3
TVs will display the 16:9 with black bars above and below the screen :

Situation 1 : 16:9 on native 4:3
*********
*-------*
*       *
*-------*
*********

Only true Pal plus decoders will use the information that is hidden in the black
bars to produce a real 16:9 image when displayed on a 16:9 screen :

Situation 2 : decoded 16:9 pal plus on native 16:9
*************
*           *
*           *
*           *
*************

Of course, regular 4:3 programs will be displayed with black bars on the left
and right side :

Situation 3 : 4:3 on native 16:9
*************
* |       | *
* |       | *
* |       | *
*************

I force MythTV (including all menus) in 4:3 mode on my 16:9 screen. However,
this gives the following result with Pal plus programs :

Situation 4 : 4:3 (with 16:9 inside) on a native 16:9
*************
* --------- *
* |       | *
* --------- *
*************

Let me explain why :
There is no card that does pal plus decoding, so MythTV always thinks it sees a
full 4:3 screen, even when there are black bars above and beyond the screen.

The solution ?
First of all, getting the full quality of a 16:9 pal plus image is never
possible, since the TV card is not able to decode the pal plus information. The
only solution here is stretching the image (without changing the size of the 4:3
recording). There is no way of knowing on forehand which image needs to be
stretched, so the only way of controlling the behaviour is to add this
functionality to a button on the remote control. I guess this could be done
using the XV extensions.

Another issue to look at is whether the frontend buttons cannot be shown on a
16:9 screen without being stretched to ovals. I guess this has something to do
with the window layout of QT.

Could somebody point me out where I have to look in the code to make some
adjustments and tell me whether XV would do the job ?

Greetz,

Kristof