diff --git a/libavcodec/xwddec.c b/libavcodec/xwddec.c
index 387b697491..c43724e538 100644
--- a/libavcodec/xwddec.c
+++ b/libavcodec/xwddec.c
@@ -155,10 +155,12 @@ static int xwd_decode_frame(AVCodecContext *avctx, void *data,
     switch (vclass) {
     case XWD_STATIC_GRAY:
     case XWD_GRAY_SCALE:
-        if (bpp != 1)
+        if (bpp != 1 && bpp != 8 || bpp != pixdepth)
             return AVERROR_INVALIDDATA;
         if (pixdepth == 1)
             avctx->pix_fmt = AV_PIX_FMT_MONOWHITE;
+        else if (pixdepth == 8)
+            avctx->pix_fmt = AV_PIX_FMT_GRAY8;
         break;
     case XWD_STATIC_COLOR:
     case XWD_PSEUDO_COLOR: