Resolution Reference?

[Chicken Warrior]

I'm kind of reluctant to post this knowing that my answers are scattered all over this forum, but I would REALLY appreciate a single list of the different resolutions you can get with the HV20 (and maybe make it a sticky?). A simple list (or two, one for NTSC, one for PAL) that states:

Camera Mode / Resolution x Resolution / 720p or 1080i (interlaced or 'progressive')/ Other Notes (advantages, disadvantages).

I'm especially confused how 24p affects the actual resolution.

If there's already a thread like this I just haven't been able to find, please redirect me.

[ethanfox]

not sure on the other questions, but 24p doesn't affect resolution at all - it just changes the frame rate and records progressive. Resolution is the same (1440x1080).

[jmalmsten]

what ethanfox said...

So there are really only 2 resolutions you can get from camera with it...

1440x1080 HDV with 1.33PAR

720x576 SD PAL, or the resolution I don't remember for NTSC SD, DV.

Those are listed in your Userguide for example... take a look... back in the end... in the middle of the list of datasheets and specs...

A third mode would be the 1920x1080 HDMI acquisition with square PAR.

in post you could get 720p downscaled or 540p overcranked 50fps slowmotion.

[Chicken Warrior]

If the resolution is the same, how come it's called 1080i and 720p. I thought there was some resolution loss to achieve progressive frames. Is one measured vertical and the other horizontal? Sorry if this is a dumb question but the user guide seems to shy away from properly explaining anything.

[Lunchbox]

HV20 doesn't support 720p. It can be 1080i (60i) or 1080p (PF24). The vertical resolution is 1080 lines of the frame size. It was shot in two consecutive fields per second in interlaced, or one full frame per second in progressive.

[Chicken Warrior]

Right, so why is it called 720p?

[Lunchbox]

Right, so why is it called 720p?

what is "IT" ? HV20 doesn't do 720p.

[jmalmsten]

the 720 I listed was the PAL 720x576... and that's 720 HORISONTAL pixels... the 720p that is a HD format is 1280x720... which is 720 pixels VERTICALLY. I think that's what may have confused Chicken Warrior

Video always list resolution in vertical pixels with the marking of i or p.
Still-photo-cams always list resolution in mega pixels... which is essentially the number of pixels in total of the picture. (vertical * horizontal).
Film always list their resolution (when scanned) in horizontal pixels. And film is inherently always progressive

They are listed in some screens as "1080i or 720p" since the bandwidth is essentially the same. It sounds weird at first sight, but one must consider that 1080i is half the resolution of 1080p but in double the normal framerate of normal progressive systems.

and as Taky says... the HV20 simply doesn't do 720p in camera. A few cam's do, but not HV20. The HV20's HD resolution is 1080 in both progressive and interlaced modes. Plus the PAL 576i SD (as opposed to HD) or NTSC 480i depending on where you bought it...

but as the old forum-saying goes... "rtfm"...

[Lunchbox]

1080i is not half the resolution of 1080p. Resolution are the same in both 1080i and 1080p. They are shoot in different mode (progressive full frame, or, interlaced in 2 fields).

[jabloomf1230]

A third mode would be the 1920x1080 HDMI acquisition with square PAR.

This comment comes up quite frequently on this message board, but in fact, this alternative is close to impractical and costs a lot more than the HV20 itself to implement. Figure that you need an HDMI capture card like the BlackMagic Intensity ($210-$250 + tax & shipping) and a computer with at least 4 fast SATA II hard drives in RAID0, just to keep up with the uncompressed HD capture. WD Raptor 150GB hard drives are running around $170 each, so you get the idea.

I could see going this route with a pro class camcorder, but with the HV20? To each his own, I guess.

[Ian-T]

I could see going this route with a pro class camcorder, but with the HV20? To each his own, I guess.

Why not? Especially, with the use of wavelet codecs, there is no need for anyone, pro or no-pro, to capture uncompressed.

[jmalmsten]

This comment comes up quite frequently on this message board, but in fact, this alternative is close to impractical and costs a lot more than the HV20 itself to implement. Figure that you need an HDMI capture card like the BlackMagic Intensity ($210-$250 + tax & shipping) and a computer with at least 4 fast SATA II hard drives in RAID0, just to keep up with the uncompressed HD capture. WD Raptor 150GB hard drives are running around $170 each, so you get the idea.

I could see going this route with a pro class camcorder, but with the HV20? To each his own, I guess.

But it is an option that gives another resolution

And the half resolution bit... I honestly don't know for sure to be honest... I was sitting there hesitating because I know it sounds wrong... but there must exist some reason why 1080i is always accompanied with 720p on HD-"ready" screens... And since interlaced frames are recorded from two separate readings at every other line and then stored on the same frame I do feel that the resolution is essentially half of 1080p... at twice the framerate... only the camera is storing it in the same resolution and framerate as a 1080p camera.

The mind boggles to the fact that we have to live with the notion of interlace... why not just make a 60p camera at half resolution if one wants the television look?

[jabloomf1230]

Why not? Especially, with the use of wavelet codecs, there is no need for anyone, pro or no-pro, to capture uncompressed.

I knew after I typed that, that someone was going to think that I was implying that capturing from HDMI was a bad idea. My point was, that at least at present, the hardware setup for doing so is about 1.5X the street cost of the HV20. Now, if you already have the big RAID0 setup for some other reason, then the additional hardware to capture @ true 1080 HD is a trivial cost and from the examples that I've seen, the HDMI capture picture quality is improved over the HDV firewire captures.

I apologize if anyone felt that I was trying to discourage people from pushing the HV20 to it's true limits. It is a heck of camcorder for the price. And some of the tricks to work around it's automatic nature , like HDMI capture, 24p workflow and the EXP Lock trick, only emphasize how versatile the HV20 is. And how clever the community is.

[Vladimir]

I just measure resolution of my HV20 (50i mode) with 4x3 test chart(EIA1956) and get 920x920 good visible lines, that actualy equal 1226x920 at 16:9.
You may open my chart results here:
http://64.72.122.139/hv20_max_sharp.png

Btw, i shoot the same chart with my second Panasonic DX1 and get 710x660 good visible lines (4x3) that equal 946x660 at 16:9
http://64.72.122.139/dx1_avchd_frame.png

That 2 charts show me advantages of a TRUE HD sensors(HV20) over pixel shi(f)t technology that Panny used in SD1-SD9

Hope you'l find that info helpful.

[jabloomf1230]

Why not? Especially, with the use of wavelet codecs, there is no need for anyone, pro or no-pro, to capture uncompressed.

True, but the two ways of doing compressed 1920X1080 with the HV20 are using Cineform Neo HD (~$600) or using the BlackMagic MJPEG codec. Unfortunately, the latter does not work properly with Vegas 8.0 Pro, because the internal Sony internal MJPEG codec conflicts with the BMD codec and the Sony codec can't be disabled. It's a Vegas flaw, but I'm not about to buy another NLE.

[Duke]

Quote:
Originally Posted by Ian-T View Post
Why not? Especially, with the use of wavelet codecs, there is no need for anyone, pro or no-pro, to capture uncompressed.

True, but the two ways of doing compressed 1920X1080 with the HV20 are using Cineform Neo HD (~$600) or using the BlackMagic MJPEG codec. Unfortunately, the latter does not work properly with Vegas 8.0 Pro, because the internal Sony internal MJPEG codec conflicts with the BMD codec and the Sony codec can't be disabled. It's a Vegas flaw, but I'm not about to buy another NLE.

I will respectfully disagree with those two statements for two or more situations. Not only does HDMI capture give you 25% more image data over HDV, but it also gives you 4:2:2 color space and data instead of 4:2:0.

HDV 4:2:0 color space gives you color data on every other pixel on one line and no color data on the next line what so ever. 4:2:2 colorspace gives data on every other pixel on all lines.

If you're doing lots of compositing or green screen the HDV composites can be 3-4 pixels off, sometimes giving a jagged edge. The direct capture data is only one pixel off. It's just cleaner.

Also, if you are really going to transfer to real film you'll want that extra image data. On a 40' screen a horizontal pixel in 1.333 aspect is between 1/3 and 1/2" while the 1920 square pixel is 1/4". It looks sharper.

Three drives will give you adequate transfer on raid0, and some of the WD 500gig drives go on sale for $100-$129. Plus if you go uncompressed you don't need a fast CPU, where if you're compressing you do.

You should look a Eugeina's comparisons of the codecs too. Cineform is good, and fast, but it's not perfect and not lossless.

My 2 cents worth,
Duke

[Vladimir]

Did you guys know, that 1920x1080 video captured from BlackMagic card actually restored from 1440x1080 before HDMI output?
The only advenages of BlackMagic capturing is non-compressed data and 4:2:2 color space. Resolution stays the same.

[Duke]

I have an inquiry in to Canon about that assumption.

The HDMI output is definitely measures 1920x1080 with square pixels and 4:2:2 colorspace. (At the very least you get the color space.)

And just as definately the HDV inside the camera is 1440x1080 with 4:2:0.

However, Canon advertises that the CMOS chip captures true 1920x1080. The HV20 CMOS chip is actually 3 megapixels and 1920x1080 is only about 2 megapixels.

Do you think the Canon engineers would compress the CMOS output to 1440, then up-convert it to 1920 again? Or just tap in before it's down-converted?

It will be interesting to see what they say.
Duke

[jabloomf1230]

I have an inquiry in to Canon about that assumption.

Good luck with that. No one's been able to pry that information loose from Canon. The 1920 stuff must be there somewhere, because the mini SD card, when used in camera mode, captures stills at that resolution.

One other thing that should be mentioned is that HDMI is a much greater advantage with a live connection (hence all the "backpack laptop storage solution" threads on this and other video websites). Once stuff is on the tape, it's definitely been converted to 1440 X 1280. And the HDMI feed has no metadata, so you also need the firewire connection to get that info.

Three drives will give you adequate transfer on raid0, and some of the WD 500gig drives go on sale for $100-$129. Plus if you go uncompressed you don't need a fast CPU, where if you're compressing you do.

If you go compressed (BMD MJPEG) HDMI with the Intensity, you are only looking at 13 MB/sec to keep up with the frame rate. Just about any recent disk drive will easily do that. But if you go with uncompressed, you are looking at consistent 170 MB/sec, which translates into 421 GB/hr. I have a RAID0 of 3 Western Digital 150GB Raptors and that's barely enough to do short segments of uncompressed. As you said, if you go compressed, the faster the CPU the better.

[Vladimir]

Do you think the Canon engineers would compress the CMOS output to 1440, then up-convert it to 1920 again? Or just tap in before it's down-converted?

Unfortunately thats correct
There was a big Russian expert test of BlackMagic card with Canon HV20, Sony HC7, Panasonic SD1 and JVC HD7
You may read it translated from Russian to English by altavista:
http://babelfish.altavista.com/babel...ntensity_2007/

The main idea of this test is to measure actual resolution of cameras directly from HDMI in 2 modes:
1) Camera mode
2) HDV playback mode

For HV20, unfortunately the MTF50 (horisontal res) lines (Camera mode) the same as (HDV playback mode), red and blue graphs

.. so (HDV mode) horis. resolution = (live Camera mode) horis. resolutin and that proves the fact that HV20 in (Camera mode) via HDMI transfer 1920->1440->1920 video (not the TRUE 1920x1080 from TRUE 3 Mpix sensor)

Btw, for other cams we may see a small difference between red/blue graphs in MTF50(horisontal res)
For example for Sony HC7:

so the Sony HC7 actually have real 1920x1080 from sensor via HDMI(and a little better horisontal resolution then in HDV playback mode), but not the Canon

[icarusi]

Do you think the Canon engineers would compress the CMOS output to 1440, then up-convert it to 1920 again? Or just tap in before it's down-converted?

Can't that be checked by just videoing a grid with sufficient resolution to exceed what 1440 is capable of, and see if it's reproduced via HDMI?