FORUMS: list search recent posts

uncompressed 4:2:2 is compressed ?!!??!

COW Forums : Compression Techniques

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
Raimondo Della Calce
uncompressed 4:2:2 is compressed ?!!??!
on Oct 15, 2008 at 2:04:05 am

I'm doing some tests with Apple/Blackmagic codecs using a Blackmagic Intensity Pro card and some clips of a movie rendered in HD from a 3D application. I must say I am not satisfied at all with the "uncompressed 8bit or 10bit 4:2:2 codec" quality, the resulting images are full of compression artefacts, they are visible very well especially in dark shots both on the pc monitor and on a HD television.
The only Blackmagic codec which solve the problem is the "Blackmagic RGB 10bit" but it's not available for editing with Intensity Pro.
Is this possible ? Does the "uncompressed" codec have a compression ? Or am I doing something wrong ?

Because the movie will be printed on film the only way I found to solve the problem is to edit using the 4:2:2 codec for the offline version, and at the end do an online with the "none" codec option.

Thank you

Raimondo Della Calce
artFive
http://www.artfive.it


Return to posts index

Daniel Low
Re: uncompressed 4:2:2 is compressed ?!!??!
on Oct 15, 2008 at 6:52:45 am

You're not doing anythingwrong.

Uncompressed means different things to different people.

4:2:2 is compressed colour space when compared to 4:4:4.

10 bit is compressed when compared to 16 bit.

Even the None codec is 'only' 8 bit

Check out this site:

http://codecs.onerivermedia.com/


__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


Return to posts index

Raimondo Della Calce
Re: uncompressed 4:2:2 is compressed ?!!??!
on Oct 15, 2008 at 7:14:35 am

Thank you Daniel,
very useful link, it's incredible that these codecs are called "uncompressed", as usual the words used are "relative", but maybe they are right, they are uncompressed images with half the color informations (!). So, to say what I meant with uncompressed we have to say "lossless".

Thank you

Raimondo





Return to posts index


Daniel Low
Re: uncompressed 4:2:2 is compressed ?!!??!
on Oct 15, 2008 at 9:24:31 am

So, to say what I meant with uncompressed we have to say "lossless".

Well then you have visually lossless or mathematically lossless!



__________________________________________________________________
Please post back saying what solved your problem. It could help others, and saying 'thanks' is free!


Return to posts index

Jesus Ali
Re: uncompressed 4:2:2 is compressed ?!!??!
on Oct 28, 2008 at 6:57:36 pm

If you are testing multiple solutions, I would suggest you try out the KONA 3 PCIe card (XENA on the PC side). It can support Dual Link SDI and 4:4:4 color space, including RGB 10-bit, which from my (admittedly limited) knowledge is as Uncompressed as you can get.

You're working with the full color value for EACH and every pixel. Photoshop's 0-255 color space is 8-bit, so you'll have even more shades for each pixel and no compression algorithms will be applied. And then the major challenges will be have a RAID fast enough to move all those pixels through 23-30 times a second.

Good luck and let us know the best solution you find!


Return to posts index

<< PREVIOUS   •   VIEW ALL   •   PRINT   •   NEXT >>
© 2017 CreativeCOW.net All Rights Reserved
[TOP]