With dvupscale.avs customized to suit your needs, open it in VirtualDub. Either run VirtualDub.exe from its directory, or right click the .avs file and choose Open With. Find VirtualDub.exe (not vdub.exe) and you'll be good to go. From now on the right click->Open With menu should show VirtualDub as an option, making access to your Avisynth scripts' output that much more convenient.

     After a few moments the program should start up, with your video displayed in two windows. The left shows the video coming into VirtualDub, right is video as it goes out of VirtualDub. Since we won't be applying any filters in VDub itself, these two remain identical through our procedure. At the bottom of the screen are the transport controls. Stop, Play Input, Play Output, and a series of others that aren't really important for our purposes. Check the VirtualDub help file to learn more.
     All you'll do now is click on the timeline in a few different places to snap the playhead there and see what your video looks like after it's passed through our deinterlacing and scaling tools. You'd do well to find some segments that feature fine detail, and areas that show diagonal lines, they'll help you get a sense of how well QTGMC does its job, even when set to one of its fastest presets.

     Once you're satisfied that everything's functioning correctly, we can do what we're here for and upscale this clip. With VirtualDub still open, load your script in Notepad if it's not still up. Change the last line back to


as it was initially. It would have been simpler to have you leave that line the way it was, not bothering with the "Super Fast" or "480sq" settings, but this way you get a little experience with both Avisynth function parameters and a wonderful time saver VirtualDub offers: save your script, switch back to VDub, and hit F2. After a few seconds the video will be updated to reflect the changes you've made. Exceptionally useful, this feature dramatically increases productivity when experimenting with scripts.

     Now that that's taken care of, it's time we compress our clip. Up in the menu bar, click Video, then Fast Recompress. VirtualDub used to convert all video input to RGB color space as a matter of course, and Fast Recompress was the only way to avoid forced conversions when they were unnecessary. As per the documentation, however, this has changed in recent releases, and as long as the VirtualDub filter list (Video->Filters or Ctrl+F) is empty, video will remain in its original color space (if supported by the selected output codec).
     Nonetheless, as I understand it Fast Recompress still offers a performance improvement, however slight. With such a slow chain of Avisynth filters, it may not matter, but I like to play it safe.

     Next we set the compression by going to Video->Compression (or Ctrl+P) and choosing "Huffyuv v2.1.1" from the list. You should be able to leave this codec set to its defaults, but be sure to click the Configure button to read some important information that may help if you run into compatibility issues.

     That's all there is to it. "OK" your way out of the two dialog boxes and hit F7 on your keyboard. This brings up the Save As AVI dialog, where you can save your video the way you would any other file. Find a convenient location, give the file a name, click OK and off you go! The safest thing to do now is uncheck the two boxes in the Status window, "Show input video" and "Show output video". We don't need VirtualDub trying to draw the result of our script to the screen while it's busy encoding, it's got a heavy enough workload as it is. You can turn Show input video back on every now and again to keep an eye on your progress, if you want, just don't leave it on for the entire encode.

     Now it's just a matter of time. Once the video is finished, the Status window will disappear, and you can go find your video in Windows Explorer. You should be able to decode the file with any media player that supports VfW codecs (as long as Huffyuv is installed on the system being used to view the file), and if my research is accurate a good number of popular video editing programs can import Huffyuv AVIs without issue. If yours is among these, you're finished! Have fun experimenting with the script, dig through the "Advanced Use" section of the documentation for a more in depth look at its various settings, take a look at the troubleshooting section for some useful tips, and please don't hesitate to contact me with any questions or comments!

     But what if your software can't open the video? And even if it can, can't anything be done about the disk space requirements of rendering these lossless clips? It turns out there is, in fact, a way to feed the output of your scripts into applications that don't directly support Avisynth. The next page will discuss the "Avisynth Virtual File System" and how it can make your life so much easier.