[Graeme Nattress]

Ah but, the Avid DV codec doesn’t stand up as well to generational loss as the Apple one! The difference is that it smooths the chroma so that it looks better on screen, but this will “bleed” over generations and the colour will leak out. The luma is also more filtered (to produce less mosquito artifacts by not letting as high a resolution through) so with the Apple codec, you must pre-filter any graphics or high resolution elements that you add yourself.

When you decode DVCproHD over SDI, you’re not just decompressing the video, but you’re also scaling it up from 960×720 to 1280×720, and the chroma, which is 4:2:2 at the compressed resolution get’s scaled up to, to be 4:2:2 at the uncompressed resolution. As we know, the scaling in FCP / Quicktime is rather poor, so if you’re viewing the footage at a proper 16:9 stretched out resolution, you’re seeing Apple scaling artifacts. But when you render in FCP, it uncompresses it to 960×720 without scaling, the effects are done and it’s recompressed, all without scaling / unscaling. Ofcourse, this means that if you do effects in FCP, then no scaling occurs until playback, and all is ok. I think this is also why people hate AIC so much, as when you convert AIC to uncompressed you see all these scaling artifacts.

Now, if I was compositing in Shake, I’d set it so that all the compositing goes on with the unscaled footage, but with the viewer so that I can see it all at it’s proper aspect ratio. Can you do this in AE, or is it square pixels only for everything??

Graeme

– http://www.nattress.com – Film Effects for FCP

[Graeme Nattress]

Details on the “PAL” DVCproHD are slim at the moment. I really don’t know enough to answer that one.

Graeme

– http://www.nattress.com – Film Effects for FCP

[Graeme Nattress]

Video has, traditionally, all been about the “format”. As you point out, the move of video into computing, the tapeless revolution and all allows us to, technically at least, move away from “the format”.

But you understand this, and hence your post. But average camerperson does not. You can here them asking now – “What format does it shoot”, and you reply – “What format do you want?” and they say “??????” in utter bemusement!

So yes, I guess there is nothing stopping a camera from being able to shoot multiple compression / frame rates etc. I guess it would thereform be “Varicam Squared” or some such cute name.

But with the first memory chip cameras with solid state recording, it isn’t going to happen. The chips that handle the compression are set in stone for cost reasons and cannot be altered. This will change, but not yet. However, within 10 years, I can see a lot of what you want happening.

And yes,shooting raw would be nice, but there’s neither the workflow tools nor the affordable cameras for it yet for people to learn how to make it work for them. This will come, however.

Thanks for your vision of the future, and I think it’s a great one!

Graeme

– http://www.nattress.com – Film Effects for FCP

[Graeme Nattress]

Sorry. Got my figures mixed up. The 1.666 is for 720p. For 1080 you must double that number as it has half as many frames per second. Got to stop writing posts when I’m asleep. 🙂

So the 1080 mode and the 720 mode have identical compression levels per pixel per frame.

Graeme

– http://www.nattress.com – Film Effects for FCP

[Graeme Nattress]

All you’ve avoided is the render back to the DV codec. You’ve done two different things:

a) DV -> Firewire -> FCP (DV gets uncompressed, Effect added, DV recompressed) ! -> Firewire -> DV Tape

b) DV -> SDI (DV gets uncompressed) -> FCP (Effect added) ! -> SDI (DV gets compressed) -> DV Tape.

Exactly the same things happen, but in different orders. From what you’re describing, you’re viewing the footage from a) & b) workflows at the ! point, and hence, as you can see in a) you’ve just compressed back to DV, but in b) you’re still uncompressed, and hence it looks better. Nothing magic going on here.

Now, if in workflow b) you subsititute a Digital Betacam deck for the DV tape, you avoid the DV compression and decimation back to 8bits, and will preserve 99.9% of the uncompressed quality you see at that point. If you’re mastering back to DV tape, there is no point capturing the DV uncompressed, as things may look better at the ! but as soon as you get back to tape, you’ve completed the decompression and recompression, lost your digital generation and there’s nothing you can do to avoid that.

Also, I should point out that FCP does not do the DV codec justice onscreen in the canvas, whereas it does display the uncompressed codecs with very much higher quality, so there’s a bit of an unlevel playing field there too, for viewing at the !.

Graeme

– http://www.nattress.com – Film Effects for FCP

[Graeme Nattress]

“What is the 1080i resolution for DVCPRO HD? Is it 1920×1080, 1440×1080 or I think I have even seen something odd like 1280×1080. Are these also 1.6666mbpf? What about 1080p, same mbpf?”

The codec itself is 1280×1080 for 1080i, each frame is 1.666mp, and yes, same for 1080p.

Graeme

– http://www.nattress.com – Film Effects for FCP

[Graeme Nattress]

I fully understand that electronic filtering is used for removal of interlace twitter by summing line pairs. However, I doubt that alias removal using a DSP is trivial, and cameras don’t usually have enough resolution for you to generate an aliassed image on the CCD, then remove it with electronic filters and still have enough resolution left over not to look blurred? Or do they? Surely the best way to remove aliassing is with the lens or a filter block ahead of the CCD, and not have to muck around with a DSP to do that?? I understand the mathematics of sampling theory, aliasing etc., but I’m lacking the detailed knowledge of the secrets of what goes on inside the camera to take this line of argument further. Anyone know exactly what’s going on for certain, or can have some luck with google and turn up some papers or something??

Graeme

– http://www.nattress.com – Film Effects for FCP

[Graeme Nattress]

“I’m not saying that the hardware codec is better than the software codec, they’re the same codec. But there is a different decoder happening in the Apple sofware than in a Panasonic deck. ”

But you say that the hardware codec looks cleaner etc. etc. and hence it must be better, right, but above you’re saying that the software codec is as good as the hardware codec.

I don’t have a lot of DVCproHD footage on my system – only what clients have sent me so that I can develop plugins that work with it, but I’ve not seen the problems you mention other than inside FCP. I don’t have a DVCproHD deck, and the whole idea of P2 is that I don’t need one. I view my footage out of the Decklink HD card to SD monitor, DLP projector and 23″ Cinema Display over SDI and HDLink and none of these methods of display show the artifacts that FCP does internally.

As I say, I’ve had the very same discussions over the DV codec – hardware v software, and I managed to prove to myself quite clearly that any differences are utterly negligible as I mentioned in an above post. If you can send me similar DVCProHD over Firewire v DVCpro over HD SDI footage, I’d be very happy to take a look and see if I can see what you are seeing and therefore be able to put my mind to work in trying to solve any problems with the firewire / Apple codec route if there are any. I’ve got a feeling, that anything you’re seeing is probably due to scaling issues from 960 to 1280 or 1280 to 1920 that could be solved, in that FCP does pretty poor scaling and that the deck’s SDI output does nice scaling.

Graeme

– http://www.nattress.com – Film Effects for FCP

[Graeme Nattress]

Luis, you’re spot on right there. Only one recompression at worst in that workflow, and seriously, even mulitple compression DVCproHD is much, much better looking that broadcast HDTV that nobody would ever know anyway.

The DV revolution was based around a couple of things – cheap, high quality cameras that were a big leap over the previous analogue models in quality, a tape format / copdec that at least equalled the old analogue broadcast standards, and native editing. Of these, it was native editing that brought the computer costs for NLE down to an affordable level.

Graeme

– http://www.nattress.com – Film Effects for FCP

[Graeme Nattress]

AFAIK, the HDX200 does 720p24 and 720p30 and 720p60, at 40, 50 and 100mps, giving a constant compression per frame of 1.6666mbpf.

Graeme

– http://www.nattress.com – Film Effects for FCP