Welcome to our community

Be a part of something great, join today!

Log in
  • Hey all, just changed over the backend after 15 years I figured time to give it a bit of an update, its probably gonna be a bit weird for most of you and i am sure there is a few bugs to work out but it should kinda work the same as before... hopefully :)

HD to SD; lot's of aliasing...

Looks like Teranex and Custom really flew on this; the unit just arrived!

We'll be testing, comparing it to the Panasonic HD decks and the software solutions.

I'll post as soon as I can.

Best regards,

Leo
 
Leo,

We who make TV spots are all in the same boat. Soon we will all edit and deliver in HD for HD air, but for a considerable time ahead there will also be the need for standard def versions. Many producers are cutting two versions HD and SD. I think we will soon be at the point that most producers
will put their emphasis on HD and only require a down convert of the HD edit. Having the Teranex will be a very cost effective/quick way to get a high quality
SD version of an HD master. I am eager to learn about the results of your Teranex demo.
 
My practical experience:

1080p master to SD master from Shake.

Every SD deliverable I tried using the 1080p master (using comressor, say DVD) had MAJOR problems.


Shot 4k, 25fps. I ended up with a 1080p master out of RedCine. Color corrected. Then downconverted in Shake using the "fit" node to PAL SD 10bit Uncompressed (blackMagic codec) with black bars (shot 2:1). All SD deliverables (DVD, Online, etc) were made out of this SD. (By the way, I got a gamma shift in the process that I corrected in FCP). Again, every SD deliverable I tried using the 1080p master through compressor had major problems with aliasing.

Still have some aliasing on my final Beta. It's not perfect but it's much better. I did not have the time to play with the resize method (mitchel, etc), just used the default. I applied a glow node (for other reasons) and it helped a bit.

Just my practical experience. Wish I had more time to test more.
 
Not sure how helpful this is, but unlike AE, combustion does have options for different resize filters, much like redcine. I havent tried a downscale in it, but it might be worth a look.
 
Unfortunately, my preliminary down-conversion tests with the Teranex Mini were disappointing. At first blush, no better than the Panasonic deck's hardware conversion.

Understand, this could be due to operator error. I've sent a link to Teranex, so perhaps they can do better. I'll report if they take a crack at it.

I'm trying to do further tests, but I've got a commercial shoot starting today, so it may have to wait for Monday.

I spoke to Teranex and they suggested that I look at their VC220 which they said does a better job at down-conversion. I'm hesitant since it costs ten times as much as the Mini.

What I'm considering is posting a link to a typical scene that really shows the problems and asking Red to convert it by their recommended method and post it so we can all evaluate it. I plan to post my link to the spot in the general forum because I think it's germane. Of course I'll follow the wishes of the Mods.

Best regards to all,

Leo
 
Can you test both 1080p and a 720p inputs to the Teranex? Every image even HD is going to have some aliasing. It's possible there's more aliasing in the 720P than is in the 1080P. RedCine has a lot more to do down converting to 720 than to 1080.
 
Hi Mark,

Actually, we've done most of the tests with 1080p. There seems to be no difference in the aliasing with either format.

Chris, I would enjoy a comprehensive RedCine manual as well, but I don't think the problem lies there. I have beautiful HD from RedCine. I've tried several of the filters, and different quality settings; can't see any difference.

Best regards,

Leo
 
Teranex better down-convert...

Teranex better down-convert...

We're able to make the Teranex produce a better SD down-convert than the Panasonic HD deck.

The Teranex has controls to soften the image and reduce detail. Stepping on the picture this way seems to produce an image less soft than using Gaussian blur.

I'm still testing...

Best regards,

Leo
 
Wow, this is good news. So add a Teranex to the must have's for SD delivery?
 
Next week I will try to do some scaling tests from 4K to SD in Scratch, but when I downscale from HD to SD I often successfully can do that first by scaling from 1080 to 720 and then to SD and that looks much better than going from 1080 to SD. So maybe the solution could be to downscale in smaller steps??

Cheers
 
Steen Linde said:
Next week I will try to do some scaling tests from 4K to SD in Scratch, but when I downscale from HD to SD I often successfully can do that first by scaling from 1080 to 720 and then to SD and that looks much better than going from 1080 to SD. So maybe the solution could be to downscale in smaller steps??

Cheers
Click to expand...


Yes, that is what I first posted. Going from 720 to SD is less
of a crunch than going 1080 to SD. Until I get Blu-Ray capabilities
out of DVD SP (hint Apple) I usually make a 720p version and
then make the SD spot from that. Even if the spot is only SD
I like to make the 720p version for web and demo anyway.
 
What do you guys think about using deinterlace filter in FCP then set it to use flicker filter in there to get rid of the antialiasing?
 
Please feel free to give my HQ batch image downsampler a try, 4k straight ->SD, no aliasing, floating point. Its getting painful to listen to how some of you guys go about downsampling, in two stages?! wow.

PM me if you`re interested (I`ll send a 400k zip file), its not for realtime situations, its for creating a SD resolution sequence from a higher resolution progressive master sequence (exactly like R1 footage), which can then be interlaced if needed using any old hardware/software. VHQ.
 
Many have to go a 2 step downconverting process:

1. 4K RAW to 1080p for HDCAM-SR playout - for offline AVID and online FFF/Quantel, archiving, versioning, etc...

2. Delivery PAL/NTSC from 1080p master for broadcast.

1080p is the de-facto standard for most broadcast and DVD projects.

Hans
 
Hans von Sonntag said:
Many have to go a 2 step downconverting process:

1. 4K RAW to 1080p for HDCAM-SR playout - for offline AVID and online FFF/Quantel, archiving, versioning, etc...

2. Delivery PAL/NTSC from 1080p master for broadcast.

1080p is the de-facto standard for most broadcast and DVD projects.

Hans
Click to expand...

I understand that, but people are being adviced to blur (radius 4etc), then resize to HD, then blur again (radius 2 etc) then resize to SD, just to get good SD results? I understand the weaknesses in many NLE packages, but its maddness to use tools that aren`t up to the job, but good idea, I`ll add the ability to export to multiple resolutions in my freeware batch 4k downsampling tool tonight, both taken straight from the 4k original, not one downsample made from another downsample, thats daft and yields lower quality results.
 
You must log in or register to reply here.
Back
Top