Goal of this system is to decrease delay from edit to preview.
This is not a solution for slow rendering. However to be able to preview timeline of any complexity, this tool is needed and therefore it makes sense to implement it as a first step towards that direction
In practice this system will work in a similar way to old image based VSE proxy system.
Main difference is:
- all strip types are supported
- any cached level can be saved
- images are created along with a cache entry (even during playback)
- images are deleted when cache is invalidated
Challenges to make this system work well are:
- minimizing removal of stored images as much as possible
- managing validity of stored images (undo, redo mainly)