Hello Shengjing Zhu, I tried to collect some more information for the maintainer, by running peek in a minimal VM.
There I got the same error message "default: No such process". After a search I received this information [1] where it is proposed to install pulseaudio. And indeed the parameter "-f pulse -i default" seems to direct ffmpeg to record from pulseaudio. And after installing it (and starting off pulseaudio manually in my minimal jwm environment) recording got further and could create successfully a file. Probably this is also causing the fault at your side? Kind regards, Bernhard [1] https://superuser.com/questions/1487109/trying-to-stream-to-youtube-default-no-such-process (gdb) bt #0 print_error (filename=filename@entry=0x7fffffffe625 "default", err=err@entry=-3) at src/fftools/cmdutils.c:794 #1 0x000055555556dd27 in open_input_file (o=o@entry=0x7fffffffdc40, filename=<optimized out>) at src/fftools/ffmpeg_opt.c:1266 #2 0x0000555555571c1c in open_files (open_file=0x55555556cca0 <open_input_file>, inout=0x55555558b81f "input", l=0x5555555e08d8) at src/fftools/ffmpeg_opt.c:3537 #3 ffmpeg_parse_options (argc=argc@entry=35, argv=argv@entry=0x7fffffffe2b8) at src/fftools/ffmpeg_opt.c:3577 #4 0x0000555555560715 in main (argc=35, argv=0x7fffffffe2b8) at src/fftools/ffmpeg.c:4538
