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-   -   1394 4:2:2 ? (https://www.dvinfo.net/forum/jvc-gy-hd-series-camera-systems/81837-1394-4-2-2-a.html)

Daniel Patton December 16th, 2006 05:32 PM

Quote:

Originally Posted by Mark Silva
Matt if your interested in 4:4:4 from prosumer cameras
check out reel-stream.com (they have modded a dvx100 to do HD and they may do the HD100 in the future)

Interesting stuff. Where do they say that they might try the same with the HD100?

Matt Setnes December 16th, 2006 05:58 PM

Quote:

Originally Posted by Mark Silva
Matt if your interested in 4:4:4 from prosumer cameras
check out reel-stream.com (they have modded a dvx100 to do HD and they may do the HD100 in the future)


hehe. Yea that's what led me into wanting 4:2:2 from the firewire. I was talking to juan at reelstream and we basically talked on how the DVX over HVX and JVC, gets more dynamic range using their method. Although I don't care for dynamic range, I just care about an untouched signal. I'd be willing to let them try it on my camera, but only if they would make it work with firewire instead of USB. From what they said the DVX provides more resolution and DR. Something about the pixels are bigger on the chip. Not sure, but not gonna change the topic so. Thanks for everyone responding.

Thomas Smet December 16th, 2006 07:20 PM

The HD from the realstream device is not 4:4:4. Only SD is 4:4:4. For HD the pixel shift is used to upsample the image which means the chroma is lower then what the luma detail is. It isn't 4:2:2 or 4:2:0 either but it isn't 4:4:4 since there would be no way to increase the chroma samples as well. It still looks great but it is not 4:4:4. It is recorded as 4:4:4 but the samples are actually kind of a funky form of 4:2:0 but not as bad as the 4:2:0 we all know so well. Juan brought this up on his forum a long long time ago before the device came out.

It is interesting though how Panasonic basically ripped off Juans idea to make the HVX200.

Mark Silva December 17th, 2006 12:11 PM

Quote:

Originally Posted by Thomas Smet
It is interesting though how Panasonic basically ripped off Juans idea to make the HVX200.

wow really?

were they not both in development for many years at the same time?

Thomas Smet December 17th, 2006 06:50 PM

who knows for sure but if you look at the way the HVX200 works with it's chips it is very much like how Juans device works. I'm not sure if you can call it ripped off but I'm sure to Panasonic it looked like a really good idea so they did some of their own research into working the HVX200 in that way. Of course I do not know what or how it happened but the timing and style of all of it does seem interesting.

Stephan Ahonen December 17th, 2006 09:16 PM

Quote:

Originally Posted by Greg Boston
I eventually went and looked in the FCP manual which also has the numbers you referenced. HDCAM SR 10 bit 4:4:4 can go to tape compressed to 440 mbs, but it gets more compression(4.2:1) vs. the 4:2:2 (2.7:1). So you sacrifice one or the other to get down to 440 on tape.

For comparison, regular old DV is about 5:1. HDCAM SR also uses a better codec (MPEG-4). The compression ratio should be a non-factor, especially when you consider that the HD2x0 "Super Encoder" is getting great-looking pictures at a compression ratio of about 34:1 (!) using MPEG-2 at 60p, albeit using interframe coding.

Nate Weaver December 17th, 2006 09:42 PM

Quote:

Originally Posted by Stephan Ahonen
For comparison, regular old DV is about 5:1. HDCAM also uses a better codec (MPEG-4).

Just for accuracy's sake, regular HDCAM is DCT based. It's HDCAM SR that's MPEG-4 based.

Stephan Ahonen December 18th, 2006 12:51 AM

Quote:

Originally Posted by Nate Weaver
Just for accuracy's sake, regular HDCAM is DCT based. It's HDCAM SR that's MPEG-4 based.

Oops, fixed. The names are way too similar for such different formats.


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