25p from Canon 5DmII to MXF 50i , is that okay?

marcel-vossen wrote on 5/19/2010, 2:48 AM
Hi there

Since Vegas can't handle my MOV files from the 5DmII very well, I render all my files to Sony MXF using the HD EX 1920x1080 50i setting, since there is no 25p available to choose.

Can anyone tell me if converting 25p footage into 50i has any disadvantages? As far as i can see it looks great!

Marcel

Comments

farss wrote on 5/19/2010, 5:02 AM
"since there is no 25p available to choose."

From memory there's no template for that as such but you can roll your own custom template no problem.

Bob.
marcel-vossen wrote on 5/19/2010, 6:34 AM
Hi Bob

Thanks for your answer!

Would the only difference be to change the field order from 'upper field first' to 'progressive'? The 50i template already has 25 frames/second.

Whats the difference, what can I expect when I use 50i to render all my footage to, since I've already done this for a large number of clips...

Thanks
farss wrote on 5/19/2010, 6:41 AM
"Would the only difference be to change the field order from 'upper field first' to 'progressive'?"
Yes, that'll do it.

"Whats the difference, what can I expect when I use 50i to render all my footage to, since I've already done this for a large number of clips..."

Not much really. What should happen is Vegas will split every frame into two fields to give what is 25PsF50. When you bring it back onto the T/L you can change the media's field order to None (Progressive) and it (Vegas) will merge the two fields it created from the original frame back into one frame.

Bob.

Laurence wrote on 5/19/2010, 8:32 AM
There's no visual difference between 25p footage stored as 25p and 25p footage stored as 50i. It can make a difference in smart-rendering. For instance if you have a 50i project and you flag the 25p footage as 50i, those sections will smart-render into a 50i project rather than rerendering. It might also make a difference in how some deinterlacers handle the footage, though these days most deinterlace algorithms do their own analysis and base what they do on that and not the video playback flags.
marcel-vossen wrote on 5/20/2010, 1:10 AM
Hi guys thanks for the answers!

I tested some stuff and found out that I definately need to render to 50i and NOT make my own preset using the 50i default and change the field order from upper field first to progressive. When I do this, my output MXF files have flashes in them where the screen turns black for a split second.

And when I let Vegas detect what my footage from the Canon actually is, it also shows its 25 frames/s WITH upper field first.

So I'll stick to the 50i setting.

Now I'll only need to know whats the difference between HD EX and HD422 presets, as far as I can see its only the Bitrate setting thats different 35 or 50 Mbps, does anyone know if 35 is enough ? I can't see this setting in the project settings when I detect my source files settings?

Cheers
farss wrote on 5/20/2010, 2:43 AM
"When I do this, my output MXF files have flashes in them where the screen turns black for a split second. "

Something really wrong there! It should just work.
I just tested this for you. I rendered a 57s clip from my EX1 shot in 25p HQ to MXF HD422 25p and the results was perfect. A few weeks ago before 9.0e came out I tried to render H.264 in QT wrapper to the exact same codec and it was a disaster. Maybe this is still a bug in the latest release.

"And when I let Vegas detect what my footage from the Canon actually is, it also shows its 25 frames/s WITH upper field first."

Clearly that's wrong.

"Now I'll only need to know whats the difference between HD EX and HD422 presets,"

The HD422 uses 4:2:2 chroma sampling. The XDCAM EX 35Mbps uses 4:2:0 chroma sampling.

Sorry you're having so much grief sorting out what should be a trivial task.

Bob.

marcel-vossen wrote on 5/20/2010, 3:27 AM
Thanks Bob,

I havent updated to 9.0e yet, I'll do that asap and try it again.

I'm sorry too to not have had a multimedia education in the past ;)

I'm an IT engineer that has followed his passion for movie making so to speak, so I do have the technical skills to understand all of this stuff, but I prefer spending time creating instead of troubleshooting and reading about file formats. I think I should though...to get the best out of my camera and editing.

I wouldnt know what chroma sampling is to be honest, I'll google that right away to see if I'm really missing out on something ;)

Cheers
farss wrote on 5/20/2010, 4:07 AM
"I'll google that right away to see if I'm really missing out on something "

Perhaps the issue to consider here is what chroma sampling there is the original video, I don't know the answer to this. Certainly no harm that I know of going UP from 4:2:0 to 4:2:2 other than a moderate increase in file size.

Bob.