YUV 任意尺寸缩放 jpeg 图片缩放问题，libjpeg 只支持 1/8, 1/4, 1/2, 1/1 的缩小。而 ffplay 对 Jpeg, 视频的缩放貌似不支持。



于是经过断断续续的编码和思考，“基本上” 解决了YUV420P格式的缩放问题。



这里的“基本上”指的是：



1）它解决了视频全屏缩小问题，没有产生颜色偏移等问题；



2）YUV 按某一特定比例对静态图缩放后，颜色可能会变；-YUV any scaling　jpeg image scaling, libjpeg support of 1/8, 1/4, 1/2, 1/1 narrowing. Zoom the ffplay right Jpeg, video seemingly not supported.



So intermittent coding and thinking, "essentially" to solve the scaling problem of YUV420P format.



Where "essentially" refers to:



1) it solves the video full screen to narrow down the problem, there is no color offset



2) the YUV by a specific proportion of the static picture scaling, color may become