解決ffmpeg轉檔遭遇error: libx264 width not divisible by 2

解決ffmpeg轉檔遭遇錯誤

[libx264 @ 0x6a371c0] width not divisible by 2 (861x909)

[vost#0:0/libx264 @ 0x6a36dc0] Error initializing output stream: Error while opening encoder for output stream #0:0 - maybe incorrect parameters such as bit_rate, rate, width or height

Conversion failed!

原本指令

ffmpeg -i demo.webm demo.mp4

改成

ffmpeg -i demo.webm -vf scale=-2:720 demo.mp4

-vf scale所指定的是寬:高；-2是指寬度要等比例修改並符合2倍數的像素、720是高度要改成720像素；如果要改成8或16的倍數就要寫-8或-16。