DV Info Net

DV Info Net (http://www.dvinfo.net/forum/)
-   Panasonic P2HD / DVCPRO HD Camcorders (http://www.dvinfo.net/forum/panasonic-p2hd-dvcpro-hd-camcorders/)
-   -   hvx200 pixel count revealed (http://www.dvinfo.net/forum/panasonic-p2hd-dvcpro-hd-camcorders/61481-hvx200-pixel-count-revealed.html)

Jaser Stockert February 25th, 2006 12:01 AM

hvx200 pixel count revealed
 
http://www.dvxuser.com/V6/showthread.php?t=47570

looks like steve mullen nailed it!

Barry Green February 25th, 2006 02:38 AM

Yeah, you gotta hand it to Steve, he figured it out down to the pixel. Well done, Mr. Mullen.

Thomas Smet February 25th, 2006 07:07 AM

The interesting thing about using pixel shift is that there is no way that the HD video could have 4:2:2 color.

Even Juan said from Andromeda that he never claimed his device gave 4:4:4 in HD modes because the color channels alternate every other pixel. He wasn't sure really what to call it but it is more like a 4:2:? that might actually be closer to a 4:2:0 but without the skipping of the every other line lick in mpeg2 4:2:0. Youwould have true blocks of color that are 2x2 pixels in size but not 2x1 pixels like in a true 4:2:2.

Yes the format records 4:2:2 but the source is not 4:2:2.

Yes it is still slightly better than HDV but not like compaing 4:2:0 to 4:2:2. If the 4:2:2 was the main reason for somebody getting the camera they may have to think about this a little bit more.

With the HVX200 even if you went analog uncompressed the HD is still pixel shifted to give this chroma reduction. With any other HDV camera and analog uncompressed at least you are getting a true 4:2:2.

Stephen L. Noe February 25th, 2006 09:20 AM

Thomas, I'm right there with you in that thought.

Quote:

Originally Posted by Thomas Smet
The interesting thing about using pixel shift is that there is no way that the HD video could have 4:2:2 color.

Even Juan said from Andromeda that he never claimed his device gave 4:4:4 in HD modes because the color channels alternate every other pixel. He wasn't sure really what to call it but it is more like a 4:2:? that might actually be closer to a 4:2:0 but without the skipping of the every other line lick in mpeg2 4:2:0. Youwould have true blocks of color that are 2x2 pixels in size but not 2x1 pixels like in a true 4:2:2.

Yes the format records 4:2:2 but the source is not 4:2:2.

Yes it is still slightly better than HDV but not like compaing 4:2:0 to 4:2:2. If the 4:2:2 was the main reason for somebody getting the camera they may have to think about this a little bit more.

With the HVX200 even if you went analog uncompressed the HD is still pixel shifted to give this chroma reduction. With any other HDV camera and analog uncompressed at least you are getting a true 4:2:2.


Jarred Land February 25th, 2006 09:38 AM

yeah.. a few people got it.. my favorite was the guys that took it apart and used a microscope to count the pixels. :)

Barlow Elton February 25th, 2006 10:57 AM

Quote:

Originally Posted by Thomas Smet
The interesting thing about using pixel shift is that there is no way that the HD video could have 4:2:2 color.

So how is it that the Canon has SDI 4.2.2 color, but employs horizontal pixel shift? Is it because it's only in one axis?

Chris Hurd February 25th, 2006 11:11 AM

Pixel Shift in the XL H1 is indeed horizontal axis only.

Giroud Francois February 25th, 2006 11:44 AM

So we enter in a new bad era for video camera , virtual pixel.
now camera can advertise any resolution (or pixel count) regardless to the real one on the CCD.
very sad in fact....

Pete Bauer February 25th, 2006 11:53 AM

Barlow, not sure I'm exactly answering your question and I'm no tech expert, so those who are may want to amplify/correct, but I'll take a stab at it...

Just as with the Panasonic, the format of the HD-SDI out (4:2:2) has nothing to do with how the signal was obtained within the CCD block or the original detail before processing. It is simply a particular kind of output; the luma and chroma detail within the CCD block get processed, and output in either SDI or HDV, or both. Same with HDV...the 4:2:0 is simply the HDV spec'ed output of the processed signal from the CCD block. So the chroma DETAIL might not quite as sharp as it would be from a true 1920x1080 4:2:2 or 4:4:4 source, but the signal is still 1920x1080 at 4:2:2

Thomas Smet February 25th, 2006 11:55 AM

yes horizontal is fine for 4:2:2 since you take only every other horizontal chroma sample. You end up with a raw 4:2:2 and then compress to 4:2:0 on the Canon.

Vertical pixel shift on the other hand kills any hope of a true 4:2:2. On the HVX200 the raw image going to the DSP has an odd form of 4:2:0 and then comprsses to 4:2:2.

On a side note however I'm sure the dvcpro50 mode on the HVX200 does give you pretty close to a 4:2:2 since the chroma shifted 1920x1080 is scaled back down to 720x480.

I really do think Panasonic would have been better off going with a 960x720 CCD block. At least then they could claim a true 4:2:2 in 720p mode.

I'm not saying the HVX200 is a bad camera and doesn't have a good image but it is clearly not capable of 4:2:2 like many have hoped.

John Jay February 25th, 2006 12:23 PM

Regardless of the sample size it appears from tests I did here

http://www.dvinfo.net/conf/showthread.php?t=60877

that the Canon has more colour resolution than the Panasonic even though its 4:2:0 versus 4:2:2, admittedly I was working with jpegs - but still - like for like...

Earl Thurston February 25th, 2006 09:17 PM

Quote:

Originally Posted by Giroud Francois
So we enter in a new bad era for video camera , virtual pixel.

This isn't new at all. I've used a GL1 for the past five years and both it and the XL1 used pixel shift to generate a full 720 x 480 image from 280K pixel CCDs. And both camera's images have looked great.

Chris Hurd February 25th, 2006 09:29 PM

Quote:

Originally Posted by Giroud Francois
now camera can advertise any resolution (or pixel count) regardless to the real one on the CCD. very sad in fact....

Not sad at all. This would be bad news only if Pixel Shift was a useless gimmick... but instead Pixel Shift is very real, very useful, and very much a good thing. Pixel Shift is something you want. It's been around for a very long time, and the majority of three-chip video cameras are using it. Pixel Shift provides more sampling points per pixel and actually does increase resolution. What counts is not the actual resolution of the CCD. What counts is the resolution that the DSP provides to the recording mechanism. Remember it was Pixel Shift in both axes that allowed the Canon XL1 to produce very good DV despite having only 250,000 effective pixels per CCD.

Ash Greyson February 25th, 2006 11:52 PM

I agree Chris but I do think there should be an asterisk next to specs that explain the details. I mean Panny has touted that the CCDs were native 1080p, if not directly, indirectly, same with the 4:2:2 color space.



ash =o)

Chris Hurd February 26th, 2006 12:27 AM

Or better yet (in my opinion), a paragraph or two in the next generation of HVX200 pre-sales marketing literature entitled "What is Pixel Shift and why is it so important to this camera."


All times are GMT -6. The time now is 04:10 PM.

DV Info Net -- Real Names, Real People, Real Info!
1998-2018 The Digital Video Information Network