dont randomly dissallow direct MBs

  some PSNR/bitrate gain for b frames with adaptive quant or QPRD

Originally committed as revision 7341 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h263.c

@@ -546,7 +546,6 @@ 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;
             }
         }

tests/ffmpeg.regression.ref

@@ -75,13 +75,13 @@ stddev: 10.40 PSNR:27.78 bytes:7602176
 600188 ./data/a-mpeg4-adv.avi
 60edc5a67271e425d0a2a52981895b81 *./data/out.yuv
 stddev: 10.25 PSNR:27.91 bytes:7602176
-e8387041071301c4527377e1666136b0 *./data/a-mpeg4-qprd.avi
-658496 ./data/a-mpeg4-qprd.avi
-d2fa3fecdf033e70590e948a3c88976b *./data/out.yuv
-stddev: 12.13 PSNR:26.44 bytes:7602176
-cf202860731f8a85d07dae559417f330 *./data/a-mpeg4-adap.avi
-400830 ./data/a-mpeg4-adap.avi
-e9fb8b8e8bef48085d19c4969b012f36 *./data/out.yuv
+8cbcdc72a33e5a8d624f38529efd93c8 *./data/a-mpeg4-qprd.avi
+657582 ./data/a-mpeg4-qprd.avi
+5b620f592a795b1caad323ab3fab0859 *./data/out.yuv
+stddev: 12.12 PSNR:26.45 bytes:7602176
+b41b9915af65da1c03f17f59a1806d0e *./data/a-mpeg4-adap.avi
+400192 ./data/a-mpeg4-adap.avi
+9dffb8079a1666c054514ab02d9d4871 *./data/out.yuv
 stddev: 14.68 PSNR:24.78 bytes:7602176
 5fff534f0b958547dfdb811d4f289931 *./data/a-mpeg4-thread.avi
 761170 ./data/a-mpeg4-thread.avi

tests/rotozoom.regression.ref

@@ -75,14 +75,14 @@ stddev:  4.24 PSNR:35.56 bytes:7602176
 173590 ./data/a-mpeg4-adv.avi
 699edf05648fdc42196b7bebef9be269 *./data/out.yuv
 stddev:  4.84 PSNR:34.41 bytes:7602176
-a5dca818743c7871287160c5834a7536 *./data/a-mpeg4-qprd.avi
-235794 ./data/a-mpeg4-qprd.avi
-2cd225619e34fe8c12d10e7a28bb6cca *./data/out.yuv
-stddev:  4.27 PSNR:35.50 bytes:7602176
-c43ef40b07d77347beedd4ee16be0646 *./data/a-mpeg4-adap.avi
-206290 ./data/a-mpeg4-adap.avi
-ac55933a03c32f3941dfc8b71d738cd0 *./data/out.yuv
-stddev:  4.10 PSNR:35.85 bytes:7602176
+7006aa0ad8643348ec0d6d87bf03202c *./data/a-mpeg4-qprd.avi
+235016 ./data/a-mpeg4-qprd.avi
+224969c07440a23b376521c484936e75 *./data/out.yuv
+stddev:  4.24 PSNR:35.56 bytes:7602176
+62c7e87076d4741eb99d76e3ec424db0 *./data/a-mpeg4-adap.avi
+205456 ./data/a-mpeg4-adap.avi
+fe20d6bd1aa019196fb6426fdd0f4779 *./data/out.yuv
+stddev:  4.08 PSNR:35.91 bytes:7602176
 8cd8940d7451925784536fe9b2f2a5e3 *./data/a-mpeg4-thread.avi
 254260 ./data/a-mpeg4-thread.avi
 d160a4224ea1af66c85178912f8d3a7c *./data/out.yuv