One last thing on psf at DVinfo.net
DV Info 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 August 6th, 2009, 11:55 PM   #1
Major Player
 
Join Date: Jul 2009
Location: Rancho Santa Margarita
Posts: 590
One last thing on psf

Ok guys. Sorry for all the questions. I read the FAQ and then I read the FAQ again. I'm still not clear if psf is retained on footage recorded to the XDR/Nano. I see it says in the FAQ that pulldown is not removed but psf is not technically "pulldown" exactly.

So I ask the question here for clarification. If my camera outputs psf, does the XDR/Nano write real progressive frames or does it write psf like my camera outputs.

Well, I should say one of my cameras outputs real progressive frames (this is nice), but the other camera outputs psf and this is the one that worries me.

If psf fixing is lumped in with pulldown removal, I guess the good news is that it will eventually be added as a feature. Just looking for a little clarifcation ...

Thanks, Aaron
Aaron Newsome is offline   Reply With Quote
Old August 7th, 2009, 06:39 AM   #2
Inner Circle
 
Join Date: Dec 2002
Location: Augusta Georgia
Posts: 5,421
Dear Aaron,

Yes, we support PSF (Progressive Segmented Frames).

Many cameras' HD-SDI output is PSF when you select a progressive frame rate on the camera such as 23.976, 23.98, 24, 29.97 or 30 progressive frames per second. This allows a non-progressive monitor to display your images.

In PSF, the original progressive frame is divided into two fields, one for even lines, one for odd numbered lines. Then the monitor gets this and either puts it back together and shows one progressive frame or displays it as two fields. Early monitors used the second option.

The Flash XDR and nanoFlash handle PSF. We have a menu option which you can select if your input is PSF.

We take the two fields, process it, and recreate the original progressive frame, then we record it (full progressive).
__________________
Dan Keaton
Augusta Georgia
Dan Keaton is offline   Reply With Quote
Old August 7th, 2009, 07:52 AM   #3
Major Player
 
Join Date: Jul 2009
Location: Rancho Santa Margarita
Posts: 590
This is excellent news! Maybe another line should be added to the FAQ.
Aaron Newsome is offline   Reply With Quote
Old September 3rd, 2009, 09:43 AM   #4
Regular Crew
 
Join Date: Aug 2009
Location: Tampa, FL
Posts: 96
Dan,

I may be a little confused here about psf. I thought I understood it, but maybe not so much. I would appreciate some input and correction, if appropriate.

My two Panasonic HDX900s are the primary cameras with which my nano is going to be used. Of course, I may be renting the nano to other shooters occasionally, so I need to understand the psf function as fully as possible, too.

My understanding of the HDX900 is this. The camera is switchable between 720p and 1080i, but it always records true progressive frames (not psf), because it uses a progressive imager (720p), which is always progressive. It has no way to produce a real interlaced image. When shooting in 1080i, it is actually producing and recording two identical progressive fields, as opposed to an odd and an even field, which would be typical of an interlace imager. When playing back, it also plays those two identical fields. This is the case whether the frame rate is 60i, 24p, 25p or 30p. (Note that the Panasonic tape-based cameras always record 60 frames, no matter what frame rate is selected. Extra frames for 24, 25 or 30 frame recordings are flagged when recorded and not shown during playback.)

Now, if my understanding of that is correct, that makes it different from the Sony F-900 and F-900R, because those cameras use interlace imagers. Those cameras natively record an interlaced image, so they must use psf to record a "progressive" image.

So, I have three questions about this.
  • Am I understanding these concepts correctly?
  • Should I be using the "psf in" function when recording the output of the HDX900? I would assume the answer to be "no" for that camera whether I am shooting 720p or 1080i, since the camera doesn't actually ever produce a real interlaced image. (This assumes I am understanding the HDX900's recording and HD-SDI output correctly.)
  • Should I be using the "psf in" function when recording the output of a Sony F900 or F900R. I would assume the answer to be "no" if I am shooting 60i. I would assume the answer to be "yes" if I am shooting 24p, 25p or 30p, which would be psf on those cameras (always interlaced).
Steve Brown is offline   Reply With Quote
Old September 3rd, 2009, 10:40 AM   #5
Inner Circle
 
Join Date: Dec 2002
Location: Augusta Georgia
Posts: 5,421
Quote:
Originally Posted by Steve Brown View Post
Dan,

Now, if my understanding of that is correct, that makes it different from the Sony F-900 and F-900R, because those cameras use interlace imagers. Those cameras natively record an interlaced image, so they must use psf to record a "progressive" image.
Steve, this is a tough subject.

As I understand it, PSF is a way to take a progressive image, and make it "psuedo interlaced" so that an interlaced HD-SDI monitor can display it.

If all of the HD-SDI monitors that were ever made supported true progressive frames, then PSF would not be needed or used (in my opinion).

PSF works by taking a progressive frame, and placing every other row into two fields.

Then, if the receiver, such as the nanoFlash or Flash XDR, knows that it is PSF, then the two fields are processed to rebuild (and record) the true progressive frame.

Thus, with PSF In Checked, if one provides us with PSF, then we rebuild the original progressive frame.

Now, certain cameras have interlaced sensors, but are able to create a progressive frame.
Normal interlaced images have a time delay between the two fields.

If one has a camera that has interlaced sensors, but builds progressive frames, then two fields can be read out so that a progressive frame can be created.

Canon does with very well with their XL H1 24F and 30F modes. I am assuming that Sony does the same thing, but I do not have this level of information.



Quote:
So, I have three questions about this.
  • Am I understanding these concepts correctly?
  • Should I be using the "psf in" function when recording the output of the HDX900? I would assume the answer to be "no" for that camera whether I am shooting 720p or 1080i, since the camera doesn't actually ever produce a real interlaced image. (This assumes I am understanding the HDX900's recording and HD-SDI output correctly.)
  • Should I be using the "psf in" function when recording the output of a Sony F900 or F900R. I would assume the answer to be "no" if I am shooting 60i. I would assume the answer to be "yes" if I am shooting 24p, 25p or 30p, which would be psf on those cameras (always interlaced).
One should never check the PSF In, if you are providing the nanoFlash a 1080i signal.
For 720p it is not necessary to check the PSF In.

For 24P, we are able to set the PSF In option internally. So one does not need to worry about PSF if your footage is 24p.

For 25P and 30P we need to know and the PSF In must be set accordingly.
If you camera's specs say PSF, please check the PSF In option.

If you get this wrong, then a quick check of the footage visually will show problems. It just will not look right, it may look interlaced.

Steve, I hope this helps.

I also welcome comments and suggestions. Maybe someone can explain this better than I, or correct me if I made a mistake.
__________________
Dan Keaton
Augusta Georgia
Dan Keaton is offline   Reply With Quote
Old September 3rd, 2009, 01:00 PM   #6
Inner Circle
 
Join Date: Dec 2005
Location: Bracknell, Berkshire, UK
Posts: 4,957
As I understand it within the specifications for SMPTE 292 HDSDi there is no provision for 1920x1080 progressive signals. As a result any progressive 1920x1080 images must be encoded as PsF in an interlace stream. So if you are working with a 1080P camcorder the HDSDi will be PsF. There is no loss of quality or motion issues when using PsF, in most cases it's use is completely transparent.
__________________
Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com
Alister Chapman is offline   Reply With Quote
Old September 3rd, 2009, 01:12 PM   #7
Inner Circle
 
Join Date: Dec 2002
Location: Augusta Georgia
Posts: 5,421
Dear Alister,

You said it better than I could.

In my opinion, if the PSF In option is set correctly, then

1. A progressive image in the camera is converted to two fields (PSF).

2. The PSF is sent out via HD-SDI.

3. The receiver, such as the nanoFlash, converts the two fields (PSF) back to progressive.

Nothing is lost in this process.
__________________
Dan Keaton
Augusta Georgia
Dan Keaton is offline   Reply With Quote
Old September 4th, 2009, 12:12 PM   #8
Regular Crew
 
Join Date: Aug 2009
Location: Tampa, FL
Posts: 96
Thanks guys. This is very helpful info and furthers my understanding of this technology. I will re-set the nano for "psf in" and check the output and files!
Steve Brown is offline   Reply With Quote
Old September 6th, 2009, 02:00 PM   #9
Major Player
 
Join Date: Jul 2009
Location: Rancho Santa Margarita
Posts: 590
The biggest difference between psf and standard interlaced is that the two fields from psf, taken from a progessive sensor, are captured at the same precise instant in time. There are no interlacing artifacts at all.
Aaron Newsome is offline   Reply With Quote
Old September 11th, 2009, 06:04 AM   #10
Major Player
 
Join Date: May 2006
Location: Teaneck, NJ
Posts: 659
Quote:
Originally Posted by Alister Chapman View Post
As I understand it within the specifications for SMPTE 292 HDSDi there is no provision for 1920x1080 progressive signals. As a result any progressive 1920x1080 images must be encoded as PsF in an interlace stream. So if you are working with a 1080P camcorder the HDSDi will be PsF. There is no loss of quality or motion issues when using PsF, in most cases it's use is completely transparent.
Then, just to clarify for my sometimes-dense mind, I should set PSF In to the ON selection when recording 1080/24p or 1080/30p from Sony EX1/3

Ned Soltz
Ned Soltz is offline   Reply With Quote
Old September 11th, 2009, 06:24 AM   #11
Inner Circle
 
Join Date: Dec 2002
Location: Augusta Georgia
Posts: 5,421
Dear Ned,

Yes. But I will verify this for you this morning.
__________________
Dan Keaton
Augusta Georgia
Dan Keaton is offline   Reply With Quote
Old September 11th, 2009, 06:43 AM   #12
Inner Circle
 
Join Date: Dec 2005
Location: Bracknell, Berkshire, UK
Posts: 4,957
The NanoFlash will work with PsF ticked or not. Sony's (and most other) cameras when set to progressive output a PsF signal which to the NanoFlash is no different to an interlace signal.

The NanoFlash does not know whether what it is seeing is Progressive or Interlace. If you tick the "PsF In" box the NanoFlash records the input as progressive. The biggest potential problem is if you are shooting interlace and you leave the box ticked as the interlace footage would be recorded as progressive. If you dropped interlaced material recorded as progressive into an interlace timeline it may not be displayed correctly.

In short if you are shooting Progressive you need to tick the box, if you are shooting interlace, no tick.

If you are at all unsure the safest is to not tick the box. Any progressive PsF material would be recorded as Interlace by the NanoFlash, but this shouldn't really make any difference when the files get played back, but it may confuse you as your files will report being interlace while the content is progressive.

I hope that makes sense.
__________________
Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com
Alister Chapman is offline   Reply With Quote
Old September 11th, 2009, 07:10 AM   #13
Inner Circle
 
Join Date: Dec 2002
Location: Augusta Georgia
Posts: 5,421
Dear Alister,

Thanks for the assistance.
__________________
Dan Keaton
Augusta Georgia
Dan Keaton is offline   Reply With Quote
Old September 11th, 2009, 07:33 AM   #14
Major Player
 
Join Date: May 2006
Location: Teaneck, NJ
Posts: 659
That makes ample sense. I appreciate the clarity of the response!

Ned
Ned Soltz is offline   Reply With Quote
Old September 14th, 2009, 05:44 PM   #15
Regular Crew
 
Join Date: Aug 2009
Location: Tampa, FL
Posts: 96
Ditto... thanks to everyone for the clarifications!
Steve Brown 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...

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

Scan Computers Int. Ltd.
+44 0871-472-4747
Bolton, Lancashire UK


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

 



All times are GMT -6. The time now is 03:31 AM.


DV Info Net -- Real Names, Real People, Real Info!
1998-2024 The Digital Video Information Network