QuickTime is a multimedia format developed by Apple, originally in 1991. The QuickTime format can handle a number of multimedia formats including video and audio. The format is propriatary and a free player is available for many operating systems including MAC and PC.
Quicktime files normally have a file extension .qt or .mov or .mp4.
To capture video files from Quicktime files with Fast video indexer you need to have a DirectShow filter for QuickTime installed. I recommend you download the Quicktime alternative and not Apples QuickTime player.