diff --git a/sub/sd_lavc.c b/sub/sd_lavc.c
index 0a969efc41..653be085c5 100644
--- a/sub/sd_lavc.c
+++ b/sub/sd_lavc.c
@@ -69,9 +69,18 @@ static bool supports_format(const char *format)
     }
 }
 
-static void guess_resolution(enum AVCodecID type, int *w, int *h)
+static void get_resolution(struct sd *sd, int wh[2])
 {
-    if (type == AV_CODEC_ID_DVD_SUBTITLE) {
+    struct sd_lavc_priv *priv = sd->priv;
+    enum AVCodecID codec = priv->avctx->codec_id;
+    int *w = &wh[0], *h = &wh[1];
+    *w = priv->avctx->width;
+    *h = priv->avctx->height;
+    if (codec == AV_CODEC_ID_DVD_SUBTITLE) {
+        if (*w <= 0 || *h <= 0) {
+            *w = priv->video_params.w;
+            *h = priv->video_params.h;
+        }
         /* XXX Although the video frame is some size, the SPU frame is
            always maximum size i.e. 720 wide and 576 or 480 high */
         // For HD files in MKV the VobSub resolution can be higher though,
@@ -89,18 +98,6 @@ static void guess_resolution(enum AVCodecID type, int *w, int *h)
     }
 }
 
-static void get_resolution(struct sd *sd, int wh[2])
-{
-    struct sd_lavc_priv *priv = sd->priv;
-    wh[0] = priv->avctx->width;
-    wh[1] = priv->avctx->height;
-    if (wh[0] <= 0 || wh[1] <= 0) {
-        wh[0] = priv->video_params.w;
-        wh[1] = priv->video_params.h;
-    }
-    guess_resolution(priv->avctx->codec_id, &wh[0], &wh[1]);
-}
-
 static void set_mp4_vobsub_idx(AVCodecContext *avctx, char *src, int w, int h)
 {
     char pal_s[128];