Initial attempt to support peak meter on iriver. It still has some

strange behaviour and readings might not be correct.


git-svn-id: svn://svn.rockbox.org/rockbox/trunk@7182 a1c6a512-1295-4272-9138-f99709370657

apps/recorder/peakmeter.c

@@ -32,6 +32,10 @@
 #include "lang.h"
 #include "peakmeter.h"
 
+#if CONFIG_HWCODEC == MASNONE
+#include "pcm_playback.h"
+#endif
+
 /* no inline in simulator mode */
 #ifdef SIMULATOR
 #define inline
@@ -552,9 +556,9 @@ inline void peak_meter_peek(void)
     int left = 8000;
     int right = 9000;
 #elif CONFIG_HWCODEC == MASNONE
-    /* FIX */
-    int left = 9000;
-    int right = 8000;
+    int left;
+    int right;
+    pcm_calculate_peaks(&left, &right);
 #else
    /* read the peak values */
     int left  = mas_codec_readreg(peak_meter_src_l);
@@ -729,8 +733,7 @@ static int peak_meter_read_l (void)
 #ifdef SIMULATOR
     peak_meter_l = 8000;
 #elif CONFIG_HWCODEC == MASNONE
-    /* FIX */
-    peak_meter_l = 8000;
+    pcm_calculate_peaks(&peak_meter_l, NULL);
 #else
     /* reset peak_meter_l so that subsequent calls of
        peak_meter_peek doesn't get fooled by an old
@@ -758,8 +761,7 @@ static int peak_meter_read_r (void) {
 #ifdef SIMULATOR
     peak_meter_l = 8000;
 #elif CONFIG_HWCODEC == MASNONE
-    /* FIX */
-    peak_meter_r = 8000;
+    pcm_calculate_peaks(NULL, &peak_meter_r);
 #else
     /* reset peak_meter_r so that subsequent calls of
        peak_meter_peek doesn't get fooled by an old

firmware/export/pcm_playback.h

@@ -25,6 +25,8 @@ void pcm_set_frequency(unsigned int frequency);
 /* This is for playing "raw" PCM data */
 void pcm_play_data(void (*get_more)(unsigned char** start, long* size));
 
+void pcm_calculate_peaks(int *left, int *right);
+
 void pcm_play_stop(void);
 void pcm_play_pause(bool play);
 bool pcm_is_paused(void);

firmware/pcm_playback.c

@@ -89,6 +89,89 @@ static void dma_stop(void)
     pcm_paused = false;
 }
 
+#define PEEK_SAMPLE_COUNT 64
+static long calculate_channel_peak_average(int channel, unsigned short *addr,
+                                           long size)
+{
+    int i;
+    long min, max;
+    int count, min_count, max_count;
+    unsigned long average, zero_point;
+
+    addr = &addr[channel];
+    average = 0;
+    
+    if (pcm_playing && !pcm_paused && addr != NULL)
+    {
+        /* Calculate the zero point and remove DC offset (should be around 32768) */
+        zero_point = 0;
+        for (i = 0; i < size; i++)
+            zero_point += addr[i*2];
+        zero_point /= i;
+
+        /*for (i = 0; i < size; i++) {
+            long peak = addr[i*2] - 32768;
+            if (peak < 0)
+                peak = 0;
+            average += peak;
+        }
+        average /= i;*/
+        
+        count = 0;
+
+        while (size > PEEK_SAMPLE_COUNT)
+        {
+            min = zero_point;
+            max = zero_point;
+            min_count = 1;
+            max_count = 1;
+            
+            for (i = 0; i < PEEK_SAMPLE_COUNT; i++)
+            {
+                unsigned long value = *addr;
+                if (value < zero_point) {
+                    min += value;
+                    min_count++;
+                }
+                if (value > zero_point) {
+                    max += value;
+                    max_count++;
+                }
+                addr = &addr[2];
+            }
+
+            min /= min_count;
+            max /= max_count;
+            
+            size -= PEEK_SAMPLE_COUNT;
+            average += (max - min) / 2;
+            //average += (max - zero_point) + (zero_point - min);
+            //average += zero_point - min;
+            count += 1;
+        }
+
+        if (count)
+        {
+            average /= count;
+            /* I don't know why this is needed. Should be fixed. */
+            average = zero_point - average;
+        }
+    }
+
+    return average;
+}
+
+void pcm_calculate_peaks(int *left, int *right)
+{
+    unsigned short *addr = (unsigned short *)SAR0;
+    long size = MIN(512, BCR0);
+        
+    if (left != NULL)
+        *left = calculate_channel_peak_average(0, addr, size);
+    if (right != NULL)
+        *right = calculate_channel_peak_average(1, addr, size);;
+}
+
 /* sets frequency of input to DAC */
 void pcm_set_frequency(unsigned int frequency)
 {