From: Michael Niedermayer <michaelni@gmx.at>
Date: Mon, 28 Jul 2008 15:44:00 +0000 (+0000)
Subject: Warning about MTs speed.
X-Git-Tag: v0.5~3437
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=e80d47411902929c3acecb7c2e3a8116095f4c70;p=platform%2Fupstream%2Flibav.git

Warning about MTs speed.

Originally committed as revision 14460 to svn://svn.ffmpeg.org/ffmpeg/trunk
---

diff --git a/libavutil/random.h b/libavutil/random.h
index 25eaf58..1e10ae4 100644
--- a/libavutil/random.h
+++ b/libavutil/random.h
@@ -35,7 +35,14 @@ typedef struct {
 void av_init_random(unsigned int seed, AVRandomState *state); ///< to be inlined, the struct must be visible, so it doesn't make sense to try and keep it opaque with malloc/free like calls
 void av_random_generate_untempered_numbers(AVRandomState *state); ///< Regenerate the untempered numbers (must be done every 624 iterations, or it will loop)
 
-/** generates a random number on [0,0xffffffff]-interval */
+/**
+ * generates a random number on [0,0xffffffff]-interval
+ *
+ * Please do NOT use the mersenne twister, it is slow, use the random generator
+ * from lfg.c/h or a simple LCG like state= state*1664525+1013904223.
+ * If you still choose to use MT, expect that you will have to provide
+ * some evidence that it makes a difference for the case where you use it.
+ */
 static inline unsigned int av_random(AVRandomState *state)
 {
     unsigned int y;