Render options have no effect on render quality

@bazza, I tried your options on this image:

and also had no quality deteriorations.

But on this image:

I get bad video quality even with your settings.
Could you please also convert the last image with your settings to see how it goes?

MP4 requires big capacity of CPU/GPU for the compression maybe your computer was not the sufficiently good.
Another option is that it was by that you do not use wonderful GNU/linux :stuck_out_tongue:

try with MPEG