Frameserver is not specific for Premiere.
The core idea is to take audio/video from your favourite application and pass it to another application without a full render, thereby saving on disk space and time. The initial reason frameserver was developed was to use video encoders which were working as standalone apps and converting say AVI -> MP4, but were not working as plugins for apps like Vegas. So if you want to use such an encoder with Vegas, you have to render uncompressed AVI from Vegas (huge disk space) and then run your encoder on this uncompressed AVI. Instead with the frameserver you create a tiny intermediate AVI which is the output of Vegas and input to your encoder, in real time.
Though it was created for this purpose, frameserver can be used between any application in which it works as a plugin and any other application which accepts standard AVI files.
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