1440 or 1920 - Techwatch: Satellite TV forums, FTA, Cable, Hardware, & Tech forums

sm_17 · 14-03-07, 07:49 AM

I've heard lots of people saying that the 1920x1080 recording capability of the HV20 is down sampled to 1440x1080 when it is saved on the tape. EVERYTHING i've read from spec sheets says that when you put the camera in "WIDE" screen mode it saves it as 1920x1080, and if you use Standard HDV (4:3) then it is saved as 1440x1080.

I don't want some bullcrap line that the Digital tape doesn't support 1920x1080, because that's bogus, It's a Data tape it could care less if you write a 1920x1080 frame to it or a 1x1 frame to it... it's gonna save it.

Shedding some light on this subject would be nice

jaelupo · 14-03-07, 06:22 PM

The HDV compression used by the HV10 and HV20 is an industry standard. This standard maximum save format of 1440x1080. Both the HV10 and HV20 can capture 1920x1080 but the HDV compression downgrades the signal. This is not a limitation on the tape itself it is a limitation of the standard. There is only one way to get true 1920x1080 resolution out of the HV20; use an HDMI capture card with the HV20 and record straight to a computer (this will not work with the HV10- no HDMI). Some people here have said you can use a 3:2 Pulldown in your video editing software to achive full 1920x1080 but I don't find that to be true. 3:2 pulldown affects the frames per second (Converts 24p to 29.97) it does not convert 1440x1080 to 1920x1080.

toni1 · 14-03-07, 07:34 PM

There is a tape limitation of amount of information you can put on it.
A one hour dv tape can take 12 gigas of data (more compressed in mpeg2-hd that in mpeg-2 sd )
1920 is about 25% more data than 1440 (this means that if it was possible and it is not, then you can squeez only 45 minutes hd video). Another problem is data rate: higher data rate to tape equal more errors.

JVC future hd Everio will register to internal hd drive at 1920 ( special jvc compression and no size limitation with a 60 giga hard drive) ; Xe still know little about real quality of that.

jaelupo · 14-03-07, 09:12 PM

Good point toni1 the amount of data needed to store 1920x1080 resolution would result in only about 30-45 minutes of video on a Mini-DV tape. I am sure Canon thought most people would not accept this. What needs to happen is for these companies to use a new type of tape technology like DLT to store more info or to use harddrives. I don't like the harddrive idea because you still have to put your video somewhere and hard drives are not the safest place for it. Tapes last much longer and are a lot cheaper.

sm_17 · 14-03-07, 11:05 PM

The amount of video that a tape can hold is less important, in my opinion, than getting the full capability of the camera.

Jaelupo - your post was the most helpful I thought HDV was a term not a standard. after looking into it I see what you are talking about. When in Wide screen Canon is using the entire CCD but rather than save it as a 1.0 pixel ratio @ 1920x1080 they are processing the video and sending 1.333 pixel ratio content and saving it @1440x1080 which is actually 4:3. When viewed on an HDTV that supports up to 1080p the image quality will be greater than 720p. 720p is approximately what 40% of the available HDTV content is anyhow. In standard you'll get a 1.0 Pixel Ratio but you won't be using 25% of your CCD.

On another note, with data buffer technology and memory being cheep I don't think saving 1920x1080 to a DV tape is a problem. I won't say for sure but my bet is that adhering to a standard that is usable was the only reason for canon not to implement saving the full res to the tapes.

toni1 · 14-03-07, 11:26 PM

Again what is important is outcome; hv10 even at 1440 has a higher outcome on mesured resolution chart than older Sony HC1 or HC3 that are also at 1440

jaelupo · 15-03-07, 05:33 AM

I agree that the video is the most important thing here, I can care less if the tape only last 10 minutes but I could get the highest possible quality. There should be a switch to turn off the HDV compression and save the fully quality of the camera.

lovehateHDV · 15-03-07, 07:19 AM

Just a reminder:

vertical resolution is what the human eye wants. Horizontal kind of "just happens."

HDV people took this into consideration. Just look at the graphics and/or text on your computer screen and you'll see that "Y" has less of perceived horizontal resolution, but still looks sharp due to high vertical resolution.

toni1 · 15-03-07, 08:23 PM

lovehateHDV, do you know where to get details about vertical percieved resolution versus horizontal. Didn't see anything about that yet

lovehateHDV · 15-03-07, 10:07 PM

I repent.

H and V are both equally important for a good picture.

14-03-07, 07:49 AM	#1 (permalink)
sm_17 Junior Member Join Date: Mar 2007 Location: Commerce TWP, USA Posts: 5 Thanks: 0 Thanked 0 Times in 0 Posts	1440 or 1920 I've heard lots of people saying that the 1920x1080 recording capability of the HV20 is down sampled to 1440x1080 when it is saved on the tape. EVERYTHING i've read from spec sheets says that when you put the camera in "WIDE" screen mode it saves it as 1920x1080, and if you use Standard HDV (4:3) then it is saved as 1440x1080. I don't want some bullcrap line that the Digital tape doesn't support 1920x1080, because that's bogus, It's a Data tape it could care less if you write a 1920x1080 frame to it or a 1x1 frame to it... it's gonna save it. Shedding some light on this subject would be nice


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14-03-07, 06:22 PM	#2 (permalink)
jaelupo Member Join Date: Feb 2007 Posts: 85 Thanks: 0 Thanked 0 Times in 0 Posts	The HDV compression used by the HV10 and HV20 is an industry standard. This standard maximum save format of 1440x1080. Both the HV10 and HV20 can capture 1920x1080 but the HDV compression downgrades the signal. This is not a limitation on the tape itself it is a limitation of the standard. There is only one way to get true 1920x1080 resolution out of the HV20; use an HDMI capture card with the HV20 and record straight to a computer (this will not work with the HV10- no HDMI). Some people here have said you can use a 3:2 Pulldown in your video editing software to achive full 1920x1080 but I don't find that to be true. 3:2 pulldown affects the frames per second (Converts 24p to 29.97) it does not convert 1440x1080 to 1920x1080.

14-03-07, 07:34 PM	#3 (permalink)
toni1 Senior Member Join Date: Feb 2007 Location: France Posts: 123 Thanks: 0 Thanked 0 Times in 0 Posts	There is a tape limitation of amount of information you can put on it. A one hour dv tape can take 12 gigas of data (more compressed in mpeg2-hd that in mpeg-2 sd ) 1920 is about 25% more data than 1440 (this means that if it was possible and it is not, then you can squeez only 45 minutes hd video). Another problem is data rate: higher data rate to tape equal more errors. JVC future hd Everio will register to internal hd drive at 1920 ( special jvc compression and no size limitation with a 60 giga hard drive) ; Xe still know little about real quality of that.

14-03-07, 09:12 PM	#4 (permalink)
jaelupo Member Join Date: Feb 2007 Posts: 85 Thanks: 0 Thanked 0 Times in 0 Posts	Good point toni1 the amount of data needed to store 1920x1080 resolution would result in only about 30-45 minutes of video on a Mini-DV tape. I am sure Canon thought most people would not accept this. What needs to happen is for these companies to use a new type of tape technology like DLT to store more info or to use harddrives. I don't like the harddrive idea because you still have to put your video somewhere and hard drives are not the safest place for it. Tapes last much longer and are a lot cheaper.

14-03-07, 11:05 PM	#5 (permalink)
sm_17 Junior Member Join Date: Mar 2007 Location: Commerce TWP, USA Posts: 5 Thanks: 0 Thanked 0 Times in 0 Posts	The amount of video that a tape can hold is less important, in my opinion, than getting the full capability of the camera. Jaelupo - your post was the most helpful I thought HDV was a term not a standard. after looking into it I see what you are talking about. When in Wide screen Canon is using the entire CCD but rather than save it as a 1.0 pixel ratio @ 1920x1080 they are processing the video and sending 1.333 pixel ratio content and saving it @1440x1080 which is actually 4:3. When viewed on an HDTV that supports up to 1080p the image quality will be greater than 720p. 720p is approximately what 40% of the available HDTV content is anyhow. In standard you'll get a 1.0 Pixel Ratio but you won't be using 25% of your CCD. On another note, with data buffer technology and memory being cheep I don't think saving 1920x1080 to a DV tape is a problem. I won't say for sure but my bet is that adhering to a standard that is usable was the only reason for canon not to implement saving the full res to the tapes.

14-03-07, 11:26 PM	#6 (permalink)
toni1 Senior Member Join Date: Feb 2007 Location: France Posts: 123 Thanks: 0 Thanked 0 Times in 0 Posts	Again what is important is outcome; hv10 even at 1440 has a higher outcome on mesured resolution chart than older Sony HC1 or HC3 that are also at 1440

15-03-07, 05:33 AM	#7 (permalink)
jaelupo Member Join Date: Feb 2007 Posts: 85 Thanks: 0 Thanked 0 Times in 0 Posts	I agree that the video is the most important thing here, I can care less if the tape only last 10 minutes but I could get the highest possible quality. There should be a switch to turn off the HDV compression and save the fully quality of the camera.

15-03-07, 07:19 AM	#8 (permalink)
lovehateHDV Senior Member Join Date: Feb 2007 Location: Seattle, Earth, Milky Way, the 4D Universe Posts: 171 Thanks: 0 Thanked 0 Times in 0 Posts	Just a reminder: vertical resolution is what the human eye wants. Horizontal kind of "just happens." HDV people took this into consideration. Just look at the graphics and/or text on your computer screen and you'll see that "Y" has less of perceived horizontal resolution, but still looks sharp due to high vertical resolution.

15-03-07, 08:23 PM	#9 (permalink)
toni1 Senior Member Join Date: Feb 2007 Location: France Posts: 123 Thanks: 0 Thanked 0 Times in 0 Posts	lovehateHDV, do you know where to get details about vertical percieved resolution versus horizontal. Didn't see anything about that yet

15-03-07, 10:07 PM	#10 (permalink)
lovehateHDV Senior Member Join Date: Feb 2007 Location: Seattle, Earth, Milky Way, the 4D Universe Posts: 171 Thanks: 0 Thanked 0 Times in 0 Posts	I repent. H and V are both equally important for a good picture.