ffmpeg -y -i 2.mp4 -c:v libx264 -vf scale=1280:720:force_original_aspect_ratio=decrease a.mp4
转码时有个视频始终失败，原视频播放正常。报错如下：
Impossible to convert between the formats supported by the filter 'graph -1 input from stream 0:0' and the filter 'auto_scale_0' Error reinitializing filters!
如果不加－vf选项转码就能成功，是什么问题呢
转码时有个视频始终失败，原视频播放正常。报错如下：
Impossible to convert between the formats supported by the filter 'graph -1 input from stream 0:0' and the filter 'auto_scale_0' Error reinitializing filters!
如果不加－vf选项转码就能成功，是什么问题呢
