Reenable filter_mb_fast for I slices and progressive CABAC P slices.

Originally committed as revision 21288 to svn://svn.ffmpeg.org/ffmpeg/trunk

libavcodec/h264_loopfilter.c

@@ -334,8 +334,10 @@ void ff_h264_filter_mb_fast( H264Context *h, int mb_x, int mb_y, uint8_t *img_y,
     mb_xy = h->mb_xy;
 
     if(mb_x==0 || mb_y==mb_y_firstrow || !s->dsp.h264_loop_filter_strength || h->pps.chroma_qp_diff ||
-        !(s->flags2 & CODEC_FLAG2_FAST) || //FIXME filter_mb_fast is broken, thus hasto be, but should not under CODEC_FLAG2_FAST
-       (h->deblocking_filter == 2 && (h->slice_table[mb_xy] != h->slice_table[h->top_mb_xy] ||
+       !(h->slice_type_nos == FF_I_TYPE ||
+         (CABAC && h->slice_type_nos == FF_P_TYPE && !FIELD_PICTURE) ||
+         (s->flags2 & CODEC_FLAG2_FAST)) ||
+       (h->deblocking_filter == 2 && (h->slice_table[mb_xy] != h->slice_table[h->top_mb_xy] || //use slice_num
                                       h->slice_table[mb_xy] != h->slice_table[mb_xy - 1]))) {
         ff_h264_filter_mb(h, mb_x, mb_y, img_y, img_cb, img_cr, linesize, uvlinesize);
         return;