[Graeme Nattress]

Here’s an EBU paper: https://www.ebu.ch/en/technical/trev/trev_301-editorial.html which talks about interlace twitter in HD formats.

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP

[Graeme Nattress]

Bump your HDV to uncompressed. De-interlace. Use Cinema tools to conform to 24p. No extra software needed, unless you need a nice de-interlacer.

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP

[Graeme Nattress]

Cheapest is probably a Dell 24″ LCD that you plug into the component out on the camera. To get better than that, a decklink multibridge extreme into a Apple cinema display or the Dell. That way, you don’t tie up the camera as much.

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP

[Graeme Nattress]

It’s not a resolution issue though – it’s an interlace issue. That’s why 1080i has no more vertical resolution than 720p.

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP

[Graeme Nattress]

HD is just the same though in an interlaced system. It doesn’t matter what resolution – if it’s interlaced, the issue is the same.

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP

[Graeme Nattress]

Excessive vertical resolution causes interline twitter on interlaced systems. To get rid of it, you reduce vertical resolution to about 70%. This has been done since the dawn of television.

From Poynton pg56 “twitter, a small scale phenonemon that is percieved as scintilation, or an extremely rapid up-and-down motion…. ….Twitter is produced… …from high contrast vertical detail in ordinary images. High quality vide cameras include optical spatial lowpass filtering to attenuate vertical detail that otherwise be liable to produce twitter.” I’ll add that with progressive cameras, where you don’t always want the spatial filtering to be there, you can do it after the CCD on a software switch. “when cgi is interlaced, vertical detail must be filtered in order to avoid flicker. a circuit to accomplish this is called a twitter filter”.

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP

[Graeme Nattress]

So that blued out control is only valid for certain modes, and in modes that it’s not relevent for, it’s blued out? Thanks for the clarification, as I’d got the misunderstanding that the menu item was just permanently blued out, and hence never choosable. I’d guess it’s choosable in the SD modes?

Reading in the HVX200 manual from the link you kindly posted, the description of the effect of thick/med/thin in “480i progressive mode” is exactly the description of interlace interline twitter.

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP

[Graeme Nattress]

Jan, all interlaced systems suffer from interlace flicker/line twitter. Take a HD CRT monitor and put unfiltered video through it, it flickers, just like NTSC on a TV or PAL on a TV. It’s a problem inherent in interlaced systems. Hence why 1080i has no more vertical resolution than 720p, because it has to be filtered. Now, most HD televisions are inherently progressive, but there’s still a large number of interlaced CRTs out there that need the filtering. Call it flicker or interlace twitter, it’s an issue. I’ve never known any CRT perform any interlace filtering as it’s always assumed that the broadcast signal is pre-filtered. If the CRT filtered, we’d never need to pre-filter our computer generated graphics before we add them to a video, but we do need to pre-filter our graphics.

“You won’t find it there, it is always Blue(that means it is not a valid choice).” Does that mean there’s a menu choice that’s never choosable? If so, then that’s ludicrous.

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP

[Graeme Nattress]

It doesn’t matter what the imager is, video has to be vertically filtered to stop interlaced twitter if displayed on a CRT. Most cameras that shoot progressive allow you to turn off the filtering on progressive images if you’re, say, going for film out, or are never going to display on a CRT. Toke’s question is a good one.

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP

[Graeme Nattress]

You phoned them yet? I got very quick and helpful service on the phone.

“For North America
pre-sales technical questions, please call 702-257-2372

For North America
after-sales technical support, please have ready details of your hardware and versions of software. Then call 317-536-5684.”

Graeme

– http://www.nattress.com – Film Effects and Standards Conversion for FCP