jit.qt.record…record to arbitrary time, like matrixset…

unless it’s undocumented, it’s not possible to record a matrix into jit.qt.record into an arbitrary frame of a movie – you can only add a frame to the end. I would love to be able to do this! This would essentially give qt.record the same ability as a jit.matrixset of 4 plane char data, but without having to pre-allocate a lot of memory , the benefits of compression, and the benefit of already having everything on the harddrive if a crash occurs.
so I guess this is a feature request, either for jit.qt.record to have a "frame" message, or for jit.matrixset to be able to use the harddrive rather than gobbling up RAM.