How are your EX1 > SD-DVDs looking?

[Craig Seeman]

It's not pans, it's zooms. A pan is likely on a similar horizontal plane. The image must change horizontally and must have VERY THIN lines.

This is the footage but you will NOT see it since this is H264.
http://thirdplanetvideo.com/CineAlta.html

That 2nd shot with the zoom out from the Japanese architecture in the water. Those tree branches in the background twitter like crazy. Also the horizontal lines on the roof of the building overlooking the water a few shots later. Other shots like the close up of tree branches are good. It's those THIN Tree branches at a distance. They're probably only a scan line (or less!).

I can probably upload the MPEG2 Elementary Stream so anyone can burn to DVD on Mac or Windows and see this.

BTW this problem isn't specific to the EX1. On another forum a user is seeing the on the HVX200 shot at 720p24. He also said it's more obvious in "nature" shots. I mentioned the trees I had shot with zoom and he said, that's what he's seeing.

What I think we need is some "intelligent" line blurring much the way a professional compression app deinterlaces by using edge detection and applied to moving areas only. Those kinds of deinterlaces only act on certain areas to keep resolution detail high. We need something similar for HD to SD conversion. It must be out there otherwise you'd be seeing this on commercial DVDs.

If you're not seeing it then maybe main concept is blurring the lines but if you look at my video above I think you'll see what kind of source I'm talking about.

Basically a horizontally thin line that moves from scanline to scanline at 1080p downrconverted to SD (even kept progress) seems to be too thin to resolve properly.

Originally Posted by Paul Kellett

Craig,i've panned left to right,up and down,slow and fast,past walls,windows and trailers with mesh sides,i ain't getting any twitter or lines or anything,just smoothflowing footage. I've purposely tried to find twitter etc but can only find it if i render wrong. I render main concept mpeg-2 for dvd-a,upper field first,the same is for 720/50p and 1080/50i.

Paul.

[Dustin Carpio]

Originally Posted by Brian Cassar

This is what I have found out to be the best way - doing a hardware downconversion - but to go thru y/c (s-video) you are losing a lot.

The only problem is that if you're going to a deck that only offers a composite or s-video in then I would choose s-video. Of course you would chose sd-sdi or component if the deck you're mastering to has it.

[Simon Wyndham]

Those who are using Compressor 3 for the MPEG encoding, have you played around with the anti-alias settings on the downconversion?

I'm new to that program, but would have assumed that this might help.

[Bob Grant]

One interesting result from trying to finesse the SD Downconvert from my last shoot with Vegas 8.
Applying an Unsharpen Mask FX prior to the downscale produces very visible twitter and aliasing. Applying it after the downconvert no such problem. It's good that one can do all this in one pass with Vegas, I'm rendering straight from the project T/L to 16:9 SD mpeg-2.

[Piotr Wozniacki]

Originally Posted by Bob Grant

One interesting result from trying to finesse the SD Downconvert from my last shoot with Vegas 8.
Applying an Unsharpen Mask FX prior to the downscale produces very visible twitter and aliasing. Applying it after the downconvert no such problem. It's good that one can do all this in one pass with Vegas, I'm rendering straight from the project T/L to 16:9 SD mpeg-2.

Bob, perhaps I'm too tired and sleepy after all day work - but don't quite follow; how do you do all this in one pass, if the Unsharpen Mask is applied AFTER downconversion? Doen't downconversion require a separate render? Please elaborate on your steps; TIA>

[Bob Grant]

Originally Posted by Piotr Wozniacki

Bob, perhaps I'm too tired and sleepy after all day work - but don't quite follow; how do you do all this in one pass, if the Unsharpen Mask is applied AFTER downconversion? Doen't downconversion require a separate render? Please elaborate on your steps; TIA>

No, downconversion etc can all be done in one pass.
Open SD 50i 16:9 project. Drop mxf clips onto T/L and edit.
You can control where in the chain an FX is applied in Vegas by The Triangle. See attached screenshot. For many FXs it doesn't matter, in this case it does. Try clicking the triangle to change its direction while monitoring the output.

[Piotr Wozniacki]

Thanks Bob - I leaned something new on Sunday :)

The Manual only mentions the possibility of using Pre/Post Toggle triangle when the event is being panned/cropped, but from what you're saying it also works with downscaling a HD clip in an SD project - am I getting you right?

[Piotr Wozniacki]

Bob, I tried it and frankly, cannot see a difference - apart that with the "pre" setting (trangle pointing to the left) the preview is slower!

What I am unclear about is this: regardless of the projects settings, I understood that the downconversion only takes place when rendering HD out to SD MPEG-2 (for SD DVD). Setting the project to SD only changes how the HD clip is previewed. Where am I wrong?

Oh, and I tried it with 25p mxf in a 25p (not 50i) SD project - does it matter?

[Bob Grant]

Originally Posted by Piotr Wozniacki

Bob, I tried it and frankly, cannot see a difference - apart that with the "pre" setting (trangle pointing to the left) the preview is slower!

What I am unclear about is this: regardless of the projects settings, I understood that the downconversion only takes place when rendering HD out to SD MPEG-2 (for SD DVD). Setting the project to SD only changes how the HD clip is previewed. Where am I wrong?

Oh, and I tried it with 25p mxf in a 25p (not 50i) SD project - does it matter?

Try looking at your output on a SD CRT monitor as you change the triangle.
I've only tried this in a 50i project with 50i footage destined for SD DVD.
Yes downconversion only takes place when rendering to SD. However using a SD project does mean you get to see what you're going to get.
If you're rendering out to HD i.e. your source and destination resolution is the same that triangle isn't going to make any difference. It does effect where Vegas applies FXs during composits e.g. adding a glow before / after a mask.

Also be warned. If you encode to 25p SD mpeg-2 the player will still output 50i unless you're very lucky. It might looks fine on a LCD, it may look bad on a CRT.

[Dennis Schmitz]

Originally Posted by Bob Grant

Try looking at your output on a SD CRT monitor as you change the triangle.
I've only tried this in a 50i project with 50i footage destined for SD DVD.
Yes downconversion only takes place when rendering to SD. However using a SD project does mean you get to see what you're going to get.
If you're rendering out to HD i.e. your source and destination resolution is the same that triangle isn't going to make any difference. It does effect where Vegas applies FXs during composits e.g. adding a glow before / after a mask.

Also be warned. If you encode to 25p SD mpeg-2 the player will still output 50i unless you're very lucky. It might looks fine on a LCD, it may look bad on a CRT.

There should be no problem with encoding with a progressive flag...


regards Dennis