ok i'm importing an avi i made out of a mkv file into after efects when i render and export from after efects the resulting file is indexing the play back is stop starting for very short time at regular intivals like once a second ,,,,, the original avi i import plays fine ,,,,, is there any simple reason why this could be happening
You are simply seeing data rate issues. Whatever the original file was, it was most certainly a compressed format but when you rendered, you chose the default Lossless module, which, as the name implies, produces an uncompressed file. These data rates never play back in realtime even on beefy systems - part of them can be loaded into memory, but when that is full, the stuttering begins, because new parts need to be loaded and the current ones unloaded. So unless you choose to output to a compressed format as well, that isn't likley to change....
very helpfull indeed that was true my ram was tied up for ages even after after efects was closed as indeed i was outputting with lossless module ,,, am now using the microsoft DV PAL out ,,,,,,,,,,,,which is better quality microsoft DV PALL or MPEG ??