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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2005 Miika Pekkarinen
* Copyright (C) 2012 Michael Sevakis
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
* as published by the Free Software Foundation; either version 2
* of the License, or (at your option) any later version.
*
* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
* KIND, either express or implied.
*
****************************************************************************/
#include "config.h"
#include "system.h"
#include "dsp_core.h"
#include "dsp_sample_io.h"
#include "dsp-util.h"
#include <string.h>
#if 0
#include <debug.h>
#else
#undef DEBUGF
#define DEBUGF(...)
#endif
/* May be implemented in here or externally.*/
void sample_output_mono(struct sample_io_data *this,
struct dsp_buffer *src, struct dsp_buffer *dst);
void sample_output_stereo(struct sample_io_data *this,
struct dsp_buffer *src, struct dsp_buffer *dst);
void sample_output_dithered(struct sample_io_data *this,
struct dsp_buffer *src, struct dsp_buffer *dst);
/** Sample output **/
#if !defined(CPU_COLDFIRE) && !defined(CPU_ARM)
/* write mono internal format to output format */
void sample_output_mono(struct sample_io_data *this,
struct dsp_buffer *src, struct dsp_buffer *dst)
{
int count = this->outcount;
const int32_t *s0 = src->p32[0];
int16_t *d = dst->p16out;
int scale = src->format.output_scale;
int32_t dc_bias = 1L << (scale - 1);
do
{
int32_t lr = clip_sample_16((*s0++ + dc_bias) >> scale);
*d++ = lr;
*d++ = lr;
}
while (--count > 0);
}
/* write stereo internal format to output format */
void sample_output_stereo(struct sample_io_data *this,
struct dsp_buffer *src, struct dsp_buffer *dst)
{
int count = this->outcount;
const int32_t *s0 = src->p32[0];
const int32_t *s1 = src->p32[1];
int16_t *d = dst->p16out;
int scale = src->format.output_scale;
int32_t dc_bias = 1L << (scale - 1);
do
{
*d++ = clip_sample_16((*s0++ + dc_bias) >> scale);
*d++ = clip_sample_16((*s1++ + dc_bias) >> scale);
}
while (--count > 0);
}
#endif /* CPU */
/**
* The "dither" code to convert the 24-bit samples produced by libmad was
* taken from the coolplayer project - coolplayer.sourceforge.net
*
* This function handles mono and stereo outputs.
*/
static struct dither_data
{
struct dither_state
{
long error[3]; /* 00h: error term history */
long random; /* 0ch: last random value */
} state[2]; /* 0=left, 1=right */
bool enabled; /* 20h: dithered output enabled */
/* 24h */
} dither_data IBSS_ATTR;
void sample_output_dithered(struct sample_io_data *this,
struct dsp_buffer *src, struct dsp_buffer *dst)
{
int count = this->outcount;
int channels = src->format.num_channels;
int scale = src->format.output_scale;
int32_t dc_bias = 1L << (scale - 1); /* 1/2 bit of significance */
int32_t mask = (1L << scale) - 1; /* Mask of bits quantized away */
for (int ch = 0; ch < channels; ch++)
{
struct dither_state *dither = &dither_data.state[ch];
const int32_t *s = src->p32[ch];
int16_t *d = &dst->p16out[ch];
for (int i = 0; i < count; i++, s++, d += 2)
{
/* Noise shape and bias (for correct rounding later) */
int32_t sample = *s;
sample += dither->error[0] - dither->error[1] + dither->error[2];
dither->error[2] = dither->error[1];
dither->error[1] = dither->error[0] / 2;
int32_t output = sample + dc_bias;
/* Dither, highpass triangle PDF */
int32_t random = dither->random*0x0019660dL + 0x3c6ef35fL;
output += (random & mask) - (dither->random & mask);
dither->random = random;
/* Quantize sample to output range */
output >>= scale;
/* Error feedback of quantization */
dither->error[0] = sample - (output << scale);
/* Clip and store */
*d = clip_sample_16(output);
}
}
if (channels > 1)
return;
/* Have to duplicate left samples into the right channel since
output is interleaved stereo */
int16_t *d = dst->p16out;
do
{
int16_t s = *d++;
*d++ = s;
}
while (--count > 0);
}
/* Initialize the output function for settings and format */
static void dsp_sample_output_format_change(struct sample_io_data *this,
struct dsp_buffer *src,
struct dsp_buffer *dst)
{
static const sample_output_fn_type fns[2][2] =
{
{ sample_output_mono, /* DC-biased quantizing */
sample_output_stereo },
{ sample_output_dithered, /* Tri-PDF dithering */
sample_output_dithered },
};
struct sample_format *format = &src->format;
bool dither = dsp_get_id((void *)this) == CODEC_IDX_AUDIO &&
dither_data.enabled;
int channels = format->num_channels;
DSP_PRINT_FORMAT(DSP Output, -1, *format);
this->output_samples[0] = fns[dither ? 1 : 0][channels - 1];
format_change_ack(format); /* always ack, we're last */
/* The real function mustn't be called with no data */
if (this->outcount > 0)
this->output_samples[0](this, src, dst);
}
void dsp_sample_output_init(struct sample_io_data *this)
{
this->output_samples[0] = sample_output_stereo;
this->output_samples[1] = dsp_sample_output_format_change;
}
/* Flush the dither history */
void dsp_sample_output_flush(struct sample_io_data *this)
{
if (dsp_get_id((void *)this) == CODEC_IDX_AUDIO)
memset(dither_data.state, 0, sizeof (dither_data.state));
}
/** Output settings **/
/* Set the tri-pdf dithered output */
void dsp_dither_enable(bool enable)
{
if (enable == dither_data.enabled)
return;
struct sample_io_data *data = (void *)dsp_get_config(CODEC_IDX_AUDIO);
dsp_sample_output_flush(data);
dither_data.enabled = enable;
data->output_samples[0] = dsp_sample_output_format_change;
}
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