# 工具简介
FFmpeg is the leading multimedia framework, able to decode, encode, transcode, mux, demux, stream, filter and play pretty much anything that humans and machines have created. It supports the most obscure ancient formats up to the cutting edge. No matter if they were designed by some standards committee, the community or a corporation. It is also highly portable: FFmpeg compiles, runs, and passes our testing infrastructure FATE (opens new window) across Linux, Mac OS X, Microsoft Windows, the BSDs, Solaris, etc. under a wide variety of build environments, machine architectures, and configurations.
FFmpeg 是一个开放源代码 (opens new window)的自由软件 (opens new window)，可以运行音频和视频多种格式的录影、转换、流功能[1] (opens new window)，包含了 libavcodec——这是一个用于多个项目中音频和视频的解码器库，以及 libavformat——一个音频与视频格式转换库。
# 常用命令
#命令
#合并
FFmpeg -f concat -i list.txt -c copy concat.mp4
-f fmt #force
-i url #input
-c #codec (copy (output only) to indicate that the stream is not to be re-encoded.)
#剪切
ffmpeg -ss 00:01:30 -t 00:00:20 -i input.mp4 -c copy output.mp4
-ss position #seeks
-t duration #time
#压缩
ffmpeg -i input.mp4 -vf scale=-1:1080 -b:v 500k -bufsize 500k -c:v hevc_nvenc -c:a copy output_1080.mp4
-vf #-filter:v
-b #bitrate
-bufsize #buffer size
-c:v #-codec:v
-c:a #-codec:a
#提取音频
ffmpeg -i input.mp4 -vn -y -acodec copy output.m4a
#合并音视频，并替换原视频的音频
ffmpeg -i video.mp4 -i audio.m4a -c:v copy -c:a copy -strict experimental -map 0:v:0 -map 1:a:0 output.mp4
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# list.txt（批处理）
file ./split.mp4
file ./split1.mp4
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