diff -Naur freepv-0.3.0.orig/src/libfreepv/Utils/signatures.cpp freepv-0.3.0/src/libfreepv/Utils/signatures.cpp
--- freepv-0.3.0.orig/src/libfreepv/Utils/signatures.cpp	2009-05-02 01:12:31.000000000 +0200
+++ freepv-0.3.0/src/libfreepv/Utils/signatures.cpp	2017-01-25 15:51:23.781294110 +0100
@@ -30,34 +30,34 @@
 
   //JPEG Signature
   char jpg_size=1;
-  short jpg_sig[]={0xD8FF};
+  unsigned short jpg_sig[]={0xD8FF};
   //PNG Signature
   char png_size=4;
-  short png_sig[]={0x5089, 0x474E, 0x0A0D, 0x0A1A};
+  unsigned short png_sig[]={0x5089, 0x474E, 0x0A0D, 0x0A1A};
   //XML Signature
   char xml_size=3;
-  short xml_sig[]={0x3F3C, 0x6D78, 0x206C};
+  unsigned short xml_sig[]={0x3F3C, 0x6D78, 0x206C};
   //DCR Signature
   char dcr_size=2;
-  short dcr_sig[]={0x4658, 0x5249};
+  unsigned short dcr_sig[]={0x4658, 0x5249};
   //MOV (MOOV atom) Signature
   char mov_moov_size=4;
-  short mov_moov_sig[]={0x0000, 0x0000, 0x6F6D, 0x766F};
+  unsigned short mov_moov_sig[]={0x0000, 0x0000, 0x6F6D, 0x766F};
   //MOV (FTYP atom) Siganture
   char mov_ftyp_size=4;
-    short mov_ftyp_sig[]={0x0000, 0x0000, 0x7466,  0x7079};
+    unsigned short mov_ftyp_sig[]={0x0000, 0x0000, 0x7466,  0x7079};
    
   //Signatures to check
   char sig_types_num=6;
-    short* signature[]={jpg_sig,png_sig,xml_sig,dcr_sig,mov_moov_sig,mov_ftyp_sig};
+    unsigned short* signature[]={jpg_sig,png_sig,xml_sig,dcr_sig,mov_moov_sig,mov_ftyp_sig};
     char sig_sizes[]={jpg_size,png_size,xml_size,dcr_size,mov_moov_size,mov_ftyp_size};
 
   const char* CheckMagicBytes(const char* filename)
   {
     FILE * p_file;
     p_file=fopen(filename, "rb");
-    short number;
-    short equal=0;
+    unsigned short number;
+    unsigned short equal=0;
     char i, type; 
     
     if(p_file==NULL){