#define MIN_QUALITY 0
#define MAX_QUALITY 100
#define MIN_VP8QP 1
#define MAX_VP8QP 63
        const float scale = MAX_VP8QP - MIN_VP8QP;
        const float vp8qp =
        scale * (MAX_QUALITY - quality) / (MAX_QUALITY - MIN_QUALITY) + MIN_VP8QP;