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iPod: Enable peakmeter

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git-svn-id: svn://svn.rockbox.org/rockbox/trunk@8516 a1c6a512-1295-4272-9138-f99709370657
This commit is contained in:
Dave Chapman 2006-02-01 00:17:36 +00:00
parent 5fff854126
commit b4bc9fd068
1 changed files with 72 additions and 70 deletions
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142
firmware/pcm_playback.c
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@ -107,70 +107,6 @@ static void dma_stop(void)
pcm_paused = false;
}
/*
* 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 = (BCR0 & 0xffffff) / 4;
short *addr = (short *) (SAR0 & ~3);
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;
}
}
/* sets frequency of input to DAC */
void pcm_set_frequency(unsigned int frequency)
{
@ -510,12 +446,6 @@ bool pcm_is_playing(void)
return pcm_playing;
}
void pcm_calculate_peaks(int *left, int *right)
{
*left=0;
*right=0;
}
long pcm_get_bytes_waiting(void)
{
return size;
@ -578,3 +508,75 @@ long pcm_get_bytes_waiting(void)
}
#endif
#if CONFIG_CPU != PNX0101
/*
* 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)
{
#ifdef HAVE_UDA1380
long samples = (BCR0 & 0xffffff) / 4;
short *addr = (short *) (SAR0 & ~3);
#elif defined(HAVE_WM8975)
long samples = size / 4;
short *addr = p;
#endif
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;
}
}
#endif