Anyone using variable frame rate DVCPRO HD?

[Paul Mogg]

Yes we are saying exactly the same thing here Uli.

What I don’t understand is this argument that importing footage via SDI somehow results in improved quality. This goes against the basic principles of digital network file transfer protocols, which do sum checking for each packet sent, so there can be no errors in transfer. SDI and Firewire are both digital file transfer protocols (with, I assume, sum checking built in), just like TCP/IP over ethernet. The resulting file captured (actually copied is a better word) should be exactly the same with either protocol. You could easily verify this for yourself with one of the basic Unix file comparison utilities that are on all OSX systems.

With the same utility you could also easily verify for yourself what I am saying that FCP doesn’t change the original captured clips during editing,

I know it sounds radical that editing natively uncompressed could result in inferior final quality to editing in DVCPRO HD, but unless both are treated as “offline” codecs, and a final “online” 10 bit uncompressed render is done in both cases, exactly that could happen.

The only advantage I see to editing in natively uncompressed HD (derived from a compressed DVCPRO HD master tape) is that what you see on screen DURING the editing proces will be of higher quality. The file sizes you have to deal with are a huge disadvantage to the process, and the final output after an “online” 10 bit uncompressed render, should be of equal quality to editing natively in DVCPRO HD (when used as an offline codec).

Also, uncompressing is uncompressing. There should be no difference in the quality of an uncompressed HD file depending on the method you choose to uncompress it, either via software or hardware (from the camera or on your Mac’s hard drive). It’s just a digital uncompress, there’s only one final outcome possible (unless the programmer’s a total moron!). Again, you can easily verify this for yourself.

I would very much like to have this confirmed or refuted by an Apple programmer, I’d be more than happy if someone knows better and can set us all straight. But based on what I know from my former years of programming in assembly language, this would seem to make sense, it seems like pretty basic stuff.

All the best,

Paul

[Gary Adcock]

[Uli Plank] “It’s very clear to me that any changes or additions other than hard cuts in a timeline set for the original codec will be degraded in quality. BUT: if you are on a tight budget and are aiming for any other output than HD on tape, like film transfer or HD-DVD, you can pull your stuff via FireWire to a Mac without additional cards or expensive RAIDs.”

This sounds like an HDV workflow- not something for HD. Without external boards or disk arrays you loose the ability to store your content, or view your video on a proper external display.The equipment needed for uncompressed editing in DVCProHD is only slightly more than what was needed for an uncompressed SD solution. At 720|24p the 8 bit captures are about 45mgs a second. Certainly within the feasibility of most external Sata or Firewire 800 drives. Neither of which are expensive.

How can one possibly See what they are doing on a computer display when those displays cannot be calibrated using blue guns? This even more an issue when working with interlaced footage as all computer displays view progressively. Working cheap and being frugal are 2 different things –but skipping basic professional practices makes all varicam users look bad- by association if nothing else.

[Uli Plank] “When you have finished offlining, you change the timeline to something better, like uncompressed 4:2:2 10 Bit and re-render.”

This is not a good idea – you gain nothing. things such as scaling and compression issues are not handled properly in this fashion. Lay it to tape and then redigitize.

Look this is still High Def- you need to have HD scopes & HD monitors – you will need HDSDI spec cables, you will need to get new lenses – that old ENG glass will not cut it. An FCP editing system for DVCPROHD complete with 8|10bit capabilities and storage can be had for under 20K — or less than the cost of the 1200 deck.

Being frugal does not have to impact your quality–but being Cheap just might.

gary adcock

Studio37
HD and Film Consultation

[Leo Ticheli]

Loading via HD SDI does not improve quality of material straight off the VariCam tape with no effects or layers. I never said or suggested differently.

We’re talking about the final product, edited with effects and layers. If you load via FireWire, every time you do an effect you are going down a generation of DVCPro HD to uncompressed and back again. This degrades the image. With each effect or layer you compound the problem. End of story.

Yes, you can off-line and then reload the sequence via HD SDI and rebuild all your effects, but why go the extra step unless you just don’t have the drive space? The new Macs are so fast that render time is not a problem with the 10-bit uncompressed HD and the extra storage space is not a big deal, at least for me.

Best regards,
Leo

Director/Cinematographer
Southeast USA

[Gary Adcock]

[Paul Mogg] “What I don’t understand is this argument that importing footage via SDI somehow results in improved quality. This goes against the basic principles of digital network file transfer protocols, which do sum checking for each packet sent, so there can be no errors in transfer.”

This argument is only valid if nothing is being doe to the file in transport, which is not the case when the files go to post. you have color correction, overlays, Lower Thirds and all sorts of graphic effects laid over your footage.

let me first say in this debate that the Varicam is unrivaled in its ability to handle the horizontal scaling issues brought on by the 1280 > 960 frame width. It’s imager was created to handle this issue. IMHO it is the best of the HD formats (the look -color – Frame rates- overall costs)
BUT the applications that you edit with are not the same None of them were ever intended to handle that same issue with gradients or motion graphics that include transparency in the way the camera’s original imager can or does.
Try it yourself – create 2 graphics that have a 50px Gaussian blur – one blurs vertically -one blurs horizontally lay that back to tape and look at the resulting image on a broadcast display ( or better yet a set of scopes) Secondly try a Lower 3rd in red or blue that gradates from 100% to something less than 25% across the bottom of a neutral image ( think sand or snow).

One other point here is that all digital tape decks decompress the image back to a video stream when going out of the BNC’s on the back of a deck. This signal, if nothing else no longer maintains a 960×720 aspect ratio but is now the full frame 1280×720 size.
Compression is not a bad thing but something one must lear to work around, understanding when to stay in DV and when you will have to work in Uncompressed is a major part of the post process.

That said I do a majority of my work in the DVCPROHD codec, I love it, but I am also very aware of what does and does not work in post using it as my main format. I also know where and how I can work around some of the issues. and I keep an open mind.

gary adcock

Studio37
HD and Film Consultation

[Rick Sebeck]

Okay gang.. I’ve been following this tread, and others, and all I still have some questions….

I am cuting a film shot on the Varicam. I have a Kona2 system with a 5.6 Xraid. With a robust system should I still “offline” in DVCPRO HD?

Am I correct in saying that-

1) Shoot in 23.98 (using seperate tapes for variable frame rates)
2) Rent a 1200a deck and digitize all the footage via firewire (capturing takes separately and not full tapes at a time) using the DVCPRO HD codec
3) Offline edit in 24fps DVCPRO HD sequence.
—Here’s where you loose me—
4) Lay to tape, then redigitize? at _____? or 4) create an uncompressed timeline and re-render

5) The film is ending on DVD and the budget is cheap, but should I still make a master of the “true” HD? Would I rent a D5 deck, and use the Kona to output the new render?

If they have the budget to do a true color correction (DaVinci / FinalTouch HD), should I do that from the DVCPRO HD suedo master and let them up-rez and output a D5?

And last- to make it worse… it is pretty intensive effects film – lots of rain and weather effects.

I am assuming it wouldn’t be cheaper to down convert to DVcam (since I have a deck) offline at 29.97, then online (rent the 1200a) at HDcam compression and output it (rent a D5 deck).

[Gary Adcock]

[Rick Sebeck] “1) Shoot in 23.98 (using seperate tapes for variable frame rates)

good plan – or just slate all of the VFR content with 15 sec slates so you do not get capture errors

2) Rent a 1200a deck and digitize all the footage via firewire (capturing takes separately and not full tapes at a time) using the DVCPRO HD codec

you really really need to PROPERLY Log and Capture separate clips if you plan on re-digitizing material or handing the content of to anything else.

3) Offline edit in 24fps DVCPRO HD sequence.
—Here’s where you loose me—
4) Lay to tape, then redigitize? at _____? or 4) create an uncompressed timeline and re-render

you gain nothing from rendering in an FCP timeline other that what you capture at. It can take 3-5 times as long to render a sequence in 10 bit with effect than it would to lay it back to tape and regdig it.

5) The film is ending on DVD and the budget is cheap, but should I still make a master of the “true” HD? Would I rent a D5 deck, and use the Kona to output the new render?”

use Static graphics and stay in DVCProHD since you are going down to SD for the delivery. you gain nothing but costs going to D5 for the workflow you state.

gary adcock

Studio37
HD and Film Consultation

[Paul Mogg]

[Gary Adcock] “you gain nothing from rendering in an FCP timeline other that what you capture at. It can take 3-5 times as long to render a sequence in 10 bit with effect than it would to lay it back to tape and regdig it.”

Gary could you please explain in detail why you think this is true as my experience so far has led me to believe that quite the opposite is true.
I’ve done many renders of multi-layered composites on the FCP timeline in 10 bit uncompressed and the improved quality is dramatic and quite obvious to the naked eye compared to a DVCPRO HD render of the same timeline, (though I’ve not yet compared the difference in FCP 5.0 which has very much improved the native DVCPRO HD rendering quality).

As for laying back to tape and re-degitizing, could you please explain technically why you reccomend this as I have to say it’s not making sense to me right now. Are you talking about doing this after having edited in native DVCPR0 HD or uncompressed HD? Why would you want to do that?

This is not meant to be confrontational, I just want to learn the best way to do this

Many thanks,

Paul

[Paul Mogg]

[Leo] “Yes, you can off-line and then reload the sequence via HD SDI and rebuild all your effects, but why go the extra step unless you just don’t have the drive space?”

Leo, why would you need to reload the sequence via HD SDI?, just duplicate your sequence then make the duplicate offline, change the sequence setting to be 10 bit uncompressed, recconnect your media to your untouched camera files that are sittting on your hard drive, and render, everything happens in one pass and you get the best possible quality.
Some people say that you don’t even need to to make the sequence offline and recconect, but I like to do that to be sure that no intermediate render files are referenced during the process.

Cheers,

Paul

[Gary Adcock]

[Paul Mogg] “Gary could you please explain in detail why you think this is true as my experience so far has led me to believe that quite the opposite is true. I’ve done many renders of multi-layered composites on the FCP timeline in 10 bit uncompressed and the improved quality is dramatic and quite obvious to the naked eye compared to a DVCPRO HD render of the same timeline, (though I’ve not yet compared the difference in FCP 5.0 which has very much improved the native DVCPRO HD rendering quality).”

First off Sorry — for the delay I was on vacation last week.

simply your video quality is not going to be improved by just rendering your compressed footage in an UC timeline, now everything that you “need to render” will look better but not the source footage and additionally you have added another layer of software vs. hardware decompression on your content. I have yet to find software the handles the 960 -1280 frame scaling / sizing any better than panasonic and aja do in hardware on their respective products. This is especially noticeable with any graphics or animations that move or blur horizontally across the screen. I can also tell you that many networks are now bouncing footage handled in this manner for delivery as it can causes issues that be very noticeable when recommpressing footage sent up to the satellites.

gary adcock

Studio37
HD and Film Consultation

[Peter Steinman]

But, after you have rendered your compressed footage to uncompressed adding uncompressed ‘graphics’ will remain uncompressed and the qualiity on your final tape out should be unchanged. Again, it sounds like what your saying is the hardware ‘uncompression’ is better then the FCP one. Seriously sounds like a codec issue as the hardware one will just be a different codec processed thru hardware.

Are you still having the same results with the new FCP 5 versions of the DVCPRO HD codec ? Many say it is much improved.