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rockbox/firmware/pcm_sw_volume.c

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/***************************************************************************
* __________ __ ___.
* Open \______ \ ____ ____ | | _\_ |__ _______ ___
* Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
* Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
* Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
* \/ \/ \/ \/ \/
* $Id$
*
* Copyright (C) 2013 by 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 "pcm.h"
#include "pcm-internal.h"
#include "dsp-util.h"
#include "fixedpoint.h"
#include "pcm_sw_volume.h"
/*
* NOTE: With the addition of 32-bit software scaling to this
* file, sometimes the "size" variable gets a little confusing.
*
* The source buffer (as of right now) is always 16-bit, and the
* destination buffer can potentially be 32-bit. I've tried to
* make it consistent: when passed in a function call, try to use
* the source buffer (16-bit) size.
*/
/* volume factors set by pcm_set_master_volume */
static uint32_t vol_factor_l = 0, vol_factor_r = 0;
#ifdef AUDIOHW_HAVE_PRESCALER
/* prescale factor set by pcm_set_prescaler */
static uint32_t prescale_factor = PCM_FACTOR_UNITY;
#endif /* AUDIOHW_HAVE_PRESCALER */
/* final pcm scaling factors */
static uint32_t pcm_new_factor_l = 0, pcm_new_factor_r = 0;
static uint32_t pcm_factor_l = 0, pcm_factor_r = 0;
static typeof (memcpy) *pcm_scaling_fn = NULL;
/* take care of some defines for 32-bit software vol */
#if (PCM_NATIVE_BITDEPTH > 16) /* >16-bit */
# define HAVE_SWVOL_32
# define PCM_VOL_SAMPLE_SIZE (2 * sizeof (int32_t))
# define PCM_DBL_BUF_SIZE_T int32_t
# if !defined(PCM_DC_OFFSET_VALUE)
/* PCM_DC_OFFSET_VALUE is only needed due to hardware quirk on Eros Q */
# define PCM_DC_OFFSET_VALUE 0
# endif
#else /* 16-BIT */
# define PCM_VOL_SAMPLE_SIZE PCM_SAMPLE_SIZE
# define PCM_DBL_BUF_SIZE_T int16_t
#endif /* 16-BIT */
/***
** Volume scaling routines
** If unbuffered, called externally by pcm driver
**/
/* TODO: #include CPU-optimized routines and move this to /firmware/asm */
#if PCM_SW_VOLUME_FRACBITS <= 16
#define PCM_F_T int32_t
#else
#define PCM_F_T int64_t /* Requires large integer math */
#endif /* PCM_SW_VOLUME_FRACBITS */
/* Scale sample by PCM factor */
static inline int32_t pcm_scale_sample(PCM_F_T f, int32_t s)
{
#if defined(HAVE_SWVOL_32)
return (f * s + PCM_DC_OFFSET_VALUE) >> (32 - PCM_NATIVE_BITDEPTH);
#else
return (f * s) >> PCM_SW_VOLUME_FRACBITS;
#endif
}
/* Either cut (both <= UNITY), no clipping needed */
static void * pcm_scale_buffer_cut(void *dst, const void *src, size_t src_size)
{
PCM_DBL_BUF_SIZE_T *d = dst;
const int16_t *s = src;
uint32_t factor_l = pcm_factor_l, factor_r = pcm_factor_r;
while (src_size)
{
*d++ = pcm_scale_sample(factor_l, *s++);
*d++ = pcm_scale_sample(factor_r, *s++);
src_size -= PCM_SAMPLE_SIZE;
}
return dst;
}
#if !defined(HAVE_SWVOL_32) /* NOTE: 32-bit scaling is hardcoded to the cut function! */
/* Either boost (any > UNITY) requires clipping */
static void * pcm_scale_buffer_boost(void *dst, const void *src, size_t src_size)
{
int16_t *d = dst;
const int16_t *s = src;
uint32_t factor_l = pcm_factor_l, factor_r = pcm_factor_r;
while (src_size)
{
*d++ = clip_sample_16(pcm_scale_sample(factor_l, *s++));
*d++ = clip_sample_16(pcm_scale_sample(factor_r, *s++));
src_size -= PCM_SAMPLE_SIZE;
}
return dst;
}
#endif
/* Transition the volume change smoothly across a frame */
static void * pcm_scale_buffer_trans(void *dst, const void *src, size_t src_size)
{
PCM_DBL_BUF_SIZE_T *d = dst;
const int16_t *s = src;
uint32_t factor_l = pcm_factor_l, factor_r = pcm_factor_r;
/* Transition from the old value to the new value using an inverted cosinus
from PI..0 in order to minimize amplitude-modulated harmonics generation
(zipper effects). */
uint32_t new_factor_l = pcm_new_factor_l;
uint32_t new_factor_r = pcm_new_factor_r;
int32_t diff_l = (int32_t)new_factor_l - (int32_t)factor_l;
int32_t diff_r = (int32_t)new_factor_r - (int32_t)factor_r;
for (size_t done = 0; done < src_size; done += PCM_SAMPLE_SIZE)
{
int32_t sweep = (1 << 14) - fp14_cos(180*done / src_size); /* 0.0..2.0 */
uint32_t f_l = fp_mul(sweep, diff_l, 15) + factor_l;
uint32_t f_r = fp_mul(sweep, diff_r, 15) + factor_r;
#if defined(HAVE_SWVOL_32)
/* do not clip to 16 bits */
*d++ = pcm_scale_sample(f_l, *s++);
*d++ = pcm_scale_sample(f_r, *s++);
#else
*d++ = clip_sample_16(pcm_scale_sample(f_l, *s++));
*d++ = clip_sample_16(pcm_scale_sample(f_r, *s++));
#endif
}
/* Select steady-state operation */
pcm_sync_pcm_factors();
return dst;
}
/* Called by completion routine to scale the next buffer of samples */
#ifndef PCM_SW_VOLUME_UNBUFFERED
static inline
#endif
void pcm_sw_volume_copy_buffer(void *dst, const void *src, size_t src_size)
{
pcm_scaling_fn(dst, src, src_size);
}
/* Assign the new scaling function for normal steady-state operation */
void pcm_sync_pcm_factors(void)
{
uint32_t new_factor_l = pcm_new_factor_l;
uint32_t new_factor_r = pcm_new_factor_r;
pcm_factor_l = new_factor_l;
pcm_factor_r = new_factor_r;
/* NOTE: 32-bit scaling is limited to 0 db <--> -74 db, we will hardcode to cut.
* MEMCPY CANNOT BE USED, because we do need to at minimum multiply each
* sample up to 32-bit size. */
#if defined(HAVE_SWVOL_32)
pcm_scaling_fn = pcm_scale_buffer_cut;
#else
if (new_factor_l == PCM_FACTOR_UNITY &&
new_factor_r == PCM_FACTOR_UNITY)
{
pcm_scaling_fn = memcpy;
}
else if (new_factor_l <= PCM_FACTOR_UNITY &&
new_factor_r <= PCM_FACTOR_UNITY)
{
pcm_scaling_fn = pcm_scale_buffer_cut;
}
else
{
pcm_scaling_fn = pcm_scale_buffer_boost;
}
#endif
}
#ifndef PCM_SW_VOLUME_UNBUFFERED
/* source buffer from client */
static const void * volatile src_buf_addr = NULL;
static size_t volatile src_buf_rem = 0;
#define PCM_PLAY_DBL_BUF_SIZE (PCM_PLAY_DBL_BUF_SAMPLE*PCM_VOL_SAMPLE_SIZE)
/* double buffer and frame length control */
static PCM_DBL_BUF_SIZE_T pcm_dbl_buf[2][PCM_PLAY_DBL_BUF_SAMPLES*2]
PCM_DBL_BUF_BSS MEM_ALIGN_ATTR;
static size_t pcm_dbl_buf_size[2];
static int pcm_dbl_buf_num = 0;
static size_t frame_size;
static unsigned int frame_count, frame_err, frame_frac;
/** Overrides of certain functions in pcm.c and pcm-internal.h **/
bool pcm_play_dma_complete_callback(enum pcm_dma_status status,
const void **addr, size_t *size)
{
/* Check status callback first if error */
if (status < PCM_DMAST_OK)
status = pcm_play_call_status_cb(status);
size_t sz = pcm_dbl_buf_size[pcm_dbl_buf_num];
if (status >= PCM_DMAST_OK && sz)
{
/* Do next chunk */
*addr = pcm_dbl_buf[pcm_dbl_buf_num];
*size = sz;
return true;
}
else
{
/* This is a stop chunk or error */
pcm_play_stop_int();
return false;
}
}
/* Equitably divide large source buffers amongst double buffer frames;
frames smaller than or equal to the double buffer chunk size will play
in one chunk */
static void update_frame_params(size_t size)
{
/* multiply by 2 for 32 bit, optimize away to 1 for 16 bit */
int count = (size * (sizeof(PCM_DBL_BUF_SIZE_T)/sizeof(int16_t))) / PCM_VOL_SAMPLE_SIZE;
frame_count = (count + PCM_PLAY_DBL_BUF_SAMPLES - 1) /
PCM_PLAY_DBL_BUF_SAMPLES;
int perframe = count / frame_count;
frame_size = perframe * PCM_VOL_SAMPLE_SIZE;
frame_frac = count - perframe * frame_count;
frame_err = 0;
}
/* Obtain the next buffer and prepare it for pcm driver playback */
enum pcm_dma_status
pcm_play_dma_status_callback_int(enum pcm_dma_status status)
{
if (status != PCM_DMAST_STARTED)
return status;
/* divide by 2 for 32 bit, optimize away to 1 for 16 bit */
size_t size = pcm_dbl_buf_size[pcm_dbl_buf_num] / (sizeof(PCM_DBL_BUF_SIZE_T)/sizeof(int16_t));
const void *addr = src_buf_addr + size;
size = src_buf_rem - size;
if (size == 0 && pcm_get_more_int(&addr, &size))
{
update_frame_params(size);
pcm_play_call_status_cb(PCM_DMAST_STARTED);
}
src_buf_addr = addr;
src_buf_rem = size;
if (size != 0)
{
/* multiply by 2 for 32 bit, optimize away to 1 for 16 bit */
size = frame_size / (sizeof(PCM_DBL_BUF_SIZE_T)/sizeof(int16_t));
if ((frame_err += frame_frac) >= frame_count)
{
frame_err -= frame_count;
size += PCM_SAMPLE_SIZE;
}
}
pcm_dbl_buf_num ^= 1;
/* multiply by 2 for 32 bit, optimize away to 1 for 16 bit */
pcm_dbl_buf_size[pcm_dbl_buf_num] = size * (sizeof(PCM_DBL_BUF_SIZE_T)/sizeof(int16_t));
pcm_sw_volume_copy_buffer(pcm_dbl_buf[pcm_dbl_buf_num], addr, size);
return PCM_DMAST_OK;
}
/* Prefill double buffer and start pcm driver */
static void start_pcm(bool reframe)
{
/* Smoothed transition might not have happened so sync now */
pcm_sync_pcm_factors();
pcm_dbl_buf_num = 0;
pcm_dbl_buf_size[0] = 0;
if (reframe)
update_frame_params(src_buf_rem);
pcm_play_dma_status_callback(PCM_DMAST_STARTED);
pcm_play_dma_status_callback(PCM_DMAST_STARTED);
pcm_play_dma_start(pcm_dbl_buf[1], pcm_dbl_buf_size[1]);
}
void pcm_play_dma_start_int(const void *addr, size_t size)
{
src_buf_addr = addr;
/* divide by 2 for 32 bit, optimize away to 1 for 16 bit */
src_buf_rem = size / (sizeof(PCM_DBL_BUF_SIZE_T)/sizeof(int16_t));
start_pcm(true);
}
void pcm_play_dma_stop_int(void)
{
pcm_play_dma_stop();
src_buf_addr = NULL;
src_buf_rem = 0;
}
#endif /* PCM_SW_VOLUME_UNBUFFERED */
/** Internal **/
/* Return the scale factor corresponding to the centibel level */
static uint32_t pcm_centibels_to_factor(int volume)
{
if (volume == PCM_MUTE_LEVEL)
return 0; /* mute */
#if defined(HAVE_SWVOL_32)
/*
* 32-bit software volume taken from pcm-alsa.c
*/
volume += 48; /* -42dB .. 0dB => 5dB .. 48dB */
/* NOTE if vol_dB = 5 then vol_shift = 1 but r = 1 so we do vol_shift - 1 >= 0
* otherwise vol_dB >= 0 implies vol_shift >= 2 so vol_shift - 2 >= 0 */
int vol_shift = volume / 3;
int r = volume % 3;
int32_t dig_vol_mult;
if(r == 0)
dig_vol_mult = 1 << vol_shift;
else if(r == 1)
dig_vol_mult = 1 << vol_shift | 1 << (vol_shift - 2);
else
dig_vol_mult = 1 << vol_shift | 1 << (vol_shift - 1);
return dig_vol_mult;
#else /* standard software volume */
/* Centibels -> fixedpoint */
return (uint32_t)fp_factor(fp_div(volume, 10, PCM_SW_VOLUME_FRACBITS),
PCM_SW_VOLUME_FRACBITS);
#endif /* HAVE_SWVOL_32 */
}
/** Public functions **/
/* Produce final pcm scale factor */
static void pcm_sync_prescaler(void)
{
uint32_t factor_l = vol_factor_l;
uint32_t factor_r = vol_factor_r;
#ifdef AUDIOHW_HAVE_PRESCALER
factor_l = fp_mul(prescale_factor, factor_l, PCM_SW_VOLUME_FRACBITS);
factor_r = fp_mul(prescale_factor, factor_r, PCM_SW_VOLUME_FRACBITS);
#endif
pcm_play_lock();
pcm_new_factor_l = MIN(factor_l, PCM_FACTOR_MAX);
pcm_new_factor_r = MIN(factor_r, PCM_FACTOR_MAX);
if (pcm_new_factor_l != pcm_factor_l || pcm_new_factor_r != pcm_factor_r)
pcm_scaling_fn = pcm_scale_buffer_trans;
pcm_play_unlock();
}
#ifdef AUDIOHW_HAVE_PRESCALER
/* Set the prescaler value for all PCM playback */
void pcm_set_prescaler(int prescale)
{
prescale_factor = pcm_centibels_to_factor(-prescale);
pcm_sync_prescaler();
}
#endif /* AUDIOHW_HAVE_PRESCALER */
/* Set the per-channel volume cut/gain for all PCM playback */
void pcm_set_master_volume(int vol_l, int vol_r)
{
vol_factor_l = pcm_centibels_to_factor(vol_l);
vol_factor_r = pcm_centibels_to_factor(vol_r);
pcm_sync_prescaler();
}
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