Pank: March 2014 Archives

ffmpeg -i input.mp4 -vf "transpose=1" output.mp4

transpose=
0 = 90 degrees counterclockwise and vertical flip (default)
1 = 90 degrees clockwise
2 = 90 degrees counterclockwise
3 = 90 degrees clockwise and vertical flip

一般都用 1 或 2, 0 跟 3 是加上鏡射反轉

ref. FFmpeg transpose