Preview Performance - Processing Power? External Monitor?

PumiceT wrote on 11/3/2004, 6:45 AM
A lot of this will be theoretical, but I'm sure it's stuff that you guys deal with daily. So, my question is this:

If my computer can't even show me a 1/2-size preview-quality on-screen preview in real-time, will a FireWire output to external monitor yield better real-time results?

Some background information:
I have a day job doing some marketing tasks for an architect. At home I do video and audio editing for fun and some side work. What I am currently working on is a video to be shown at a trade-show. It's mostly still images being panned and rotated to create some sense of motion / activity. I'm using VV4 on a 3.4 GHz P4 with 1 Gb RAM. I can use Draft-quality for real-time previews, but if I bump it up to Preview-quality, it takes a good 3 seconds or so to show me each frame on-screen. I get the impression that if VV can't show me a real-time preview on my screen, it won't show me anything better on an external device. Am I wrong? Does the external device do some of the work that my computer isn't capable of doing? If it's a matter of the processor not being "beefy" enough, what kind of processing power is needed for DVD-size projects to be viewed real-time (external or on-screen)?? At home I'm planning to upgrade my PC, so I'm looking to get something that can handle some real-time video previews on-screen and/or external.

Please school me. :)

Comments

Chienworks wrote on 11/3/2004, 6:50 AM
In my experience an external firewire preview will run even worse than the on screen preview window. However, the problem you are seeing would seem to be due to the complexity of the project. You are using stills and transforms, both of which take a lot of processing power. This is what causes the jerkiness you see while previewing. But, you are not going to show your audience the preview of the unrendered project. When you show it to them you will be using the finished and rendered version which should play back smoothly both on screen and through firewire.

If you need to see what some small sections will look like played back smoothly while editing you should consider using dynamic RAM previews for those sections.
PumiceT wrote on 11/3/2004, 7:13 AM
:( Not exactly what I was hoping to hear, but I suppose it's what I'd expect. It only makes sense, since rendering takes about an hour per minute of video, I guess it's nearly impossible to expect to cut that to real-time rendering.

Why, then, would I consider getting some way to do an external monitor? Is it simply to avoid burning DVDs to use for previewing? I suppose that would save some time and media. I'll still have to wait a few hours to render the video. If I was using pretty straight-forward video pieces, would it take less time to render? I ask this because I have another project coming up that will use video footage, but is likely to be a total of 120 minutes or so. I can't see waiting 120 hours for it all to render.
johnmeyer wrote on 11/3/2004, 7:24 AM
rendering takes about an hour per minute of video,

Wow! You are definitely doing something more than panning and zooming stills.

Things that make a difference in preview of stills:

1. Resolution of stills. Anything much above 720x480 (for NTSC) is more than you need, unless you are zooming. If you are importing 5 megapixel stills directly from your neat, new digital camera, without reducing the resolution, then you are going to tax Vegas considerably. It must downsample and display in real time, and that's a lot of pixels to process. Most photo programs can batch process stills. If you aren't going to do much zooming, I suggest you downsample to something between 720x480 and 1200x800. At 1200x800, you can still zoom in to almost 1/4 of the original pic, and still have full 720x480 resolution in the output. Save as PNG format, if you can.

2. fX. If you start putting fX on any video or any still, the preview speed will slow. Track, event, and buss fX all count. Also, if you have the videoscopes displayed, that will cause frames to be recompressed and will slow preview.

3. Your rendering time will increase substantially if you use Best for rendering (in the Render As - Custom dialog). Generally you should use "Best" when your project consists of stills, but for test renders, you might want to use "Good" in order to speed up the process.

If preview speed is important, another trick is to temporarily change the project resolution. Click on the project icon (just above the preview window) and change resolution to 360x240 (1/4 resolution for NTSC). The preview window (both on-screen and external) will get a little "grainy," but the preview speed will increase remarkably.
PumiceT wrote on 11/3/2004, 7:40 AM
I just realized something that is slowing things down tremendously - Super Sampling. I'm sure I don't need to keep it at maximum for my realtime previews nor my temporary daily renderings. That alone bumped my speed way up.

Yeah, I know about the still image resolutions. I reduce them unless I'm zooming into 1:1 pixel level - which I wish was a zoom level setting - I'd like to know whether I can expect some antialiasing or if I'm at the right zoom / crop level. Also, I wish the pan/crop dialog would let me zoom out further and use a bigger area. If I plan on zooming into and out from a 4000x3000 px image, I can't zoom out much at all. It would be nice if I could just move the IMAGE not the crop-area (as an option, not the only way).