HDV vs. HD

[Graeme Nattress]

Metaphorically speaking, "HDV is to HD what DV is to SD" is about right, but looking how close DV is to uncompressed SD, and how close HDV is to uncompressed HD, I'd say that HDCAM is to HD as DV is to SD, from a technical compression point of view. Actually, I'd say both HDCAM and DVCproHD are, when compared to uncompressed HD, worse than how DV compares to uncompressed SD. Which is a pity, really....

Graeme

[Steve Crisdale]

Originally Posted by Graeme Nattress

Metaphorically speaking, "HDV is to HD what DV is to SD" is about right, but looking how close DV is to uncompressed SD, and how close HDV is to uncompressed HD, I'd say that HDCAM is to HD as DV is to SD, from a technical compression point of view. Actually, I'd say both HDCAM and DVCproHD are, when compared to uncompressed HD, worse than how DV compares to uncompressed SD. Which is a pity, really....

Graeme

Yikes... that should mess with a few newbee minds!!!

I know it's nice to split hairs, and atoms... but isn't it enough for the majority of people coming to HD/HDV to know that they don't have to obtain a "whizz-bang" over the top "George Lucas will accept nothing less", camera to obtain very acceptable results that will display no worse than what the viewing device they are most likely going to be watching it on can handle?

The similarities I'm seeing here; to the printing industries' inability to accept the realities of Digital image processing, is almost uncanny. I think of all those printers who used to say "you can't get a decent print on a quarto page from less than 1200dpi at 100%" or "flatbed scanners will never be good enough for decent print quality", and wonder how many of them are now dead.

They just refused to see that the average punter doesn't get to see the original... and if the images they do see are still damned fine - they'll be satisfied. Oh... no, these dudes had to have image quality that was suitable for billboard size, just to do some mambie pambie magazine - then they whinged when their Macs choked under the size of the RIP.

I'm sure we'd never see a Digital Video version of that though...

[Laurence Kingston]

I know that my shooting style is changing: much less camera movement. Much less handheld stuff. More static tripod with fewer pans and zooms. I'll probably order one of those new Steadicam Merlins when they're available. Anything to cut down and smooth out movement so as not to stress the mpeg compression.

[Tim Kolb]

Originally Posted by Graeme Nattress

Metaphorically speaking, "HDV is to HD what DV is to SD" is about right, but looking how close DV is to uncompressed SD, and how close HDV is to uncompressed HD, I'd say that HDCAM is to HD as DV is to SD, from a technical compression point of view. Actually, I'd say both HDCAM and DVCproHD are, when compared to uncompressed HD, worse than how DV compares to uncompressed SD. Which is a pity, really....

Graeme

Heh heh... Boy is THAT the truth. At SIGGRAPH last year some guy walks up to me in a booth, working on a Prospect HD post system and he looks at it and is impressed...then he asks if it's compressed. I tell him yes, and he says there's "...no way I could work with compressed post." Then I asked him what he was shooting on...he says HCDAM. I pointed out that HDCAM was compressed and he got a little snooty "No, I don't think you UNDERSTAND...HDCAM is a BROADCAST format..." I told him that he was shooting video that was being subsampled to 1440 and THEN was only 3:1:1.

...you'd think I just threw his puppy down a well.

The one thing that HDV does have going for it is that it is still a move up from SD when shot skillfully...it will be around for a while and I suspect most of us will be watching it on television at some point no matter what anyone says.

With the Panasonic 200 camera...keep in mind that the Varicams that I've seen have optics on the front that cost as much as a cartload of these new DVX200 cameras... Thinking that the image quality will be equivalent is probably optimistic.

Interestingly, I see most users judging potential P2 capacity based on 100 Mbits/sec. It's important to note that when you're shooting 24p with the Varicam on tape that the camera still records 60p to the cassette, and you simply playout 24 frames...40% of 60 frames...therefore your net bitrate is actually 40 Mbits/sec. P2 cards will actually record using only active frames so your net bitrate on the card is actually 40 Mbits/sec...making about 2.5x the capacity on a P2 card that most are thinking they would have at 100 Mbits/sec.

[Graeme Nattress]

A lot of "problems" with HD are hidden by it's higher resolution. You can get away with more artifacts as they're a quarter of the size on screen, and most screens can't show the ful detail anyway. That's how HDCAM got away with it - the CRTs people were viewing it with just don't show enough detail for you to easily make out it's issues. The same applies to all the HD formats.

That's not to say that moving to higher resolutions is bad. I just get frustrated that the move to higher resolutions means more and more visible compression than DV which was thought of to be strictly the lower limit of what is acceptable in SD terms.

That doesn't mean I won't like or use affordable HD formats, but I'm going to be writing a lot more de-artifacting code.....

Graeme

[Lewis Lehman]

and we thank you for it. Your filters have helped my workflow to DVD be faster and cleaner.

lewis

[Daniel Kohl]

Originally Posted by Tim Kolb

P2 cards will actually record using only active frames so your net bitrate on the card is actually 40 Mbits/sec...making about 2.5x the capacity on a P2 card that most are thinking they would have at 100 Mbits/sec.

Tim, can you quickly explain what active frames are about?

[Tim Kolb]

Originally Posted by Daniel Kohl

Tim, can you quickly explain what active frames are about?

Active Frames is what Panasonic calls the actual frames you are using when you play back. On a Varicam, you always shoot 60p. When you tell the camera you're shooting 24p, you play back 24 interpolated frames from the 60p stream.

The 100 Mbit/sec data rate for DVC ProHD is based on 60p, if you are only using 24 frames, you are using 40% of the 60 frames/sec you were shooting...those 24 frames are the "active" frames.

On P2, the nice thing is that the card is dynamic enough that it can restrict recording to the active frames only. If you are shooting 24p, this would mean that your effective data rate is actually more like 40 Mbits/sec, giving you 2.5 times the space on the P2 card when you compare it to 100 Mbits/sec.

[Tim Kolb]

Originally Posted by Tim Kolb

... giving you 2.5 times the space on the P2 card when you compare it to 100 Mbits/sec.

I should've said "duration"...obviously the data space is the same, but the record length attainable is 2.5X vs 100 Mbits/sec

[Kevin Shaw]

Originally Posted by Tim Kolb

The 100 Mbit/sec data rate for DVC ProHD is based on 60p, if you are only using 24 frames, you are using 40% of the 60 frames/sec you were shooting...those 24 frames are the "active" frames.

Tim: I can see how this would apply when shooting at 720p resolution, but what about at 1080p? If the normal frame rate for the HVX200 at 1080p is 30 fps, would the data rate at 24p be 24/30 * 100 Mbps = 80 Mbps?

[Graeme Nattress]

The 1080p/i DVCproHD codec is different to the 720p one, and can't be fooled into doing the "active frames" trick, and always records at 100mbps, hence 1080p24 is recorded as 1080i60 with a pulldown pattern, which is a shame really....

Graeme

[Steve Crisdale]

Originally Posted by Graeme Nattress

The 1080p/i DVCproHD codec is different to the 720p one, and can't be fooled into doing the "active frames" trick, and always records at 100mbps, hence 1080p24 is recorded as 1080i60 with a pulldown pattern, which is a shame really....

Graeme

Bump.... Was that the sound of a P2 card suddenly bloating?!!

[Tim Kolb]

Originally Posted by Graeme Nattress

The 1080p/i DVCproHD codec is different to the 720p one, and can't be fooled into doing the "active frames" trick, and always records at 100mbps, hence 1080p24 is recorded as 1080i60 with a pulldown pattern, which is a shame really....

Graeme

I agree. I think that mant users will end up working with 720p with the DVX200 camera as data space is (of course) pricey.

Or...there may be some Hard Disk acquisition solution soon that will be appropriate. Stay tuned...

[Kevin Shaw]

Originally Posted by Tim Kolb

Or...there may be some Hard Disk acquisition solution soon that will be appropriate. Stay tuned...

Firestore has already announced that they'll offer a drive-based recording solution for the HVX200, but I don't think this will entirely solve the recording expense issue for this camera. Panasonic says to figure about 1 GB/minute for full-bandwidth HD recording, which means an 80GB Firestore with an expected retail price of $2000 would only hold 80 minutes of footage. Given that, the option to record at 720p/30 with a bandwidth of 50 Mbps or 720p/24 with a bandwidth of 40 Mbps would still be useful even with the hard drive option. Otherwise, you'd need a stack of Firestores to get through any long event, and that would cost more than the camera itself.

[Tim Kolb]

Originally Posted by Kevin Shaw

Firestore has already announced that they'll offer a drive-based recording solution for the HVX200,

I suspect that FireStore won't be the only option out there for long...though I doubt that you'll find many less expensive options any time soon.