4:4:4 - 4:1:1 - 4:2:1 - Explaination please ?

Interesting comparisons Graeme. Congratulations. As far as the Firefire/SDI transfer is considdered it is generally accepted to better stay in Firewire mode unless the player is part of an uncompresssed network (SDI routers, recorders...), or long lines are involved (SDI up to 300m). Quite often, in order to avoid decompression/recompression quality losses, DV footage is just being packaged (not decompressed nor upsampled) in an SDI compatible datastream (QSDI for Sony environments) for routing through an SDI infrastructure. B.t.w. how did you unsmooth the smoothed chroma?
 
I don't unsmooth smoothed chroma! I smooth unsmoothed chroma!

SDI is useful for all the reasons you mention. Firewire is however best for 99% of uses of DV.

Graeme
 
Thanks for the many interesting awnsers and links. Even the "who cares" joke is an awnser worth considering. A lot of this technical information is not very important to make a good image. But I just get really pissed off when I don't know the way things work.

It is still a bit confusing for the moment. Would I actually see this 4 pixel group compression result if I was to zoom in all the way in photoshop for example ?

Anyway Ill go read the different web links and ill come back here with more questions , see ya soon...

-sfx
 
It all depends on how the codec presents the chroma sampling informatio to you, but the chances are that yes, on a large colour contrast, you'll see the blockyness if you zoom in - see my white paper for examples thereof.

Graeme
 
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