Maybe I don't understand exactly how AviSynth works "under-the-hood" but as far as I can tell it basically "listens" for players to request an AVS file. When a player does this AviSynth jumps in and processes the AVS script and provides back a regular AVI or MPEG file thus making the entire process, except for the unconventional file extension, transparent to the player. Meaning the player does not need to know anything about AVS files to play the results. Well I would like to get this working with my Media Server (Mezzmo) because it would allow me to add subtitles to media without my BluRay Player having to support it. However Mezzmo seems to filter the files it makes available by extensions and thus it filters out AVS files. I tried asking at the Mezzmo Support but so far articles I have seen, seem to indicate that AviSynth would need to be integrated into the Media Server for the Media Server to be able to support AVS files. First, I don't understand why. Assuming that the Media Server works similar to a player (when it is streaming the requested file) then AviSynth should intercept the request to stream the AVS file, process the script, and return (to the Media Server) the post processed AVI or MPEG file. As such, as I see it, the Media Server does not need to have AviSynth integrated except for allowing it to request AVS files. Second, if he objective of AviSynth is to be as transparent (to the end player) as possible, why does it use AVS extensions (which some poor players might filter out) instead of using the conventional file extensions (e.g. AVI, MPEG, MP4, MKV, etc). This would allow it to be used even with programs that do an initial filtering by extension (which is a bad practice but it still happens). Yes, this might make it a bit confusing when trying to figure out which files are real content files and which are scripts but generally the file size will give it away. AviSynth could then identify these files either by still keeping AVS in the file name (e.g. MyMovie.Avs.Avi) or by having a quick look at the beginning of the file for either a AVS tag or by seeing that the contents do not conform to one of the standard content containers. It seems to me that if AviSynth has gone this far to be transparent why not take the extra step to make it fully transparent.