Making changes to the video file

hagadorn · Post by **hagadorn** » Tue Sep 05, 2006 2:18 am

If I've already created the video file but then I realize that I want to make a couple of minor changes, should I go back to the VSP project file, make the changes to the clips involved and then create a brand new video file? Or should I make the changes to the same video file and re-create it? If I do it the second way, will the file quality be degraded every time I change it and re-save it? Will Smartrender make it save faster because it is only taking into account the new changes?

Post by **Ken Berry** » Tue Sep 05, 2006 2:23 am

Yes to all three!!!

I mean, yes, making changes to an already rendered mpeg will result in some degradation, but how evident this will be to the naked eye is another matter. And yes, using Smart Render will only affect those few areas you have adjusted -- but you will recall the polemic over Smart Render and whether using it can lead to other problems. Try it and see.

And yes, just to be sure, I personally would probably go back to my project, make the changes, and then make a whole new mpeg...

hagadorn · Post by **hagadorn** » Tue Sep 05, 2006 2:30 am

Thank you, Ken - you're always so helpful! Since time isn't really an issue here, I think I will play it safe and go back to the project file.

MrA · Post by **MrA** » Tue Sep 05, 2006 3:15 am

just curious, even if the file is already saved as an mpeg, doesn't VS "smart" read the file and save it as an already rendered mpeg file?

hagadorn · Post by **hagadorn** » Tue Sep 05, 2006 3:21 am

Are you suggesting that it doesn't touch the unchanged parts, thus maintaining the quality of them?

heinz-oz · Post by **heinz-oz** » Tue Sep 05, 2006 4:21 am

In theory, yes, in practise, yes and no. The whole thing depends on the type of changes you are doing. too much detail to go into here. Since hagadorn indicated that time is not a priority, the return to the original project avi files is the best option.

hagadorn · Post by **hagadorn** » Tue Sep 05, 2006 4:25 am

Heinz, they are mpeg files. I thought AVI files would be too large.

Post by **Ken Berry** » Tue Sep 05, 2006 4:30 am

MrAmigo -- essentially you are right. That is the whole purpose of 'smart render': to 'see' only the changes made to an existing mpeg file and only to render the changes, thus preserving the original quality of the rest of the video. But as Heinz has indicated, depending on the nature and extent of the changes, in the past Smart Render has sometimes worked but has often messed things up, including by putting video and audio out of sync, it seems.

Some of our members have recently been doing some experiments to see if this defect has continued in VS10. The results are a bit mixed. However, it seems that, even without Smart Render, you may be able to re-render 2 or 3 times without apparent degradation in quality if you leave non-square pixel rendering switched off, and only engage it when actually on the last stage and are going to burn the video to DVD.

It's really one of thos 'try it and see' things. It works perfectly well for some people, while others have no end of trouble with it. If you find it works for you, then go ahead and use it. But if you experience problems, then one of the first things you should do is to switch Smart Render off. After all, it will only be a matter of minutes more to do a full render, and you have just spent hours actually editing your project...