Dealing with 4:2:2 to mpeg-2

farss wrote on 8/20/2004, 4:25 PM
I'm led to believe the Declink SD card will work with Vegas, perhaps it's not yet 100% but the few wrinkles still to be ironed out aren't a worry to me.
Now having got the footage in I'm assuming I can cut the footage in Vegas (I mean cut, that's all I need, no FXs). Having done that I then need to encode to mpeg-2. I'm assuming Vegas will send my footage to the encoder preserving 4:2:2. Yes I know the DVD spec means it' s still going to be 4:2:0 however that's not the only difference to consider, there's much less compression on the source material than I'd have coming from DV25.

Other possible workflow is SDI into a hardware encoder but I've yet to quite figure out how I cope in that scenario if I need to do even the most basic edit.

So I guess my question is given that the target medium is DVD and the source is 4:2:2 just how much better will the final product look by keeping it SD through the chain versus say ingesting as DV25 and feeding that to the encoder?

Bob.

Comments

Spot|DSE wrote on 8/20/2004, 5:42 PM
For you, I don't know that I'd worry about it Bob, unless you're doing a lot of processes, titles, composites, etc. If you are, then you'll perhaps see benefit. I've got some media I can render back out...But since your source is 4:2:0 anyway, I'm wondering what the transcode would do for you, if anything.
Now, if you ingest 4:2:2 from a 4:2:2 SOURCE such as the XDCam, HDCam, etc, you'll see a big difference. Julian Ramm from the Xpri team was showing me some of this today at the Cinefest show, and it's pretty sweet.
Geez, I wish I could afford an HDcam.
farss wrote on 8/20/2004, 5:52 PM
The source will be 4:2:2 from DigiBetacam, and yes it was shot that way, not some dodgy upres. It's already edited, just needs authoring to DVD, potentialy lots of work and client has reasonably deep pockets. I'd like to stick to what I know, Vegas and DVDA, authoring doesn't need to be complex, just straight forward choose clip and play it stuff so going to a high end authoring app would be overkill. But these guys are quality fanatics that I've built a good reputation with on the audio side.

My options are coming out of J30 via firewire as DV25 or J3 as SDI.

From what you're saying the latter is going to give a much better result. The SDI cards for just SD seem pretty cheap so maybe I'll take a trip to the bleeding edge of Vegas, wind up the GHz in the CPU and see what I can break :)

Bob.
RBartlett wrote on 8/21/2004, 12:21 PM
Vegas is based on an 8bit RGB pipeline. Same as Premiere6.5 and earlier and most NLEs frankly.

Good news for 4:2:2 is that Vegas will not break this when held in either a YUV 4:2:2 8bit format (like quite a few AVI based captures will use from SDI) or an RGB24 AVI.

Even if you mix in some DV, your NTSC DVD will be less mucked about with than if you ran DV throughout. If you were talking of PAL DV then much of this would also be moot with PAL DV using 4:2:0.

It is a shame Vegas will compand/relevel 8bit + 10bit YUV and 10bit RGB. Although as has been described here extensively, SD-DV in particular always runs through nicely despite the apparent dynamic range mismatch.

Seriously consider setting your SDI card to catch RGB24 uncompressed AVI if you wish to control everything at the acquisition phase. You can probably set it to do that somewhere. YMMV, but that would be my ideal approach for SDI with today's Vegas.