Question about 1440 x 1080 at DVinfo.net

Sean Lee · June 9th, 2009, 03:34 PM

I'm totally lost about the Aspect Ratio and need some assistance. Can anyone explain, or direct me to proper thread which explains this?

When i shoot in HDV mode, my HVR-A1 shoots 1440 x 1080 (i believe), but the ratio of 1440:1080 is 4:3 instead of 16:9. But on the screen it appears as 16:9.

And when i shoot in Standard DV mode, and select 16:9, it comes out as 720 x 480, which is neither 16:9 or 4:3, but 3:2. I'm starting to think that # of pixels has nothing to do with aspect ratio.

One extra question, if I edit 1440 x 1080 footage and 1920 x 1080 footage on same timeline, would there be any problem? I'm thinking about getting a XH-A1 and use along with my HVR-A1.

Brian Boyko · June 9th, 2009, 04:18 PM

Quote:

Originally Posted by Sean Lee

I'm totally lost about the Aspect Ratio and need some assistance. Can anyone explain, or direct me to proper thread which explains this?

When i shoot in HDV mode, my HVR-A1 shoots 1440 x 1080 (i believe), but the ratio of 1440:1080 is 4:3 instead of 16:9. But on the screen it appears as 16:9.

And when i shoot in Standard DV mode, and select 16:9, it comes out as 720 x 480, which is neither 16:9 or 4:3, but 3:2. I'm starting to think that # of pixels has nothing to do with aspect ratio.

One extra question, if I edit 1440 x 1080 footage and 1920 x 1080 footage on same timeline, would there be any problem? I'm thinking about getting a XH-A1 and use along with my HVR-A1.

This is funky, but in 1440x1080, you're not shooting square pixels. You're shooting rectangular ones that are 1.333 times wider than they are tall.

Essentially, you're shooting is a 16:9 image onto a 4:3 sensor; and the way this is done is because the camera lens and sensor are anamorphic - or, in layman's terms, "squished like a funhouse mirror."

Similarly, in Standard DV, 720x480 is 3:2, but if you squish it one way, so that the pixels are .9 times as wide as they are tall, you get a 4:3 image. If you squish it the other way, so that they're 1.2 times as wide as they are tall, you get a 16:9 image.

Sean Lee · June 9th, 2009, 04:29 PM

Thanks so much brian. It makes sense now.
So, if I shot 16:9 on SD miniDV, for the Setting on Final Cut, I should choose "DV-NTSC Anamorphic" instead of "DV-NTSC" or "DV-NTSC Firewire Basic"?

And, can 1440 x 1080 mix up with 1920 x 1080 on a same timeline?

Robert M Wright · June 10th, 2009, 10:34 AM

The Canon XH-A1 shoots 1440x1080. There is no such thing as 1920x1080 HDV.

HDV camcorders don't use anamorphic lenses and sensors with 4:3 physical dimensions. They use sensors that are indeed 16:9 in shape.

If your NLE supports it, you can mix 1440x1080 and 1920x1080 footage on the same timeline. Works just fine with Edius.

Bruno Donnet · June 11th, 2009, 04:29 AM

Quote:

Originally Posted by Brian Boyko

Essentially, you're shooting is a 16:9 image onto a 4:3 sensor; and the way this is done is because the camera lens and sensor are anamorphic

No!
There's no anamorphic process at the lens/sensor stages! All the HDV cams ('pro' or not) have a 16:9 image from the lens to the sensor. If the sensor has a 4:3 shape, some top and bottom pixels are simply not used in HDV mode (and the full 4:3 surface is only usable for the 4:3 SD mode or the photo mode).

The conversion from the 16:9 ratio to the anamorphic 4:3 ratio is done at the electronic image processor stage (for HDV: 1440 horizontal pixels, each one representing 1.33 width of a 'displayable' pixel).

Robert M Wright · June 11th, 2009, 10:38 AM

To the best of my knowledge (perhaps I'm mistaken) all HDV cameras use sensors that have a physical 16x9 shape. How the image gets to 1440x1080 from the sensor differs by camera. If I recall correctly, the Canon XH-A1 uses 16x9 shaped sensors with 1440x1080 pixels to begin with. I believe the HDR-FX1 uses 16x9 shaped sensors with 960x1080 pixels, and obviously there's some digital processing (pixel shifting) involved to generate a 1440x1080 image for recording. I'm not sure, but I think the HVR-A1 uses a single 16x9 shaped CMOS chip with 1920x1080 pixels (and downscales for recording).

Robert M Wright · June 11th, 2009, 10:46 AM

I just looked it up. The HVR-A1 uses a 2.97 4x3 dimension CMOS sensor (cropping the image from the chip for HDV).

Gene Gajewski · June 11th, 2009, 02:49 PM

Quote:

Originally Posted by Bruno Donnet

No!
There's no anamorphic process at the lens/sensor stages! All the HDV cams ('pro' or not) have a 16:9 image from the lens to the sensor. If the sensor has a 4:3 shape, some top and bottom pixels are simply not used in HDV mode (and the full 4:3 surface is only usable for the 4:3 SD mode or the photo mode).

The conversion from the 16:9 ratio to the anamorphic 4:3 ratio is done at the electronic image processor stage (for HDV: 1440 horizontal pixels, each one representing 1.33 width of a 'displayable' pixel).

Actually, no conversion at all if the sensor has physically 1440x1080 pixels - it's just stored as is on DV tape. When playing back the tape, the data is read as is - the 1.333 pixel aspect ratio is inferred so that square pixel monitors can produce the proper scale to get a 16x9 display.

Of course - if your monitoring the output of the camera from an analog output - the conversion is done in camera.

Bryan Daugherty · June 12th, 2009, 12:07 AM

Quote:

Originally Posted by Robert M Wright

...I think the HVR-A1 uses a single 16x9 shaped CMOS chip with 1920x1080 pixels (and downscales for recording).

To my knowledge the only cameras out there that use a sensor that is 1920x1080 is the SONY EX1 and EX3. All other cameras get to 1920x1080 through interpolation, stretching, or pixel shifting. All HDV output to 1440x1080 or smaller (think 720p.) This information is based on a video tutorial on the XDCAM EX format and can be viewed at the link below.

What's So Great about XDCAM EX? - on Vortex Media

(Note: I originally found this on the XDCAM thread here on DVi...)

Gene Gajewski · June 12th, 2009, 05:57 AM

Quote:

Originally Posted by Bryan Daugherty

To my knowledge the only cameras out there that use a sensor that is 1920x1080 is the SONY EX1 and EX3. All other cameras get to 1920x1080 through interpolation, stretching, or pixel shifting. All HDV output to 1440x1080 or smaller (think 720p.) This information is based on a video tutorial on the XDCAM EX format and can be viewed at the link below.

What's So Great about XDCAM EX? - on Vortex Media

(Note: I originally found this on the XDCAM thread here on DVi...)

Umm, I think some (all?) of the consumer AVCHD cameras use full 1920x1080 sensors. No?

It's just HDV that does 1440X1080.

Robert M Wright · June 12th, 2009, 07:41 AM

Consumer AVCHD cameras use sensors with all sorts of different pixel counts. Canon has one out now that has close to a 9 megapixel sensor. Panasonic leans on pixel shifting with 3 chippers that have fairly low pixel counts. Most AVCHD camcorders that record 1920x1080, can also record 1440x1080.

Gene Gajewski · June 12th, 2009, 11:54 PM

Exactly.

Somewhat OT:

I wonder if a large pixel count bayer-sensor interpolating to a lower resolution beats a 3 chip with lower resolution?

Robert M Wright · June 13th, 2009, 10:07 AM

The TM300 (and sister models) look promising. Previous Panny 3-chipper consumer AVCHD cams have been somewhat disappointing though.

Gene Gajewski · June 14th, 2009, 10:08 AM

Quote:

Originally Posted by Robert M Wright

The TM300 (and sister models) look promising. Previous Panny 3-chipper consumer AVCHD cams have been somewhat disappointing though.

Gonna be a while before I go for my next camera, current finances being what they are.

I think for me the issue in the furture is going to be low light sensitivity. I think, resolutio-wise, most of the upper-end consumer/pro-sumer cameras are doing fantastic. Exposre control, etc...

Robert M Wright · June 14th, 2009, 10:20 AM

What I like about the TM300, from what I've read, is perhaps the best low light performance of any consumer cam thus far, combined with fairly robust manual control (especially compared to consumer cams from other major mfgs).

When the TM300 (and sister models) come down to well under $1k, I'll start seriously considering selling and replacing an HV20.

June 9th, 2009, 03:34 PM	#1
Sean Lee New Boot Join Date: Apr 2009 Location: Norwalk, CA Posts: 17	Question about 1440 x 1080 I'm totally lost about the Aspect Ratio and need some assistance. Can anyone explain, or direct me to proper thread which explains this? When i shoot in HDV mode, my HVR-A1 shoots 1440 x 1080 (i believe), but the ratio of 1440:1080 is 4:3 instead of 16:9. But on the screen it appears as 16:9. And when i shoot in Standard DV mode, and select 16:9, it comes out as 720 x 480, which is neither 16:9 or 4:3, but 3:2. I'm starting to think that # of pixels has nothing to do with aspect ratio. One extra question, if I edit 1440 x 1080 footage and 1920 x 1080 footage on same timeline, would there be any problem? I'm thinking about getting a XH-A1 and use along with my HVR-A1. __________________ Wedding Videographer in Orange County, CA http://oneframemedia.wordpress.com

June 9th, 2009, 04:29 PM	#3
Sean Lee New Boot Join Date: Apr 2009 Location: Norwalk, CA Posts: 17	Thanks so much brian. It makes sense now. So, if I shot 16:9 on SD miniDV, for the Setting on Final Cut, I should choose "DV-NTSC Anamorphic" instead of "DV-NTSC" or "DV-NTSC Firewire Basic"? And, can 1440 x 1080 mix up with 1920 x 1080 on a same timeline? __________________ Wedding Videographer in Orange County, CA http://oneframemedia.wordpress.com

June 10th, 2009, 10:34 AM	#4
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	The Canon XH-A1 shoots 1440x1080. There is no such thing as 1920x1080 HDV. HDV camcorders don't use anamorphic lenses and sensors with 4:3 physical dimensions. They use sensors that are indeed 16:9 in shape. If your NLE supports it, you can mix 1440x1080 and 1920x1080 footage on the same timeline. Works just fine with Edius.

June 11th, 2009, 10:38 AM	#6
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	To the best of my knowledge (perhaps I'm mistaken) all HDV cameras use sensors that have a physical 16x9 shape. How the image gets to 1440x1080 from the sensor differs by camera. If I recall correctly, the Canon XH-A1 uses 16x9 shaped sensors with 1440x1080 pixels to begin with. I believe the HDR-FX1 uses 16x9 shaped sensors with 960x1080 pixels, and obviously there's some digital processing (pixel shifting) involved to generate a 1440x1080 image for recording. I'm not sure, but I think the HVR-A1 uses a single 16x9 shaped CMOS chip with 1920x1080 pixels (and downscales for recording).

June 11th, 2009, 10:46 AM	#7
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	I just looked it up. The HVR-A1 uses a 2.97 4x3 dimension CMOS sensor (cropping the image from the chip for HDV).

June 12th, 2009, 07:41 AM	#11
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	Consumer AVCHD cameras use sensors with all sorts of different pixel counts. Canon has one out now that has close to a 9 megapixel sensor. Panasonic leans on pixel shifting with 3 chippers that have fairly low pixel counts. Most AVCHD camcorders that record 1920x1080, can also record 1440x1080.

June 12th, 2009, 11:54 PM	#12
Gene Gajewski Regular Crew Join Date: Sep 2007 Location: Edgewood, NM Posts: 162	Exactly. Somewhat OT: I wonder if a large pixel count bayer-sensor interpolating to a lower resolution beats a 3 chip with lower resolution?

June 13th, 2009, 10:07 AM	#13
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	The TM300 (and sister models) look promising. Previous Panny 3-chipper consumer AVCHD cams have been somewhat disappointing though.

June 14th, 2009, 10:20 AM	#15
Robert M Wright Inner Circle Join Date: Jan 2006 Location: Minnesota (USA) Posts: 2,171	What I like about the TM300, from what I've read, is perhaps the best low light performance of any consumer cam thus far, combined with fairly robust manual control (especially compared to consumer cams from other major mfgs). When the TM300 (and sister models) come down to well under $1k, I'll start seriously considering selling and replacing an HV20.