DV Rack with HDV

[Maheel Perera]

DV Rack has intoduced an addition to work with. It will defenetely eliminate the dreaded drop out issue.

I learned from there site that DSE is a user of DV Rack.

DSE, Have you tried the HDV addition for the DV Rack?.

[Jerry Waters]

I'm not DSE but I just installed HDV Rack. It seems to work OK but I had a couple of questions I sent in to support. (I'm having a problem with a laptop to external firewire hard drive at the moment and haven't been using it as much as I'd like.)

[Mark Mapes]

Maheel,
Don't know whether DSE is frequenting the boards these days as he's out on the Sony HDV Roadshow, which is relevant because his presentation includes none other than the HDV PowerPak upgrade to DV Rack (as well as ULTRA 2 with it's new HDV support). In the event that he doesn't drop by for a while, I'd be happy to field any questions you may have.

That goes for you, too, Jerry. Our call volume has been higher than usual with the recent release of the two products mentioned above as well as a couple of others. Still, you'll probably hear back from our customer support desk shortly, but feel free to post your questions here either way. I'll warn you up front though that I probably be of little help when it comes to troubleshooting your problems with the external hdd--that kind of hardware question is much more up the alley of our guys on the phones.

[Jerry Waters]

My first problem with HDV Rack was not getting m2t files. Finally, I realized I had just been using the camera with down convert and set the camera for firewire HDV and the m2t showed up. The problem now seems to be my notebook. It is a Vaio but about 3 years old and an AMD chip and it is marginal. Everything seems very slow and I can't get the playback of the clip to work though it seems to be recording the clips. I think I'll install it on my edit computer and test it there - a 2.8 intel with 2 gig of ram and see how it works there. If the notebook has to be upgraded, I want to wait as long as possible with the new chips coming out.

[Steven Fokkinga]

Hi Mark,

Is monitoring HDV with HDVrack realtime (so 25 fps Pal and 30 fps NTSC)? And if so, what kind of laptop specs would you need at minimum? Like Jerry, I'd like to buy a new laptop that can handle hdvrack realtime, but I am not sure if those are already within reach...

[Mark Mapes]

You have control over the frame rate and resolution. In fact there are two settings related to resolution: MPEG Res (full or half) and Lines Displayed (Both, Odd, or Even.) Adjusting these three settings lets you "tune" display quality to get the most out of the system without maxing out the CPU, which results in artifacting and dropped frame. Note that these settings affect only what you see when monitoring; the full HDV stream is recorded regardless.

My understanding is that today's hardware is not capable of delivering full- framerate/full-res HDV performance. (We did not build a super-system to see what was possible.) With a 3.2 GHz processor, you should be able to get either full framerate or full-resolution--sounds like you'd opt for full framerate. Keep in mind that you'll scarcely be able to tell the difference between MPEG Resolution at Half vs. Full because the Field Monitor is much smaller than the HD frame. The difference will only become apparent when you use the zoom feature in the Field Monitor.

With something down in the 2 GHz neighborhood, you'll need to keep both framerate and resolution throttled back when recording. Our beta testers who ran with those settings reported that the results were entirely acceptable.

You specifically ask about monitoring HDV. If that's all you'll be doing (i.e., not recording), then adjusting these decompressor throttles is less critical because occasional artifacting and dropped frames aren't that big a deal--there's no recording to be compromised.

[Jerry Waters]

Thanks for all that, HOWEVER, I would like to know my capabilities so I'll know how to use it. Are you saying I can't record full HDV AND that I can't see clips recorded? Or can I record full HDV and set the playback of clips at a lesser resolution and/or framerate? If I could do the last, wonderful. If I can't trust the HDV that I'm capturing to hard drive, then I would only use the monitor feature and record avi or quicktime so I could play clips back for the talent, etc. My main interest is in feature length productions. So I guess my question is, "Can I trust getting good enough captures to use and have tape as a backup?" (as done with DV) or iare the recordings done by HDV the backup and/or the "playback at the shoot" footage.
Thanks.

[John McGinley]

I think it's clear what he's saying is, regardless of what you see on the monitor HDV Rack is saving the file without error.

The monitoring is just a preview of what you're getting.

If the preview is studdering because your system is too slow, you're still saving an uncorrupted HDV file.

And that for the purposes of previewing the incoming data stream, you can either choose, full speed video or full res video but no system is currently able to handle both. But the HDV stream you're saving on the drive is full res and fullspeed.

That about right Mark?

[Mark Mapes]

DV Rack always records the full video stream. Nothing that you do in DV Rack has any effect on what is recorded. However, if have the three throttle controls set such that your CPU ever reaches 100%, then data will be lost in the recorded clip--that can manifest itself as dropped frames or as artifacts within the image.

If you do a few test recording and play with different combinations of throttle settings while watching your CPU usage (through Task Manager), you will quickly determine which combination gives you safe CPU headroom. As long as you stick with a "safe" combination while recording, you can be confident that you'll get intact recordings.

I'm lobbying for the implementation of what we could term an auto-throttle that would monitor CPU usage--if it exceeds a threshold setting, then the program would automatically reduce one or more of the throttle settings. Think of it as overdraft protection. I'd be interested in whether customers would find that a desirable feature.

You write: "(I can) set the playback of clips at a lesser resolution and/or framerate." Just to be clear, the three throttles affect both monitoring of the live feed, regardless of whether you're recording or not, and playback of recorded clips.

Bottom line: With the throttles set correctly, you should have complete faith in HDV recordings from DV Rack.

[Jerry Waters]

Mi culpa. I didn't read your message well enough and skimmed over "the full HDV
stream is recorded regardless" the first time. There is another "problem" I forgot to mention, and from what you are saying the throttle is the problem there also -- there is a terrific lag time between what the camera is seeing and what the Rack monitor shows. A person can walk in, sit in a chair the camera is focused on and Rack will be showing an empty chair for several seconds before the person appears in the monitor.

I'll try resetting things and let you know how it goes.

[John McGinley]

If you're using an FX1 the firewire is about a 2 second delay, I think the Z1 has more of realtime firewire transfer.

[Douglas Spotted Eagle]

Actually, they are the same, a 2 set of GOP behind. Due to the M2T decode, it's not realtime from any camera.
Although it seems a little squirrelly at first, you get used to it really fast, and other than doing a rack focus, it won't bother you, or rather, it doesn't bother me.

[John McGinley]

Ahh, I was going off this chart which probably came out before the camera was actually in hand.

http://www.hdvinfo.net/articles/sonyhdrfx1/compare.php

[Maheel Perera]

You are back DSE. How about sharing your views regarding the HDV power pack for DV Rack.

[Douglas Spotted Eagle]

I love the HDV powerpak for HDV Rack. It takes a little getting used to in terms of the latency of the m2t stream, but unless Serious Magic partners with a laptop video card company to decode the stream via hardware....it'll always be there. Once you get past the latency, it's very useful. great for setting up the shot, great for field monitoring.