First off, to get this over with, the phrase is "Viola!", not "Wallah!". I used to make the mistake myself, it's pretty common to spell it phonetically, but you wouldn't want to do it with a client who knows better.

Okay, prerenders in Vegas. Yes, they could be TONS better. A prerender in Vegas renders the timeline, not the media, which is why when you add a new track you've changed the timeline and the prerender goes away. The logic Vegas uses to determine this could be improved, obviously, to account for the fact that the new track is still empty.

Prerenders could be treated as new media on a new track, albeit a track that's 4 pixels high that you can't directly manipulate. The point of it is that the prerender should be subject to the same ripple behavior as everything else-when you ripple all tracks then the prerender gets rippled too.

I suppose that Vegas could do something more complicated to validate prerenders, like calculating a checksum so that it could tell if the content of the timeline really changed. This would probably incur more overhead, but if you were just rippling or moving media on a track above another empty track, or above a track with a still image or static generated media, this might save more prerenders.

Yes, PPro does a better job. Vegas could do better than PPro. But prerenders in ppro are fundamentally different from vegas in their purpose and in the thinking behind them.

Vegas is what I'd call a resampling edit system. By this I mean that everything you put onto the timeline gets resampled to fit the timeline's specs, and more importantly, it gets resampled as it's played. This means that all the conversion happens in the CPU and RAM. The advantage is that you can get frames that are the same as uncompressed footage, at least in your preview window.

In contrast, I'd call PPro a conforming edit system. You pick a project type before you start, and you pick a place where all the prerenders will be placed. PPro then tries to make sure that everything conforms to the project type. As far as I know, if your project type is NTSC DV and you put something other than DV footage on the timeline, PPro will show you a red line to tell you it needs to be rendered. presumable PPro renders it to the DV codec.

Which is better? Well, it depends. If you really feel compelled to prerender things then PPro's approach is more logical. It caters to old timers (who probably aren't that old) who are used to starting a project with a specific output in mind. So if you know that everything is going back out to via your Xena card's SDI output then you render everything to that. PPro takes that choice away and you don't need to think about it.

Prerendering isn't a core activity in Vegas. Vegas doesn't need to know that the project is a Xena SDI project, or that it's going to be put back to DV tape. Vegas just wants to know the the frame size, interlacing mode, and frame rate. Beyond that, it's an uncompressed format for the time the frame exists in RAM. The tradeoff is that you can't always get full framerate playback, but it's easy to get good quality output in a variety of formats, and it's easy to switch a project's template mid stride. You can actually choose a prerender format in Vegas, and you could conceivable make unplayable 128bit uncompressed prerenders.

All this is really just to say that prerenders in PPro aren't just implemented better, they have to be implemented better. And, conversely, prerenders in Vegas are implemented poorly because they aren't absolutely vital. There one of those many things in Vegas that could be much better but are largely neglected because the budget for them was spent long ago.

(Disclaimer: It's Sunday and I'm away from anything with either PPro or Vegas on it, so all my assumptions about how things work are from memory)

Rob Mack