diff --git a/tools_common.c b/tools_common.c
index 4f2ac74..8825528 100644
--- a/tools_common.c
+++ b/tools_common.c
@@ -83,11 +83,12 @@
   struct FileTypeDetectionBuffer *detect = &input_ctx->detect;
   int plane = 0;
   int shortread = 0;
+  const int bytespp = (input_ctx->fmt & VPX_IMG_FMT_HIGH) ? 2 : 1;
 
   for (plane = 0; plane < 3; ++plane) {
     uint8_t *ptr;
-    const int w = (plane ? (1 + yuv_frame->d_w) / 2 : yuv_frame->d_w);
-    const int h = (plane ? (1 + yuv_frame->d_h) / 2 : yuv_frame->d_h);
+    const int w = vpx_img_plane_width(yuv_frame, plane);
+    const int h = vpx_img_plane_height(yuv_frame, plane);
     int r;
 
     /* Determine the correct plane based on the image format. The for-loop
@@ -108,7 +109,7 @@
     }
 
     for (r = 0; r < h; ++r) {
-      size_t needed = w;
+      size_t needed = w * bytespp;
       size_t buf_position = 0;
       const size_t left = detect->buf_read - detect->position;
       if (left > 0) {