This adds custom proxy file storage to the sequencer. Reasoning: sometimes low resolution versions are already available as a seperate file built by the capture application. So there is no real reason to make blender build it's own seperate proxy. This also somewhat fixes (aehm works around :) ) [#13632] Creating Proxy Takes Over Process, Should be Background Since now you can just fire up ffmpeg to build your proxies in the background. (You could have done before and build a directory of jpeg files, but then you would have to rename all the files since otherwise things are off by one...)