configure: add some blank lines to improve readability
[ffmpeg.git] / libavformat / timefilter.c
index 7109a0a..4a58224 100644 (file)
@@ -1,7 +1,9 @@
 /*
  * Delay Locked Loop based time filter
  * Copyright (c) 2009 Samalyse
+ * Copyright (c) 2009 Michael Niedermayer
  * Author: Olivier Guilyardi <olivier samalyse com>
+ *         Michael Niedermayer <michaelni gmx at>
  *
  * This file is part of FFmpeg.
  *
@@ -31,14 +33,14 @@ struct TimeFilter {
     double cycle_time;
     double feedback2_factor;
     double feedback3_factor;
-    double integrator2_state;
+    double clock_period;
     int count;
 };
 
-TimeFilter * ff_timefilter_new(double feedback2_factor, double feedback3_factor)
+TimeFilter * ff_timefilter_new(double clock_period, double feedback2_factor, double feedback3_factor)
 {
     TimeFilter *self        = av_mallocz(sizeof(TimeFilter));
-    self->integrator2_state = 1.0;
+    self->clock_period      = clock_period;
     self->feedback2_factor  = feedback2_factor;
     self->feedback3_factor  = feedback3_factor;
     return self;
@@ -51,25 +53,97 @@ void ff_timefilter_destroy(TimeFilter *self)
 
 void ff_timefilter_reset(TimeFilter *self)
 {
-    self->cycle_time = 0;
     self->count      = 0;
 }
 
 double ff_timefilter_update(TimeFilter *self, double system_time, double period)
 {
     self->count++;
-    if (!self->cycle_time) {
+    if (self->count==1) {
         /// init loop
-        self->cycle_time        = system_time;
+        self->cycle_time    = system_time;
     } else {
         double loop_error;
-        self->cycle_time+= self->integrator2_state * period;
+        self->cycle_time   += self->clock_period * period;
         /// calculate loop error
-        loop_error = system_time - self->cycle_time;
+        loop_error          = system_time - self->cycle_time;
 
         /// update loop
-        self->cycle_time        += FFMAX(self->feedback2_factor, 1.0/(self->count)) * loop_error;
-        self->integrator2_state += self->feedback3_factor * loop_error / period;
+        self->cycle_time   += FFMAX(self->feedback2_factor, 1.0/(self->count)) * loop_error;
+        self->clock_period += self->feedback3_factor * loop_error / period;
     }
     return self->cycle_time;
 }
+
+#ifdef TEST
+#include "libavutil/lfg.h"
+#define LFG_MAX ((1LL << 32) - 1)
+
+int main(void)
+{
+    AVLFG prng;
+    double n0,n1;
+#define SAMPLES 1000
+    double ideal[SAMPLES];
+    double samples[SAMPLES];
+#if 1
+    for(n0= 0; n0<40; n0=2*n0+1){
+        for(n1= 0; n1<10; n1=2*n1+1){
+#else
+    {{
+        n0=7;
+        n1=1;
+#endif
+            double best_error= 1000000000;
+            double bestpar0=1;
+            double bestpar1=0.001;
+            int better, i;
+
+            av_lfg_init(&prng, 123);
+            for(i=0; i<SAMPLES; i++){
+                ideal[i]  = 10 + i + n1*i/(1000);
+                samples[i] = ideal[i] + n0 * (av_lfg_get(&prng) - LFG_MAX / 2)
+                                           / (LFG_MAX * 10LL);
+            }
+
+            do{
+                double par0, par1;
+                better=0;
+                for(par0= bestpar0*0.8; par0<=bestpar0*1.21; par0+=bestpar0*0.05){
+                    for(par1= bestpar1*0.8; par1<=bestpar1*1.21; par1+=bestpar1*0.05){
+                        double error=0;
+                        TimeFilter *tf= ff_timefilter_new(1, par0, par1);
+                        for(i=0; i<SAMPLES; i++){
+                            double filtered;
+                            filtered=  ff_timefilter_update(tf, samples[i], 1);
+                            error += (filtered - ideal[i]) * (filtered - ideal[i]);
+                        }
+                        ff_timefilter_destroy(tf);
+                        if(error < best_error){
+                            best_error= error;
+                            bestpar0= par0;
+                            bestpar1= par1;
+                            better=1;
+                        }
+                    }
+                }
+            }while(better);
+#if 0
+            double lastfil=9;
+            TimeFilter *tf= ff_timefilter_new(1, bestpar0, bestpar1);
+            for(i=0; i<SAMPLES; i++){
+                double filtered;
+                filtered=  ff_timefilter_update(tf, samples[i], 1);
+                printf("%f %f %f %f\n", i - samples[i] + 10, filtered - samples[i], samples[FFMAX(i, 1)] - samples[FFMAX(i-1, 0)], filtered - lastfil);
+                lastfil= filtered;
+            }
+            ff_timefilter_destroy(tf);
+#else
+            printf(" [%f %f %9f]", bestpar0, bestpar1, best_error);
+#endif
+        }
+        printf("\n");
+    }
+    return 0;
+}
+#endif