Screen Capture in ffmpeg with jerky movement
The rtbufsize is only affecting the audio.

Try

ffmpeg.exe
-thread_queue_size 512 -report -rtbufsize 100M -f dshow -i "audio=Missaggio stereo (Realtek High Definition Audio)"
-rtbufsize 1000M -thread_queue_size 512 -video_size 848x480 -f dshow -i "video=screen-capture-recorder"
-vf "crop=713:379:18:43,scale=848:480,setsar=1"
-vcodec libx264 -preset ultrafast -maxrate 6M -bufsize 12M -pix_fmt yuv420p -g 60
-acodec libmp3lame -b:a 128k -ac 2 -ar 44100
-f flv rtmp://a.rtmp.youtube.com/live2/xxxx-xyyv-0rrm-f9g2
-filter:v "crop=713:379:18:43" "c:\mbiWebTV\Capture\Capture_20170225_165829.mkv"