diff --git a/videoframe.cc b/videoframe.cc
index 6cb2961..ae992e9 100644
--- a/videoframe.cc
+++ b/videoframe.cc
@@ -59,7 +59,7 @@ int VideoFrame::SetSize(int w, int h) {
 
 int VideoFrame::ConvertToJpeg(InMemoryFile *imf, int quality) {
     unsigned char *outbuffer = NULL;
-	size_t outbuffersize;
+    unsigned long int outbuffersize;
     struct jpeg_compress_struct cinfo;
     struct jpeg_error_mgr jerr;
     JSAMPROW row_pointer[1];	/* pointer to JSAMPLE row[s] */