A Lil’ Compression Lesson

Yesterday, I was experimenting with different compression settings to achieve optimal picture quality. Compressing video for web is tricky because you need to find the perfect balance between file size and image quality. Make the quality too high and you increase load time, make the quality too low and your images are annoyingly muddy. In this particular case, the video was for a CD-ROM so you have a bit more leeway when it comes to file size. You still want to be careful though, as some CD-ROM drives are slower than others and if a video file is too large, choppy playback will result. For most flash videos for web I use the settings 300kb/s video quality, automatic keyframes, 64k mono sound. The result is usually a quick loading sharp video. The settings may need to be adjusted for video size and whether or not you want the ability to scrub. Scrubbing will only occur on keyframes so you may want to bump it up to every 6 or even 4 frames. This will drastically increase file size but will really help image quality as well as allow scrubbing. For the CD-ROM, I made the video 600kb/s with keyframes every 6 frames. This increased file size from 14 mb to 25mb, but the picture quality was greatly enhanced and the file is still small enough to play smoothly.