DVD Maximization Question at DVinfo.net

Dale Connelly · November 3rd, 2005, 12:25 PM

Can we maximize DVD capability with HDV down conversion, not to the DV standard, but somewhere in between? It is my understanding that DVD is based on 480i, which is 852x480 and DV is 720x480. Can we use the extra 132 lines on the DVD with a good DVD authoring tool that can use HDV?

George Griswold · November 3rd, 2005, 06:02 PM

Let me take a stab at this....

I am not sure where the 852 number came from, that is new to me. You can have 720X480 in various forms-- DV25, DV50, etc. Sometimes there is 720X486...

If the camera could export a downconverted HDV through the component outs (I don't know if that output downconverts) you could bring it into a system as NTSC component at DV50 or 1:1 resolution (say with Avid MOJO) that would look better than DV25. I have never tried it... but pondered the subject more than once.

Just reckless speculation, but worth a try. Dale I think they will move this thread over to a post-production forum--- if they do, can you email me with your progress. Friday I may try this with my Avid MOJO and Z1 just to try it out. I need to see if the Component out outputs NTSC... I have a hunch that stays HD, but I don't know...

I know there are pricey, but wonderful converters that can do HD to NTSC conversions, but may not be practical for civilians/ non-broadcasters.

Boyd Ostroff · November 3rd, 2005, 06:31 PM

Sorry, you're mixing apples with oranges. DVD's are 720x480. However if you shoot widescreen anamorphic then the pixels are squashed. On playback if you view anamorphic 16:9 on a monitor with square pixels it will be stretched to about 854x480, but that is something the monitor itself does. The DVD stores the image in squashed format as 720x480. If you're working in standard definition NTSC then 720x480 is really your only option...

Dale Connelly · November 3rd, 2005, 06:45 PM

Quote:

Originally Posted by George Griswold

I am not sure where the 852 number came from,

George,

Thank you for the reply. I got the 852 number from various sites claiming the resolution of the DVD format. Here are some:

http://hometheater.about.com/od/dvdb...uhddvdinfo.htm
http://www.geocities.com/columbiaisa/dvd_hddvd.htm

http://pages.ebay.com/buy/guides/tv-...-buying-guide/

Would this be someone's mistake that has propagated thru the web?

Thanks,
Dale

Dale Connelly · November 4th, 2005, 09:53 PM

Quote:

Originally Posted by Boyd Ostroff

On playback if you view anamorphic 16:9 on a monitor with square pixels it will be stretched to about 854x480, but that is something the monitor itself does.

OK, I understand now. The monitor is capable of 854, not the signal. It stretches the 720 to be 854. This seems like an unnatural translation. A signal pixel must share a screen pixel with another signal pixel every now and then, causing a lack of sharpness.

Thanks for clearing this up.

Boyd Ostroff · November 4th, 2005, 10:25 PM

Yep, that's true, when you scale 720 to 854 there will be some issues since the number of pixels on a screen is an integer. Some monitors do a better job than others though depending on the scaling hardware/software, but it will always involve pixel blending/antialiasing which makes the image appear soft up close.

There are "enhanced definition" screens with native resolutions of 854x480. I think these do a little cleaner job than true HD displays with DVD material because 720x480 has both horizontal and vertical scaling issues with a 1280x720 screen.

In terms of theory, each video pixel has its own aspect ratio. So a widescreen image can still be 720x480 but the pixels are each a little wider. But a 4:3 image doesn't map properly to 720x480 square pixels either. On a device like an LCD screen it would be scaled to 640x480 so the individual pixels are skinnier. On an analog device this would be less of an issue than it is on LCD or plasma monitors.

George Griswold · November 5th, 2005, 06:25 AM

Is it just me or is this pixel, monitor thing a confusing hell-hole? I finally figured out how to make a clean DVD exported from Avid... I thought I was going insane! I tried Cleaner XL went to Sorenson-- works great.

Just my rant,
Thank you,
George

November 3rd, 2005, 12:25 PM	#1
Dale Connelly New Boot Join Date: Oct 2005 Location: Texarkana, Texas Posts: 24	DVD Maximization Question Can we maximize DVD capability with HDV down conversion, not to the DV standard, but somewhere in between? It is my understanding that DVD is based on 480i, which is 852x480 and DV is 720x480. Can we use the extra 132 lines on the DVD with a good DVD authoring tool that can use HDV? Last edited by Dale Connelly; November 3rd, 2005 at 03:53 PM.

November 3rd, 2005, 06:02 PM	#2
George Griswold Major Player Join Date: Apr 2005 Location: New Orleans, LA Posts: 218	Let me take a stab at this.... I am not sure where the 852 number came from, that is new to me. You can have 720X480 in various forms-- DV25, DV50, etc. Sometimes there is 720X486... If the camera could export a downconverted HDV through the component outs (I don't know if that output downconverts) you could bring it into a system as NTSC component at DV50 or 1:1 resolution (say with Avid MOJO) that would look better than DV25. I have never tried it... but pondered the subject more than once. Just reckless speculation, but worth a try. Dale I think they will move this thread over to a post-production forum--- if they do, can you email me with your progress. Friday I may try this with my Avid MOJO and Z1 just to try it out. I need to see if the Component out outputs NTSC... I have a hunch that stays HD, but I don't know... I know there are pricey, but wonderful converters that can do HD to NTSC conversions, but may not be practical for civilians/ non-broadcasters. __________________ George T. Griswold, Jr. www.videonow.info New Orleans

November 5th, 2005, 06:25 AM	#7
George Griswold Major Player Join Date: Apr 2005 Location: New Orleans, LA Posts: 218	Is it just me or is this pixel, monitor thing a confusing hell-hole? I finally figured out how to make a clean DVD exported from Avid... I thought I was going insane! I tried Cleaner XL went to Sorenson-- works great. Just my rant, Thank you, George __________________ George T. Griswold, Jr. www.videonow.info New Orleans

November 3rd, 2005, 06:31 PM	#3
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,800	Sorry, you're mixing apples with oranges. DVD's are 720x480. However if you shoot widescreen anamorphic then the pixels are squashed. On playback if you view anamorphic 16:9 on a monitor with square pixels it will be stretched to about 854x480, but that is something the monitor itself does. The DVD stores the image in squashed format as 720x480. If you're working in standard definition NTSC then 720x480 is really your only option...

November 4th, 2005, 10:25 PM	#6
Boyd Ostroff Wrangler Join Date: Dec 2002 Location: Mays Landing, NJ Posts: 11,800	Yep, that's true, when you scale 720 to 854 there will be some issues since the number of pixels on a screen is an integer. Some monitors do a better job than others though depending on the scaling hardware/software, but it will always involve pixel blending/antialiasing which makes the image appear soft up close. There are "enhanced definition" screens with native resolutions of 854x480. I think these do a little cleaner job than true HD displays with DVD material because 720x480 has both horizontal and vertical scaling issues with a 1280x720 screen. In terms of theory, each video pixel has its own aspect ratio. So a widescreen image can still be 720x480 but the pixels are each a little wider. But a 4:3 image doesn't map properly to 720x480 square pixels either. On a device like an LCD screen it would be scaled to 640x480 so the individual pixels are skinnier. On an analog device this would be less of an issue than it is on LCD or plasma monitors.