Basic #
Get help from command line #
ffmpeg -hbash
Some useful help here
Global options (affect whole program instead of just one file:
-loglevel loglevel set logging level
-v loglevel set logging level
-y overwrite output files
-n never overwrite output files
Video options:
-r rate set frame rate (Hz value, fraction or abbreviation)
-s size set frame size (WxH or abbreviation)
-aspect aspect set aspect ratio (4:3, 16:9 or 1.3333, 1.7777)
-vn disable video
-vcodec codec force video codec ('copy' to copy stream)
-vf filter_graph set video filters
-ab bitrate audio bitrate (please use -b:a)
-b bitrate video bitrate (please use -b:v)
Audio options:
-aq quality set audio quality (codec-specific)
-ar rate set audio sampling rate (in Hz)
-ac channels set number of audio channels
-an disable audio
-acodec codec force audio codec ('copy' to copy stream)
-vol volume change audio volume (256=normal)
-af filter_graph set audio filterstext
Examples #
去除和取出声音 #
ffmpeg -i example.mkv -c copy -an nosound.mkv
ffmpeg -i input.avi -vn -acodec copy output.aacshell
裁剪 #
ffmpeg -i input.m4a -ss 0 -t 18 cut.m4ashell
- -ss 表开始，
HH:MM:SS.xxx - -t 表时长
- -to 表结束
拼接 #
ffmpeg -safe 0 -f concat -i list.txt -c copy output.mp4shell
list.txt 内容为：
file 1.mp4
file 2.mp4text
生成静音的音频 #
ffmpeg -f lavfi -i anullsrc -t 5 -c:a libvorbis output.oggshell
把视频和音频合起来 #
ffmpeg -i all.mp4 -i all.m4a -c:v copy -c:a aac -strict experimental output.mp4shell
合理转成 GIF #
The standard way to use ffmpeg for GIFs is
Generate a palette from the video
ffmpeg -y -i file.mp4 -vf palettegen palette.pngbash
Then,
ffmpeg -y -i file.mp4 -i palette.png -filter_complex paletteuse -r 10 -s 320x480 file.gifbash
More options documented here.
所以使用我的 ffmpegroup脚本，第二步就是
ffmpegroup mp4/gif -z"-i palette.png -filter_complex paletteuse -r 10 -s 200x200 -y"bash
直接倍速 #
ffmpeg -i input.mkv -filter:v "setpts=PTS/60" output.mkvbash
或者更快的，但是会有音频问题，而且转出来帧率吓死人，并没有多少压缩作用，请慎用：
ffmpeg -itsscale 0.01666 -i input.mkv -c copy output.mkvbash