optimize IDCT of rows with mostly zero coefficients

[ffmpeg] / libavcodec / h263.c

diff --git a/libavcodec/h263.c b/libavcodec/h263.c
index d86ee8f81d907b0557459e95edb446bb11975978..27b66a0c81224d413f319091d19512e10bbf2abe 100644 (file)
--- a/libavcodec/h263.c
+++ b/libavcodec/h263.c
@@ -486,6 +486,20 @@ static inline void restore_ac_coeffs(MpegEncContext * s, DCTELEM block[6][64], i
     }
 }
 
+/**
+ * init s->current_picture.qscale_table from s->lambda_table
+ */
+static void ff_init_qscale_tab(MpegEncContext *s){
+    int8_t * const qscale_table= s->current_picture.qscale_table;
+    int i;
+
+    for(i=0; i<s->mb_num; i++){
+        unsigned int lam= s->lambda_table[ s->mb_index2xy[i] ];
+        int qp= (lam*139 + FF_LAMBDA_SCALE*64) >> (FF_LAMBDA_SHIFT + 7);
+        qscale_table[ s->mb_index2xy[i] ]= clip(qp, s->avctx->qmin, s->avctx->qmax);
+    }
+}
+
 /**
  * modify qscale so that encoding is acually possible in h263 (limit difference to -2..2)
  */
@@ -493,6 +507,8 @@ void ff_clean_h263_qscales(MpegEncContext *s){
     int i;
     int8_t * const qscale_table= s->current_picture.qscale_table;
 
+    ff_init_qscale_tab(s);
+
     for(i=1; i<s->mb_num; i++){
         if(qscale_table[ s->mb_index2xy[i] ] - qscale_table[ s->mb_index2xy[i-1] ] >2)
             qscale_table[ s->mb_index2xy[i] ]= qscale_table[ s->mb_index2xy[i-1] ]+2;
@@ -507,7 +523,6 @@ void ff_clean_h263_qscales(MpegEncContext *s){
             int mb_xy= s->mb_index2xy[i];
 
             if(qscale_table[mb_xy] != qscale_table[s->mb_index2xy[i-1]] && (s->mb_type[mb_xy]&CANDIDATE_MB_TYPE_INTER4V)){
-                s->mb_type[mb_xy]&= ~CANDIDATE_MB_TYPE_INTER4V;
                 s->mb_type[mb_xy]|= CANDIDATE_MB_TYPE_INTER;
             }
         }
@@ -546,7 +561,6 @@ void ff_clean_mpeg4_qscales(MpegEncContext *s){
         for(i=1; i<s->mb_num; i++){
             int mb_xy= s->mb_index2xy[i];
             if(qscale_table[mb_xy] != qscale_table[s->mb_index2xy[i-1]] && (s->mb_type[mb_xy]&CANDIDATE_MB_TYPE_DIRECT)){
-                s->mb_type[mb_xy]&= ~CANDIDATE_MB_TYPE_DIRECT;
                 s->mb_type[mb_xy]|= CANDIDATE_MB_TYPE_BIDIR;
             }
         }
@@ -3196,7 +3210,7 @@ static inline int mpeg4_is_resync(MpegEncContext *s){
     }
 
     while(v<=0xFF){
-        if(s->pict_type==B_TYPE || (v>>(8-s->pict_type)!=1))
+        if(s->pict_type==B_TYPE || (v>>(8-s->pict_type)!=1) || s->partitioned_frame)
             break;
         skip_bits(&s->gb, 8+s->pict_type);
         bits_count+= 8+s->pict_type;
@@ -5914,6 +5928,10 @@ static int decode_vop_header(MpegEncContext *s, GetBitContext *gb){
                            - ROUNDED_DIV(s->last_non_b_time - s->pp_time, s->t_frame))*2;
         s->pb_field_time= (  ROUNDED_DIV(s->time, s->t_frame)
                            - ROUNDED_DIV(s->last_non_b_time - s->pp_time, s->t_frame))*2;
+        if(!s->progressive_sequence){
+            if(s->pp_field_time <= s->pb_field_time || s->pb_field_time <= 1)
+                return FRAME_SKIPPED;
+        }
     }
 //av_log(s->avctx, AV_LOG_DEBUG, "last nonb %"PRId64" last_base %d time %"PRId64" pp %d pb %d t %d ppf %d pbf %d\n", s->last_non_b_time, s->last_time_base, s->time, s->pp_time, s->pb_time, s->t_frame, s->pp_field_time, s->pb_field_time);