[FFmpeg-cvslog] r23219 - in branches/0.6: . libavcodec/mpegaudiodec.c

[siretart]

Author: siretart
Date: Fri May 21 20:32:58 2010
New Revision: 23219

Log:
Make lsf_sf_expand() 4 times faster.


backport r23096 by michael

Modified:
   branches/0.6/   (props changed)
   branches/0.6/libavcodec/mpegaudiodec.c

Modified: branches/0.6/libavcodec/mpegaudiodec.c
==============================================================================
--- branches/0.6/libavcodec/mpegaudiodec.c	Fri May 21 20:27:16 2010	(r23218)
+++ branches/0.6/libavcodec/mpegaudiodec.c	Fri May 21 20:32:58 2010	(r23219)
@@ -1315,23 +1315,32 @@ static int mp_decode_layer2(MPADecodeCon
     return 3 * 12;
 }
 
-static inline void lsf_sf_expand(int *slen,
+#define SPLIT(dst,sf,n)\
+    if(n==3){\
+        int m= (sf*171)>>9;\
+        dst= sf - 3*m;\
+        sf=m;\
+    }else if(n==4){\
+        dst= sf&3;\
+        sf>>=2;\
+    }else if(n==5){\
+        int m= (sf*205)>>10;\
+        dst= sf - 5*m;\
+        sf=m;\
+    }else if(n==6){\
+        int m= (sf*171)>>10;\
+        dst= sf - 6*m;\
+        sf=m;\
+    }else{\
+        dst=0;\
+    }
+
+static av_always_inline void lsf_sf_expand(int *slen,
                                  int sf, int n1, int n2, int n3)
 {
-    if (n3) {
-        slen[3] = sf % n3;
-        sf /= n3;
-    } else {
-        slen[3] = 0;
-    }
-    if (n2) {
-        slen[2] = sf % n2;
-        sf /= n2;
-    } else {
-        slen[2] = 0;
-    }
-    slen[1] = sf % n1;
-    sf /= n1;
+    SPLIT(slen[3], sf, n3)
+    SPLIT(slen[2], sf, n2)
+    SPLIT(slen[1], sf, n1)
     slen[0] = sf;
 }