jack的视频编码工作台

先Y后U后V，无冗余信息

A video sequence stored in the YUV format is stored  by concatenating
consecutive frames into a single big file. Each frame contains the Y pixels
for that frame first, followed by the U pixels (actually Cr pixel), followed
by V pixels (actually Cb pixels). Each component is raster-scanned from
the top left corner down to the bottom right corner.
Each pixel value is stored as a 8 bit unsigned character.

For example, a frame in a QCIF sequence with 176x144 Y pixels and
88x72 U and V pixels is stored in the following order:

           176
     +-------------+
     |                      |
     |     Y              | 144
     |                      |
     |                      |
     +-------------+
       88
     +------+
     |  U      |
     |           |72
     +------+
     |  V      |
     |           |72
     +------+