4:2:2 vs 4:2:0 example; 4:4:4 would be even nicer... at DVinfo.net

Go Back   DV Info Net > The Tools of DV and HD Production > External Video Recording Solutions > Convergent Design Odyssey

Convergent Design Odyssey
...and other Convergent Design products.


Reply
 
Thread Tools Search this Thread
Old May 29th, 2010, 01:10 AM   #1
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
4:2:2 vs 4:2:0 example; 4:4:4 would be even nicer...

Just for comparison sake, I have blown up a very small fragment of the same scene, recorded both on my EX1 SxS card (using the 35 Mbps, 4:2:0 codec), and on my nanoFlash (50 Mbps, 4:2:2).

One can easily see how the vertical color resolution is doubled in the latter case. But looking at the picture, I've dreaming of how nice the full 4:4:4 color would look - while 4:2:2 removed all the vertical jaggies at the red flower edge, the horizontal edge is still ugly...

Well, it's nice to dream, isn't it :)
Attached Thumbnails
4:2:2 vs 4:2:0 example; 4:4:4 would be even nicer...-red-35-mbps-420-both-h-v-jaggies.png   4:2:2 vs 4:2:0 example; 4:4:4 would be even nicer...-red-50-mbps-422-still-h-jaggies.png  

__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply With Quote
Old May 29th, 2010, 09:17 AM   #2
Trustee
 
Join Date: Sep 2006
Location: Montreal, Quebec, Canada
Posts: 1,138
Red Camera Stills

Hi Piotr:
The Nano Flash recorded still looked significantly superior to the 4:2:0 in terms of both color and resolution. However, both images looked really bad ! Could you post uncompressed .Tiffs to this thread (Sorry, I don't know if this web site can handle Tiffs but it's worth a try). I don't know to what degree the .png stills are affecting the image quality.

EDIT: Piotr, what resolution was the RED camera shooting the flowers at ? 2K, 3K, 4K ?
Mark Job is offline   Reply With Quote
Old May 29th, 2010, 09:53 AM   #3
Major Player
 
Join Date: Jan 2010
Location: Tinton Falls, NJ
Posts: 749
Or maybe just show us a still of the full frame from either EX1 or Nano to get an idea how much you've blown this up?
Thanks for posting the pictures!
Dave Sperling is offline   Reply With Quote
Old May 29th, 2010, 11:32 AM   #4
Major Player
 
Join Date: Sep 2008
Location: Vancouver, Canada
Posts: 975
Piotr good discussion topic. Ultimately, topics like this can lead to better use of the nanoFlash.

Just on an anecdotal level (which all of our comments will be without using scopes and such) I find pros and cons in the image quality of both.

Focusing on the nanoFlash image, it should be emphasized that this is a 50Mbit image and as such it is dealing with more color (chroma) information in that bit range which could account for the clearly visible mosquito noise in the darker portions of the image.

I think it would be more instructive to do a series of shots at various bitrates. What this tells me, in a practical sense, as I do a lot of low light work that I should be using higher bitrates than 50Mbits if I expect that I will have to grade in a serious manner in low light situations.

It will be interesting to see if we can determine what factors go into creating mosquito noise.

-Andrew
Andrew Stone is offline   Reply With Quote
Old May 29th, 2010, 11:58 AM   #5
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Gentlemen,

In this little ad hoc example, I didn't want to compare bit rates, but color resolution. Perhaps it will suffice to say that both pictures are some 427x240 pixels fragments, blown up to the full 1920x1080 size.
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply With Quote
Old May 29th, 2010, 01:59 PM   #6
Major Player
 
Join Date: Sep 2008
Location: Vancouver, Canada
Posts: 975
Piotr I don't believe you can leave bitrates out of the discussion as the bitrate determines the amount of color mangling that occurs with the source. If you are using 50Mbit on 422 color and 35 Mbit on 420 then your result is going to be relatively close as the 50Mbit crunching has to deal with more source data than the 35 Mbit. Providing a higher bitrate image would allow a better "triangulation" to figure out what is playing into the various kinds of distortion that are being introduced.

-Andrew
Andrew Stone is offline   Reply With Quote
Old May 29th, 2010, 02:17 PM   #7
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Andrew,

True, but no bitrate will change the color subsampling method; with 4:2:2 only the vertical color resolution is doubled compared to 4:2:0 (see the graphics in http://dougkerr.net/pumpkin/articles/Subsampling.pdf).
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply With Quote
Old May 29th, 2010, 04:32 PM   #8
Trustee
 
Join Date: Mar 2007
Location: Sherman Oaks, CA
Posts: 1,259
Right, I'm sure that the higher bit rates look better. But this wasn't meant to be an exhaustive test, just an experiment to show how much 4:2:2 really helps.
__________________
Avid Media Composer 3.1.3. Boris Red and Continuum Complete. Vegas 8.0c. TMPGEnc Xpress Pro 4.0
Peter Moretti is offline   Reply With Quote
Old May 30th, 2010, 04:51 AM   #9
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Quote:
Originally Posted by Andrew Stone View Post
Focusing on the nanoFlash image, it should be emphasized that this is a 50Mbit image and as such it is dealing with more color (chroma) information in that bit range which could account for the clearly visible mosquito noise in the darker portions of the image.-Andrew
Andrew and Peter,

You're absolutely right the darker portions of the 50/422 image show a little less mosquito noise around edges than the 35/420 version does. And this is where the higher bitrates, available with the nanoFlash, really shine!

Having said that, I have deliberately compared two images, created with more or less the same effective bitrate (50 Mbps at 4:2:2 isn't really much more than 35 Mbps at 4:2:0, considering it must compress larger amount of the color information). So it's good to know that even in this scenario, there is less mosquito noise in nanoFlash files - at 180 (280), it would probably be virtually invisible.

Quote:
Originally Posted by Peter Moretti View Post
Right, I'm sure that the higher bit rates look better. But this wasn't meant to be an exhaustive test, just an experiment to show how much 4:2:2 really helps.
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive

Last edited by Piotr Wozniacki; May 30th, 2010 at 09:16 AM.
Piotr Wozniacki is offline   Reply With Quote
Old May 30th, 2010, 07:08 AM   #10
Inner Circle
 
Join Date: Dec 2002
Location: Augusta Georgia
Posts: 5,413
Dear Piotr,

I think this is a very interesting and informative discussion.

In your example, I calculate that this is 22.2222% of the entire image, or approximate a 450% zoon (if I calculated correctly). I base this on your reporting that the image area is 427x240 and the original image was 1920 x 1080.

Alister Chapman has posted on this blog, an analysis of Sony's 35 Mbps 4:2:0 versus 50 Mbps 4:2:2. He concludes that the compression ratio is about the same.

I think it be worthwhile to show what is possible with the tools that you already have.

Thus, I feel that one could record using I-Frame Only, at 220 Mbps or 280 Mbps I-Frame Only and then zoom in to check the quality. One could compare this to 35 Mbps 4:2:0, or 50 Mbps 4:2:2 or anything else they desire.
__________________
Dan Keaton
Augusta Georgia
Dan Keaton is offline   Reply With Quote
Old May 30th, 2010, 08:38 AM   #11
Trustee
 
Join Date: Sep 2006
Location: Montreal, Quebec, Canada
Posts: 1,138
What About The Quantization ?

Hi Friends:
Very interesting discussion. What about the difference in *Quantization* between the way MPEG 2 @ 4:2:0 (Probably also 1440 x 1080 pixels ??) color space is being encoded versus Full Raster HD 1920 x 1080 pixels @ 4:2:2 color space MPEG - 2 at 50 Mbps ? I have seen 25 Mbps HDV Mpeg - 2 .m2t files with only 1440 x 1080 pixels look visually free of Mosquito noise and blocking artifacts, while I've seen 35 Mbps MPEG - 2 not look as good. Can we ascertain what the Quantization factors are from the two examples ? My point being there are other factors which can be colouring what we are seeing here. EDIT: Data rate isn't everything, but it certainly is an important factor of course.
Mark Job is offline   Reply With Quote
Old May 30th, 2010, 10:39 AM   #12
Major Player
 
Join Date: Jan 2010
Location: Tinton Falls, NJ
Posts: 749
Hi Mark,
Remember, there are 2 different 35 Mbps codecs - both 4:2:0.
The one for the EX cameras is 1920x1080, the one for the PDW-355 series disc cameras is 1440x1080.
Also, I believe both the 35 Mbps codecs are VBR, as opposed to the 25 Mbps HDV codec and 50 Mbps XDcam422 codec which are both CBR.
Just more variables for the equation...
At least we all seem to agree that the 100 Mbps (and higher) Nano recordings look better than the lower bit rate camera-based ones!
Dave Sperling is offline   Reply With Quote
Old May 30th, 2010, 01:09 PM   #13
Trustee
 
Join Date: Sep 2006
Location: Montreal, Quebec, Canada
Posts: 1,138
All the Variables !

Quote:
Originally Posted by Dave Sperling View Post
Hi Mark,
Remember, there are 2 different 35 Mbps codecs - both 4:2:0.
The one for the EX cameras is 1920x1080, the one for the PDW-355 series disc cameras is 1440x1080.
Also, I believe both the 35 Mbps codecs are VBR, as opposed to the 25 Mbps HDV codec and 50 Mbps XDcam422 codec which are both CBR.
Just more variables for the equation...
At least we all seem to agree that the 100 Mbps (and higher) Nano recordings look better than the lower bit rate camera-based ones!
...Hi Dave: Yes indeed, you'e absolutely right :-) Also, HDV MPEG 2 m2t file quality can vary in quality from camera to camera as well @ 25 Mbps encode rate. The one in the Canon XL H1 camcorder is truly excellent, but I understood it to be a VBR encoder, and it was for this reason that it was above average. Perhaps Dan or Chris Hurd would know what kind of MPEG - 2 encoder is in the XL H1 ? Dan I thought the Sony XDCAM HD 4:2:2 hardware encoder CD uses in the XDR & Nano Flash was a VBR encoder ? (I hope I'm not transversing private corporate information asking about this ?)
Mark Job is offline   Reply With Quote
Old May 30th, 2010, 01:30 PM   #14
Inner Circle
 
Join Date: Dec 2002
Location: Augusta Georgia
Posts: 5,413
Dear Mark,

JVC used what has become to be known as HDV 1, 18.7 Mbps (I think)

Sony and Canon used 25 Mbps, known as HDV 2 (as far as I remember).

I do not know if HDV 2 is VBR or CBR.

I do know that our 50 Mbps 4:2:2 and above Long-GOP codecs are CBR (Constant Bit Rate).

Our I-Frame Only and 18 and 35 Mbps codecs are VBR.
__________________
Dan Keaton
Augusta Georgia
Dan Keaton is offline   Reply With Quote
Old May 30th, 2010, 02:48 PM   #15
Inner Circle
 
Join Date: Aug 2006
Location: Poland
Posts: 4,086
Quote:
Originally Posted by Dan Keaton View Post
I do not know if HDV 2 is VBR or CBR.
Dan,
The HDV as used in Sony camcorders is 25 Mbps CBR.

Mark,
You're right that even the same standard (like the said 25 Mbps 420 HDV) can be implemented better or worse. One of the examples of very poor implementation of that codec has been the Sony's V1 camcorder, which - particularly in its 25p version - suffered from many artifacts (macroblocking, mosquito noise, and some peculiar phenomenon known as "oil pain effect"). It was also very easy to "break"...I owned that camera, and sold it away as soon as the EX1 was announced.

I'm very happy now with the excellent XDCAM EX 35 Mbps VBR codec of the EX1, but even more so - with the codec options offered in Convergent Design recorders!
__________________
Sony PXW-FS7 | DaVinci Resolve Studio; Magix Vegas Pro; i7-5960X CPU; 64 GB RAM; 2x GTX 1080 8GB GPU; Decklink 4K Extreme 12G; 4x 3TB WD Black in RAID 0; 1TB M.2 NVMe cache drive
Piotr Wozniacki is offline   Reply
Reply

DV Info Net refers all where-to-buy and where-to-rent questions exclusively to these trusted full line dealers and rental houses...

Professional Video
(800) 833-4801
Portland, OR

B&H Photo Video
(866) 521-7381
New York, NY

Z.G.C.
(973) 335-4460
Mountain Lakes, NJ

Abel Cine Tech
(888) 700-4416
N.Y. NY & L.A. CA

Precision Camera
(800) 677-1023
Austin, TX

DV Info Net also encourages you to support local businesses and buy from an authorized dealer in your neighborhood.
  You are here: DV Info Net > The Tools of DV and HD Production > External Video Recording Solutions > Convergent Design Odyssey

Thread Tools Search this Thread
Search this Thread:

Advanced Search

 



Google
 

All times are GMT -6. The time now is 07:46 PM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2017 The Digital Video Information Network