[PD] (GEM) mjpeg decoding performance question

[Matteo Sisti Sette]

Hi,

I'm trying to find the codec with best performance to use with gem in 
Ubuntu.

Up to now the best I've found is MJPEG, but the funny thing is that if I 
code the file myself with MJPEG using Avidemux, I get much better 
performance than with a file also coded with MJPEG that I was given.

What can it be due to? When I code the file with MJPEG the only 
parameter I can change is "quality"

Does it depend entirely on the quality setting, or is it possible that 
different implementations of the encoder encode in such a way that it is 
then more or less expensive for the decoder to decode?

thanks
m.