EX1 Picture Profile - HD to SD

Discuss all aspects of the EX series camcorders here.
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alan.fleury
Posts: 5
Joined: February 28th, 2012, 7:00 pm

EX1 Picture Profile - HD to SD

Post by alan.fleury » February 28th, 2012, 7:10 pm

I have been trying to understand the detail settings for capturing video in 1080P which ultimately gets converted via Sony Vegas Pro to SD for DVD. I have read leaving detail off or if turning it on, the level should be set to -30ish and the frequency to a positive value to avoid aliasing, jagged edges, etc. (which I have experienced after the downconvert). I saw a profile Alister posted which is as follows:

AC-SD Camera look. To mimic an older SD camcorder based on a DSR400, good for HD to SD conversion.
Matrix – Cinema, Level +15
Detail Level +20, Detail Frequency -35, White Limit +35, Black limit +45
Knee, Manual, Level 90, Slope 0.
Gamma Standard 2, Gamma Level +5
Black Gamma -10
Black Level -10

This confused me as the detail level is positive (making the picture sharper) and the Frequency negative (also making the detial lines finer). I have not tested this when shooting for an HD to SD post conversion. Does this profile work? If so, help me understand why.
alisterchapman
Site Admin
Posts: 431
Joined: February 1st, 2011, 7:43 pm

Re: EX1 Picture Profile - HD to SD

Post by alisterchapman » March 1st, 2012, 6:11 pm

Frequency in the negative makes the detail edges fatter, so that when the image is scaled down to SD, they are still visible and more than 1 pixel wide, so they don't twitter. SD needs a lot more detail enhancement than HD which is whey the level is higher.

Have you also looked at this: http://www.xdcam-user.com/2011/03/getti ... hd-camera/

and this: http://www.xdcam-user.com/2009/11/getti ... rsampling/

Both in the "Tech Notes" section of my blog: http://www.xdcam-user.com/tech-notes/
alan.fleury
Posts: 5
Joined: February 28th, 2012, 7:00 pm

Re: EX1 Picture Profile - HD to SD

Post by alan.fleury » March 3rd, 2012, 2:21 pm

Thank You Alister,

I am still a little confused. In the post http://www.xdcam-user.com/2009/11/getti ... rsampling/ you say that you have also found that another problem is that the detail settings on an HD camera are not optimised for SD. The detail correction edges created in HD are very thin and when these are down converted to SD they all but disappear and can cause further aliasing. The solution is to make the detail correction edges thicker (on an EX turn detail frequency down to -60 to -99) but this then looks ugly in HD. to make them thicker should I not set detail to a negative value? The picture profile you posted has the detail on at +20?

and in the post http://www.xdcam-user.com/2011/03/getti ... hd-camera/ you suggest On a Sony camera the thickness of the detail correction edges is controlled using the “frequency” setting. Setting this to a negative number will thicken up the detail edges, very often you need to go all the way to -99 to get an appreciable difference. You find the -35 works well? Does the white and black limiter have any major affect on aliasing and twitter?

I ask these questions as I have shot some theater events recently with detail on (all defaults 0) and when down rezzed it was unwatchable on a good HD tv. A lot of twitter and artifacts on cloths, faces, etc. I needed a gaussian blur in post which made the image softer than I wanted, but eliminated the harshnes of the image.
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