ffmpeg -fflags +genpts -i 01_1.mkv -i 01_2.mkv -ss 00:00:00 -to 01:06:19 -vcodec hevc -x265-params crf=20 -sn -acodec ac3 -filter_complex '[0:0] [input]scale=iw*sar:ih[out] [0:1] [0:2] [1:0] [1:1] [1:2] concat=n=2:v=1:a=2 [v] [a1] [a2]' -map '[v]' -map '[a1]' -map '[a2]' e01.mkv