FFMPEG 设置code profile, video &am

ffmpeg -i pscale.mp4 -profile:v baseline -level 3.0  -b:v 694k -b:a 128k -ac 2 output.mp4

输出的output.mp4
codec profile 设为baseline@3.0,
video stream bitrate设为694k bps,
audio stream bitrate设为128k bps, 双声道