ffmpeg -opencl_options platform_idx=1 -opencl_options device_idx=0 -hwaccel none -v 0 -i /tmp/foo/_pre.mp4 -map 0 -f mpegts -vbsf h264_mp4toannexb -acodec copy -codec:v libx264 -sc_threshold 0 -keyint_min 25 -g 25 -flags -global_header -f segment -segment_format mpegts -segment_time 4 -b:v 600k -maxrate 600k -bufsize 600k -bt 600k -x264opts opencl -loglevel info -segment_list /tmp/foo/medium.m3u8 /tmp/foo/medium%03d.ts