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  • 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...

L

Leo Ticheli

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Come to my rescue!

Red footage looks great in HD, but I'm getting a lot of aliasing after converting to SD.

So far I've used Compressor and Final Cut on the Red Cine processed files, both with bad results; only thing that's worked OK so far is using Red Cine to produce 720p files and running them the Panasonic HD deck to use it's hardware converter.

I've tried just about every setting on Red Cine, selecting files of 1080, 720, and SD.

Is a Teranex the only answer?

Help!

Best regards to all,

Leo
 
I just did a successful 4k to DV (to miniDV) conversion. It may not be the "best" way but the SD results are great. I opened a 1080p 10-bit uncompressed timeline in FCP, dropped a 2k proxie on it and exported using QT conversion to the DV codec (Make sure when you are downconverting to set the quality to maximum). I didnt see any problems with the image at all and it looked like the best DV footage I have ever seen (quality wise).

Im sure there is a better way...but hey, it works!
 
Leo
Would you please make a very specific, step by step description of your workflow and include hardware (Kona or not, which decks etc).
Thanks
Rob Gardner
 
Tomorrow I'm going to try running the HD through After Effects to see if that produces better results.

The only software solution I've found so far is the FCS Flicker filter under the Video tab in filters. It works, but not my favorite solution.

OK, you tech-heads, share your wealth of knowledge!

Best regards,

Leo
 
Leo:

Are you exporting self-contained movies out of FCP and then dropping them into the "Advanced Format Conversion" section of Compressor? If so, which preset are you choosing? What is the nature of the aliasing? Is it on text? Often times, there can be issues with even vs. odd fields. I have found problems attempting to push to compressor right off the FCP timeline. Any further info could help.

Best Regards,

Nick.
 
The trick I use in FCP is to apply a small gaussian blur before the downsampling as the downsample filters are not always the best. Also, ensure high quality motion is on in the sequence settings.

Graeme
 
Graeme Nattress said:
The trick I use in FCP is to apply a small gaussian blur before the downsampling as the downsample filters are not always the best. Also, ensure high quality motion is on in the sequence settings.

Graeme
Click to expand...

That's a bad way of getting around it. Are there resize filters available for FCP? Something like lanczos?
 
GFIRob said:
Leo
Would you please make a very specific, step by step description of your workflow and include hardware (Kona or not, which decks etc).
Thanks
Rob Gardner
Click to expand...

I'm shooting 4K 16x9; have found the problem with both 29.97 and 23.97 fps.

Taking the R3D files into RedCine. Have tried a variety of project settings, including Red 4K, 1080, 720, and 720x486.

Have tried outputting a various quality settings with no effect on the aliasing.

Importing the resultant quicktime files, both ProRez and Uncompressed 10-bit, into FCS and letting FCS do the down-convert.

Also tried down-converting with Compressor.

No apparent difference.

Aliasing appears on machines with Black Magic as well as Kona 3. Also same on both Tiger and Leopard Macs.

As I mentioned, the HD files are stunning, but the SD conversions are not acceptable.

Best regards,

Leo
 
After Effects

After Effects

Leo,

As a fellow Varicam owner I feel your pain. I too have not had an easy road from Red to SD. Redcine renders to SD have been noisey and aliased. My work flow for Varicam to SD has been to use the Panasonic 130 HD deck's down converted SDI out to an SDI 2 ME switcher using real time gamma correction, proc amps, chroma keying and wipes to color correct. A very fast and efficient work flow. After discovering the Redcine to SD noise and aliasing my best results have been what you are doing. I have Redcine make a 720 23.976 and use After Effects to apply unsharp mask rendering a prores 720 P. Then I recapture it on my Panasonic 130 HD deck's HD SDI in from my Kona 3's HD SDI out. Then I recapture using the down conversion from the 130 with the 130's enhancement on and use my switchers for color correct. I am not planning on buying Scratch even though that would seem to be a solution. The problem I see with Scratch is that you are

baked in with your color correcion after rendering and that is not even going into the archaic nature of Scratch's off line model. I beleive the future belongs to Cineform. Real time 4K on the timeline with 3D LUT's for realime color correction. Not to mention 10 FPS conversion from R3D to Cinefom codec.
 
Hi Leo,

Can't you make 720p HD files, play them back in FCP and let the Kona 3 do the downcovert without using compressor, or rendering anything? I seem to think thats how we make digibeta dubs of HD shows, we never make an SD file.

I may be foggy, or forgetting something or maybe you already tried that.

Nick
 
I have tried the down-converter function in the Kona 3 and it's no better than the software methods I've tried.

Anyone out there using the Teranex?

Thanks to all for the efforts to help!

Leo
 
Sounds like FCP and Compressor are using simple linear or sync algorithms for scaling - definitely something that can cause creepy edges.

I'd suggest using Mitchell or Gaussian filters in RedCine (I use Scratch...). They both have softening properties. If the resulting image is too soft, try the Lanczos filter.

If RedCine is not an option (I know, you've already rendered...), then I strongly suggest using software that allows you to select the proper scaling filter algorithm. I don't use AE much, but I don't think user selectable scaling filters are offered, but I'm guessing its a flavor of bilinear filter which is an all-around kind of algorithm that may or may not work in your case.

I can HIGHLY recommend Shake or Nuke for their powerful scaling tools that make use of a full range of algorithms for up and down scaling.

I don't see the need for a dedicated hardware solution for this unless realtime is a critical feature. Downconverting is a piece of cake with the right software.


regards,

john t.
 
Thank you, John,

I'll try the filters you suggested in RedCine this morning. I have already tried the Gaussian filter, but I'll take another look at it. It didn't seem to have any positive effect on the profound aliasing.

Will also try running through Shake and After Effects.

Hope I don't have to go to Scratch, but however this is solved, high-quality SD is absolutely vital in commercial production.

Best regards,

Leo
 
Leo,

You have properly tried this already but just in case you haven't...

- in compressor u can manually set the resize filter quality - it should be set to best (enable frame control - using the inspector). U can also set antialiasing and detail levels.

Hope it helps...
 
So if you HD source is progressive are you keeping your SD project progressive? I see this when people drop HD files into an interlaced SD project.
 
We don't use no stinking interlaced!

Best regards,

Leo
 
Leo,

Long time lurker - first post. Still sitting on the fence - waiting for the workflow to knock me off. ;)

Try this - set the codec to "none" rather than uncompressed, or prores. When I take 1080i HD edit timelines from FCP and compress them for SD DVD, or Flash.

For best quality, these are the steps I do.

1. Export the completed - efx, color, sound, etc. - FCP timeline to a self-contained QT file - same settings and codec as sequence.
2. Import into AE for scaling and deinterlacing, and frame rate (if needed), scale to final size - keeping square pixels - VIP.
3. Render out of AE with QT codec set to "none".
4. Bring into compression program and output as needed - DVD / Flash, QT H264, etc. I use one of three depending on the deliverable - Compressor, Episode, or Bitvice.

Give this a shot - it should work in your case, even considering the additional down scaling from 4K. I've noticed that going from QT codec to QT codec, even with the "uncompressed" ones, you can get some unexplained aliasing in the final QT clip. I mean, in the AE window you can see the clean edges at 100% full quality view - but when looking at the QT clip in a open window beside it, you have ratty edges - even with high quality selected in the QT properties window. I just lump it into the odd voodoo stuff. In my experience the only way to avoid this odd aliasing is to use the none setting as the codec on QT renders for final output for compression. Needless to say, this is a all-done-with-editing process only clip, not playable unless you have one big mutha of an array.

This won't work for the original clip conversions from the Red programs for editing purposes, but if you use the QT wrapper files in FCP and output from there it should work the same.

Hopefully this will help.

Bill
 
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