With my Canon HG21 clips SVRT used to work great in PD8, now it states 100% rendering required even though the only changes to the original clips are trimming. However in Produce states SVRT will work in Produce but if used is much slower than Hardware video encoder.
Thus I gave up on SVRT since using PD9 and only use HVE plus it has never worked with my new Canon HFS21.
George Dell Studio XPS 9100
Intel(R) Core(TM) i7 CPU 960 @ 3.20GHz
64 Bit Operating Sytem
12 GB DDR3 SDRAM
NVIDIA GeForce GTX 470 1248 MB Memory
Canon HF S21 & Canon HG21