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 :)

Challenge to Red: HD to SD...

Downloading the second file now. What codec are you using for SD?

There are all kinds of tricks to do this really well. If I manage to get all my rabbits out of the hat I'll post a little how to.
 
I've been using uncompressed 10-bit, although I did try ProRez as well.

Thanks!

Leo
 
I'm downloading as well. I'm planning to do quite a bit of DVD work with the RED so it would be good to resolve this!

Jim
 
I am not sure what your SD stuff looks like. I have fairly sharp eye but I can't see any artifacts, issues etc. with my SD shot converted from HD from Red. One difference that I may be dealing with is the unconventional format I am going to right out of RedCine. I am going straight to PJPG quicktime, and my SD codec is exactly the same. I am using compressor and the Sd looks great. The only problem I ses is the convert from 24 to 30 and the slight stutter that occurs, speaking of the 3:2 pulldown, what I really want to do is simply speed up the footage a bit is some cases, since I am not dealing with sound. Anyone know a way to go to 30 FPS from 24 by simply speeding up the footage an avoiding the pull down issue?
 
Uploading a test now. It might be a bit aggressive. This clip has some of the most offensive things for aliasing to deal with. The sine wave looking grill is straight out of a engineers nightmare.


1) Use the gaussian filter in RC as it is a little smoother for this stuff. I tend to export in 1080 as well, it gives AE a little more to downsample.

2) Set up a 23.976 AE 720x486 composition (you'll add 3:2 on the render)

3) put your clip on the timeline and resize to your liking.

4) Make a second copy of it and lay it on top of the old one.

5) add a box blur to the top layer, I use 2 pixels and 2 instances for the settings.

6) this will look pretty blurry, but hit the "t" key and twirl down the opacity on the layer till its a good mix.

7) preview, tweak, rinse, repeat.

8) sometimes it helps to move the blurred clip one frame out of sync, play around with other blur settings, sometimes its worth trying the "time-echo" filter to enhance any motion blur.
 
This is a pretty problematic file. I usually don't have to go through all the hoops I posted above.

I got it alias free on my 20" Sony production monitor. On my 8" it shows a little at the end of the pan, and only in the grill's farthest back corner. Short of a traveling matte on the grill it'd be hard to fix.

Apple uncompressed 8bit 720x486 D1 29.97 143megs
http://www.freedomfromgravity.com/red/alias_test.zip
 
Leo Ticheli said:
Here are Graeme's instructions:

1) put the red footage in an HD timeline.
2) apply gaussian blur. Range 2 to 4 pixels
3) nest that HD sequence into a SD sequence
4) adjust amount of blur as necessary.

In image processing, from any camera, there's always a trade between resolution and aliasing.

5) also try a very small unsharp mask, strength 100, radius 2 on the nest in the SD timeline if you have to pre-blur too much to reduce the aliasing.

Best regards,

Leo
Click to expand...

I think the basic idea here is to use the gaussian blur as a lowpass filter (to remove high frequencies that will have nowhere to go when the image shrinks), so if you`ve got 4096 pixels and downsample to 1280, you would need to blur by a factor of at least 4096/1280=3.2 pixels, probably just a little more, to be safe from high frequencies causing aliasing. The two applications of blur suggested above are most likely to compensate for an inadequate downsampling function in applications built mainly for speed and lower resolutions?


PS, If you use the correct amount of blur, you should be able to downsample directly to SD from 4k without going through HD, depending on software used.
 
Mike Prevette said:
This is a pretty problematic file. I usually don't have to go through all the hoops I posted above.

I got it alias free on my 20" Sony production monitor.

Apple uncompressed 8bit 720x486 D1 29.97 143megs
http://www.freedomfromgravity.com/red/alias_test.zip
Click to expand...

Hmmm.. playing back on my JVC 24" I'm seeing a lot of jaggies. The front grill and the golf flag. I don't think I've ever seen a clip like this.

My suggestion was going to be to work off the 1K proxy as I've noticed mine tend to look really good with no aliasing. But since this is 16:9 that's not going to work. Maybe shooting 16:9 hosed this clip somehow. I'd sure like to see a 2:1 version. I don't see any particular reason to shoot 16:9 knowing that the workflow isn't there yet.

I've tried downloading the R3D but it keeps failing for some reason.
 
Are you playing out on a standard SD monitor? What are card are you passing it through?

Sending a SD file to a highres HD monitor with a crap scaling algorithm will result in lots of jaggies yes. The only proper place to display SD is on a SD monitor preferably the tube kind ;)
 
What about this one?

just scaled down without blur.

SD-Test1

ftp.ltpro.com
ftp://r3d@ftp.ltpro.com:21/mnt/sda5/r3d/SD-Test1

user name is r3d, password is: red5standby

Let me know if it's good enough for SD broadcast.

Tek

P. S. Personally I like to crop rather than scaled. Don't like squeezing look.

Yup, I can post 4k-16x9 RED files. LOL

7.jpg
 
The best result I've got so far:

1. Export 2k from REDCine OpenEXR seq.
2. In AfterEffects created 2k composition and applied 2.0 box blur
3. Created new comp PAL/SD (sorry, no NTSC, I'm in Europe. Thou I thing it would work just the same, the only difference is no need for 2:3) size and put previous comp downscaled.

There is a link:
ftp.studioinvitro.lt
user: red@studioinvitro.lt
pass: one

Regards,
Mykolas

P.S. It's uploading now, should be on site 12:45 GTM

EDIT: It's on site. Connect with ftp client, please. It seams it does not work with browser.
 
Mike Prevette said:
Are you playing out on a standard SD monitor? What are card are you passing it through?
Click to expand...

Just sending it 1:1 to my JVC via DVI with Quicktime player. No scaling going on when I'm viewing.

Check frames 22 and 23 for instance. That's where I'm seeing huge jaggies. If I step through a frame at a time there are several frames that are perfect and then a couple like those pop up and I'm seeing it in the playback.
 
What about keeping this PROGRESSIVE all the way and using a KONA to output to tape.

If you are going to DVD then there is no reason at all to introduce an interlaced picture (even at SD resolution). I would suggest creating an SD compressor preset that uses the optical flow engine and make sure you encode a progressive MPEG-2 stream.

For tape out keep everything progressive until the final output.

RED is never going to like interlaced images because it records progressive frames. Keep it all progressive until the very last step(tape out) and keep your DVD, web, QT's, etc (digital stream images) progressive at all times.

David
 
Mine was progressive all the way. It does not matter if you record to tape with KONA - it stays progressive (technically it is interlaced thou both fields are identical and it plays progressive).
 
I dont understand.

I use FCP, use "best" motion setting and i have stunning results.
 
Hi Antoine,

Perhaps you are not working with high-contrast material with closely spaced lines. If you read all the posts on this thread you may understand the problem.

Best regards,

Leo
 
joelnet said:
Just sending it 1:1 to my JVC via DVI with Quicktime player. No scaling going on when I'm viewing.

Check frames 22 and 23 for instance. That's where I'm seeing huge jaggies. If I step through a frame at a time there are several frames that are perfect and then a couple like those pop up and I'm seeing it in the playback.
Click to expand...

WELL OF COURSE YOUR SEEING JAGGIES! Those are interlacing lines from the 3:2 pulldown. THEY ARE SUPPOSED TO BE THERE!

Your looking at a SD Interlaced video on a LCD computer monitor! through Quicktime player nonetheless! FAIL!

SD video should only be viewed on a proper SD monitor, through a proper output card.
 
I agree about keeping it progressive until the very last step. Then I treat it just like I do film, I drop 3:2pulldown into it so it flows just like my film transfers.
 
Here is a frame capture from it playing out of QT.
All resizing and color work done in REDCINE.
Playing out I see no jaggies looks great.
Was Encoded to Prores 422 HQ.
On the output For Filter I used Sinc instead of Linear
 
Please don't think I'm ungrateful to all trying to help with this, but the terrible aliasing is definitely there no matter what you do in RedCine.

A small Quick Time player view won't tell you what's going on. Drop it onto a FCS sequence and play it out on a good monitor.

Posts saying the aliasing is not there are simply dead wrong and do not contribute to solving this.

Again, I sincerely thank those trying to help.

Best regards,

Leo
 
You must log in or register to reply here.
Back
Top