diff --git a/mpeg/mpga.h b/mpeg/mpga.h
index 4571c7b..95de2ac 100644
--- a/mpeg/mpga.h
+++ b/mpeg/mpga.h
@@ -214,15 +214,18 @@ static inline bool mpga_sync_compare(const uint8_t *p_mpga1, const uint8_t *p_mp
 /* same but only takes into account meaningful fields */
 static inline bool mpga_sync_compare_formats(const uint8_t *p_mpga1, const uint8_t *p_mpga2)
 {
+    if (!(p_mpga1[0] == p_mpga2[0] &&
+          (p_mpga1[1] & 0xfe) == (p_mpga2[1] & 0xfe) &&
+          (p_mpga1[2] & 0xfc) == (p_mpga2[2] & 0xfc)))
+        return false;
+
     /* consider stereo and joint stereo the same - because encoders can
      * switch on the fly */
     uint8_t i_mode1 = mpga_get_mode(p_mpga1);
     uint8_t i_mode2 = mpga_get_mode(p_mpga2);
     if (i_mode1 == MPGA_MODE_JOINT) i_mode1 = MPGA_MODE_STEREO;
     if (i_mode2 == MPGA_MODE_JOINT) i_mode2 = MPGA_MODE_STEREO;
-    return p_mpga1[0] == p_mpga2[0] &&
-           (p_mpga1[1] & 0xfe) == (p_mpga2[1] & 0xfe) &&
-           (p_mpga1[2] & 0xfc) == (p_mpga2[2] & 0xfc) && i_mode1 == i_mode2;
+    return i_mode1 == i_mode2;
 }
 
 #ifdef __cplusplus