Differences between CBR and VBR -- Looking for instructional documentation...

[Dave Draper]

Is there anywhere I can find detailed instructional documentation on the differences between CBR and VBR, what their parameters / sub-settings are responsible for, as well as how each setting should be configured when shooting with the 7D?

It confuses the heck out of me...

DD.

[1%]

on digic iv
'VBr' encodes at fixed qp and isn't really vbr.

Cbr adjusts qp via prediction on the fly.

2x rate just has prediction scaled up so it picks lower qps.

Read H.264 documentation if you aren't sure what that means.

[Dave Draper]

Many thanks for your reply, 1%.

Interesting that CBR isn't actually fixed on Digic IV.

So I'm guessing VBR is the way ahead for maximum picture quality on the 7D, right?

And excuse the ignorance, but what does "qp" stand for?

[1%]

the 'vbr' is just fixed quality. it will be the best image but the camera won't necessarily handle writing it out. cbr will switch qualities and hopefully stop it from stopping but ymMv

qp is quality in h264.

[Dave Draper]

Makes sense -- Thanks for the clarification!

If it's not asking too much, would you be willing to explain each option in the VBR menu, what they do, and what settings are recommended for whatever scene types?

[Dave Draper]

If not, is there anywhere I can read up on Magic Lantern's VBR settings?

[1%]

its just fixed quality vs predicted quality. "CBR" may do better on the run, VBR you'll have to test each scene and see if it stops.

guides are on here or magic lantern wikia (may be old)

[Dave Draper]

OK, cool -- many thanks.

What do the "Flush every" and "GOP size" settings do when in VBR mode?

I couldn't find these covered in the user guide.

[1%]

gop size sets just that. I set it to 3 for I/P and 1 for all I

flush rate is how fast it writes, not sure if you can have flush of 1 and gop of 3 on 7D, on 600D its one setting as far as i know (and have been able to use it).