I'm posting a guide on how to download video files from YouTube because some people are surprised that it's even possible.

The first step is to navigate to any YouTube video you want. I'll use this one for my example. Then look at the address bar in your web browser. The address should start with "http://youtube.com/watch?", followed by one or more request parameters. A request parameter looks like "name=value", and they are separated by ampersands. So an URL with a bunch of request parameters would look like "http://youtube.com/watch?v=zoEu9xRH-e4&user=Nebu+Pookins", which contains 2 parameters: "v", whose value is "zoEu9xRH-e4"; "user", whose value is "Nebu+Pookins".

The parameter you are interested in is "v". Its value is the ID which uniquely identifies the video. Copy and paste the address into notepad, and delete all the other parameters except for the v parameter. So you should end up with something which looks like "http://youtube.com/watch?v=zoEu9xRH-e4". Furthermore, if you see a hash sign, you should delete the hash sign and everything that follows after it. The hash sign indicates an in-page anchor that can be linked to. So if your URL looks like "http://youtube.com/watch?v=zoEu9xRH-e4#EndOfComments", you need to delete the "#EndOfComments" part.

Once you have your URL fixed up properly, head over to VideoDownloader and paste your URL into the form there, and click "download". The site will probably tell you that you need to rename the downloaded file so that it has an ".FLV" extension, and your browser will probably by default give it a ".HTML" extension. Follow the advice of the site, and save your file with a .FLV extension (in my example, I name the file "Sukoshi Yoshi.flv").

If you get a message saying "This service is unavailable", just try again 5 seconds later. If you get a message saying "Invalid URL", then you probably didn't clean up the URL properly. The most common mistake is to forget to remove the hash mark and everything after it.

Once you've downloaded the file, you'll end up with an FLV file. I couldn't get the FLV file to play in Media Player Classic, but it plays in VLC. However, you can't fast-forward or rewind using the VLC player. You can either just live with not being able to rewind or fastfoward, or you can try to convert the FLV file to an AVI file.

Download the Riva FLV Encoder. Despite the name, the program can also decode FLV files. Once you have Riva FLV Encoder running, just drag and drop your FLV file onto Riva. On the right hand side, you'll see a resolution drop down box. YouTube videos always have a resolution of 320x240, so change the resolution to that. In the lower mid-left part of the screen, you'll see an "output filename", which will have an .flv extension. Change that to an avi extension (e.g. "Sukoshi Yoshi.avi"), and click encode. The app will dim itself for a while, and when it comes back, the file will have finished encoding.

If you try to play the file now, you may find that some files play it just fine, but Media Player Classic won't be able to play it. To fix that, download the Avi FourCC Changer. You can't drag and drop your file onto this program, you have to click the folder icon and browse to and open your file. When you've selected your file, you'll see the two drop down boxes get some 4 letter characters. Change the lower one to "XVID" (make sure it's all uppercase; that's important), then click the apply button. Your video should now play in Media Player Classic.

The VideoDownloader site I mentioned earlier actually has a Firefox extension, which is what I actually use. Just note that you still need to fiddle around with the URL sometimes. If the address bar says something like "http://youtube.com/watch?v=zoEu9xRH-e4#EndOfComments" and I activate the extension, it'll fail to download. You have to edit the URL to something like "http://youtube.com/watch?v=zoEu9xRH-e4", then hit enter so that firefox actually reloads the page with the new URL, and then activate the extension.