FFmpeg 使用

添加关键帧

被压缩过的视频丢失关键帧导致seekTo无效，需要给视频添加关键帧

ffmpeg -i 2.mp4 -c:v libx264 -x264opts keyint=5 -y keyint10.mp4

修改分辨率

-i /sdcard/bankinfo/-484870439.mp4 -vf scale=1920:1080 -threads 5 -preset ultrafast  -y /sdcard/bankinfo/-484870439.resolution.mp4

旋转视频

90

 -i /sdcard/bankinfo/-484870439.mp4 -vf transpose=1  -threads 5 -preset ultrafast /sdcard/bankinfo/-484870439.rotate.mp4

180

-i /sdcard/bankinfo/-484870439.mp4 -vf transpose=1,transpose=1  -threads 5 -preset ultrafast /sdcard/bankinfo/-484870439.rotate.mp4

270

-i /sdcard/bankinfo/-484870439.mp4 -vf transpose=2  -threads 5 -preset ultrafast /sdcard/bankinfo/-484870439.rotate.mp4

截取

-i /sdcard/bankinfo/-484870439.mp4 -filter:v  crop=1920:780:0:0: -threads  5  -preset  ultrafast  -strict  -2  -c:a  copy /sdcard/bankinfo/-484870439.crop.mp4

按时间剪切

建议重新编码，否则无法精确

-i /sdcard/bankinfo/-484870439.mp4 -ss 00:00.000 -to 00:40.000 -threads 5 -preset ultrafast /sdcard/bankinfo/-484870439/-484870439.openmouth.mp4

将视频转换为图片

-i /sdcard/bankinfo/-484870439.mp4 -threads 5 -preset ultrafast /sdcard/bankinfo/-484870439/frame_%05d.png

将图片转换为视频

-i /sdcard/bankinfo/-147259681/temp/frame_%d.png -vcodec mpeg4  -b:v 3000k -threads 5 -preset ultrafast  /sdcard/bankinfo/-147259681.reduce.mp4