From e37654521144e1d224f0044268643f20e3b8a363 Mon Sep 17 00:00:00 2001
From: Dan Everton <dan@iocaine.org>
Date: Thu, 23 Feb 2006 21:13:03 +0000
Subject: Make peak meter work in simulator for SWCODEC targets.

git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8815 a1c6a512-1295-4272-9138-f99709370657
---
 apps/recorder/peakmeter.c | 13 +++++-----
 uisimulator/sdl/sound.c   | 65 +++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 7 deletions(-)

diff --git a/apps/recorder/peakmeter.c b/apps/recorder/peakmeter.c
index 0142a9d093..f70e9ae709 100644
--- a/apps/recorder/peakmeter.c
+++ b/apps/recorder/peakmeter.c
@@ -44,9 +44,7 @@
 #include "pcm_record.h"
 #endif
 
-#ifndef SIMULATOR /* this is not used in the sim */
 static bool pm_playback = true; /* selects between playback and recording peaks */
-#endif
 
 #endif
 
@@ -539,11 +537,7 @@ void peak_meter_peek(void)
 {
     int left, right;
    /* read current values */
-#ifdef SIMULATOR
-    pm_cur_left  = left  = 8000;
-    pm_cur_right = right = 9000;
-#elif CONFIG_CODEC == SWCODEC
-
+#if CONFIG_CODEC == SWCODEC
     if (pm_playback)
         pcm_calculate_peaks(&pm_cur_left, &pm_cur_right);
 #ifdef HAVE_RECORDING        
@@ -555,8 +549,13 @@ void peak_meter_peek(void)
     left  = pm_cur_left;
     right = pm_cur_right;
 #else
+#ifndef SIMULATOR
     pm_cur_left  = left  = mas_codec_readreg(pm_src_left);
     pm_cur_right = right = mas_codec_readreg(pm_src_right);
+#else
+    pm_cur_left  = left  = 8000;
+    pm_cur_right = right = 9000;
+#endif
 #endif
 
     /* check for clips
diff --git a/uisimulator/sdl/sound.c b/uisimulator/sdl/sound.c
index 23d8718411..ae9d5f9053 100644
--- a/uisimulator/sdl/sound.c
+++ b/uisimulator/sdl/sound.c
@@ -24,6 +24,7 @@
 #include <stdlib.h>
 #include <stdbool.h>
 #include <memory.h>
+#include "kernel.h"
 #include "sound.h"
 #include "SDL.h"
 
@@ -142,6 +143,70 @@ bool pcm_is_playing(void)
     return pcm_playing;
 }
 
+/*
+ * This function goes directly into the DMA buffer to calculate the left and
+ * right peak values. To avoid missing peaks it tries to look forward two full
+ * peek periods (2/HZ sec, 100% overlap), although it's always possible that
+ * the entire period will not be visible. To reduce CPU load it only looks at
+ * every third sample, and this can be reduced even further if needed (even
+ * every tenth sample would still be pretty accurate).
+ */
+
+#define PEAK_SAMPLES  (44100*2/HZ)  /* 44100 samples * 2 / 100 Hz tick */
+#define PEAK_STRIDE   3       /* every 3rd sample is plenty... */
+
+void pcm_calculate_peaks(int *left, int *right)
+{
+    long samples = pcm_data_size / 4;
+    short *addr = pcm_data;
+
+    if (samples > PEAK_SAMPLES)
+        samples = PEAK_SAMPLES;
+
+    samples /= PEAK_STRIDE;
+
+    if (left && right) {
+        int left_peak = 0, right_peak = 0, value;
+
+        while (samples--) {
+            if ((value = addr [0]) > left_peak)
+                left_peak = value;
+            else if (-value > left_peak)
+                left_peak = -value;
+
+            if ((value = addr [PEAK_STRIDE | 1]) > right_peak)
+                right_peak = value;
+            else if (-value > right_peak)
+                right_peak = -value;
+
+            addr += PEAK_STRIDE * 2;
+        }
+
+        *left = left_peak;
+        *right = right_peak;
+    }
+    else if (left || right) {
+        int peak_value = 0, value;
+
+        if (right)
+            addr += (PEAK_STRIDE | 1);
+
+        while (samples--) {
+            if ((value = addr [0]) > peak_value)
+                peak_value = value;
+            else if (-value > peak_value)
+                peak_value = -value;
+
+            addr += PEAK_STRIDE * 2;
+        }
+
+        if (left)
+            *left = peak_value;
+        else
+            *right = peak_value;
+    }
+}
+
 Uint8 overflow[8192];
 Uint32 overflow_amount = 0;
 
-- 
cgit