Shoot 720/60p or 1080/60i for SD-SDI downconversion? at DVinfo.net

John Dewey · March 26th, 2009, 03:41 PM

Hello everyone,

I have a shoot coming up later this week that I will be using my EX3 on. I'm shooting a hockey practice, some coach/player drills, and some stand-ups with an on camera talent.

I will then be feeding the footage as SD from my EX3 via the SD-SDI connector at the local Comcast Sports facility.

My question is, which will yield better results being downconverted to SD from the EX3's SD-SDI output, 720/60p HQ or 1080/60i HQ? Will it make a difference either way?

Thanks in advance for any help you can provide.

Andy Shipsides · March 26th, 2009, 03:55 PM

You should have your camera in 1080 for sure. Starting at the higher resolution will produce a better down converted image.

David C. Williams · March 26th, 2009, 05:11 PM

The BBC recommended 720P for down converts in PAL to reduce twittering. It may work the same for NTSC.

Simon Denny · March 26th, 2009, 07:45 PM

If you are going to edit the footage and then go to SD DVD MPEG-2, I use 720/50p and the results are better than 1080/25p down converted.
But re-reading your question you're going out live from the camera then I would shoot at the highest resolution.

John Dewey · March 29th, 2009, 05:39 PM

Thanks for the suggestions everyone.

The shoot was today, and I ended up shooting everything in 720/60p HQ due to the fact that I was shooting alot of fast moving hockey players on the ice.

I just wanted to follow up to say that the SD-SDI downconverted 720/60p HQ footage looked fantastic. It looked very close to the original HD footage. I was very impressed and so was the client.

Thanks again!

Ronnie Martin · March 31st, 2009, 02:23 PM

Quote:

Originally Posted by John Dewey

Thanks for the suggestions everyone.

The shoot was today, and I ended up shooting everything in 720/60p HQ due to the fact that I was shooting alot of fast moving hockey players on the ice.

I just wanted to follow up to say that the SD-SDI downconverted 720/60p HQ footage looked fantastic. It looked very close to the original HD footage. I was very impressed and so was the client.

Thanks again!

I shoot dirt racing at night with the EX-3 in ever changing light conditions. It has been my impression that I should be shooting 1080i (actually 1440x1080i). My editing platform is Edius/GV 5.1 and my final project is distributed in SD DVD. The footage when viewed on my Hd monitor looks stunning. However, during the down conversion process artifacts show up on horizontal lines or objects. I have tried all the methods (22 step vir dub process included)
and still get the artifacts. It seems to be related on panning from left to right. Could it be that shooting 720 60p as you are doing would eliminate this problem? I have mainly shot 1440X1080i rather than 1920X1080i because of the limited space on my SXS capture cards.
I can usually get the whole event using two 16gig cards. Most of the time I am shooting from top of a press box in poor light and do not want to remove and replace the SXS cards
there by opening up the camera to the dust and dirt much less the possibility of dropping one of those expensive cards.

Thanks
Ronnie Martin
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Gints Klimanis · April 3rd, 2009, 02:01 PM

Quote:

Originally Posted by Andy Shipsides

You should have your camera in 1080 for sure. Starting at the higher resolution will produce a better down converted image.

Not always. Most HD cable channels are 1280x720, so shooting at 1080i would result in more noise in space due to the compression burden of more pixels, more noise over time due to the lower frame rate , but less noise due to the increased light sensitivity of the interlaced modes on the EX1.

Dennis Dillon · April 3rd, 2009, 02:31 PM

Sometimes less is better. For Network Mags, that are still SD, we use 720 60p. Reason being we have done many tests both for high motion and static situations and have done blind tests with the 720 60p always winning out. I have been told the science behind this by Gary Adcock. see Meet Gary Adcock
That being said, the material is 720 for future releases, not the best in a 1080p world. So if the future of your material will be for HD rebroadcast, go with 1080, and save all original BPAV files.
BTW all my down conversions are via SD-SDI out to a SD XD 1500 deck.

Alister Chapman · April 3rd, 2009, 02:40 PM

The problem is with the way software converters handle fields and the excessive amount of picture detail when down converting to SD. A dedicated SD camera will have an optical low pass filter or electronic low pass filter to reduce the image sharpness so that you don't get twitter and aliasing. A simple software HD to SD conversion doesn't apply any softening so the SD image ends up overly sharp which looks bad. Also if you shoot 50/60P each frame gets converted to a field which seems to be handled better by most software converters. As the 720P picture has less detail than the 1920x1080 picture it is easier to get a good quality SD downconversion.

Marc Myers · April 3rd, 2009, 02:51 PM

It's been said elsewhere on this forum but EX1 just doesn't do great download to SD. But if it's what you have, it's what you have. When we're in the studio we output HD-SDI directly to DVCAM and a PDW-F75. That SD footage is outstanding. It's the compression that causes the misery. I've not done exhaustive tests but subjectively the best results have been 720P for me when final output is DVD for distribution to Cable systems, etc.

John Peterson · April 3rd, 2009, 04:06 PM

Quote:

Originally Posted by Dennis Dillon

BTW all my down conversions are via SD-SDI out to a SD XD 1500 deck.

What is the exact model of that deck Dennis?

Thanks,

John

Dennis Dillon · April 4th, 2009, 06:19 AM

John,
The deck is a PDW-1500 Sony XD. The newer PDWHD-1500 will work as well.

March 26th, 2009, 03:41 PM	#1
John Dewey Major Player Join Date: Jul 2006 Location: Tinley Park, Illinois Posts: 288	Shoot 720/60p or 1080/60i for SD-SDI downconversion? Hello everyone, I have a shoot coming up later this week that I will be using my EX3 on. I'm shooting a hockey practice, some coach/player drills, and some stand-ups with an on camera talent. I will then be feeding the footage as SD from my EX3 via the SD-SDI connector at the local Comcast Sports facility. My question is, which will yield better results being downconverted to SD from the EX3's SD-SDI output, 720/60p HQ or 1080/60i HQ? Will it make a difference either way? Thanks in advance for any help you can provide.

March 26th, 2009, 03:55 PM	#2
Andy Shipsides Sponsor: Abel CineTech Join Date: Feb 2009 Location: New York, NY Posts: 361	You should have your camera in 1080 for sure. Starting at the higher resolution will produce a better down converted image. __________________ Andy Shipsides -Camera Technology Specialist AbelCineTech, New York - Visit our Blog - http://blog.abelcine.com

March 26th, 2009, 05:11 PM	#3
David C. Williams Major Player Join Date: Jun 2008 Location: melb.vic.au Posts: 447	The BBC recommended 720P for down converts in PAL to reduce twittering. It may work the same for NTSC. __________________ www.davidwilliams.com.au

March 29th, 2009, 05:39 PM	#5
John Dewey Major Player Join Date: Jul 2006 Location: Tinley Park, Illinois Posts: 288	very nice SD-SDI downconversion Thanks for the suggestions everyone. The shoot was today, and I ended up shooting everything in 720/60p HQ due to the fact that I was shooting alot of fast moving hockey players on the ice. I just wanted to follow up to say that the SD-SDI downconverted 720/60p HQ footage looked fantastic. It looked very close to the original HD footage. I was very impressed and so was the client. Thanks again!

April 3rd, 2009, 02:40 PM	#9
Alister Chapman Inner Circle Join Date: Dec 2005 Location: Bracknell, Berkshire, UK Posts: 4,957	The problem is with the way software converters handle fields and the excessive amount of picture detail when down converting to SD. A dedicated SD camera will have an optical low pass filter or electronic low pass filter to reduce the image sharpness so that you don't get twitter and aliasing. A simple software HD to SD conversion doesn't apply any softening so the SD image ends up overly sharp which looks bad. Also if you shoot 50/60P each frame gets converted to a field which seems to be handled better by most software converters. As the 720P picture has less detail than the 1920x1080 picture it is easier to get a good quality SD downconversion. __________________ Alister Chapman, Film-Maker/Stormchaser http://www.xdcam-user.com/alisters-blog/ My XDCAM site and blog. http://www.hurricane-rig.com

March 26th, 2009, 07:45 PM	#4
Simon Denny Trustee Join Date: Jul 2007 Location: Australia Posts: 1,409	If you are going to edit the footage and then go to SD DVD MPEG-2, I use 720/50p and the results are better than 1080/25p down converted. But re-reading your question you're going out live from the camera then I would shoot at the highest resolution.

April 3rd, 2009, 02:31 PM	#8
Dennis Dillon Major Player Join Date: Nov 2006 Location: Hobe Sound, Florida Posts: 213	Sometimes less is better. For Network Mags, that are still SD, we use 720 60p. Reason being we have done many tests both for high motion and static situations and have done blind tests with the 720 60p always winning out. I have been told the science behind this by Gary Adcock. see Meet Gary Adcock That being said, the material is 720 for future releases, not the best in a 1080p world. So if the future of your material will be for HD rebroadcast, go with 1080, and save all original BPAV files. BTW all my down conversions are via SD-SDI out to a SD XD 1500 deck.

April 3rd, 2009, 02:51 PM	#10
Marc Myers Regular Crew Join Date: Nov 2008 Location: Long Island, NY and Northeast PA Posts: 132	It's been said elsewhere on this forum but EX1 just doesn't do great download to SD. But if it's what you have, it's what you have. When we're in the studio we output HD-SDI directly to DVCAM and a PDW-F75. That SD footage is outstanding. It's the compression that causes the misery. I've not done exhaustive tests but subjectively the best results have been 720P for me when final output is DVD for distribution to Cable systems, etc.

April 4th, 2009, 06:19 AM	#12
Dennis Dillon Major Player Join Date: Nov 2006 Location: Hobe Sound, Florida Posts: 213	John, The deck is a PDW-1500 Sony XD. The newer PDWHD-1500 will work as well.