In a perfect world, your green screen footage would be transferred uncompressed to your hard disk for manipulation in your effects application. That type of machinery is typically out of reach for most users of software compositing packages on lower end operating systems. Most digitizing software applies some level of M-JPEG compression on the input stream. Use the lowest compression ratio possible.

 Facts About Bandwidth

• Uncompressed BetacamSP 
• Roughly 20MB/sec or 700KB/frame. 
• Based on a 648x486 resoltuion two field image. 
• Avid AVR 77 
• 400KB/frame or 12MB/sec. 
• Media 100 NTSC compressor 
• 300KB/frame or 9MB/sec. 
• Digitizing with Adobe Premiere and the Media100qxc. 
• In the Media100 proper, you need the HDR option to achieve 300KB/frame. 

• Compression artifacts introduced during digitization will show up as detail in the backing of your green screen footage. 
• Compression artifacts hamper the Ultimatte process. 
• AVR 77 and Media100's 300KB/frame are adequate for the digitizing process. 
• This is close to 4:1 compression, although documentation on both the Avid and Media100 list these rates as 2:1 compression (virtually lossless). 
• High quality properly lit camera original is the best way to avoid complications in the Ultiomatte process. 
• Compression in a camera original, is amplified by compression during the digitization process with either the Avid or the Media100 low end products. Creating footage that is impossible to composite.