Merge remote-tracking branch 'qatar/master'

* qatar/master:
  mpegvideo: initialize dummy reference frames.

Conflicts:
	libavcodec/mpegvideo.c
	tests/ref/fate/filter-yadif-mode1

The luma init is left at 0x80 as it was previously, and tested and
working since a long time. Its also mandated to be 0x80 by at least
one specification. Cases that need different values already had
code in place to handle them.
Merged-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/mpegvideo.c

@@ -1465,6 +1465,9 @@ int ff_MPV_frame_start(MpegEncContext *s, AVCodecContext *avctx)
              s->last_picture_ptr->f.data[0] == NULL) &&
             (s->pict_type != AV_PICTURE_TYPE_I ||
              s->picture_structure != PICT_FRAME)) {
+            int h_chroma_shift, v_chroma_shift;
+            av_pix_fmt_get_chroma_sub_sample(s->avctx->pix_fmt,
+                                             &h_chroma_shift, &v_chroma_shift);
             if (s->pict_type != AV_PICTURE_TYPE_I)
                 av_log(avctx, AV_LOG_ERROR,
                        "warning: first frame is no keyframe\n");
@@ -1485,6 +1488,15 @@ int ff_MPV_frame_start(MpegEncContext *s, AVCodecContext *avctx)
                 return -1;
             }
 
+            memset(s->last_picture_ptr->f.data[0], 0x80,
+                   avctx->height * s->last_picture_ptr->f.linesize[0]);
+            memset(s->last_picture_ptr->f.data[1], 0x80,
+                   (avctx->height >> v_chroma_shift) *
+                   s->last_picture_ptr->f.linesize[1]);
+            memset(s->last_picture_ptr->f.data[2], 0x80,
+                   (avctx->height >> v_chroma_shift) *
+                   s->last_picture_ptr->f.linesize[2]);
+
             if(s->codec_id == AV_CODEC_ID_FLV1 || s->codec_id == AV_CODEC_ID_H263){
                 for(i=0; i<avctx->height; i++)
                     memset(s->last_picture_ptr->f.data[0] + s->last_picture_ptr->f.linesize[0]*i, 16, avctx->width);