h264: merge the two reinit blocks in slice_header_parse()

The only difference is that the first of them contains a
ff_h264_flush_change() call. While that is not necessary in the second
block, it should cause no problems either.

Reduce the verbosity of the reinit log message from info to verbose,
since now it will be displayed during every decode session.

libavcodec/h264_slice.c

@@ -1201,7 +1201,7 @@ static int h264_slice_header_parse(H264Context *h, H264SliceContext *sl)
         }
     }
 
-    if (h->context_initialized && needs_reinit) {
+    if (!h->context_initialized || needs_reinit) {
         h->context_initialized = 0;
         if (sl != h->slice_ctx) {
             av_log(h->avctx, AV_LOG_ERROR,
@@ -1219,7 +1219,7 @@ static int h264_slice_header_parse(H264Context *h, H264SliceContext *sl)
             return ret;
         h->avctx->pix_fmt = ret;
 
-        av_log(h->avctx, AV_LOG_INFO, "Reinit context to %dx%d, "
+        av_log(h->avctx, AV_LOG_VERBOSE, "Reinit context to %dx%d, "
                "pix_fmt: %d\n", h->width, h->height, h->avctx->pix_fmt);
 
         if ((ret = h264_slice_header_init(h)) < 0) {
@@ -1228,23 +1228,6 @@ static int h264_slice_header_parse(H264Context *h, H264SliceContext *sl)
             return ret;
         }
     }
-    if (!h->context_initialized) {
-        if (sl != h->slice_ctx) {
-            av_log(h->avctx, AV_LOG_ERROR,
-                   "Cannot (re-)initialize context during parallel decoding.\n");
-            return AVERROR_PATCHWELCOME;
-        }
-
-        if ((ret = get_pixel_format(h)) < 0)
-            return ret;
-        h->avctx->pix_fmt = ret;
-
-        if ((ret = h264_slice_header_init(h)) < 0) {
-            av_log(h->avctx, AV_LOG_ERROR,
-                   "h264_slice_header_init() failed\n");
-            return ret;
-        }
-    }
 
     frame_num = get_bits(&sl->gb, sps->log2_max_frame_num);
     if (!h->setup_finished)