Defining, High Defintion

[Guest Daniel J. Ashley-Smith]

How can you define high definition? You could just have a non high definition camera that runs at the same specs and does the same thing.

 

Where?s the line? Where?s the point where the camera becomes a high definition camera?

[David Mullen ASC]

"High definition" just means a recording or display with more lines of picture than standard defintion video. Right now, 720 lines (1280 x 720) is considered the minimum something can be considered high definition. Some don't consider that high definition though; it's only a little more than twice as many pixels as PAL video.

[John Pytlak RIP]

All you ever wanted to know, and more:

 

http://www.udayton.edu/~cps/cps460/notes/displays/a_54.pdf

 

GUIDE

TO THE USE OF THE

ATSC DIGITAL TELEVISION STANDARD

 

http://www.tutorgig.com/encyclopedia/getde...h_Definition_TV

 

http://www.poynton.com/DVAI/index.html

 

http://www.windowsmoviemakers.net/PapaJohn...tion_Video.aspx

 

Film production for HDTV:

 

http://www.kodak.com/country/US/en/motion/...l/super16.shtml

 

http://www.kodak.com/country/US/en/motion/...nflFilmsP.shtml

 

http://www.kodak.com/country/US/en/motion/...2002/lowP.shtml

 

http://www.kodak.com/country/US/en/motion/...01/cheers.shtml

 

http://www.kodak.com/US/en/motion/16mm/why/?id=0.1.4.3&lc=en

[John Sprung]

Right now, 720 lines (1280 x 720) is considered the minimum

Actually the lowest resolution HD format is 1080i. With a Kell factor of 0.65, it's equivalent to 702 progressive lines. And that's pushing it. Interlace line counts are kinda like shop vac horsepower or "peak music power" ratings for amplifiers.

 

Remember that interlace means only half the lines are really there in each field.

 

 

 

 

-- J.S.

[Guest Pete Wright]

Hi,

 

I have a question. Does the interlaced mode reduce only the vertical resolution, or the horizontal resolution too?

 

What exactly is the Kell factor?

 

Pete

[Guest Daniel J. Ashley-Smith]

I have a question. Does the interlaced mode reduce only the vertical resolution or the horizontal resolution too?

 

As far as I understood interlaced video was just 2 frames interlaced as opposed to one frame progressive.. The resolution isn't changed, the camera just operates at 50 fps instead of the progressive 25 and it links 2 frames into each other. This make the motion look a lot faster, more like a home video as opposed to a feature length film. Personally, I hate it.

 

I was having a debate about interlaced video the other day, with someone who thinks it's better. He said that the idea of interlaced is that it blurs the motion and captures at a much higher speed capturing all the action. But, I think it looks to fast, and doesn't capture the atmosphere. Looks like a home video, and less like a film. And besides that you can?t edit special fx aswell. (Cheap and crappy looking....)

[Landon D. Parks]

In my honnest opinion, if the camera says "HD" then its HD. If the camera says its "SD" "DV" "DVC-PRO" "DVCPRO - 50", then its SD.

 

Now, DVC-PRO HD (Panasonic) and HDCAM (Sony) are HD formats. DV, DVC, DVCAM, DVC-PRO 50, SVHS, VHS, Hi8 are all SD.

 

you will know when somthing is TRUE HD, only when it records to HDCAM, DVCPRO-HD or HD 4:4:4 Transparent.

 

In my honest opinion, when cameras say they record HD to DV tape, they are not HD. (Panasonic 720p Consumer Camcorder).

 

I know known of that probably makes sence, but thats my take on it.

[Alvin Pingol]

What exactly is the Kell factor?

http://members.aol.com/ajaynejr/kell.htm

[David Mullen ASC]

Interlaced-scan means that there are two fields that create one frame of video; each field contains alternate lines.

 

If the camera shoots 60 fields per second interlaced-scan (60i) instead of 30 fps progressive scan (30P) then it means that 60 images are taken per second but each image is only a field containing every other line of video.

 

Therefore, interlaced-scan capture causes a drop in vertical resolution for moving objects or shots since the movement is in two different positions on the two fields that create one frame. When combined, you get a "sawtooth" edge.

 

This is also why many people consider the two common HD broadcast formats -- 60i/1080 and 60P/720 -- as being similar-looking in resolution.

[David Mullen ASC]

> In my honnest opinion, if the camera says "HD" then its HD.

 

> In my honest opinion, when cameras say they record HD to DV tape, they are not HD. (Panasonic 720p Consumer Camcorder).

 

Are you thinking of the 720P JVC HDV camera? Panasonic currently has a 720P professional camera (the Varicam) and a 480P pro camera (NTSC SDX900) and 480P consumer camera (NTSC DVX100A), plus the PAL versions, but I don't know of a Panasonic consumer 720P camera yet.

 

Anyway, these consumer HDV (Mini-DV) cameras do say that they are HD so you seem to be contradicting yourself. If they record 720P, then they are HD by most definitions no matter how compressed that recording is.

[Landon D. Parks]

Are you thinking of the 720P JVC HDV camera?

Yes, sorry. JVC

 

Anyway, these consumer HDV (Mini-DV) cameras do say that they are HD so you seem to be contradicting yourself. If they record 720P, then they are HD by most definitions no matter how compressed that recording is.

Yes, well. Maybee I should have said that a Little differently.

 

In my opinion, it can only be called true HD when it records to an HD format. Such a DVC-PRO HD, HDCAM, HD-CAM SR, or Full Bandwidth 4:4:4 Uncompressed Capture.

 

Im sure the JVC has lovly resolution, but by the time it gets compressed by the DV format, what, DV is like 25mb/s? campared to 185mb/s on HDCAM. I would think the heavy compression would make the "HD" image have some terrible artifcats that just should not be there. And I have doubts that the JVC HD even records all the 720p. Is that possible to record 720p to MiniDV tape? if so, then I would think it would either have to speed up the tape drive, or compress the image more. Neither one is very healthy.

 

I dont know. Maybee I dont know what im talking about. But thats what I always thought.

[David Mullen ASC]

Well, I never said the HDV (Mini-DV HD) recording didn't suck, only that it has more resolution than standard definition video. It's "HD" -- just not very good HD.

 

The HD that gets digitally transmitted is just as compressed as HDV, by the way, all the way down to 19 Mb/sec or so. It's just that it's not a good idea to ACQUIRE the image with that much compression to begin with, versus transmitting the final image with that much compression.

 

You can't really use the guideline of HD being whatever tape format is labelled HD -- a manufacturer could label a tape format anyway they want, as "HDV" proves. Technically, DVCPROHD is also called DVCPRO100, so it's all just a matter of labelling.

 

720P is HDTV; it just might not be very good-looking if highly compressed with poor color. Of course, most of our impressions of HDV are currently based on the image coming out of a single-chip consumer camera that sells for $3000.

 

You don't want to fall into trap of trying to narrowly define, label, and catogorize things. Quality in general in more of a continuum and does not always fall into neat categories. Ultimately, labels matter less than results.

[John Sprung]

The other important factor is what you're using as a display. If you compare 1080i and 720p on a 1080i CRT TV set, using the set's internal downconversion from 720p to 1080i, chances are the native 1080i will look better. Such tests show you the quality of the TV set's internal conversion more than anything else.

 

Go instead to a DLP projector mapping the 720p 1 to 1 to the pixels on the chip, and upconverting the 1080i, and the comparison will probably go the other way.

 

Interlace is a relic of the analog CRT era. It's a mistake in the digital age.

 

 

 

--J.S.

[mudbrick]

I shoot in HDV on a daily basis. I used to shoot DVC100 or Varicam HD, but I left that job for this one.

 

HDV looks moves and reads on the screen like total garbage. I can't stand how it looks. Now when I watch my HD broadcast at home, that image looks great. It could be my shooting, or it could be the fact that the JVC HD gy10u is crap.

 

Although it pains me to say this, I can't give a verdict yet on HDV. I have shot with the Cinealta and it looks amazing as does the Varicam. Those are both well built cameras with incredible pieces of glass. Until an EFP/ENG HDV camera comes out the verdict is out on this format.

 

HD is a buzz word right now. Everyone is slinging it around. HD is defined by lines of resolution. Same thing as NTSC. Frame rate, compression, or "quality" have nothing to do with HD.

[John Sprung]

HDV looks moves and reads on the screen like total garbage. I can't stand how it looks. Now when I watch my HD broadcast at home, that image looks great

The first ATSC broadcast encoders cost about $500k. Now they're still in the $50k - 100k range. The whole HDV camera costs a lot less, so what can they put into the compression module? Odds are that the difference you're seeing is in the quality of the compression used.

 

 

-- J.S.

[David Mullen ASC]

There's a big difference between shooting on a $3000 HDV consumer camcorder with a single-chip and shooting on 35mm, lets say, and broadcasting it in HD at the same compression rate.

[Alvin Pingol]

We must also remember that the JVC HDV camera is first generation! Anything first generation in the world of technology isn't going to be its best, and the JVC will receive additional heat left and right since everyone has expected so much out of it.

 

Now first generation 24P SD camera (Panasonic) is a different story, as Panasonic had already been making SD cameras. The only new technology there was better image sensor/processing and, obviously, 24P processing.

 

HDV is an entirely new system. I'm sure that in the near future, $3000 HDV cameras will look 10 times better than the first gen JVC.

 

(Okay... maybe not 10 times better... but you get the point)

[Guest Frank Miller]

There is nothing wrong with the HDV format. Nanotechnology processors that are appearing can process the picture a lot more efficiently than the compression that is used on Varicam. The Varicam is too compressed. It is someting like 7x, with old compression technology.

 

Two new JVC cameras will be introduced this year that will give the Varicam run for the money. Did you try to color-correct the Varicam footage?

 

There are new software programs to clean the HDV footage.

 

Wait for the new HDV. Forget the old HDV. And forget Super 8, and soon forget S16. New HD XDCAM will be available early next year.

 

Frank