ffmpeg
Install
$ brew install ffmpeg
Check the version:
$ ffmpeg -version
ffmpeg version 7.0.2 Copyright (c) 2000-2024 the FFmpeg developers
built with Apple clang version 14.0.0 (clang-1400.0.29.202)
configuration: --prefix=/usr/local/Cellar/ffmpeg/7.0.2 --enable-shared --enable-pthreads --enable-version3 --cc=clang --host-cflags= --host-ldflags= --enable-ffplay --enable-gnutls --enable-gpl --enable-libaom --enable-libaribb24 --enable-libbluray --enable-libdav1d --enable-libharfbuzz --enable-libjxl --enable-libmp3lame --enable-libopus --enable-librav1e --enable-librist --enable-librubberband --enable-libsnappy --enable-libsrt --enable-libssh --enable-libsvtav1 --enable-libtesseract --enable-libtheora --enable-libvidstab --enable-libvmaf --enable-libvorbis --enable-libvpx --enable-libwebp --enable-libx264 --enable-libx265 --enable-libxml2 --enable-libxvid --enable-lzma --enable-libfontconfig --enable-libfreetype --enable-frei0r --enable-libass --enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libopenjpeg --enable-libspeex --enable-libsoxr --enable-libzmq --enable-libzimg --disable-libjack --disable-indev=jack --enable-videotoolbox --enable-audiotoolbox
libavutil 59. 8.100 / 59. 8.100
libavcodec 61. 3.100 / 61. 3.100
libavformat 61. 1.100 / 61. 1.100
libavdevice 61. 1.100 / 61. 1.100
libavfilter 10. 1.100 / 10. 1.100
libswscale 8. 1.100 / 8. 1.100
libswresample 5. 1.100 / 5. 1.100
libpostproc 58. 1.100 / 58. 1.100
Usage
Trim
$ ffmpeg -i input.mp4 -ss 00:02:22 -to 00:03:33 -c copy out.mp4
Scale
$ ffmpeg -i input.mp4 -vf scale=1920:1080 out.mp4
Change FPS
$ ffmpeg -i input.mp4 -vf fps=25 out.mp4
Check
$ ffmpeg -v error -i input.mp4 -f null
mkv to mp4
$ ffmpeg -i input.mkv -c:a copy -c:v copy -f mp4 out.mp4
Note
mp4 cannot contain ass subtitles.
Extract subtitle
$ ffmpeg -i input.mkv -map 0:s:1 -c:s copy -f ass out.ass
Concat files
Create a file confiles.txt:
file 'a.mp3'
file 'b.mp3'
Then you can concat a.mp3 and b.mp3 by:
$ ffmpeg -f concat -safe 0 -i confiles.txt -c copy out.mp3