As Andrea noted ffv1.mkv preset no longer works, file encodes but crash cingg on reimport. ffmpeg itself behaves .. strange ffmpeg -i zeldaHQ.flv -c:v ffv1 -default_mode 0 -frames 100 mkv_tedt.mkv -loglevel debug only muxes 3 frames? [matroska @ 0xb400007a8916a870] stream 1 end duration = 336 [AVIOContext @ 0xb400007a59164790] Statistics: 33361 bytes written, 0 seeks, 1 writeouts [out#0/matroska @ 0xb400007a39163010] Output file #0 (mkv_tedt.mkv): [out#0/matroska @ 0xb400007a39163010] Output stream #0:0 (video): 3 frames encoded; 3 packets muxed (27141 bytes); [out#0/matroska @ 0xb400007a39163010] Output stream #0:1 (audio): 112 frames encoded (7147 samples); 19 packets muxed (1905 bytes); ---- but same command with -an (no audio) muxes all 100 frames ?! vp8/vp9/theora mkv profiles seems to be unaffected