We've been using Compressor as our main encoder for a couple years without problems. However, I now have a project that random blockiness occurs regardless of Compressor's settings. The clips are a couple minutes long with 3-4 talking heads keyed over an animated background. In the foreground is a lower third graphic ID. The artifacts are always just below the ID graphic and only on certain interviews, but occur consistently on those same clips even if they're in another sequence. I've tried different Compressor settings with no success. Out of curiosity I encoded with a demo of Bitvice and the artifacts went away. Any suggestions how I get Compressor to encode this cleanly?