h264: always copy linesizes in thread update

Fixes inconsistencies in context

Found-by: Mateusz "j00ru" Jurczyk and Gynvael Coldwind
Signed-off-by: Michael Niedermayer <michaelni@gmx.at>

libavcodec/h264.c

@@ -1216,15 +1216,15 @@ static int decode_update_thread_context(AVCodecContext *dst,
         }
         h->context_reinitialized = 1;
 
-        /* update linesize on resize for h264. The h264 decoder doesn't
-         * necessarily call ff_MPV_frame_start in the new thread */
-        s->linesize   = s1->linesize;
-        s->uvlinesize = s1->uvlinesize;
-
         h264_set_parameter_from_sps(h);
         //Note we set context_reinitialized which will cause h264_set_parameter_from_sps to be reexecuted
         h->cur_chroma_format_idc = h1->cur_chroma_format_idc;
     }
+    /* update linesize on resize for h264. The h264 decoder doesn't
+     * necessarily call ff_MPV_frame_start in the new thread */
+    s->linesize   = s1->linesize;
+    s->uvlinesize = s1->uvlinesize;
+
     /* copy block_offset since frame_start may not be called */
     memcpy(h->block_offset, h1->block_offset, sizeof(h->block_offset));