Half Life Movies

From Rabbi Blog

I read from time to time that you need FRAPS or a third party recording tool to capture HL*.exe based games. This is not entirely true. It is possible to export the frames from HL1 based games and both frames & sound from HL2 based games, however the process when first approached may be slightly more tedious than using a third party tool.

Frame Rates & Quality

I'll preface this by saying that this ends up being a non issue if your hardware can run the engine at 100fps+ on all high settings with all environmental CVARs set to high. For examples of CVAR settings within the game, see DoD Source Tweaking.

Toned Down Settings

The largest caveat of using this method comes down to frame rates and quality. When using a third party capture tool, you are capturing exactly what the game engine is producing at that time. This includes any jitters, bumps and snags that may be occurring during the rendering process. Depending on your hardware state, you may not be playing HL games at that the fullest settings due to frame rate rendering issues. For example, you may have HDR turned off even though your card is HDR capable and environmental settings are at Medium in order to achieve the 60fps and higher levels of game play. Whatever settings you are using is what will be captured in real time and you will normally take that hit in visual quality.

Wide Open Settings

Using the engine's ability to export the frames bypasses this issue. It allows you to crank the settings to high and the engine will export the frames not in real time, but rather it will take as much time it needs to render the combination requested video settings and how many frames per second you are requesting. For example, I want 3 minutes of demo footage at 30 fps and I'm using GameCam. I can record this in 3 minutes of real time, however I may need to adjust my video settings to achieve a smooth play and a hit to quality is taken. Instead, I use the engine to render the 3 minutes of the demo at 30fps and I move all video settings to the highest settings: the real time needed to do this process will ultimately result in how long it takes your hardware to render the 5400 frames individually.


The first instructions I came across were in a .pdf file and after a search this morning the following instructions were found over on the Valve Dev Community. I was quite suprised at the Recorder article as this has developed substantially since the last time I looked at .dem exporting a year ago (2006).

Rather than recreate the wheel:







Left 4 Dead (short)


Left 4 Dead (long)