MLTProxy

This functionality helps managing video proxy files (generation and swapping) in MLT projects.
MLT is an open standard used in Shotcut, OpenShot, Kdenlive and possibly other NLE programs.
See: MLT on Wikipedia

This was tested with mlt projects from Shotcut video editor on Ubuntu Linux.

Function has been added in the version 0.93. In the main program, switch to the "MLT Proxy" tab.
Use button to navigate to and load your video project from a .mlt file.
When loaded, a list of all the video clips defined in the mlt project will appear. Each clip will have one of statuses described below:
ambigous - meaning that in the same location as the video file there are both the hi-res and the low-res proxy files found. This is not a normal situation, because at a given time only one (either low-res or hi-res) proxy should be present. If both are present, something is wrong. You should manually resolve this conflict by deleting one of both of the proxy files found.
original - a video clip that has no proxy files yet
Hi-re - when (only) a low-res proxy exists, means that the clip itself is a high definition (HD) (or just orignal) clip
Low-res - when (only) a hi-res proxy exists, means that the clip itself is a low resolution proxy, and the original clip has been renamed to the name of the clip appended with ".hrs".
missi***ng - this status means that a clip is listed inside mlt projec, but is not found on the computer.

Proxy switching works by swapping video file names. Hi-res proxy files (original clips) are backed-up with file extension .hrv, and low-res proxy files with file extension .lrv. For example, if you have an original clip video1.mp4 and no proxies, this will be listed with original status. When you choose to generate a Low-res proxy for this clip (use popup menu, left mouse click), then it will be generated and named video1.mp4.lrv, and the same clip will now be listed with status Hi-res because a low-res proxy is found, so the clip itself must be the original one.
If you now use the popup menu to toggle the proxy, then the original clip will be renamed to clip1.mp4.hrv and the low-res proxy to clip1.mp4. Now the status will be updated to Low-res because if a hi-res proxy exists, it must be the original clip renamed, and the clip1.mp4 now is in reality a low-res proxy.
This is why under normal circumstances only one of the proxy files (either lrv or hrv) should exist. Or none. If both lrv and hrv proxy files exist simultaneously, it means that something is not well, and such clip would marked with a status ambiguous.

The popup menu allows for gnerating proxy files for each clip listed separately. It aslo allows to enable all available RLV proxies or all available HRV proxies, in bulk for the entire list.

Example of using this with Shotcut editor, is that you switch all the Low-res proxies, then open the mlt project in Shotcut, and editting feels much faster. Then, you close the project in Shotcut, swap all the proxies to high resolution ones, and finally reopen the project in Shotcut for rendering. The idea is so that you use LRV for editting because then the editing is faster and more responsive, but you use HRV for rendering, because it yelds the highest render quality.