HDV Aspect Ratio questions at DVinfo.net

Mike McKay · September 3rd, 2008, 02:29 PM

I have a project shot on FX1, I made a Vegas 8 project with 1440x1080 properties, de-interlace set to blend fields. I started the project in Vegas 6 with 1920x1080 properties then decided to just get V8. My question is that I made widescreen SD DVD's from both as tests and they look exactly the same on any TV I play them, I'm happy with it, I just don't understand the difference? Is the 1440 just getting up-rezzed on render?
Also, what prompted the question is that I'm trying to incorporate a Google Earth screen capture into the project and gave up trying to use laggy software like Fraps to capture and just shot my 1680x1080 LCD monitor with the FX1....it looks great, smooth etc, however as soon as I drop that into my timeline it doesn't look as sharp as the footage I see when shooting it? I guessed it was because the screen res is different? Any ideas.

Richard Hunter · September 4th, 2008, 08:01 AM

Hi Mike. Your SD DVD is 720x480 resolution, so the HDV footage is actually being downrezzed on render. And putting HDV footage on a 1920x1080 timeline will most likely cause an uprez step from 1440x1080 before final render so there is no point doing that unless you have a good reason.

Regarding the monitor footage, the Vegas preview window will not show you the full quality of the image. Have you tried rendering a section to see what it really looks like?

Richard

Perrone Ford · September 4th, 2008, 08:09 AM

1440 is not uprezzed to get to 1920. The pixel shape is merely changed from 1.33:1 to 1:1.

Quote:

Originally Posted by Richard Hunter

Hi Mike. Your SD DVD is 720x480 resolution, so the HDV footage is actually being downrezzed on render. And putting HDV footage on a 1920x1080 timeline will most likely cause an uprez step from 1440x1080 before final render so there is no point doing that unless you have a good reason.

Regarding the monitor footage, the Vegas preview window will not show you the full quality of the image. Have you tried rendering a section to see what it really looks like?

Richard

Mike McKay · September 4th, 2008, 11:31 AM

Thanks guys, turns out I'm an idiot, when I shot my monitor to capture the google earth sequence I forgot to focus......hence not looking as sharp....duh!

I just can't wrap my head around the whole pixel shape thing, I know my camera chips are 1440x1080 and when I output directly to a 1920x1080 display in HD it looks totally fine...I don't understand shape change from 1.33:1 to 1:1, if they change shape should that not effect how it looks or the aspect ratio?

Richard Hunter · September 6th, 2008, 02:25 AM

Quote:

Originally Posted by Perrone Ford

1440 is not uprezzed to get to 1920. The pixel shape is merely changed from 1.33:1 to 1:1.

If you did that, it would just change the frame aspect ratio which would make the image look squashed.

For a 1920x1080, 16:9 final output, the 1440 rectangular pixels per line have to be resampled to 1920 square pixels upon rendering. There is no real increase in resolution because no real new data is created, but the pixel count definitely has to be uprezzed.

For a project where the timeline footage properties do not match, I believe that Vegas will convert the footage to the project properties for playback and/or processing (can't prove it though). If so, then for HDV footage in a 1920 project, the 1440 rectangular pixels will be resampled to 1920.

For an HDV project with HDV footage, the 1440 rectangular pixels still have to be converted to square pixels for viewing in the preview window (because PC monitors have square pixels), but that is for display only and does not affect the resolution used when applying filters and transitions, etc.

Richard

September 3rd, 2008, 02:29 PM	#1
Mike McKay Regular Crew Join Date: Jan 2006 Location: Vancouver Posts: 125	HDV Aspect Ratio questions I have a project shot on FX1, I made a Vegas 8 project with 1440x1080 properties, de-interlace set to blend fields. I started the project in Vegas 6 with 1920x1080 properties then decided to just get V8. My question is that I made widescreen SD DVD's from both as tests and they look exactly the same on any TV I play them, I'm happy with it, I just don't understand the difference? Is the 1440 just getting up-rezzed on render? Also, what prompted the question is that I'm trying to incorporate a Google Earth screen capture into the project and gave up trying to use laggy software like Fraps to capture and just shot my 1680x1080 LCD monitor with the FX1....it looks great, smooth etc, however as soon as I drop that into my timeline it doesn't look as sharp as the footage I see when shooting it? I guessed it was because the screen res is different? Any ideas.

September 4th, 2008, 08:01 AM	#2
Richard Hunter Trustee Join Date: Dec 2004 Location: Lipa City Batangas, Philippines Posts: 1,110	Hi Mike. Your SD DVD is 720x480 resolution, so the HDV footage is actually being downrezzed on render. And putting HDV footage on a 1920x1080 timeline will most likely cause an uprez step from 1440x1080 before final render so there is no point doing that unless you have a good reason. Regarding the monitor footage, the Vegas preview window will not show you the full quality of the image. Have you tried rendering a section to see what it really looks like? Richard

September 4th, 2008, 11:31 AM	#4
Mike McKay Regular Crew Join Date: Jan 2006 Location: Vancouver Posts: 125	Thanks guys, turns out I'm an idiot, when I shot my monitor to capture the google earth sequence I forgot to focus......hence not looking as sharp....duh! I just can't wrap my head around the whole pixel shape thing, I know my camera chips are 1440x1080 and when I output directly to a 1920x1080 display in HD it looks totally fine...I don't understand shape change from 1.33:1 to 1:1, if they change shape should that not effect how it looks or the aspect ratio?