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-   -   Keying AVCHD? (https://www.dvinfo.net/forum/avchd-format-discussion/112012-keying-avchd.html)

Andy Tejral January 9th, 2008 11:52 AM

Keying AVCHD?
They said you couldn't chroma key with DV. They said you couldn't chroma key with HDV.

(They also said you couldn't chroma key with u-matic--and they were pretty much correct.)

Can you key with footage from a AVCHD camera?

Kaku Ito January 9th, 2008 11:58 AM

I guess you are talking really strict.

DV has mosquito noise that makes it hard. HDV shouldn't be that bad, I tried with Canon G1 and it wasn't bad using Reflecmedia with green light ring.

If you shoot with AVCHD with progressive format, like 24p or 30p that Panasonic SD9 or Canon HG10 let you, should be a lot better. Was AVCHD 4:2:0? Then people here had told me greet light would work better.

When I get my SD9, I will do some tests with Reflecmedia.

Andy Tejral January 9th, 2008 02:05 PM


Originally Posted by Kaku Ito (Post 805539)
I guess you are talking really strict.

Yeah, I'm looking for decent. Doesn't have to be perfect but I'll settle for 'pretty good.'

I think I'm going to go for a HV20--I like the idea of tapeless workflow but the price of the HV20 is hard to ignore. And its available now.

Kaku Ito January 9th, 2008 08:15 PM

If you have to have footage that needs motion, then HV20 is not it. I do have one, but the rolling shutter issue would drive you crazy for rotoscoping (I guess the type of work I imagine you have to do that, too).

SD9 is coming out end of this month, so I would wait.

John Calder January 10th, 2008 05:56 AM

Good results HV20 greenscreen
I am getting good results from an HV20 with greenscreen. Ref Cave scene of this clip:
Or higher definition at Lulu but it is a biggie at 190MB - Free download, no registration needed:
No special processing here, only the simple "bluescreen" preset in NLE "ULead Mediastudio Pro 8",

Big advance on my earlier experiments with a Canon Optura:
IMHO this looks reasonable on Youtube but it has had a lot of post-production technology thrown at it. Also I find low-res Youtube format is kind to greenscreen experiments.

About AVCHD .. referring to the test reports at:
These people are reporting that HDV is performing better than AVCHD.

But, the only result that counts is to actually try it and I do not know of any published test yet.
A theoretical wild thought, HDV and AVCHD both depend on frames having similarities so they can save space by only detailing some areas at longer intervals like 0.5 sec. Now a greenscreen shot has a LOT of temporal similarity = areas that remain the same over time - so that situation may be kind to both HDV and AVCHD and cause them to perform better than they do in "normal" film-making? It needs testing to find out. I like what I have seen with HDV so I am sticking to that in the meantime, plus I can borrow an HV20 but none of my contacts have any kind of AVCHD camera. The closest I have got to AVCHD is a greenscreen test I organised through these forums for the Sanyo HD1 camera which uses an MPEG-4 compression which is related to AVCHD but simpler. The owner shot the tests and I keyed them. The results were surprisingly good. Ref:

Kaku Ito January 10th, 2008 06:01 AM

Thanks John, save my time lol.

Jon Fairhurst January 10th, 2008 01:14 PM


Originally Posted by Kaku Ito (Post 805892)
SD9 is coming out end of this month, so I would wait.

I believe that it will be released later in the US.

At CES I heard March as well as May-or-June for US release from some Pana representatives.

As far as image quality goes, it is 17 mbps for 1080p 24. The sensors are 3CCD with 960x540 resolution. It is upscaled to 1920x1080 in the camera. The sensor is only 1/6", so low-light noise could be a problem.

We look forward to early reviews from Japan.

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