A1: Progressive Vs. Interlaced dilemma

[Fergus Anderson]

Originally Posted by Michael Mann

Fergus, try to modify the default MainConcept-mpeg-template (HDV 720-25p) that comes with Vegas. Set frame rate to 50 fps (progressive) and increase the bitrate from 18.3 to about 40 Mbit/s.

For even better renders I modify the AVI CineForm template (HDV 720-25p Intermediate) that comes with Vegas.

I am sure the Vegas deinterlacing procedure is not BOB but something much more "intelligent", since the render - although it is "only" 720 - looses almost no definition/resolution compared to the native 1080.

By the way: I always use the Classic Media Player to play back the rendered 50p files.

Thanks Michael I'll give it a try when I get home.

Just wondered why 40mbs is necessary for 720-50p mpeg file? HDV is 25mbs - is it because effectively vegas is creating twice as many frames and you therefore need more bitrate to encode it as well as 50i at 25mbs? It seems a shame to increase the file size. I wonder what the effect would be of taking the 50p file into vegas and then rendering to wm9 25p? A more "progressive" looking encode?

Can MPC play back the cineform codec? I have a feeling my PC might be a touch underpowered (P4 2.8 1GB ram)

Do you think you would gain any resolution by going from 720 to 1080-50p?

VLC effectively does this process on the fly using the BOB deinterlace option (ie doubling to 50fps) - Linear seems even better but is very demanding!

Cheers
Fergus

[Michael Mann]

Originally Posted by Fergus Anderson

HDV is 25mbs - is it because effectively vegas is creating twice as many frames and you therefore need more bitrate to encode it as well as 50i at 25mbs?

Yes, I guess so, it's twice as much frames!
25 MBit/s does work, too, but my impression is that a little more blocking artifacts occur.

Originally Posted by Fergus Anderson

Can MPC play back the cineform codec?

Yes, it can. But your CPU might be a little too slow. I use P4 3.4.

Originally Posted by Fergus Anderson

Do you think you would gain any resolution by going from 720 to 1080-50p?

Yes, resolution would be still a little better.
But I simply didn't find out yet how to render to 1080 50p with the MainConcept/Cineform codecs. The codecs always crash in 1080 50p mode. If you find a solution - please tell me, since I am a resultion fan myself.

Originally Posted by Fergus Anderson

VLC effectively does this process on the fly using the BOB deinterlace option (ie doubling to 50fps) - Linear seems even better but is very demanding!

Yes, I use VLC myself to compare native 1080-50i (VLC linear deinterlacing on the fly) with rendered 720-50p (MPC). My impression is that rendered 720 50p looks better in terms of motion definition and almost as good in terms of resolution.

[Fergus Anderson]

Thanks again Michael - the advice is much appreciated.
I love the look of linear in VLC but on my system it stutters a bit (hard to resist the temptation to go to a Core Duo!)

I'm interested to hear your views since I think that motion definition is very important to the overall impression of the footage - I will see if I have any joy going to 1080-50p mpeg2. You could always try WM9 advanced profile for 1080-50p which works fine for me (except my system struggles with that at high bitrate!)

As an aside I am having an issue with the contrast/brightness/levels of the footage imported into Vegas. I find that if I drag an m2t into vegas and do nothing the render (and preview) is always noticably brighter / washed out (even though the levels/brightness are set to 0.00) Have you experienced anything similar? I was thinking opf posting in the vegas forum as Im stuck as to why this is happening.

Cheers

[Michael Mann]

Originally Posted by Fergus Anderson

You could always try WM9 advanced profile for 1080-50p which works fine for me ...

Fergus, I never tried rendering to 1080 50p with WM9. Thanks for the proposal. I am going to test this.

Originally Posted by Fergus Anderson

As an aside I am having an issue with the contrast/brightness/levels of the footage imported into Vegas. I find that if I drag an m2t into vegas and do nothing the render (and preview) is always noticably brighter / washed out (even though the levels/brightness are set to 0.00) Have you experienced anything similar?

Yes, I have, but only if I render to DIVX, XVID, WM9 etc. That's why I am a bit disappointed by these codecs.

Mostly I render to MainConcept HDV (.m2t) or to CineForm - both give me exactly the same contrast/brightness/levels like the native m2t. Even if I decrease the bitrates for .m2t renders to 10 Mbit/s, the levels keep unchanged, only blocking artifact increase. Please try rendering to .m2t or to CineForm and give me a short feedback how your resulting contrast/brightness/levels look.

[Fergus Anderson]

Well I have tried the mpeg versus wm9 test and you are right - the brightness is only increased on the wm9 encodes - very frustrating!!!

the cineform encode played fine in MPC at 720p so thansk for the tip! Filesize is huge though even compared to mpeg2 at 40mbs. For the filesize I think wm9 at 720p is a good compromise at 50fps as 12.5mbs seems adequate for decent quality. Its just a shame the brightness/contrast gets messed up....

Sadly I also have the error in vegas if I try mpeg2 in 1080-50p :(

Thanks again for all advice
Fergus

PS do you have Vegas set to progressive or top field first in the project properties?

[Michael Mann]

Originally Posted by Fergus Anderson

the cineform encode played fine in MPC at 720p so thansk for the tip! Filesize is huge though even compared to mpeg2 at 40mbs.

That's right. I only render to CineForm when I want extra high quality, or when the render is intermediate, that is part of another edit.

Originally Posted by Fergus Anderson

... do you have Vegas set to progressive or top field first in the project properties?

I leave it in "top field first" mode, although I am quite sure it does not make any difference when rendering to 50p - I think I tested this once. (Better double-check it!)

Pleased to hear that you're satisfied with the results, Fergus! And good to have verified my own findings.