That's not correct. I've recompressed FRAPs files by STREAMING the video (no changes in compression) or by choosing even very generous compression settings, but setting it to use MP3 audio. I've turned 3GB files into 300MB. I kid you not, recompressing to use MP3 CODEC on my FRAPS holding folder saved me something on the order of 100GB (it's a 1TB drive, I store a lot).
EDIT: You chose a 2 minute clip, though... I think you'll notice more savings on the longer clips, naturally, when you compress in MP3.
Then 99% of those size savings came from compressing the video. If you look at the properties of any video file in Media Player Classic, click the MediaInfo tab, then you can see how much of the file is taken up by video, and how much is audio. I can't find any video files on my hard drive where the audio is more than 6% of the total size. For Fraps files they are all in the 1% range, often rounded down to 0%. The audio component is literally insignificant compared to video, and this is an indisputable fact to anyone looking at the actual numbers and thinking mathematically.
In response to your edit, the length of the video file doesn't matter because its a ratio. The only thing that could matter is if you're recording video at really low quality settings, and audio at really high quality settings. That doesn't seem to make much sense though, and the amount of audio still wouldn't be significant.
Compressing raw Fraps video files to save space is fine, but you lose quality. Those savings are mostly not coming from getting rid of the audio, because there isn't that much audio to get rid of.
If you know you're not going to keep the audio, you can avoid this whole discussion and just uncheck the "Record sound" setting in Fraps. Then everyone here will agree that your entire Fraps file consists of nothing but video, and nothing is being wasted on audio.
Edit:
The best practice for the highest quality end-product is to keep everything in the highest quality format until the end, when you render a video file. If you transcode your Fraps files and then use the transcoded files as your source files for your video project, it will look worse than if you kept the raw Fraps files to work from.
Furthermore, and you perform this experiment easily yourself if you wish, its been my experience that options that reduce Fraps capture quality, such as "Half-size" recording, are not worth the reduction in quality. You'd think the files would be 1/4th the size, but they are much bigger than that. Same goes for "Force lossless RGB capture". I always enable lossless capture, because it looks far better and is only marginally larger on my hard drive.
Going back to my previous statement, "If you transcode your Fraps files and then use the transcoded files as your source files for your video project, it will look worse than if you kept the raw Fraps files to work from." If you must save space and cannot keep the raw files, you're better off capturing full-size lossless, then transcoding down, than you are capturing half-size and lossy. You definitely will lose a lot of quality if you both capture half-size and/or lossy, and additionally transcode down. You probably want to avoid that if you care what your video looks like.
One place you
can safely save some size is by reducing the FPS. I see no need at all to capture at over 30 FPS. Furthermore, if you're in AH Film Viewer and capturing at half speed, you can halve your capture rate (to 15 FPS, for example) because when you double the speed again in your video editor, it will go back to being normal FPS. This technique will not have an affect on your video quality, unlike the other things mentioned.
