H.264: improve qp_thresh check

Eliminate redundant check in filter_mb_fast, consider bit depth in calculating qp_thresh.

libavcodec/h264.c

@@ -2931,7 +2931,9 @@ static int decode_slice_header(H264Context *h, H264Context *h0){
             }
         }
     }
-    h->qp_thresh= 15 + 52 - FFMIN(h->slice_alpha_c0_offset, h->slice_beta_offset) - FFMAX3(0, h->pps.chroma_qp_index_offset[0], h->pps.chroma_qp_index_offset[1]);
+    h->qp_thresh = 15 + 52 - FFMIN(h->slice_alpha_c0_offset, h->slice_beta_offset)
+                 - FFMAX3(0, h->pps.chroma_qp_index_offset[0], h->pps.chroma_qp_index_offset[1])
+                 + 6 * (h->sps.bit_depth_luma - 8);
 
 #if 0 //FMO
     if( h->pps.num_slice_groups > 1  && h->pps.mb_slice_group_map_type >= 3 && h->pps.mb_slice_group_map_type <= 5)

libavcodec/h264_loopfilter.c

@@ -216,7 +216,7 @@ void ff_h264_filter_mb_fast( H264Context *h, int mb_x, int mb_y, uint8_t *img_y,
     MpegEncContext * const s = &h->s;
     int mb_xy;
     int mb_type, left_type, top_type;
-    int qp, qp0, qp1, qpc, qpc0, qpc1, qp_thresh;
+    int qp, qp0, qp1, qpc, qpc0, qpc1;
     int chroma = !(CONFIG_GRAY && (s->flags&CODEC_FLAG_GRAY));
     int chroma444 = CHROMA444;
 
@@ -241,10 +241,6 @@ void ff_h264_filter_mb_fast( H264Context *h, int mb_x, int mb_y, uint8_t *img_y,
     qp1 = (qp + qp1 + 1) >> 1;
     qpc0 = (qpc + qpc0 + 1) >> 1;
     qpc1 = (qpc + qpc1 + 1) >> 1;
-    qp_thresh = 15+52 - h->slice_alpha_c0_offset;
-    if(qp <= qp_thresh && qp0 <= qp_thresh && qp1 <= qp_thresh &&
-       qpc <= qp_thresh && qpc0 <= qp_thresh && qpc1 <= qp_thresh)
-        return;
 
     if( IS_INTRA(mb_type) ) {
         static const int16_t bS4[4] = {4,4,4,4};