diff options
Diffstat (limited to 'firmware')
| -rw-r--r-- | firmware/pcm_playback.c | 113 |
1 files changed, 107 insertions, 6 deletions
diff --git a/firmware/pcm_playback.c b/firmware/pcm_playback.c index 16e8f5e3af..7382661f48 100644 --- a/firmware/pcm_playback.c +++ b/firmware/pcm_playback.c @@ -98,6 +98,8 @@ size_t pcm_get_bytes_waiting(void) static int pcm_freq = 0x6; /* 44.1 is default */ +int peak_left = 0, peak_right = 0; + /* Set up the DMA transfer that kicks in when the audio FIFO gets empty */ static void dma_start(const void *addr, size_t size) { @@ -205,7 +207,6 @@ void DMA0(void) SAR0 = (unsigned long)next_start; /* Source address */ BCR0 = next_size; /* Bytes to transfer */ DCR0 |= DMA_EEXT; - } else { @@ -846,6 +847,109 @@ bool pcm_is_paused(void) { return pcm_paused; } + +#if defined(CPU_COLDFIRE) +/* Peaks ahead in the DMA buffer based upon the calling period to + attempt to compensate for the delay. Keeps a moving average of + length four. */ +void pcm_calculate_peaks(int *left, int *right) +{ + unsigned long samples; + unsigned long *addr, *end; + long peak_p, peak_n; + + static unsigned long last_peak_tick = 0; + static unsigned long frame_period = 0; + + /* Throttled peak ahead based on calling period */ + unsigned long period = current_tick - last_peak_tick; + + /* Keep reasonable limits on period */ + if (period < 1) + period = 1; + else if (period > HZ/5) + period = HZ/5; + + frame_period = (3*frame_period + period) >> 2; + + last_peak_tick = current_tick; + + if (!pcm_playing || pcm_paused) + { + peak_left = peak_right = 0; + goto peak_done; + } + + samples = (BCR0 & 0xffffff) >> 2; + addr = (long *)(SAR0 & ~3); + samples = MIN(frame_period*44100/HZ, samples); + end = addr + samples; + peak_p = peak_n = 0; + + if (left && right) + { + if (samples > 0) + { + long peak_rp = 0, peak_rn = 0; + + do + { + long value = *addr; + long ch; + + ch = value >> 16; + if (ch > peak_p) peak_p = ch; + else if (ch < peak_n) peak_n = ch; + + ch = (short)value; + if (ch > peak_rp) peak_rp = ch; + else if (ch < peak_rn) peak_rn = ch; + + addr += 4; + } + while (addr < end); + + peak_left = MAX(peak_p, -peak_n); + peak_right = MAX(peak_rp, -peak_rn); + } + } + else if (left || right) + { + if (samples > 0) + { + if (left) + { + /* Put left channel in low word */ + addr = (long *)((short *)addr - 1); + end = (long *)((short *)end - 1); + } + + do + { + long value = *(short *)addr; + + if (value > peak_p) peak_p = value; + else if (value < peak_n) peak_n = value; + + addr += 4; + } + while (addr < end); + + if (left) + peak_left = MAX(peak_p, -peak_n); + else + peak_right = MAX(peak_p, -peak_n); + } + } + +peak_done: + if (left) + *left = peak_left; + + if (right) + *right = peak_right; +} +#else /* * 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 @@ -860,7 +964,6 @@ bool pcm_is_paused(void) { /* Up to 1/50th of a second of audio for peak calculation */ /* This should use NATIVE_FREQUENCY, or eventually an adjustable freq. value */ #define PEAK_SAMPLES (44100/50) - void pcm_calculate_peaks(int *left, int *right) { #if (CONFIG_CPU == S3C2440) @@ -870,10 +973,7 @@ void pcm_calculate_peaks(int *left, int *right) short *addr; short *end; { -#ifdef CPU_COLDFIRE - size_t samples = (BCR0 & 0xffffff) / 4; - addr = (short *) (SAR0 & ~3); -#elif defined(HAVE_WM8975) || defined(HAVE_WM8758) \ +#if defined(HAVE_WM8975) || defined(HAVE_WM8758) \ || defined(HAVE_WM8731) || defined(HAVE_WM8721) \ || (CONFIG_CPU == PNX0101) size_t samples = p_size / 4; @@ -931,3 +1031,4 @@ void pcm_calculate_peaks(int *left, int *right) } #endif } +#endif /* CPU_COLDFIRE */ |