2014 update: Note, this is a very outdated tutorial.There are various ways to get decent HD-quality videos up on Youtube now, which generally follow the same sort of flow. Youtube's post-processing has gotten significantly better since this was written.
Record your video using some lossless recording program (30fps is all that's needed since Youtube limits the framerate), join multiple parts together using VirtualDub or something similar and upscale the video to 960x720 (DO NOT ADD LETTERBOXING), and encode the video (AVI is perfectly fine) using x264 or something. You don't really have to use MeGUI to encode.
Read the latest posts for tips on various things.
You might often see a Touhou video on Youtube that looks like
this. Then later you go and see something like
this and go HOW DO I DO THAT?!???
First of all, download a recording program that can record uncompressed video such as Fraps or CamStudio. CamStudio has a free trial and stuff, but you'll probably just want to go buy the program anyways. Secondly, go grab MeGUI
here. You'll also need
Avisynth. Not only that, but a bunch of filters. Go get those elsewhere. I'm not sure which you need, but just get as many as you think will be useful, lol.
Record your video using the program. If possible, record at 60 fps instead of the default 30fps some programs use.
Programs like Fraps usually cut videos into segments to keep audio and video in sync and other such things. This is where you'll want VirtualDub. Well, get it anyways; it's a good program.
Open the first part of your avi video with VirtualDub. The amount of frames pop up at the bottom, you can watch it and trim off unneeded segments, if need be. Under File, choose "Append AVI segment". Choose the next video in line and it'll put itself on the end of your clip. Do this until all your files are in one video.
At the moment, don't bother with much else unless you know what you're doing. Choose "Save as AVI". The rendering process takes a while to finish, so just wait it out.
Now, you have one giant file with your entire video. This is the time to open MeGUI. If it's your first time, it'll ask you for a bunch of updates. Just choose them all.
Under Tools, choose AVS Script Creator. This should open up a new window. For Video Input, choose your new giant AVI file. A preview window should pop up, just exit.
Go to the Edit menu. Here it should show four placeholder options with a # in front. Replace them with these lines:
BicubicResize(960, 720, 0, 0.5) # Bicubic (Neutral)
AddBorders(160, 0, 160, 0, 0)
ConvertToYV12()
You can also switch "Neutral" with "Sharp" and "Soft". Sharp might be good for some videos, but I just go with Neutral.
Click Save at the bottom. Another window should pop up with BIG. Just exit again.
In the Encoder settings option, you should have a bunch of options. I haven't experimented much, but Youtube likes x264 video, so choose "x264: *scratchpad*. If the File format underneath it isn't set to MP4, set it.
Click Config. Ignore most of the stuff, set the bitrate option at the top to something like 5000. The bitrate does not enable HD video, it just improves the quality once a standard has been set. I'm setting in to 10000 for lols.
For the Audio Input option, once again choose your full video file. Under Encoder settings here, choose Lame MP3: *scratchpad*.
NOTE: YOUTUBE NO LONGER HAS FAAC SUPPORT OR SOMETHING. LAME MP3 ALL THE WAY.
Press Config. If the ABR level isn't set to 192 already, set it. Don't bother with anything higher, Youtube dumbs it down.
At the bottom of the screen, click AutoEncode. Container should say MP4. Under Size and Bitrate, choose No Target Size and hit Queue.
Go to the Queue menu. There should be three items on the list; an MP3 file, an x264 MP4 file and a muxer. Just go to the bottom and hit Start.
Once again, just wait. Set Priorities to Normal, or if you're not using the computer while you wait, Above Normal. Above Normal kills your processing speed for absolutely everything else, but Normal just kind of slows things down. You'll have to change Priority three times as it processes different files.
And this should be it. You have for new MP4 file, in a fairly small file. Well, at least enough to throw onto Youtube.
For those thinking that it's a lot of work, it only really is to install the programs. This is generally what you do.
SHORT VERSION
-Record video
-Join all the pieces together with VirtualDub and save
-Open MeGUI and create a script with the video
-Go to the Edit tab and resize
BicubicResize(960, 720, 0, 0.5) # Bicubic (Neutral)
AddBorders(160, 0, 160, 0, 0)
ConvertToYV12()-Set to mp4 video (x264) and configure bitrate
-Set audio to the video (FAAC)
-AutoEncode with no target size
-Mux it and done.