Right, we are ready to begin. Run up VirtualDub. You will be greeted with a fairly standard looking application.

File->Open, select your file.

On the Video menu, make sure "Full Processing Mode" is selected, as shown.>

Back to the Video menu, select "compression". You will be greeted with the dialog as shown.

You should have XviD as an option, right at the bottom. If you don't, you haven't installed XviD.

Click on the "Configure" Button.

Now you'll get a XviD Configuration box like shown. Don't worry about 95% of it.

change the "Encoding type" to "Twopass - 1st pass"

Quick explanation: When you compress a video, the compressor looks at the video stream and compresses it to the size you specify, the bitrate. Now if you say "make me a video that is a constant 600 kilobits per second" then you'll get a video that is all 600 kbps.

However, some scenes on your video won't need 600kbps, for instance a black screen needs hardly any kbps. However, fast moving scenes need a heap more than 600kbps - or they will end up looking "chunky."

So, by passing over the file twice, the first pass it checks out where it needs the most kbps, and the least, and builds a table. On the second pass (later), it uses an *average* of 600kbps and uses more or less bits where needed. This means a much better quality video!

Press Ok a few times.

Now, on the Audio menu, ensure that "Full processing mode" is selected.

Go back to the Audio menu, click on Compression.

From the list on the left, click on Lame MP3.

Now, on the right, select the best audio bitrate. As a hint, most MP3 music on the internet is "44100Hz, 128kbps CBR (constant bitrate), Stereo." If you are going for super-dooper quality audio, use a higher kbps. I wouldn't go above 256kbps, that is heaps.

If you are aiming for really really small filesizes, drop down as far as 112kbps, or 96kbps, but don't go below 80kbps - that will sound pretty scratchy.

If you have only a mono soundtrack, halve the kbps (ie, only one channel!)

Press Ok to go back.

VirtualDub can do more than just compress videos, it can apply filters as it compresses - such as brightness/contrast, resizing, cropping. Lets apply a few just to get that filesize down.

From the Video menu select Filters.

Click on "Add"

You'll get a list of filters, scroll down to "smoother" and press Ok.

You'll get a box as shown. This is the amount of smoothing. Wind it up to 3, and tick the prenoise filter.

Quick explanation: By smoothing out the video a bit, the compression doesn't have to store as much data, so the filesize will drop even further. Better still, if your source video was from a video camera, some of the "noise" will be filtered out as well, improving the eventual "look" of your video.

Let's add another filter - resize.

Press Add again.

scroll down to resize, press Ok.

I like to use 384x288 - this is half of the PAL size, and is 4:3 ratio. You could however use whatever you like, even distort the aspect ratio.

Oh, and like in the image, make sure you choose "Lanczos3" as the resize mode - it is by far the best method!

If your video has dodgy edges - especially if it was captured from a video camera, cropping is useful too.

In the filters box select the resize filter and press "Cropping. You can now blank out as much of any edge of the video that is messy.

Back on the main VirtualDub page, select File-> "Save As Avi".

Now, since this is the first pass of a two pass process, the first file is going to be junk. So, give it a junk name, stick it somewhere that you can delete later on.

Make sure you tick the box in the bottom "Don't run this job now..." - we'll cue up the first pass and second pass and run them together in a moment.

Select from the Video menu "Compression", then select XviD again, then press "Configure."

Now select the encoding type to "Twopass - 2nd pass".

At this stage The "Target Bitrate"/"Target Size" button will become active. You have a choice, you can either nominate a file size and the resulting video will be that size, or specify a bitrate and the average bitrate will be that.

For really quick and dirty web videos, drop the bitrate down to between 300-400. It will be pretty clunky. For a nice web video but a pretty small size, go 500-600. For a video that you won't notice any clunkyness at all, go 700-800+.

Once you've made the file, you'd view it and say "hmm, I might go more on the bitrate" and repeat this process until you have the tradeoff between small filesize and nice quality.

If you are making a really big movie and you simply want it to fit on a CD, then switch to Target Size mode and type in either 650000kb or 700000kb, depending on whether you are using a 650mb or 700mb CD.

Everything else remains the same (ie the audio, the filters, etc, they all remember the last state) so go File Save As AVI again.

This time it is the real file so give it a name, put it somewhere nice. Again, don't forget to tick the "Don't run this job now..." box.

From File select "Job Control".

What you will see now is the two "jobs" you have queued up sitting in wait to be processed.

Press the "Start" button, and away it will go.

Depending on the file sizes, it will take a while - a few minutes if the video is only a minute long, to several hours if the movie is over an hour long.

You can check on the progress by popping up the "Show status" window.

Once the jobs are completed, you can delete the first pass file and delete all the jobs from the job control list. Check out your file, see what the quality is like for the file size. Good Luck!

JAW, 16 Sep 2004.