Fraps & VirtualDub: How to save disk space and enjoy good quality, small file size HD video clips

The biggest problem most of us face while recording gameplay clips with Fraps is its disk space usage. Fraps records everything uncompressed, continuously (free version is limited to 30 sec.) and sequential. Meaning from start till stop the “whole” clip is split into single 4GB files (I believe due FAT32 filesize restrictions).

The length of a single 4 GB clip depends on the resolution and the in-game scene you record it in. For example, for me a 4 GB clip has about 90 sec. worth of gameplay in 1920×1200 resolution.

Because of this uncompressed real-time recording your frame-rates drops significantly while playing. There is NO way to keep up 40+fps with Fraps running unless you have one hell of a monster system.

Imagine what happens when you want to capture a 30+ min gameplay clip. Either you buy yourself a Terabyte HDD or you use a very simple trick: recording in half-size, upscaling and sharpening. Read the whole How-To guide!

Recording in Half-screen/size

Before we start with VirtualDub transcoding, upscaling and sharpening, we first have to record our gameplay. We do not record our gameplay in full-screen/size mode, as usual, but in half-screen/size:

This means if you have a game running at 1920×1200 resolution, Fraps will record it at 960×600, or if you run it at 1280×1024, Fraps will record 640×512, etc. Which in turn translates into much more gameplay time in each 4 GB file.

Another example: While recording in 1920×1200, I only got about 90 sec. (1:30 min) per 4 GB file, recording in half the resolution (i.e. 960×600) resulted in about 360 sec. (6 min) per 4 GB file. Whole 270 sec. more!

Upscaling and Sharpening

We want HD Quality, so we’re going to upscale and sharpen our recorded clip. Start up VirtualDub, open the uncompressed file, change in “Video” -> “Full Processing Mode” and “Audio” -> “Full Processing Mode”, then set your VirtualDub according to this screenshot:

Save your settings via “File” -> “Save processing settings” or Ctrl+S, so you can simply load them in the future. Saves a lot of time!

Addendum: Regarding “Threads”; QuadCores = 6, DualCores = 3.

You’ll need VirtualDub and a codec-pack which has the H.264 codec, like the “K-Lite Mega Codec Pack“. The settings in the screenshot are the same ones like in “VirtualDub 720p HD settings for YouTube! [Good quality, small file size]“, what differs, however, is that we are also going to use the “sharpen” filter.

We call the method to resize a lower resolution (960×600) to a higher resolution (1280×720, in this case), UPSCALING (sometimes also refereed to as up-converting). For your information, 1280×720 is the Standard HD (720p) resolution. The other is Ultra-HD or Full-HD (1080p, 1920×1080).

However due the upscaling method we lose quality, which is where the filter “sharpen” comes in. Upscaling from lower to higher resolutions causes the image to “blur”. Sharpen removes the blur and, well, sharpens the image.

You’ll have to experiment with the slider in preview mode around a bit, until you find the result best to your liking. I found myself settling down between 23-30, depending on each clip.

When everything is set, start transcoding via “File” -> “Save as AVI”.

Two important VirtualDub settings you should not forget:

“Options” -> “Preferences” -> “Threading”: Set the “Video Compression Threads” to 1. This is important if you have a multi-core CPU to make use of the multiple cores and in turn speed up the transcoding process.

Since VirtualDub Version 1.9.4 there’s an option to use your GPU as part of the transcoding process. Make use of it to additionally speed up your transcoding process. “Options” -> “Preferences” -> “3D accel”, hack in the box.

Addendum 23.10.2009:
There’s currently a problem causing VirtualDub 1.9.4/5/6/7, crashing under Windows 7. The culprit is 3D accel! Turn it off under “Preferences” -> “3D accel” and enjoy VirtualDub once again!

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