HD or "Glorfied SD"

[Jacques Mersereau]

<<<In defence of HDV. HDV is deliverable 25 Mbps HD.>>>

I have heard this argument before. Does this mean if you are delivering on
DVD you want to acquire footage at 6.4 mbps? Not me brother.

IMO, the HD I've seen via cable looks fine until someone turns his/her
head or smiles and then you see HORRIBLE macroblocks. Talk about
jaggies, the Olympic's looked hideous as soon as the action started.
I want to see beautiful people's perfect teeth and eyes, not a mosaic.

I plan to acquire my footage at the highest possible
quality I can afford and THEN deliver/compress it in whatever low resolution
format is required. I don't want to start with the lowest bandwidth at
the beginning of the production process.

[A. J. deLange]

Just spotted this:
[QUOTE]

The issue, as I have mentioned many times before is that a 1/3" camera at HD resolutions cannot give anywhere near HD detail above around f5. Apparently the Sony Z1 etc have an option to stop you going above this f-stop for this very reason. Here is the technical explanation why http://forums.dvdoctor.net/showthrea...4&page=1&pp=10


The reasoning here and at the referenced URL is backwards. The spread of the Airy disk (a perfect point source is spread on the image plane by diffraction so that it isn't a point but a disk with rings - the spread pattern is called an Airy disk after the first Astronomer Royal) increases as the aperture decreases. Thus if a lens is diffraction limited at f/5 you cannot use it a apertures smaller than f/5. At larger apertures it would be OK. It is true that a smaller CCDs require smaller apertures for a given image size and exposure so that the diffraction limit may be reached at high f stop numbers.

You can do a crude demonstration of this by taking two pieces of paper and forming a slit right in front of your eye while looking at a light background. The gap will appear to be filled with dark lines. The narrower the slit the farther apart these lines are. As you pull the pieces of paper apart these lines ((diffraction fringes) get closer together and collapse into the edges. The deal with a lens in the circular extension of this principal.

[Edit: unless of course by "above" f/5 they mean a larger numerical aperture and a smaller hole in which case the thinking is right though I guess I don't really think that a 5.4 mm lens is difraction limited at f/5 wrt a 1/3 inch CCD. No point in asking Canon for MTF data on this lens, I suppose but as people are there....]

[Thomas Smet]

Saying HDV isn't HD is like saying a DVD isn't SD or that DV isn't real SD because it is only 720x480 instead of 720x486.

What makes HDV not real HD for some people?

Is it the 1440x1080 resolution compared to the full 1920x1080 spec? Well HDCAM also uses 1440x1080 with 3:1:1 color.

DVCPROHD only uses 960x720 or 1280x1080.

So in terms of resolution 1080 HDV is just as good and 720 is actually better.

While keying may not be perfect with HDV it is a lot better than it was with DV. In the past however with DV we never had an option for uncompressed output. With HDV we now have options. If you really don't want to capture via SDI or component for HD then why not use SD uncompressed? It would be much better than DV and even DVCPRO50. You can even capture through an SDI card for $300.00 on the Apple as DVCPRO50 turning the XLH1 into a DVCPRO50 camera.

[Mike Marriage]

Originally Posted by Simon Wyndham

HDV is a limiting factor. Any camera worth its salt should record and compress individual frames. If P2 comes down in price soon enough and Panasonic introduce much lower end HD cameras that use it, I cannot foresee HDV lasting much longer. I can't see anyone choosing 25Mbps HDV over 100Mbps DVCproHD.

I believe HDV is an interim format. The development of solid state and optical recording is such that there will be a lot more flexibility.

I agree, HDV is not perfect for pro users, but P2 and DVCPROHD is FAR from perfect in lower end cameras. P2 is not going to be selling to consumers any time soon, as you are not going to be able to fit more than an hour of 1080i/p on P2 until 2007! Even then, you'll need 2 32GB cards which will be around $3000, WAY out of consumer territiry JUST FOR THE CARDS! Competition may bring prices down slightly, but don't bank on it.

Pany have started to introduce low end SD cameras which take SD memory cards, but may move on to record HD on SD cards - that'll really confuse consumers!

HDV is interim in the way that it records HD onto miniDV tape because no manufacturer was willing to develop a new tape mechanism when tape is nearing the end of its life cycle. Whether HDV's MPEG2 codec continues to be used on solid state remains to be seen, but it is then not technically HDV so for sure, HDV will die, but first it is going to completely dominate the low end HD world like DV has done since the mid 90's with SD.

I will quite happily bet that in 5 years there will be far more cameras shooting HDV than DVCPROHD, probably by a factor of 10.

I also believe that HDV will outlive DVCPROHD, which is already showing its age.

I am waiting for MPEG 4 cameras, with codecs like H.264. Even at 25Mbps that would look great!

[Jacques Mersereau]

<<<I also believe that HDV will outlive DVCPROHD, which is already showing its age. >>>

How old is MPEG2 again?

<<<I am waiting for MPEG 4 cameras, with codecs like H.264. Even at 25Mbps that would look great!>>>

Or at least a LOT better than HDV!!!

[Mike Marriage]

Originally Posted by Jacques Mersereau

<<<I also believe that HDV will outlive DVCPROHD, which is already showing its age. >>>

How old is MPEG2 again?

Bitrate wise though, DVCPRO is not that efficient anymore. MPEG2 use is certainly increasing rapidly, and will continue to do so for some while.

Personally I would like to use something newer, we have better codecs, why not use them - Maybe it is just a question of processing power..?

[Simon Wyndham]

Originally Posted by A. J. deLange

Just spotted this:
[Edit: unless of course by "above" f/5 they mean a larger numerical aperture and a smaller hole in which case the thinking is right though I guess I don't really think that a 5.4 mm lens is difraction limited at f/5 wrt a 1/3 inch CCD. No point in asking Canon for MTF data on this lens, I suppose but as people are there....]

Yes, we mean above f5 as in numerically.

Alan Roberts, the guy who wrote the reply to me at that site, made his living out of that kind of thing. Walter Graff has also been commenting on this problem, which was the reason why I asked Alan about it. AFAIK the Sony cameras even have an option on their menues to limit the f-stop settings for this very reason.

[Lawrence Bansbach]

Originally Posted by Mike Marriage

I am waiting for MPEG 4 cameras, with codecs like H.264. Even at 25Mbps that would look great!

Me too. A general rule of thumb is that MPEG4 requires about half the data rate of MPEG2 to achieve the same image quality.

[Dalen Johnson]

Originally Posted by Thomas Smet

What makes HDV not real HD for some people?

This is what makes it not real for me:
[Quote from Jacques Mersereau in earlier post]

IMO, the HD I've seen via cable looks fine until someone turns his/her
head or smiles and then you see HORRIBLE macroblocks. Talk about
jaggies, the Olympic's looked hideous as soon as the action started.
I want to see beautiful people's perfect teeth and eyes, not a mosaic.

I plan to acquire my footage at the highest possible
quality I can afford and THEN deliver/compress it in whatever low resolution
format is required. I don't want to start with the lowest bandwidth at
the beginning of the production process.

[End Quote]

This pretty much sums up the issue I think

[Dalen Johnson]

Originally Posted by Thomas Smet

If you really don't want to capture via SDI or component for HD then why not use SD uncompressed? It would be much better than DV and even DVCPRO50. You can even capture through an SDI card for $300.00 on the Apple as DVCPRO50 turning the XLH1 into a DVCPRO50 camera.

This is not a bad option, but it is only useful in the studio.
Not really practical in the field.

[Jacques Mersereau]

So, how old is MPEG2?

[Steve Connor]

All this is theory, fact is shoot HDV bump it to uncompressed 10 bit and I have found ZERO issues with artifacts, we use HDCam as well and in terms of picture quality(not theoretical picture quality), once you've bumped HDV up to 10 bit the quality of the HDV material comes surprisingly close to the expensive cameras.

HDV is a revelation, some of you may turn your noses up at it saying it's not REAL HD, but I'm earning money with it now and I am very, VERY happy with the quality. The Panny cam may be good, but P2 and even the firestore (worlds most expensive hardrive) stinks for our docco workflow.

[Jacques Mersereau]

<<<All this is theory, fact is shoot HDV bump it to uncompressed 10 bit and I have found ZERO issues with artifacts>>>


Interesting. I know HDV does a good job most times, but
what kind of shooting and/or content do you acquire? You claim you
have never had a single artifact recorded to tape because of
HDV's compression? Is that what you are claiming?

If so, has HDV *ever* made you alter your shooting 'style' in order to avoid
compression artifacts?

[Greg Boston]

Originally Posted by Jacques Mersereau

<<<All this is theory, fact is shoot HDV bump it to uncompressed 10 bit and I have found ZERO issues with artifacts>>>


Interesting. I know HDV does a good job most times, but
what kind of shooting and/or content do you acquire? You claim you
have never had a single artifact recorded to tape because of
HDV's compression? Is that what you are claiming?

If so, has HDV *ever* made you alter your shooting 'style' in order to avoid
compression artifacts?

Jacques, with regard to mis-quoting, you'll find it much less likely if you reply using the quote button on someone's post. You don't have to include the whole thing but more importantly, if someone then quotes your post, any earlier post you quoted in it won't get carried forward and cause the scenario you referenced earlier.

Just a friendly wrangler tip for ya...
-gb-

[Thomas Smet]

HDV is a lot different than HD mpeg2 broadcast. A lot of times the bitrates used for broadcast are much lower.

Take 720p broadcast for example. Here we have a mpeg2 signal lower than the bitrate for HDV but on top of that it is compressing 60p instead of 30p. That means that even if you had a broadcast at 19.7 Mbits/s that video quality gets cut in half because of the double frame rate.

I know the Olympics were 1080i. Does anybody know what the bitrate was for that? I am sure it was lower than 25Mbits/s.

When 1080i is broadcast is it at 1440x1080 or 1920x1080? If it is 1920 then that means a 25Mbit broadcast would have slight lower quality than a HDV would due to the extra pixels. I think usually 1080i is around 12 or 15 mbits but I don't know for sure. It depends on the station.

For the most part the only people I have ever seen complain about the quality of HDV are those that haven't used it yet.

There was some footage recently on here shot with an HC1 at 1080i bouncing up and down some stairs with the camera shaking all over the place. The video actually held up very well with all of the messy motion going on. This was a heck of a lot more motion than you would usually see in a shot which shows that HDV can work very well.

A 1080i/p HDV video is about equal to a DVD encoded at 5.5 Mbits/s
A 720p 30p HDV video is about equal to a DVD encoded at 7.3 Mbits/s

A 1080i broadcast at only 15Mbits/s is about equal to DVD at only 3.3 Mbit/s