From 5dd35b43f1cd3dddaddaae8e2f267117b5fa2d54 Mon Sep 17 00:00:00 2001
From: Anton Khirnov <anton@khirnov.net>
Date: Fri, 21 Oct 2011 11:47:39 +0200
Subject: Move timefilter code from lavf to lavd.

It's only used in the JACK device.

Fixes linking shared lavd with JACK enabled.
---
 libavdevice/timefilter.c | 151 +++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 151 insertions(+)
 create mode 100644 libavdevice/timefilter.c

(limited to 'libavdevice/timefilter.c')

diff --git a/libavdevice/timefilter.c b/libavdevice/timefilter.c
new file mode 100644
index 0000000000..332d33b5e8
--- /dev/null
+++ b/libavdevice/timefilter.c
@@ -0,0 +1,151 @@
+/*
+ * 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 Libav.
+ *
+ * Libav is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * Libav is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+
+#include "config.h"
+#include "timefilter.h"
+#include "libavutil/mem.h"
+
+struct TimeFilter {
+    /// Delay Locked Loop data. These variables refer to mathematical
+    /// concepts described in: http://www.kokkinizita.net/papers/usingdll.pdf
+    double cycle_time;
+    double feedback2_factor;
+    double feedback3_factor;
+    double clock_period;
+    int count;
+};
+
+TimeFilter * ff_timefilter_new(double clock_period, double feedback2_factor, double feedback3_factor)
+{
+    TimeFilter *self        = av_mallocz(sizeof(TimeFilter));
+    self->clock_period      = clock_period;
+    self->feedback2_factor  = feedback2_factor;
+    self->feedback3_factor  = feedback3_factor;
+    return self;
+}
+
+void ff_timefilter_destroy(TimeFilter *self)
+{
+    av_freep(&self);
+}
+
+void ff_timefilter_reset(TimeFilter *self)
+{
+    self->count      = 0;
+}
+
+double ff_timefilter_update(TimeFilter *self, double system_time, double period)
+{
+    self->count++;
+    if (self->count==1) {
+        /// init loop
+        self->cycle_time    = system_time;
+    } else {
+        double loop_error;
+        self->cycle_time   += self->clock_period * period;
+        /// calculate loop error
+        loop_error          = system_time - self->cycle_time;
+
+        /// update loop
+        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)
+
+#undef printf
+
+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
-- 
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