refine the JPEG decoding interface
refine the JPEG decoding interface

pma1/libva,chenxianqin/vaapi-libva,gbeauchesne/libva,pma1/libva,zzhhui/libva,Distrotech/libva,01org/iotg-lin-gfx-libva,01org/iotg-lin-gfx-libva,chenxianqin/vaapi-libva,gbeauchesne/libva,zzhhui/libva,01org/iotg-lin-gfx-libva,chenxianqin/vaapi-libva,Distrotech/libva,01org/libva-cros,01org/libva-cros,pma1/libva,gbeauchesne/libva,zzhhui/libva,01org/libva-cros,Distrotech/libva