Use the following command to reproduce this issue:
make fate-vp8-size-change HWACCEL="vaapi -vaapi_device \
/dev/dri/renderD128 -hwaccel_output_format yuv420p"
SAMPLES=../fate-suite/.

At the same time, reconstruct the public logic as a function.
Signed-off-by: Yun Zhou <yunx.z.zhou@intel.com>
Signed-off-by: Jun Zhao <jun.zhao@intel.com>
Signed-off-by: Mark Thompson <sw@jkqxz.net>