diff --git a/libavcodec/avs.c b/libavcodec/avs.c
index 17d4e10fa4..801e1bcd78 100644
--- a/libavcodec/avs.c
+++ b/libavcodec/avs.c
@@ -162,6 +162,7 @@ static av_cold int avs_decode_init(AVCodecContext * avctx)
     AvsContext *const avs = avctx->priv_data;
     avctx->pix_fmt = PIX_FMT_PAL8;
     avcodec_get_frame_defaults(&avs->picture);
+    avcodec_set_dimensions(avctx, 318, 198);
     return 0;
 }