[mythtv] patch: Via HwDec Checks

[Kenneth Aafløy]

> while playing with changing channels and such, I have come across two
> points.
> 
> Could someone explain to me the fundamental difference 
> between if (osd)
> and if (osd != 0), as the former managed to slip a null 
> pointer through
> on my setup?

Forget this,

I'm: stupid stupid stupid .... (repeated 100 times).

The problem is that some code is overwriting MythTV's code somehow.
 
> On a malformed stream, the avformatdecoder:render_viaslice 
> could receive
> null pointers for s and/or src.

This is still valid though.

Also the videoout_viaslice:DrawSlice is not very well prepared for
invalid pointers, lengths, data. A patch will come when I feel that I've
done something right.

Kenneth