$ ffmpeg -v debug -filter_complex testsrc=r=15,trim=end_frame=10,setpts=PTS/2,fps=15 -f null - ffmpeg version 4.0.3 Copyright (c) 2000-2018 the FFmpeg developers built with gcc 8 (GCC) configuration: --prefix=/usr --bindir=/usr/bin --datadir=/usr/share/ffmpeg --docdir=/usr/share/doc/ffmpeg --incdir=/usr/include/ffmpeg --libdir=/usr/lib64 --mandir=/usr/share/man --arch=x86_64 --optflags='-O2 -g -pipe -Wall -Werror=format-security -Wp,-D_FORTIFY_SOURCE=2 -Wp,-D_GLIBCXX_ASSERTIONS -fexceptions -fstack-protector-strong -grecord-gcc-switches -specs=/usr/lib/rpm/redhat/redhat-hardened-cc1 -specs=/usr/lib/rpm/redhat/redhat-annobin-cc1 -m64 -mtune=generic -fasynchronous-unwind-tables -fstack-clash-protection -fcf-protection' --extra-ldflags='-Wl,-z,relro -Wl,-z,now -specs=/usr/lib/rpm/redhat/redhat-hardened-ld ' --extra-cflags=' ' --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libvo-amrwbenc --enable-version3 --enable-bzlib --disable-crystalhd --enable-fontconfig --enable-frei0r --enable-gcrypt --enable-gnutls --enable-ladspa --enable-libaom --enable-libass --enable-libbluray --enable-libcdio --enable-libdrm --enable-indev=jack --enable-libfreetype --enable-libfribidi --enable-libgsm --enable-libmp3lame --enable-nvenc --enable-openal --enable-opencl --enable-opengl --enable-libopenjpeg --enable-libopus --enable-libpulse --enable-librsvg --enable-libsoxr --enable-libspeex --enable-libtheora --enable-libvorbis --enable-libv4l2 --enable-libvidstab --enable-libvmaf --enable-libvpx --enable-libx264 --enable-libx265 --enable-libxvid --enable-libzvbi --enable-avfilter --enable-avresample --enable-postproc --enable-pthreads --disable-static --enable-shared --enable-gpl --disable-debug --disable-stripping --shlibdir=/usr/lib64 --enable-libmfx --enable-runtime-cpudetect libavutil 56. 14.100 / 56. 14.100 libavcodec 58. 18.100 / 58. 18.100 libavformat 58. 12.100 / 58. 12.100 libavdevice 58. 3.100 / 58. 3.100 libavfilter 7. 16.100 / 7. 16.100 libavresample 4. 0. 0 / 4. 0. 0 libswscale 5. 1.100 / 5. 1.100 libswresample 3. 1.100 / 3. 1.100 libpostproc 55. 1.100 / 55. 1.100 Splitting the commandline. Reading option '-v' ... matched as option 'v' (set logging level) with argument 'debug'. Reading option '-filter_complex' ... matched as option 'filter_complex' (create a complex filtergraph) with argument 'testsrc=r=15,trim=end_frame=10,setpts=PTS/2,fps=15'. Reading option '-f' ... matched as option 'f' (force format) with argument 'null'. Reading option '-' ... matched as output url. Finished splitting the commandline. Parsing a group of options: global . Applying option v (set logging level) with argument debug. Applying option filter_complex (create a complex filtergraph) with argument testsrc=r=15,trim=end_frame=10,setpts=PTS/2,fps=15. Successfully parsed a group of options. [Parsed_testsrc_0 @ 0x56530a3a70c0] Setting 'r' to value '15' [Parsed_testsrc_0 @ 0x56530a3a70c0] size:320x240 rate:15/1 duration:-1.000000 sar:1/1 [Parsed_trim_1 @ 0x56530a3a8180] Setting 'end_frame' to value '10' [Parsed_setpts_2 @ 0x56530a3a90c0] Setting 'expr' to value 'PTS/2' [Parsed_fps_3 @ 0x56530a3a9f40] Setting 'fps' to value '15' [Parsed_fps_3 @ 0x56530a3a9f40] fps=15/1 [Parsed_fps_3 @ 0x56530a3a9f40] 0 frames in, 0 frames out; 0 frames dropped, 0 frames duplicated. Parsing a group of options: output url -. Applying option f (force format) with argument null. Successfully parsed a group of options. Opening an output file: -. Successfully opened the file. Stream mapping: fps -> Stream #0:0 (wrapped_avframe) Press [q] to stop, [?] for help cur_dts is invalid (this is harmless if it occurs once at the start per stream) detected 4 logical cores [Parsed_testsrc_0 @ 0x56530a3a8f80] Setting 'r' to value '15' [Parsed_testsrc_0 @ 0x56530a3a8f80] size:320x240 rate:15/1 duration:-1.000000 sar:1/1 [Parsed_trim_1 @ 0x56530a3ad340] Setting 'end_frame' to value '10' [Parsed_setpts_2 @ 0x56530a3ae2c0] Setting 'expr' to value 'PTS/2' [Parsed_fps_3 @ 0x56530a3af0c0] Setting 'fps' to value '15' [Parsed_fps_3 @ 0x56530a3af0c0] fps=15/1 [AVFilterGraph @ 0x56530a3a79c0] query_formats: 5 queried, 4 merged, 0 already done, 0 delayed [Parsed_trim_1 @ 0x56530a3ad340] TB:0.066667 FRAME_RATE:15.000000 SAMPLE_RATE:nan Output #0, null, to 'pipe:': Metadata: encoder : Lavf58.12.100 Stream #0:0, 0, 1/15: Video: wrapped_avframe, 1 reference frame, rgb24, 320x240 [SAR 1:1 DAR 4:3], 0/1, q=2-31, 200 kb/s, 15 fps, 15 tbn, 15 tbc (default) Metadata: encoder : Lavc58.18.100 wrapped_avframe [Parsed_fps_3 @ 0x56530a3af0c0] Read frame with in pts 0, out pts 0 Last message repeated 1 times [Parsed_fps_3 @ 0x56530a3af0c0] Set first pts to 0 [Parsed_fps_3 @ 0x56530a3af0c0] Dropping frame with pts 0 [Parsed_fps_3 @ 0x56530a3af0c0] Read frame with in pts 1, out pts 1 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 0 to pts 0 [Parsed_fps_3 @ 0x56530a3af0c0] Read frame with in pts 1, out pts 1 [Parsed_fps_3 @ 0x56530a3af0c0] Dropping frame with pts 1 [Parsed_fps_3 @ 0x56530a3af0c0] Read frame with in pts 2, out pts 2 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 1 to pts 1 [Parsed_fps_3 @ 0x56530a3af0c0] Read frame with in pts 2, out pts 2 [Parsed_fps_3 @ 0x56530a3af0c0] Dropping frame with pts 2 [Parsed_fps_3 @ 0x56530a3af0c0] Read frame with in pts 3, out pts 3 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 2 to pts 2 [Parsed_fps_3 @ 0x56530a3af0c0] Read frame with in pts 3, out pts 3 [Parsed_fps_3 @ 0x56530a3af0c0] Dropping frame with pts 3 [Parsed_fps_3 @ 0x56530a3af0c0] Read frame with in pts 4, out pts 4 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 3 to pts 3 [Parsed_fps_3 @ 0x56530a3af0c0] Read frame with in pts 4, out pts 4 [Parsed_fps_3 @ 0x56530a3af0c0] Dropping frame with pts 4 [Parsed_fps_3 @ 0x56530a3af0c0] EOF is at pts 10 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 4 to pts 4 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 4 to pts 5 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 4 to pts 6 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 4 to pts 7 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 4 to pts 8 [Parsed_fps_3 @ 0x56530a3af0c0] Writing frame with pts 4 to pts 9 [Parsed_fps_3 @ 0x56530a3af0c0] Duplicated frame with pts 4 5 times [out_0_0 @ 0x56530a3b0080] EOF on sink link out_0_0:default. No more output streams to write to, finishing. frame= 10 fps=0.0 q=-0.0 Lsize=N/A time=00:00:00.66 bitrate=N/A speed= 187x video:5kB audio:0kB subtitle:0kB other streams:0kB global headers:0kB muxing overhead: unknown Output file #0 (pipe:): Output stream #0:0 (video): 10 frames encoded; 10 packets muxed (5360 bytes); Total: 10 packets (5360 bytes) muxed 0 frames successfully decoded, 0 decoding errors [Parsed_fps_3 @ 0x56530a3af0c0] 10 frames in, 10 frames out; 5 frames dropped, 5 frames duplicated.