[Paul Mogg]

Thank yoiu, I see what you mean, you’re saying that if for instance you want a 5fps slomo, the Varicam only records those actual 5 frames every 1/5 sec and pads out the 60p stream that goes to tape with dupes.

But still, it seems that if you’re happy with variable framerates on the HVX900 that are wholly divisible into 60, such as 6,12,15 etc., if you have software that can create a stream from every other 6th, 12th or whatever frame within the 60p stream, the timing at which the frames were recorded will have been correct, and therefore the slomo should be correct. Assuming of course that you set your shutter speed to produce the desired motion blur for the target framerate. Anything wrong with this?

Paul

[Paul Mogg]

Thank you for posting Gary, so you are saying that the issue is that Harware based decompression and scaling from 960*720 to 1280*720 is far superior to doing it in software, I appreciate you clearing that up. I can see how that could be true. If it were just the decompression at issue I would maybe take odds with that idea, but I can see how the hardware scaling could be superior, unfortunately I don’t own a deck to test it with myself so I’ll take your word for it.

May I ask what kind of differences in the picture are you seeing in decompressing and scaling through hardware versus software? Are they pronounced or extremely subtle? Are you still finding this to be true when comparing with the new FCP 5.0 (and later) DVCPRO HD codec, which seems to have dramatically improved display and rendering quality under FCP?

The reason I’m asking is that I’m in the middle of editing a feature and need to determine what advantage I might gain from recapturing the original footage via SDI versus the Firewire capture I used, I’m not seeing any artifacts in the footage that I would have thought are atrributable to scaling problems, so I’m intrigued.

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

[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]

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

[Paul Mogg]

Hi Leo,
I’m afraid I’m not understanding your argument at all regarding firewire loading and would like to know what I’m missing here.

If you record to tape on the Varicam, you are incurring a certain loss in quality inherent in the compression of the DVCPRO HD format, so let’s start by saying that’s a given (unless you output uncompressed on the fly direct to hard disk from the camera while shooting, and perhaps this is what you’re saying and what I’m missing here).

If you load via Firewire into a Mac from tape, that’s a bit for bit file copy of what is on the tape, and there’s no loss in quality there, just like copying a Microsoft word file from one computer to another.

If you then edit these captured clips in FCP, the original clips themselves do not get changed or degraded at all during editing, the only quality loss occurs when you have to render due to adding effects and filters, or on output. In which case the original camera files STILL do not get changed, it is only the render files that you are viewing during editing that will have quality degradation in them.

So it seems to me that the most efficient workflow with the minimal quality loss (next to recording uncompressed direct from the camera while shooting) is to capture via firewire, edit natively in the DVCPRO HD format, as an offline format. Then, when you are finished editing, re-render out your entire timeline as uncompressed 720p HD. This way the original files from the tape only get decompressed the once, and all of the effects, transitions, filters etc. are rendered out uncompressed also in just the one pass. It seems logical to me that this workflow would produce the minimal quality loss possible, and should actually be equal in final output quality to native editing in uncompressed HD format, while not having to deal with the massive data size of uncompressed HD during editing (again, this is unless the original capture from the camera was uncompressed and DVCPRO HD is avoided altogether.)

It also seem logical that if you were to edit uncompressed, add lots of effects etc, and then fail to do a complete re-render from the original camera files ( that I assume were decompressed after capture ) at the end, you would end up with inferior quality to the DVCPRO HD workflow I’ve outlined, as you would be outputting material that had probably been re-rendered mutliple times during the editing process.

I’d be very pleased if someone could set me straight if I’m wrong in any way here, as I dearly want to understand the arguments being made so as to get the best possible quality for the film I’m working on right now. I’d rather look like an idiot and get it right, if that’s what it takes.

Many thanks,

Paul

[Paul Mogg]

Hi Rodrigo,
Thanks for the great posting. I have too many questions I’m sure, but could you please comment on how much the colour changed from what you’d see on your editing monitor to the final projected output? Does the colour wash-out a lot? I’m going through a similar process and was wondering if I had to do a film-out, would it be advisable to ourput a kind of super-saturated digital version to compensate for any loss in colour saturation caused by the film transfer. Also, did you shoot in Film Rec. or Video Rec. and did you online uncompressed? The new rendering in FCP 5.0 looks so good that I’m wondering how much gain there is in onlining uncompressed for just straight cuts sections that only have mild colour correction.

Many thanks in advance,

Paul

[Paul Mogg]

Wow! What can I say, that will be a pretty amazing little camera, and incredible that you’ll be able to do true “overcranked” style slo-mo, I love that with the Varicam. How will this camera create 1080/ 24p? Is each CCD 1280*720 and then it’s uprezzed or something? Sorry I’m not familiar with the way the DVX100 works.

Paul

[Paul Mogg]

Hi Folks,
As I posted on the HDV forum, this looks like a very exciting little camera. I so much prefer the DVCPRO HD codec to HDV MPEG. But am I reading the preliminary specs correctly that it will record 1080 24p and 720 60p?? I didn’t think DVCPRO HD currently supported 1080 24p. Also, if it does support 720 60p, does this mean we’ll be able to get the lovely slow motion you can get with the Varicam by using the FRC plugin in FCP?

I’m sure the response will be “wait till NAB”, but I just had to ask the question!

Thanks,

Paul