20:36:23.493: [x264 encoder: 'streaming_h264'] preset: faster
20:38:10.463: Output 'adv_stream': Total frames output: 3485
20:38:10.463: Output 'adv_stream': Total drawn frames: 3107 (6417 attempted)
20:38:10.463: Output 'adv_stream': Number of lagged frames due to rendering lag/stalls: 3310 (51.6%)
20:38:10.467: ==== Streaming Stop ================================================
20:38:10.474: Video stopped, number of skipped frames due to encoding lag: 3438/3516 (97.8%)
Increase your streaming bitrate and/or increase your streaming CPU preset to veryfast or superfast. You're trying to crush a high bitrate source down to a low bitrate, and the CPU preset you've chosen is trying to make the machine work hard to do it at a higher quality than your CPU can match-- you're dropping half your frames on rendering and nearly al of them on encoding.
