Update xwax to 1.4, no major changes.

8 files changed, 165 insertions, 105 deletions

diff --git a/lib/xwax/debug.h b/lib/xwax/debug.h
index 4b06ba4f73..cc2872b6a7 100644
--- a/lib/xwax/debug.h
+++ b/lib/xwax/debug.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Mark Hills <mark@pogo.org.uk>
+ * Copyright (C) 2013 Mark Hills <mark@xwax.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -23,7 +23,11 @@
 #include <stdio.h>
 
 #ifdef DEBUG
-#define debug(...) fprintf(stderr, __VA_ARGS__)
+#define debug(...) { \
+    fprintf(stderr, "%s:%d: ", __FILE__, __LINE__); \
+    fprintf(stderr, __VA_ARGS__); \
+    fputc('\n', stderr); \
+}
 #define dassert(x) assert(x)
 #else
 #define debug(...)
diff --git a/lib/xwax/lut.c b/lib/xwax/lut.c
index 7ae7733cf7..6f02680e5c 100644
--- a/lib/xwax/lut.c
+++ b/lib/xwax/lut.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Mark Hills <mark@pogo.org.uk>
+ * Copyright (C) 2013 Mark Hills <mark@xwax.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
diff --git a/lib/xwax/lut.cpp b/lib/xwax/lut.cpp
index 30dadfd95e..a10face3f4 100644
--- a/lib/xwax/lut.cpp
+++ b/lib/xwax/lut.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Mark Hills <mark@pogo.org.uk>
+ * Copyright (C) 2013 Mark Hills <mark@xwax.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -46,13 +46,13 @@ int lut_init(struct lut *lut, int nslots)
             " (%d slots per hash, %zuKb)\n",
             hashes, nslots, nslots / hashes, bytes / 1024);
 
-    lut->slot = (struct slot*)malloc(sizeof(struct slot) * nslots);
+    lut->slot = static_cast<struct slot*>(malloc(sizeof(struct slot) * nslots));
     if (lut->slot == NULL) {
         perror("malloc");
         return -1;
     }
 
-    lut->table = (slot_no_t*)malloc(sizeof(slot_no_t) * hashes);
+    lut->table = static_cast<slot_no_t*>(malloc(sizeof(slot_no_t) * hashes));
     if (lut->table == NULL) {
         perror("malloc");
         return -1;
diff --git a/lib/xwax/lut.h b/lib/xwax/lut.h
index a156f492a3..29361c5b98 100644
--- a/lib/xwax/lut.h
+++ b/lib/xwax/lut.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Mark Hills <mark@pogo.org.uk>
+ * Copyright (C) 2013 Mark Hills <mark@xwax.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
diff --git a/lib/xwax/pitch.h b/lib/xwax/pitch.h
index ab0cad5dd8..abf35e3c4d 100644
--- a/lib/xwax/pitch.h
+++ b/lib/xwax/pitch.h
@@ -1,5 +1,5 @@
 /* 
- * Copyright (C) 2012 Mark Hills <mark@pogo.org.uk>
+ * Copyright (C) 2013 Mark Hills <mark@xwax.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
diff --git a/lib/xwax/timecoder.c b/lib/xwax/timecoder.c
index ec11bbd0de..082af25d87 100644
--- a/lib/xwax/timecoder.c
+++ b/lib/xwax/timecoder.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Mark Hills <mark@pogo.org.uk>
+ * Copyright (C) 2013 Mark Hills <mark@xwax.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -18,6 +18,7 @@
  */
 
 #include <assert.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -26,7 +27,7 @@
 #include "debug.h"
 #include "timecoder.h"
 
-#define ZERO_THRESHOLD 128
+#define ZERO_THRESHOLD (128 << 16)
 
 #define ZERO_RC 0.001 /* time constant for zero/rumble filter */
 
@@ -194,7 +195,7 @@ static inline bits_t rev(bits_t current, struct timecode_def *def)
 static int build_lookup(struct timecode_def *def)
 {
     unsigned int n;
-    bits_t current, last;
+    bits_t current;
 
     if (def->lookup)
         return 0;
@@ -208,12 +209,17 @@ static int build_lookup(struct timecode_def *def)
     current = def->seed;
 
     for (n = 0; n < def->length; n++) {
+        bits_t next;
+
         /* timecode must not wrap */
         dassert(lut_lookup(&def->lut, current) == (unsigned)-1);
         lut_push(&def->lut, current);
-        last = current;
-        current = fwd(current, def);
-        dassert(rev(current, def) == last);
+
+        /* check symmetry of the lfsr functions */
+        next = fwd(current, def);
+        dassert(rev(next, def) == current);
+
+        current = next;
     }
 
     def->lookup = true;
@@ -284,7 +290,7 @@ static void init_channel(struct timecoder_channel *ch)
  */
 
 void timecoder_init(struct timecoder *tc, struct timecode_def *def,
-                    double speed, unsigned int sample_rate)
+                    double speed, unsigned int sample_rate, bool phono)
 {
     assert(def != NULL);
 
@@ -297,13 +303,16 @@ void timecoder_init(struct timecoder *tc, struct timecode_def *def,
 
     tc->dt = 1.0 / sample_rate;
     tc->zero_alpha = tc->dt / (ZERO_RC + tc->dt);
+    tc->threshold = ZERO_THRESHOLD;
+    if (phono)
+        tc->threshold >>= 5; /* approx -36dB */
 
     tc->forwards = 1;
     init_channel(&tc->primary);
     init_channel(&tc->secondary);
     pitch_init(&tc->pitch, tc->dt);
 
-    tc->ref_level = 32768.0;
+    tc->ref_level = INT_MAX;
     tc->bitstream = 0;
     tc->timecode = 0;
     tc->valid_counter = 0;
@@ -360,16 +369,17 @@ void timecoder_monitor_clear(struct timecoder *tc)
  */
 
 static void detect_zero_crossing(struct timecoder_channel *ch,
-                                 signed int v, double alpha)
+                                 signed int v, double alpha,
+                                 signed int threshold)
 {
     ch->crossing_ticker++;
 
     ch->swapped = false;
-    if (v > ch->zero + ZERO_THRESHOLD && !ch->positive) {
+    if (v > ch->zero + threshold && !ch->positive) {
         ch->swapped = true;
         ch->positive = true;
         ch->crossing_ticker = 0;
-    } else if (v < ch->zero - ZERO_THRESHOLD && ch->positive) {
+    } else if (v < ch->zero - threshold && ch->positive) {
         ch->swapped = true;
         ch->positive = false;
         ch->crossing_ticker = 0;
@@ -384,31 +394,35 @@ static void detect_zero_crossing(struct timecoder_channel *ch,
 
 static void update_monitor(struct timecoder *tc, signed int x, signed int y)
 {
-    int px, py, p;
-    double v, w;
+    int px, py, size, ref;
 
     if (!tc->mon)
         return;
 
+    size = tc->mon_size;
+    ref = tc->ref_level;
+
     /* Decay the pixels already in the montior */
 
     if (++tc->mon_counter % MONITOR_DECAY_EVERY == 0) {
-        for (p = 0; p < SQ(tc->mon_size); p++) {
+        int p;
+
+        for (p = 0; p < SQ(size); p++) {
             if (tc->mon[p])
                 tc->mon[p] = tc->mon[p] * 7 / 8;
         }
     }
 
-    v = (double)x / tc->ref_level / 2;
-    w = (double)y / tc->ref_level / 2;
+    assert(ref > 0);
 
-    px = tc->mon_size / 2 + (v * tc->mon_size / 2);
-    py = tc->mon_size / 2 + (w * tc->mon_size / 2);
+    /* ref_level is half the prevision of signal level */
+    px = size / 2 + (long long)x * size / ref / 8;
+    py = size / 2 + (long long)y * size / ref / 8;
 
-    /* Set the pixel value to white */
+    if (px < 0 || px >= size || py < 0 || py >= size)
+        return;
 
-    if (px > 0 && px < tc->mon_size && py > 0 && py < tc->mon_size)
-        tc->mon[py * tc->mon_size + px] = 0xff;
+    tc->mon[py * size + px] = 0xff; /* white */
 }
 
 /*
@@ -453,9 +467,10 @@ static void process_bitstream(struct timecoder *tc, signed int m)
 
     /* Adjust the reference level based on this new peak */
 
-    tc->ref_level = (tc->ref_level * (REF_PEAKS_AVG - 1) + m) / REF_PEAKS_AVG;
+    tc->ref_level -= tc->ref_level / REF_PEAKS_AVG;
+    tc->ref_level += m / REF_PEAKS_AVG;
 
-    debug("%+6d zero, %+6d (ref %+6d)\t= %d%c (%5d)\n",
+    debug("%+6d zero, %+6d (ref %+6d)\t= %d%c (%5d)",
           tc->primary.zero,
           m, tc->ref_level,
 	  b, tc->valid_counter == 0 ? 'x' : ' ',
@@ -464,17 +479,16 @@ static void process_bitstream(struct timecoder *tc, signed int m)
 
 /*
  * Process a single sample from the incoming audio
+ *
+ * The two input signals (primary and secondary) are in the full range
+ * of a signed int; ie. 32-bit signed.
  */
 
 static void process_sample(struct timecoder *tc,
 			   signed int primary, signed int secondary)
 {
-    signed int m; /* pcm sample, sum of two shorts */
-
-    detect_zero_crossing(&tc->primary, primary, tc->zero_alpha);
-    detect_zero_crossing(&tc->secondary, secondary, tc->zero_alpha);
-
-    m = abs(primary - tc->primary.zero);
+    detect_zero_crossing(&tc->primary, primary, tc->zero_alpha, tc->threshold);
+    detect_zero_crossing(&tc->secondary, secondary, tc->zero_alpha, tc->threshold);
 
     /* If an axis has been crossed, use the direction of the crossing
      * to work out the direction of the vinyl */
@@ -517,6 +531,10 @@ static void process_sample(struct timecoder *tc,
     if (tc->secondary.swapped &&
        tc->primary.positive == ((tc->def->flags & SWITCH_POLARITY) == 0))
     {
+        signed int m;
+
+        /* scale to avoid clipping */
+        m = abs(primary / 2 - tc->primary.zero / 2);
 	process_bitstream(tc, m);
     }
 
@@ -557,24 +575,29 @@ void timecoder_cycle_definition(struct timecoder *tc)
 
 /*
  * Submit and decode a block of PCM audio data to the timecode decoder
+ *
+ * PCM data is in the full range of signed short; ie. 16-bit signed.
  */
 
-void timecoder_submit(struct timecoder *tc, const signed short *pcm, size_t npcm)
+void timecoder_submit(struct timecoder *tc, signed short *pcm, size_t npcm)
 {
     while (npcm--) {
-	signed int primary, secondary;
+	signed int left, right, primary, secondary;
+
+        left = pcm[0] << 16;
+        right = pcm[1] << 16;
 
         if (tc->def->flags & SWITCH_PRIMARY) {
-            primary = pcm[0];
-            secondary = pcm[1];
+            primary = left;
+            secondary = right;
         } else {
-            primary = pcm[1];
-            secondary = pcm[0];
+            primary = right;
+            secondary = left;
         }
 
 	process_sample(tc, primary, secondary);
+        update_monitor(tc, left, right);
 
-        update_monitor(tc, pcm[0], pcm[1]);
         pcm += TIMECODER_CHANNELS;
     }
 }
@@ -595,17 +618,20 @@ signed int timecoder_get_position(struct timecoder *tc, double *when)
 {
     signed int r;
 
-    if (tc->valid_counter > VALID_BITS) {
-        r = lut_lookup(&tc->def->lut, tc->bitstream);
+    if (tc->valid_counter <= VALID_BITS)
+        return -1;
+
+    r = lut_lookup(&tc->def->lut, tc->bitstream);
+    if (r == -1)
+        return -1;
 
-        if (r >= 0) {
-            //normalize position to milliseconds, not timecode steps -- Owen
-            r = (float)r * (1000.0 / (tc->def->resolution * tc->speed));
-            if (when)
-                *when = tc->timecode_ticker * tc->dt;
-            return r;
-        }
+    if (r >= 0) {
+        // normalize position to milliseconds, not timecode steps -- Owen
+        r = (double)r * (1000.0 / ((double)tc->def->resolution * tc->speed));
     }
 
-    return -1;
+    if (when)
+        *when = tc->timecode_ticker * tc->dt;
+
+    return r;
 }
diff --git a/lib/xwax/timecoder.h b/lib/xwax/timecoder.h
index fda86fff5e..3304eee641 100644
--- a/lib/xwax/timecoder.h
+++ b/lib/xwax/timecoder.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Mark Hills <mark@pogo.org.uk>
+ * Copyright (C) 2013 Mark Hills <mark@xwax.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -58,6 +58,7 @@ struct timecoder {
     /* Precomputed values */
 
     double dt, zero_alpha;
+    signed int threshold;
 
     /* Pitch information */
 
@@ -83,14 +84,14 @@ struct timecode_def* timecoder_find_definition(const char *name);
 void timecoder_free_lookup(void);
 
 void timecoder_init(struct timecoder *tc, struct timecode_def *def,
-                    double speed, unsigned int sample_rate);
+                    double speed, unsigned int sample_rate, bool phono);
 void timecoder_clear(struct timecoder *tc);
 
 int timecoder_monitor_init(struct timecoder *tc, int size);
 void timecoder_monitor_clear(struct timecoder *tc);
 
 void timecoder_cycle_definition(struct timecoder *tc);
-void timecoder_submit(struct timecoder *tc, const signed short *pcm, size_t npcm);
+void timecoder_submit(struct timecoder *tc, signed short *pcm, size_t npcm);
 signed int timecoder_get_position(struct timecoder *tc, double *when);
 
 /*
diff --git a/lib/xwax/timecoder_win32.cpp b/lib/xwax/timecoder_win32.cpp
index 2059ebdd53..18910382f5 100755
--- a/lib/xwax/timecoder_win32.cpp
+++ b/lib/xwax/timecoder_win32.cpp
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2012 Mark Hills <mark@pogo.org.uk>
+ * Copyright (C) 2013 Mark Hills <mark@xwax.org>
  *
  * This program is free software; you can redistribute it and/or
  * modify it under the terms of the GNU General Public License
@@ -18,6 +18,7 @@
  */
 
 #include <assert.h>
+#include <limits.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
@@ -28,7 +29,7 @@
 #include "debug.h"
 #include "timecoder.h"
 
-#define ZERO_THRESHOLD 128
+#define ZERO_THRESHOLD (128 << 16)
 
 #define ZERO_RC 0.001 /* time constant for zero/rumble filter */
 
@@ -98,7 +99,7 @@ static struct timecode_def timecodes[] = {
         0x041040,
         1500000,
         605000,
-        false        
+        false
     },
     {
         "traktor_b",
@@ -140,6 +141,7 @@ static struct timecode_def timecodes[] = {
         NULL
     }
 };
+
 /*
  * Calculate LFSR bit
  */
@@ -198,7 +200,7 @@ static inline bits_t rev(bits_t current, struct timecode_def *def)
 static int build_lookup(struct timecode_def *def)
 {
     unsigned int n;
-    bits_t current, last;
+    bits_t current;
 
     if (def->lookup)
         return 0;
@@ -212,12 +214,17 @@ static int build_lookup(struct timecode_def *def)
     current = def->seed;
 
     for (n = 0; n < def->length; n++) {
+        bits_t next;
+
         /* timecode must not wrap */
         dassert(lut_lookup(&def->lut, current) == (unsigned)-1);
         lut_push(&def->lut, current);
-        last = current;
-        current = fwd(current, def);
-        dassert(rev(current, def) == last);
+
+        /* check symmetry of the lfsr functions */
+        next = fwd(current, def);
+        dassert(rev(next, def) == current);
+
+        current = next;
     }
 
     def->lookup = true;
@@ -288,7 +295,7 @@ static void init_channel(struct timecoder_channel *ch)
  */
 
 void timecoder_init(struct timecoder *tc, struct timecode_def *def,
-                    double speed, unsigned int sample_rate)
+                    double speed, unsigned int sample_rate, bool phono)
 {
     assert(def != NULL);
 
@@ -301,13 +308,16 @@ void timecoder_init(struct timecoder *tc, struct timecode_def *def,
 
     tc->dt = 1.0 / sample_rate;
     tc->zero_alpha = tc->dt / (ZERO_RC + tc->dt);
+    tc->threshold = ZERO_THRESHOLD;
+    if (phono)
+        tc->threshold >>= 5; /* approx -36dB */
 
     tc->forwards = 1;
     init_channel(&tc->primary);
     init_channel(&tc->secondary);
     pitch_init(&tc->pitch, tc->dt);
 
-    tc->ref_level = 32768.0;
+    tc->ref_level = INT_MAX;
     tc->bitstream = 0;
     tc->timecode = 0;
     tc->valid_counter = 0;
@@ -338,7 +348,7 @@ int timecoder_monitor_init(struct timecoder *tc, int size)
 {
     assert(tc->mon == NULL);
     tc->mon_size = size;
-    tc->mon = (unsigned char*)malloc(SQ(tc->mon_size));
+    tc->mon = static_cast<unsigned char*>(malloc(SQ(tc->mon_size)));
     if (tc->mon == NULL) {
         perror("malloc");
         return -1;
@@ -364,16 +374,17 @@ void timecoder_monitor_clear(struct timecoder *tc)
  */
 
 static void detect_zero_crossing(struct timecoder_channel *ch,
-                                 signed int v, double alpha)
+                                 signed int v, double alpha,
+                                 signed int threshold)
 {
     ch->crossing_ticker++;
 
     ch->swapped = false;
-    if (v > ch->zero + ZERO_THRESHOLD && !ch->positive) {
+    if (v > ch->zero + threshold && !ch->positive) {
         ch->swapped = true;
         ch->positive = true;
         ch->crossing_ticker = 0;
-    } else if (v < ch->zero - ZERO_THRESHOLD && ch->positive) {
+    } else if (v < ch->zero - threshold && ch->positive) {
         ch->swapped = true;
         ch->positive = false;
         ch->crossing_ticker = 0;
@@ -388,31 +399,35 @@ static void detect_zero_crossing(struct timecoder_channel *ch,
 
 static void update_monitor(struct timecoder *tc, signed int x, signed int y)
 {
-    int px, py, p;
-    double v, w;
+    int px, py, size, ref;
 
     if (!tc->mon)
         return;
 
+    size = tc->mon_size;
+    ref = tc->ref_level;
+
     /* Decay the pixels already in the montior */
 
     if (++tc->mon_counter % MONITOR_DECAY_EVERY == 0) {
-        for (p = 0; p < SQ(tc->mon_size); p++) {
+        int p;
+
+        for (p = 0; p < SQ(size); p++) {
             if (tc->mon[p])
                 tc->mon[p] = tc->mon[p] * 7 / 8;
         }
     }
 
-    v = (double)x / tc->ref_level / 2;
-    w = (double)y / tc->ref_level / 2;
+    assert(ref > 0);
 
-    px = tc->mon_size / 2 + (v * tc->mon_size / 2);
-    py = tc->mon_size / 2 + (w * tc->mon_size / 2);
+    /* ref_level is half the prevision of signal level */
+    px = size / 2 + (long long)x * size / ref / 8;
+    py = size / 2 + (long long)y * size / ref / 8;
 
-    /* Set the pixel value to white */
+    if (px < 0 || px >= size || py < 0 || py >= size)
+        return;
 
-    if (px > 0 && px < tc->mon_size && py > 0 && py < tc->mon_size)
-        tc->mon[py * tc->mon_size + px] = 0xff;
+    tc->mon[py * size + px] = 0xff; /* white */
 }
 
 /*
@@ -457,9 +472,10 @@ static void process_bitstream(struct timecoder *tc, signed int m)
 
     /* Adjust the reference level based on this new peak */
 
-    tc->ref_level = (tc->ref_level * (REF_PEAKS_AVG - 1) + m) / REF_PEAKS_AVG;
+    tc->ref_level -= tc->ref_level / REF_PEAKS_AVG;
+    tc->ref_level += m / REF_PEAKS_AVG;
 
-    debug("%+6d zero, %+6d (ref %+6d)\t= %d%c (%5d)\n",
+    debug("%+6d zero, %+6d (ref %+6d)\t= %d%c (%5d)",
           tc->primary.zero,
           m, tc->ref_level,
 	  b, tc->valid_counter == 0 ? 'x' : ' ',
@@ -468,17 +484,16 @@ static void process_bitstream(struct timecoder *tc, signed int m)
 
 /*
  * Process a single sample from the incoming audio
+ *
+ * The two input signals (primary and secondary) are in the full range
+ * of a signed int; ie. 32-bit signed.
  */
 
 static void process_sample(struct timecoder *tc,
 			   signed int primary, signed int secondary)
 {
-    signed int m; /* pcm sample, sum of two shorts */
-
-    detect_zero_crossing(&tc->primary, primary, tc->zero_alpha);
-    detect_zero_crossing(&tc->secondary, secondary, tc->zero_alpha);
-
-    m = abs(primary - tc->primary.zero);
+    detect_zero_crossing(&tc->primary, primary, tc->zero_alpha, tc->threshold);
+    detect_zero_crossing(&tc->secondary, secondary, tc->zero_alpha, tc->threshold);
 
     /* If an axis has been crossed, use the direction of the crossing
      * to work out the direction of the vinyl */
@@ -521,6 +536,10 @@ static void process_sample(struct timecoder *tc,
     if (tc->secondary.swapped &&
        tc->primary.positive == ((tc->def->flags & SWITCH_POLARITY) == 0))
     {
+        signed int m;
+
+        /* scale to avoid clipping */
+        m = abs(primary / 2 - tc->primary.zero / 2);
 	process_bitstream(tc, m);
     }
 
@@ -561,24 +580,29 @@ void timecoder_cycle_definition(struct timecoder *tc)
 
 /*
  * Submit and decode a block of PCM audio data to the timecode decoder
+ *
+ * PCM data is in the full range of signed short; ie. 16-bit signed.
  */
 
-void timecoder_submit(struct timecoder *tc, const signed short *pcm, size_t npcm)
+void timecoder_submit(struct timecoder *tc, signed short *pcm, size_t npcm)
 {
     while (npcm--) {
-	signed int primary, secondary;
+	signed int left, right, primary, secondary;
+
+        left = pcm[0] << 16;
+        right = pcm[1] << 16;
 
         if (tc->def->flags & SWITCH_PRIMARY) {
-            primary = pcm[0];
-            secondary = pcm[1];
+            primary = left;
+            secondary = right;
         } else {
-            primary = pcm[1];
-            secondary = pcm[0];
+            primary = right;
+            secondary = left;
         }
 
 	process_sample(tc, primary, secondary);
+        update_monitor(tc, left, right);
 
-        update_monitor(tc, pcm[0], pcm[1]);
         pcm += TIMECODER_CHANNELS;
     }
 }
@@ -599,17 +623,22 @@ signed int timecoder_get_position(struct timecoder *tc, double *when)
 {
     signed int r;
 
-    if (tc->valid_counter > VALID_BITS) {
-        r = lut_lookup(&tc->def->lut, tc->bitstream);
+    if (tc->valid_counter <= VALID_BITS)
+        return -1;
 
-        if (r >= 0) {
-            //normalize position to milliseconds, not timecode steps -- Owen
-            r = (float)r * (1000.0 / (tc->def->resolution * tc->speed));
-            if (when)
-                *when = tc->timecode_ticker * tc->dt;
-            return r;
-        }
+    r = lut_lookup(&tc->def->lut, tc->bitstream);
+    if (r == -1)
+        return -1;
+
+    if (r >= 0) {
+        // normalize position to milliseconds, not timecode steps -- Owen
+        r = static_cast<double>(r)
+                * (1000.0
+                   / (static_cast<double>(tc->def->resolution) * tc->speed));
     }
 
-    return -1;
+    if (when)
+        *when = tc->timecode_ticker * tc->dt;
+
+    return r;
 }