Keying with the Z1U

Daniel Broadway · August 19th, 2005, 06:02 PM

Unfortunately, the MPEG artifacts are still present when I downconvert to SD. I don't know why though. I figured it would smooth them out, but it doesn't.

Vincent Burnett · August 19th, 2005, 07:22 PM

Has anyone tried bring the HDV into Vegas and then using Vegas to create an image sequence, which can be used for compositing in various apps. It seems that one could retain the HDV quality with this approach. It is much slower though.

Vincent Burnett

Boyd Ostroff · August 19th, 2005, 07:34 PM

I think that Daniel is saying that the "HDV quality" is the problem when it comes to keying. If that's the case then it doesn't matter how you process it.... garbage in = garbage out.

I haven't tried myself, so I just don't know, but a number of other people have made the same observation that HDV doesn't work so well for this kind of application.

Daniel Broadway · August 19th, 2005, 08:29 PM

Yes, that is correct.

The reason I started this investigation is that we have a Z1U at school. A friend of mine and I are going to be shooting a lightsaber duel for a school project. The whole thing will take place in photorealistic virtual sets. I have to be able to get perfect keys for this. It has to be seemless.

Now, I have found work arounds for DV, and I can get very clean keys with it. But with HDV, I just can't do anything to get decent keys.

Vincent Burnett · August 19th, 2005, 08:51 PM

HDV color quality should be atleast as good as DV.

Daniel Broadway · August 20th, 2005, 06:21 AM

You would think. Now, HDV does look beautiful as native footage. But once you try to key it, it presents all sorts of problems. However, I have been able to get professional keys from DV. Take a look...

http://img.photobucket.com/albums/v5...rbrawlComp.jpg

Boyd Ostroff · August 20th, 2005, 06:37 AM

When Adam Wilt reviewed the Z1 in DV magazine he said

Quote:

Single-frame or slow-mo playback reveals blocking or quilting errors, scattered and localized mosquito noise, offset spatial details, and posterization.

I wouldn't recommend HDV for compositing, slow-mo, or still frames, but overall the compression losses were less than I see in over-the-air or satellite HDTV broadcasts.

http://www.dv.com/reviews

Stephen Finton · August 20th, 2005, 06:43 AM

Quote:

Originally Posted by Daniel Broadway

You would think. Now, HDV does look beautiful as native footage. But once you try to key it, it presents all sorts of problems. However, I have been able to get professional keys from DV. Take a look...

http://img.photobucket.com/albums/v5...rbrawlComp.jpg

Have you tried working with the video uncompressed when you are adding effects? I think perhaps you may be compressing it twice to get your final output. You can tweak your compression settings or go uncompressed. While the video file will be massive, if it is uncompressed, it will save you the headache of trying to get your compression settings right to avoid artifacts.

Daniel Broadway · August 20th, 2005, 06:25 PM

No, I use uncompressed footage.

August 19th, 2005, 06:02 PM	#16
Daniel Broadway Regular Crew Join Date: Jan 2003 Location: Alabama Posts: 165	Unfortunately, the MPEG artifacts are still present when I downconvert to SD. I don't know why though. I figured it would smooth them out, but it doesn't.

August 19th, 2005, 07:22 PM	#17
Vincent Burnett New Boot Join Date: Apr 2005 Posts: 20	Has anyone tried bring the HDV into Vegas and then using Vegas to create an image sequence, which can be used for compositing in various apps. It seems that one could retain the HDV quality with this approach. It is much slower though. Vincent Burnett

August 19th, 2005, 07:34 PM	#18
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,801	I think that Daniel is saying that the "HDV quality" is the problem when it comes to keying. If that's the case then it doesn't matter how you process it.... garbage in = garbage out. I haven't tried myself, so I just don't know, but a number of other people have made the same observation that HDV doesn't work so well for this kind of application.

August 19th, 2005, 08:29 PM	#19
Daniel Broadway Regular Crew Join Date: Jan 2003 Location: Alabama Posts: 165	Yes, that is correct. The reason I started this investigation is that we have a Z1U at school. A friend of mine and I are going to be shooting a lightsaber duel for a school project. The whole thing will take place in photorealistic virtual sets. I have to be able to get perfect keys for this. It has to be seemless. Now, I have found work arounds for DV, and I can get very clean keys with it. But with HDV, I just can't do anything to get decent keys.

August 19th, 2005, 08:51 PM	#20
Vincent Burnett New Boot Join Date: Apr 2005 Posts: 20	HDV color quality should be atleast as good as DV.

August 20th, 2005, 06:21 AM	#21
Daniel Broadway Regular Crew Join Date: Jan 2003 Location: Alabama Posts: 165	You would think. Now, HDV does look beautiful as native footage. But once you try to key it, it presents all sorts of problems. However, I have been able to get professional keys from DV. Take a look... http://img.photobucket.com/albums/v5...rbrawlComp.jpg

August 20th, 2005, 06:25 PM	#24
Daniel Broadway Regular Crew Join Date: Jan 2003 Location: Alabama Posts: 165	No, I use uncompressed footage.