The PSNR values are of varying usefulness, though at least
the DTS and AAC ones are useful with the right shift value.
Note: due to usage of floats some of these may fail on other
architectures.
In that case they should be converted into a CMD = stddev
FATE test, but it seems useful to try this way first.
Signed-off-by: NReimar Döffinger <Reimar.Doeffinger@gmx.de>