/**
* \file pcm/pcm_adpcm.c
* \ingroup PCM_Plugins
* \brief PCM Ima-ADPCM Conversion Plugin Interface
* \author Abramo Bagnara <abramo@alsa-project.org>
* \author Uros Bizjak <uros@kss-loka.si>
* \author Jaroslav Kysela <perex@perex.cz>
* \date 2000-2001
*/
/*
* PCM - Ima-ADPCM conversion
* Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
* Copyright (c) 1999 by Uros Bizjak <uros@kss-loka.si>
* Jaroslav Kysela <perex@perex.cz>
*
* Based on Version 1.2, 18-Dec-92 implementation of Intel/DVI ADPCM code
* by Jack Jansen, CWI, Amsterdam <Jack.Jansen@cwi.nl>, Copyright 1992
* by Stichting Mathematisch Centrum, Amsterdam, The Netherlands.
*
* This library is free software; you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as
* published by the Free Software Foundation; either version 2.1 of
* the License, or (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*
*/
/*
These routines convert 16 bit linear PCM samples to 4 bit ADPCM code
and vice versa. The ADPCM code used is the Intel/DVI ADPCM code which
is being recommended by the IMA Digital Audio Technical Working Group.
The algorithm for this coder was taken from:
Proposal for Standardized Audio Interstreamge Formats,
IMA compatibility project proceedings, Vol 2, Issue 2, May 1992.
- No, this is *not* a G.721 coder/decoder. The algorithm used by G.721
is very complicated, requiring oodles of floating-point ops per
sample (resulting in very poor performance). I have not done any
tests myself but various people have assured my that 721 quality is
actually lower than DVI quality.
- No, it probably isn't a RIFF ADPCM decoder either. Trying to decode
RIFF ADPCM with these routines seems to result in something
recognizable but very distorted.
- No, it is not a CDROM-XA coder either, as far as I know. I haven't
come across a good description of XA yet.
*/
#include "bswap.h"
#include "pcm_local.h"
#include "pcm_plugin.h"
#include "plugin_ops.h"
#ifndef PIC
/* entry for static linking */
const char *_snd_module_pcm_adpcm = "";
#endif
#ifndef DOC_HIDDEN
typedef void (*adpcm_f)(const snd_pcm_channel_area_t *dst_areas,
snd_pcm_uframes_t dst_offset,
const snd_pcm_channel_area_t *src_areas,
snd_pcm_uframes_t src_offset,
unsigned int channels, snd_pcm_uframes_t frames,
unsigned int getputidx,
snd_pcm_adpcm_state_t *states);
typedef struct {
/* This field need to be the first */
snd_pcm_plugin_t plug;
unsigned int getput_idx;
adpcm_f func;
snd_pcm_format_t sformat;
snd_pcm_adpcm_state_t *states;
} snd_pcm_adpcm_t;
#endif
/* First table lookup for Ima-ADPCM quantizer */
static const char IndexAdjust[8] = { -1, -1, -1, -1, 2, 4, 6, 8 };
/* Second table lookup for Ima-ADPCM quantizer */
static const short StepSize[89] = {
7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
};
static char adpcm_encoder(int sl, snd_pcm_adpcm_state_t * state)
{
short diff; /* Difference between sl and predicted sample */
short pred_diff; /* Predicted difference to next sample */
unsigned char sign; /* sign of diff */
short step; /* holds previous StepSize value */
unsigned char adjust_idx; /* Index to IndexAdjust lookup table */
int i;
/* Compute difference to previous predicted value */
diff = sl - state->pred_val;
sign = (diff < 0) ? 0x8 : 0x0;
if (sign) {
diff = -diff;
}
/*
* This code *approximately* computes:
* adjust_idx = diff * 4 / step;
* pred_diff = (adjust_idx + 0.5) * step / 4;
*
* But in shift step bits are dropped. The net result of this is
* that even if you have fast mul/div hardware you cannot put it to
* good use since the fix-up would be too expensive.
*/
step = StepSize[state->step_idx];
/* Divide and clamp */
pred_diff = step >> 3;
for (adjust_idx = 0, i = 0x4; i; i >>= 1, step >>= 1) {
if (diff >= step) {
adjust_idx |= i;
diff -= step;
pred_diff += step;
}
}
/* Update and clamp previous predicted value */
state->pred_val += sign ? -pred_diff : pred_diff;
if (state->pred_val > 32767) {
state->pred_val = 32767;
} else if (state->pred_val < -32768) {
state->pred_val = -32768;
}
/* Update and clamp StepSize lookup table index */
state->step_idx += IndexAdjust[adjust_idx];
if (state->step_idx < 0) {
state->step_idx = 0;
} else if (state->step_idx > 88) {
state->step_idx = 88;
}
return (sign | adjust_idx);
}
static int adpcm_decoder(unsigned char code, snd_pcm_adpcm_state_t * state)
{
short pred_diff; /* Predicted difference to next sample */
short step; /* holds previous StepSize value */
char sign;
int i;
/* Separate sign and magnitude */
sign = code & 0x8;
code &= 0x7;
/*
* Computes pred_diff = (code + 0.5) * step / 4,
* but see comment in adpcm_coder.
*/
step = StepSize[state->step_idx];
/* Compute difference and new predicted value */
pred_diff = step >> 3;
for (i = 0x4; i; i >>= 1, step >>= 1) {
if (code & i) {
pred_diff += step;
}
}
state->pred_val += (sign) ? -pred_diff : pred_diff;
/* Clamp output value */
if (state->pred_val > 32767) {
state->pred_val = 32767;
} else if (state->pred_val < -32768) {
state->pred_val = -32768;
}
/* Find new StepSize index value */
state->step_idx += IndexAdjust[code];
if (state->step_idx < 0) {
state->step_idx = 0;
} else if (state->step_idx > 88) {
state->step_idx = 88;
}
return (state->pred_val);
}
#ifndef DOC_HIDDEN
void snd_pcm_adpcm_decode(const snd_pcm_channel_area_t *dst_areas,
snd_pcm_uframes_t dst_offset,
const snd_pcm_channel_area_t *src_areas,
snd_pcm_uframes_t src_offset,
unsigned int channels, snd_pcm_uframes_t frames,
unsigned int putidx,
snd_pcm_adpcm_state_t *states)
{
#define PUT16_LABELS
#include "plugin_ops.h"
#undef PUT16_LABELS
void *put = put16_labels[putidx];
unsigned int channel;
for (channel = 0; channel < channels; ++channel, ++states) {
const char *src;
int srcbit;
char *dst;
int src_step, srcbit_step, dst_step;
snd_pcm_uframes_t frames1;
const snd_pcm_channel_area_t *src_area = &src_areas[channel];
const snd_pcm_channel_area_t *dst_area = &dst_areas[channel];
srcbit = src_area->first + src_area->step * src_offset;
src = (const char *) src_area->addr + srcbit / 8;
srcbit %= 8;
src_step = src_area->step / 8;
srcbit_step = src_area->step % 8;
dst = snd_pcm_channel_area_addr(dst_area, dst_offset);
dst_step = snd_pcm_channel_area_step(dst_area);
frames1 = frames;
while (frames1-- > 0) {
int16_t sample;
unsigned char v;
if (srcbit)
v = *src & 0x0f;
else
v = (*src >> 4) & 0x0f;
sample = adpcm_decoder(v, states);
goto *put;
#define PUT16_END after
#include "plugin_ops.h"
#undef PUT16_END
after:
src += src_step;
srcbit += srcbit_step;
if (srcbit == 8) {
src++;
srcbit = 0;
}
dst += dst_step;
}
}
}
void snd_pcm_adpcm_encode(const snd_pcm_channel_area_t *dst_areas,
snd_pcm_uframes_t dst_offset,
const snd_pcm_channel_area_t *src_areas,
snd_pcm_uframes_t src_offset,
unsigned int channels, snd_pcm_uframes_t frames,
unsigned int getidx,
snd_pcm_adpcm_state_t *states)
{
#define GET16_LABELS
#include "plugin_ops.h"
#undef GET16_LABELS
void *get = get16_labels[getidx];
unsigned int channel;
int16_t sample = 0;
for (channel = 0; channel < channels; ++channel, ++states) {
const char *src;
char *dst;
int dstbit;
int src_step, dst_step, dstbit_step;
snd_pcm_uframes_t frames1;
const snd_pcm_channel_area_t *src_area = &src_areas[channel];
const snd_pcm_channel_area_t *dst_area = &dst_areas[channel];
src = snd_pcm_channel_area_addr(src_area, src_offset);
src_step = snd_pcm_channel_area_step(src_area);
dstbit = dst_area->first + dst_area->step * dst_offset;
dst = (char *) dst_area->addr + dstbit / 8;
dstbit %= 8;
dst_step = dst_area->step / 8;
dstbit_step = dst_area->step % 8;
frames1 = frames;
while (frames1-- > 0) {
int v;
goto *get;
#define GET16_END after
#include "plugin_ops.h"
#undef GET16_END
after:
v = adpcm_encoder(sample, states);
if (dstbit)
*dst = (*dst & 0xf0) | v;
else
*dst = (*dst & 0x0f) | (v << 4);
src += src_step;
dst += dst_step;
dstbit += dstbit_step;
if (dstbit == 8) {
dst++;
dstbit = 0;
}
}
}
}
#endif
static int snd_pcm_adpcm_hw_refine_cprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
{
snd_pcm_adpcm_t *adpcm = pcm->private_data;
int err;
snd_pcm_access_mask_t access_mask = { SND_PCM_ACCBIT_SHM };
err = _snd_pcm_hw_param_set_mask(params, SND_PCM_HW_PARAM_ACCESS,
&access_mask);
if (err < 0)
return err;
if (adpcm->sformat == SND_PCM_FORMAT_IMA_ADPCM) {
snd_pcm_format_mask_t format_mask = { SND_PCM_FMTBIT_LINEAR };
err = _snd_pcm_hw_param_set_mask(params, SND_PCM_HW_PARAM_FORMAT,
&format_mask);
} else {
err = _snd_pcm_hw_params_set_format(params,
SND_PCM_FORMAT_IMA_ADPCM);
}
if (err < 0)
return err;
err = _snd_pcm_hw_params_set_subformat(params,
SND_PCM_SUBFORMAT_STD);
if (err < 0)
return err;
params->info &= ~(SND_PCM_INFO_MMAP | SND_PCM_INFO_MMAP_VALID);
return 0;
}
static int snd_pcm_adpcm_hw_refine_sprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *sparams)
{
snd_pcm_adpcm_t *adpcm = pcm->private_data;
snd_pcm_access_mask_t saccess_mask = { SND_PCM_ACCBIT_MMAP };
_snd_pcm_hw_params_any(sparams);
_snd_pcm_hw_param_set_mask(sparams, SND_PCM_HW_PARAM_ACCESS,
&saccess_mask);
_snd_pcm_hw_params_set_format(sparams, adpcm->sformat);
_snd_pcm_hw_params_set_subformat(sparams, SND_PCM_SUBFORMAT_STD);
return 0;
}
static int snd_pcm_adpcm_hw_refine_schange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params,
snd_pcm_hw_params_t *sparams)
{
int err;
unsigned int links = (SND_PCM_HW_PARBIT_CHANNELS |
SND_PCM_HW_PARBIT_RATE |
SND_PCM_HW_PARBIT_PERIOD_SIZE |
SND_PCM_HW_PARBIT_BUFFER_SIZE |
SND_PCM_HW_PARBIT_PERIODS |
SND_PCM_HW_PARBIT_PERIOD_TIME |
SND_PCM_HW_PARBIT_BUFFER_TIME |
SND_PCM_HW_PARBIT_TICK_TIME);
err = _snd_pcm_hw_params_refine(sparams, links, params);
if (err < 0)
return err;
return 0;
}
static int snd_pcm_adpcm_hw_refine_cchange(snd_pcm_t *pcm ATTRIBUTE_UNUSED, snd_pcm_hw_params_t *params,
snd_pcm_hw_params_t *sparams)
{
int err;
unsigned int links = (SND_PCM_HW_PARBIT_CHANNELS |
SND_PCM_HW_PARBIT_RATE |
SND_PCM_HW_PARBIT_PERIOD_SIZE |
SND_PCM_HW_PARBIT_BUFFER_SIZE |
SND_PCM_HW_PARBIT_PERIODS |
SND_PCM_HW_PARBIT_PERIOD_TIME |
SND_PCM_HW_PARBIT_BUFFER_TIME |
SND_PCM_HW_PARBIT_TICK_TIME);
err = _snd_pcm_hw_params_refine(params, links, sparams);
if (err < 0)
return err;
return 0;
}
static int snd_pcm_adpcm_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
{
return snd_pcm_hw_refine_slave(pcm, params,
snd_pcm_adpcm_hw_refine_cprepare,
snd_pcm_adpcm_hw_refine_cchange,
snd_pcm_adpcm_hw_refine_sprepare,
snd_pcm_adpcm_hw_refine_schange,
snd_pcm_generic_hw_refine);
}
static int snd_pcm_adpcm_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * params)
{
snd_pcm_adpcm_t *adpcm = pcm->private_data;
snd_pcm_format_t format;
int err = snd_pcm_hw_params_slave(pcm, params,
snd_pcm_adpcm_hw_refine_cchange,
snd_pcm_adpcm_hw_refine_sprepare,
snd_pcm_adpcm_hw_refine_schange,
snd_pcm_generic_hw_params);
if (err < 0)
return err;
err = INTERNAL(snd_pcm_hw_params_get_format)(params, &format);
if (err < 0)
return err;
if (pcm->stream == SND_PCM_STREAM_PLAYBACK) {
if (adpcm->sformat == SND_PCM_FORMAT_IMA_ADPCM) {
adpcm->getput_idx = snd_pcm_linear_get_index(format, SND_PCM_FORMAT_S16);
adpcm->func = snd_pcm_adpcm_encode;
} else {
adpcm->getput_idx = snd_pcm_linear_put_index(SND_PCM_FORMAT_S16, adpcm->sformat);
adpcm->func = snd_pcm_adpcm_decode;
}
} else {
if (adpcm->sformat == SND_PCM_FORMAT_IMA_ADPCM) {
adpcm->getput_idx = snd_pcm_linear_put_index(SND_PCM_FORMAT_S16, format);
adpcm->func = snd_pcm_adpcm_decode;
} else {
adpcm->getput_idx = snd_pcm_linear_get_index(adpcm->sformat, SND_PCM_FORMAT_S16);
adpcm->func = snd_pcm_adpcm_encode;
}
}
assert(!adpcm->states);
adpcm->states = malloc(adpcm->plug.gen.slave->channels * sizeof(*adpcm->states));
if (adpcm->states == NULL)
return -ENOMEM;
return 0;
}
static int snd_pcm_adpcm_hw_free(snd_pcm_t *pcm)
{
snd_pcm_adpcm_t *adpcm = pcm->private_data;
free(adpcm->states);
adpcm->states = NULL;
return snd_pcm_hw_free(adpcm->plug.gen.slave);
}
static int snd_pcm_adpcm_init(snd_pcm_t *pcm)
{
snd_pcm_adpcm_t *adpcm = pcm->private_data;
unsigned int k;
for (k = 0; k < pcm->channels; ++k) {
adpcm->states[k].pred_val = 0;
adpcm->states[k].step_idx = 0;
}
return 0;
}
static snd_pcm_uframes_t
snd_pcm_adpcm_write_areas(snd_pcm_t *pcm,
const snd_pcm_channel_area_t *areas,
snd_pcm_uframes_t offset,
snd_pcm_uframes_t size,
const snd_pcm_channel_area_t *slave_areas,
snd_pcm_uframes_t slave_offset,
snd_pcm_uframes_t *slave_sizep)
{
snd_pcm_adpcm_t *adpcm = pcm->private_data;
if (size > *slave_sizep)
size = *slave_sizep;
adpcm->func(slave_areas, slave_offset,
areas, offset,
pcm->channels, size,
adpcm->getput_idx, adpcm->states);
*slave_sizep = size;
return size;
}
static snd_pcm_uframes_t
snd_pcm_adpcm_read_areas(snd_pcm_t *pcm,
const snd_pcm_channel_area_t *areas,
snd_pcm_uframes_t offset,
snd_pcm_uframes_t size,
const snd_pcm_channel_area_t *slave_areas,
snd_pcm_uframes_t slave_offset,
snd_pcm_uframes_t *slave_sizep)
{
snd_pcm_adpcm_t *adpcm = pcm->private_data;
if (size > *slave_sizep)
size = *slave_sizep;
adpcm->func(areas, offset,
slave_areas, slave_offset,
pcm->channels, size,
adpcm->getput_idx, adpcm->states);
*slave_sizep = size;
return size;
}
static void snd_pcm_adpcm_dump(snd_pcm_t *pcm, snd_output_t *out)
{
snd_pcm_adpcm_t *adpcm = pcm->private_data;
snd_output_printf(out, "Ima-ADPCM conversion PCM (%s)\n",
snd_pcm_format_name(adpcm->sformat));
if (pcm->setup) {
snd_output_printf(out, "Its setup is:\n");
snd_pcm_dump_setup(pcm, out);
}
snd_output_printf(out, "Slave: ");
snd_pcm_dump(adpcm->plug.gen.slave, out);
}
static const snd_pcm_ops_t snd_pcm_adpcm_ops = {
.close = snd_pcm_generic_close,
.info = snd_pcm_generic_info,
.hw_refine = snd_pcm_adpcm_hw_refine,
.hw_params = snd_pcm_adpcm_hw_params,
.hw_free = snd_pcm_adpcm_hw_free,
.sw_params = snd_pcm_generic_sw_params,
.channel_info = snd_pcm_generic_channel_info,
.dump = snd_pcm_adpcm_dump,
.nonblock = snd_pcm_generic_nonblock,
.async = snd_pcm_generic_async,
.mmap = snd_pcm_generic_mmap,
.munmap = snd_pcm_generic_munmap,
.query_chmaps = snd_pcm_generic_query_chmaps,
.get_chmap = snd_pcm_generic_get_chmap,
.set_chmap = snd_pcm_generic_set_chmap,
};
/**
* \brief Creates a new Ima-ADPCM conversion PCM
* \param pcmp Returns created PCM handle
* \param name Name of PCM
* \param sformat Slave (destination) format
* \param slave Slave PCM handle
* \param close_slave When set, the slave PCM handle is closed with copy PCM
* \retval zero on success otherwise a negative error code
* \warning Using of this function might be dangerous in the sense
* of compatibility reasons. The prototype might be freely
* changed in future.
*/
int snd_pcm_adpcm_open(snd_pcm_t **pcmp, const char *name, snd_pcm_format_t sformat, snd_pcm_t *slave, int close_slave)
{
snd_pcm_t *pcm;
snd_pcm_adpcm_t *adpcm;
int err;
assert(pcmp && slave);
if (snd_pcm_format_linear(sformat) != 1 &&
sformat != SND_PCM_FORMAT_IMA_ADPCM)
return -EINVAL;
adpcm = calloc(1, sizeof(snd_pcm_adpcm_t));
if (!adpcm) {
return -ENOMEM;
}
adpcm->sformat = sformat;
snd_pcm_plugin_init(&adpcm->plug);
adpcm->plug.read = snd_pcm_adpcm_read_areas;
adpcm->plug.write = snd_pcm_adpcm_write_areas;
adpcm->plug.init = snd_pcm_adpcm_init;
adpcm->plug.gen.slave = slave;
adpcm->plug.gen.close_slave = close_slave;
err = snd_pcm_new(&pcm, SND_PCM_TYPE_ADPCM, name, slave->stream, slave->mode);
if (err < 0) {
free(adpcm);
return err;
}
pcm->ops = &snd_pcm_adpcm_ops;
pcm->fast_ops = &snd_pcm_plugin_fast_ops;
pcm->private_data = adpcm;
pcm->poll_fd = slave->poll_fd;
pcm->poll_events = slave->poll_events;
pcm->tstamp_type = slave->tstamp_type;
snd_pcm_set_hw_ptr(pcm, &adpcm->plug.hw_ptr, -1, 0);
snd_pcm_set_appl_ptr(pcm, &adpcm->plug.appl_ptr, -1, 0);
*pcmp = pcm;
return 0;
}
/*! \page pcm_plugins
\section pcm_plugins_adpcm Plugin: Ima-ADPCM
This plugin converts Ima-ADPCM samples to linear or linear to Ima-ADPCM samples
from master Ima-ADPCM conversion PCM to given slave PCM. The channel count,
format and rate must match for both of them.
\code
pcm.name {
type adpcm # Ima-ADPCM conversion PCM
slave STR # Slave name
# or
slave { # Slave definition
pcm STR # Slave PCM name
# or
pcm { } # Slave PCM definition
format STR # Slave format
}
}
\endcode
\subsection pcm_plugins_adpcm_funcref Function reference
<UL>
<LI>snd_pcm_adpcm_open()
<LI>_snd_pcm_adpcm_open()
</UL>
*/
/**
* \brief Creates a new Ima-ADPCM conversion PCM
* \param pcmp Returns created PCM handle
* \param name Name of PCM
* \param root Root configuration node
* \param conf Configuration node with copy PCM description
* \param stream Stream type
* \param mode Stream mode
* \retval zero on success otherwise a negative error code
* \warning Using of this function might be dangerous in the sense
* of compatibility reasons. The prototype might be freely
* changed in future.
*/
int _snd_pcm_adpcm_open(snd_pcm_t **pcmp, const char *name,
snd_config_t *root, snd_config_t *conf,
snd_pcm_stream_t stream, int mode)
{
snd_config_iterator_t i, next;
int err;
snd_pcm_t *spcm;
snd_config_t *slave = NULL, *sconf;
snd_pcm_format_t sformat;
snd_config_for_each(i, next, conf) {
snd_config_t *n = snd_config_iterator_entry(i);
const char *id;
if (snd_config_get_id(n, &id) < 0)
continue;
if (snd_pcm_conf_generic_id(id))
continue;
if (strcmp(id, "slave") == 0) {
slave = n;
continue;
}
SNDERR("Unknown field %s", id);
return -EINVAL;
}
if (!slave) {
SNDERR("slave is not defined");
return -EINVAL;
}
err = snd_pcm_slave_conf(root, slave, &sconf, 1,
SND_PCM_HW_PARAM_FORMAT, SCONF_MANDATORY, &sformat);
if (err < 0)
return err;
if (snd_pcm_format_linear(sformat) != 1 &&
sformat != SND_PCM_FORMAT_IMA_ADPCM) {
snd_config_delete(sconf);
SNDERR("invalid slave format");
return -EINVAL;
}
err = snd_pcm_open_slave(&spcm, root, sconf, stream, mode, conf);
snd_config_delete(sconf);
if (err < 0)
return err;
err = snd_pcm_adpcm_open(pcmp, name, sformat, spcm, 1);
if (err < 0)
snd_pcm_close(spcm);
return err;
}
#ifndef DOC_HIDDEN
SND_DLSYM_BUILD_VERSION(_snd_pcm_adpcm_open, SND_PCM_DLSYM_VERSION);
#endif