A Quartz Composer plugin I widely use in my QC compositions is "Sampler" by Tom Butterworth. It allows to loop live video, MIDI data, or any other values. I mainly use it for video frames and that would be enough for me. I'm aware that one could write a composition do achieve that right in Vuo - and I did - but the plugin is surely somehow more efficient. My looping composition in fact, if feeded with 1080 frames, quickly makes macbook fans running and cpu values raising - while Tom's plugin seems by far more efficient.