diff --git a/libavcodec/vc1dec.c b/libavcodec/vc1dec.c
index 40a3e501dd..750f4dff1c 100644
--- a/libavcodec/vc1dec.c
+++ b/libavcodec/vc1dec.c
@@ -698,9 +698,7 @@ static int vc1_decode_frame(AVCodecContext *avctx, void *data,
                                                     slices[n_slices].buf);
                     init_get_bits(&slices[n_slices].gb, slices[n_slices].buf,
                                   buf_size3 << 3);
-                    /* assuming that the field marker is at the exact middle,
-                       hope it's correct */
-                    slices[n_slices].mby_start = s->mb_height + 1 >> 1;
+                    slices[n_slices].mby_start = avctx->coded_height + 31 >> 5;
                     slices[n_slices].rawbuf = start;
                     slices[n_slices].raw_size = size + 4;
                     n_slices1 = n_slices - 1; // index of the last slice of the first field
@@ -903,13 +901,41 @@ static int vc1_decode_frame(AVCodecContext *avctx, void *data,
             s->picture_structure = PICT_BOTTOM_FIELD - v->tff;
             if ((ret = avctx->hwaccel->start_frame(avctx, buf_start, buf_start_second_field - buf_start)) < 0)
                 goto err;
-            if ((ret = avctx->hwaccel->decode_slice(avctx, buf_start, buf_start_second_field - buf_start)) < 0)
-                goto err;
+
+            if (n_slices1 == -1) {
+                // no slices, decode the field as-is
+                if ((ret = avctx->hwaccel->decode_slice(avctx, buf_start, buf_start_second_field - buf_start)) < 0)
+                    goto err;
+            } else {
+                if ((ret = avctx->hwaccel->decode_slice(avctx, buf_start, slices[0].rawbuf - buf_start)) < 0)
+                    goto err;
+
+                for (i = 0 ; i < n_slices1 + 1; i++) {
+                    s->gb = slices[i].gb;
+                    s->mb_y = slices[i].mby_start;
+
+                    v->pic_header_flag = get_bits1(&s->gb);
+                    if (v->pic_header_flag) {
+                        if (ff_vc1_parse_frame_header_adv(v, &s->gb) < 0) {
+                            av_log(v->s.avctx, AV_LOG_ERROR, "Slice header damaged\n");
+                            ret = AVERROR_INVALIDDATA;
+                            if (avctx->err_recognition & AV_EF_EXPLODE)
+                                goto err;
+                            continue;
+                        }
+                    }
+
+                    if ((ret = avctx->hwaccel->decode_slice(avctx, slices[i].rawbuf, slices[i].raw_size)) < 0)
+                        goto err;
+                }
+            }
+
             if ((ret = avctx->hwaccel->end_frame(avctx)) < 0)
                 goto err;
 
             // decode second field
             s->gb = slices[n_slices1 + 1].gb;
+            s->mb_y = slices[n_slices1 + 1].mby_start;
             s->picture_structure = PICT_TOP_FIELD + v->tff;
             v->second_field = 1;
             v->pic_header_flag = 0;
@@ -922,8 +948,35 @@ static int vc1_decode_frame(AVCodecContext *avctx, void *data,
 
             if ((ret = avctx->hwaccel->start_frame(avctx, buf_start_second_field, (buf + buf_size) - buf_start_second_field)) < 0)
                 goto err;
-            if ((ret = avctx->hwaccel->decode_slice(avctx, buf_start_second_field, (buf + buf_size) - buf_start_second_field)) < 0)
-                goto err;
+
+            if (n_slices - n_slices1 == 2) {
+                // no slices, decode the field as-is
+                if ((ret = avctx->hwaccel->decode_slice(avctx, buf_start_second_field, (buf + buf_size) - buf_start_second_field)) < 0)
+                    goto err;
+            } else {
+                if ((ret = avctx->hwaccel->decode_slice(avctx, buf_start_second_field, slices[n_slices1 + 2].rawbuf - buf_start_second_field)) < 0)
+                    goto err;
+
+                for (i = n_slices1 + 2; i < n_slices; i++) {
+                    s->gb = slices[i].gb;
+                    s->mb_y = slices[i].mby_start;
+
+                    v->pic_header_flag = get_bits1(&s->gb);
+                    if (v->pic_header_flag) {
+                        if (ff_vc1_parse_frame_header_adv(v, &s->gb) < 0) {
+                            av_log(v->s.avctx, AV_LOG_ERROR, "Slice header damaged\n");
+                            ret = AVERROR_INVALIDDATA;
+                            if (avctx->err_recognition & AV_EF_EXPLODE)
+                                goto err;
+                            continue;
+                        }
+                    }
+
+                    if ((ret = avctx->hwaccel->decode_slice(avctx, slices[i].rawbuf, slices[i].raw_size)) < 0)
+                        goto err;
+                }
+            }
+
             if ((ret = avctx->hwaccel->end_frame(avctx)) < 0)
                 goto err;
         } else {
