My tests (with -vo x11 -fs -ao gst -ac dspmp3 options): * mpeg4@400x224x25fpsx250kbps+mp3@128kbps=> 90-100% CPU * h264@300x240x12fpsx250kbps+mp3@128kbps=> 90-100% CPU * flv/mpeg1@300x240x25fpsx250kbps+mp2@128kbps=> 50-70% CPU