/**
* \file pcm/pcm_mulaw.c
* \ingroup PCM_Plugins
* \brief PCM Mu-Law Conversion Plugin Interface
* \author Abramo Bagnara <abramo@alsa-project.org>
* \date 2000-2001
*/
/*
* PCM - Mu-Law conversion
* Copyright (c) 2000 by Abramo Bagnara <abramo@alsa-project.org>
*
*
* 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
*
*/
#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_mulaw = "";
#endif
#ifndef DOC_HIDDEN
typedef void (*mulaw_f)(const snd_pcm_channel_area_t *src_areas,
snd_pcm_uframes_t src_offset,
const snd_pcm_channel_area_t *dst_areas,
snd_pcm_uframes_t dst_offset,
unsigned int channels, snd_pcm_uframes_t frames,
unsigned int getputidx);
typedef struct {
/* This field need to be the first */
snd_pcm_plugin_t plug;
unsigned int getput_idx;
mulaw_f func;
snd_pcm_format_t sformat;
} snd_pcm_mulaw_t;
#endif
static inline int val_seg(int val)
{
int r = 0;
val >>= 7;
if (val & 0xf0) {
val >>= 4;
r += 4;
}
if (val & 0x0c) {
val >>= 2;
r += 2;
}
if (val & 0x02)
r += 1;
return r;
}
/*
* s16_to_ulaw() - Convert a linear PCM value to u-law
*
* In order to simplify the encoding process, the original linear magnitude
* is biased by adding 33 which shifts the encoding range from (0 - 8158) to
* (33 - 8191). The result can be seen in the following encoding table:
*
* Biased Linear Input Code Compressed Code
* ------------------------ ---------------
* 00000001wxyza 000wxyz
* 0000001wxyzab 001wxyz
* 000001wxyzabc 010wxyz
* 00001wxyzabcd 011wxyz
* 0001wxyzabcde 100wxyz
* 001wxyzabcdef 101wxyz
* 01wxyzabcdefg 110wxyz
* 1wxyzabcdefgh 111wxyz
*
* Each biased linear code has a leading 1 which identifies the segment
* number. The value of the segment number is equal to 7 minus the number
* of leading 0's. The quantization interval is directly available as the
* four bits wxyz. * The trailing bits (a - h) are ignored.
*
* Ordinarily the complement of the resulting code word is used for
* transmission, and so the code word is complemented before it is returned.
*
* For further information see John C. Bellamy's Digital Telephony, 1982,
* John Wiley & Sons, pps 98-111 and 472-476.
*/
static unsigned char s16_to_ulaw(int pcm_val) /* 2's complement (16-bit range) */
{
int mask;
int seg;
unsigned char uval;
if (pcm_val < 0) {
pcm_val = 0x84 - pcm_val;
mask = 0x7f;
} else {
pcm_val += 0x84;
mask = 0xff;
}
if (pcm_val > 0x7fff)
pcm_val = 0x7fff;
/* Convert the scaled magnitude to segment number. */
seg = val_seg(pcm_val);
/*
* Combine the sign, segment, quantization bits;
* and complement the code word.
*/
uval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0x0f);
return uval ^ mask;
}
/*
* ulaw_to_s16() - Convert a u-law value to 16-bit linear PCM
*
* First, a biased linear code is derived from the code word. An unbiased
* output can then be obtained by subtracting 33 from the biased code.
*
* Note that this function expects to be passed the complement of the
* original code word. This is in keeping with ISDN conventions.
*/
static int ulaw_to_s16(unsigned char u_val)
{
int t;
/* Complement to obtain normal u-law value. */
u_val = ~u_val;
/*
* Extract and bias the quantization bits. Then
* shift up by the segment number and subtract out the bias.
*/
t = ((u_val & 0x0f) << 3) + 0x84;
t <<= (u_val & 0x70) >> 4;
return ((u_val & 0x80) ? (0x84 - t) : (t - 0x84));
}
#ifndef DOC_HIDDEN
void snd_pcm_mulaw_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)
{
#define PUT16_LABELS
#include "plugin_ops.h"
#undef PUT16_LABELS
void *put = put16_labels[putidx];
unsigned int channel;
for (channel = 0; channel < channels; ++channel) {
const unsigned char *src;
char *dst;
int src_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];
src = snd_pcm_channel_area_addr(src_area, src_offset);
dst = snd_pcm_channel_area_addr(dst_area, dst_offset);
src_step = snd_pcm_channel_area_step(src_area);
dst_step = snd_pcm_channel_area_step(dst_area);
frames1 = frames;
while (frames1-- > 0) {
int16_t sample = ulaw_to_s16(*src);
goto *put;
#define PUT16_END after
#include "plugin_ops.h"
#undef PUT16_END
after:
src += src_step;
dst += dst_step;
}
}
}
void snd_pcm_mulaw_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)
{
#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) {
const char *src;
char *dst;
int src_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];
src = snd_pcm_channel_area_addr(src_area, src_offset);
dst = snd_pcm_channel_area_addr(dst_area, dst_offset);
src_step = snd_pcm_channel_area_step(src_area);
dst_step = snd_pcm_channel_area_step(dst_area);
frames1 = frames;
while (frames1-- > 0) {
goto *get;
#define GET16_END after
#include "plugin_ops.h"
#undef GET16_END
after:
*dst = s16_to_ulaw(sample);
src += src_step;
dst += dst_step;
}
}
}
#endif /* DOC_HIDDEN */
static int snd_pcm_mulaw_hw_refine_cprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
{
snd_pcm_mulaw_t *mulaw = 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 (mulaw->sformat == SND_PCM_FORMAT_MU_LAW) {
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_MU_LAW);
}
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_mulaw_hw_refine_sprepare(snd_pcm_t *pcm, snd_pcm_hw_params_t *sparams)
{
snd_pcm_mulaw_t *mulaw = 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, mulaw->sformat);
_snd_pcm_hw_params_set_subformat(sparams, SND_PCM_SUBFORMAT_STD);
return 0;
}
static int snd_pcm_mulaw_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_mulaw_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_mulaw_hw_refine(snd_pcm_t *pcm, snd_pcm_hw_params_t *params)
{
return snd_pcm_hw_refine_slave(pcm, params,
snd_pcm_mulaw_hw_refine_cprepare,
snd_pcm_mulaw_hw_refine_cchange,
snd_pcm_mulaw_hw_refine_sprepare,
snd_pcm_mulaw_hw_refine_schange,
snd_pcm_generic_hw_refine);
}
static int snd_pcm_mulaw_hw_params(snd_pcm_t *pcm, snd_pcm_hw_params_t * params)
{
snd_pcm_mulaw_t *mulaw = pcm->private_data;
snd_pcm_format_t format;
int err = snd_pcm_hw_params_slave(pcm, params,
snd_pcm_mulaw_hw_refine_cchange,
snd_pcm_mulaw_hw_refine_sprepare,
snd_pcm_mulaw_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 (mulaw->sformat == SND_PCM_FORMAT_MU_LAW) {
mulaw->getput_idx = snd_pcm_linear_get_index(format, SND_PCM_FORMAT_S16);
mulaw->func = snd_pcm_mulaw_encode;
} else {
mulaw->getput_idx = snd_pcm_linear_put_index(SND_PCM_FORMAT_S16, mulaw->sformat);
mulaw->func = snd_pcm_mulaw_decode;
}
} else {
if (mulaw->sformat == SND_PCM_FORMAT_MU_LAW) {
mulaw->getput_idx = snd_pcm_linear_put_index(SND_PCM_FORMAT_S16, format);
mulaw->func = snd_pcm_mulaw_decode;
} else {
mulaw->getput_idx = snd_pcm_linear_get_index(mulaw->sformat, SND_PCM_FORMAT_S16);
mulaw->func = snd_pcm_mulaw_encode;
}
}
return 0;
}
static snd_pcm_uframes_t
snd_pcm_mulaw_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_mulaw_t *mulaw = pcm->private_data;
if (size > *slave_sizep)
size = *slave_sizep;
mulaw->func(slave_areas, slave_offset,
areas, offset,
pcm->channels, size,
mulaw->getput_idx);
*slave_sizep = size;
return size;
}
static snd_pcm_uframes_t
snd_pcm_mulaw_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_mulaw_t *mulaw = pcm->private_data;
if (size > *slave_sizep)
size = *slave_sizep;
mulaw->func(areas, offset,
slave_areas, slave_offset,
pcm->channels, size,
mulaw->getput_idx);
*slave_sizep = size;
return size;
}
static void snd_pcm_mulaw_dump(snd_pcm_t *pcm, snd_output_t *out)
{
snd_pcm_mulaw_t *mulaw = pcm->private_data;
snd_output_printf(out, "Mu-Law conversion PCM (%s)\n",
snd_pcm_format_name(mulaw->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(mulaw->plug.gen.slave, out);
}
static const snd_pcm_ops_t snd_pcm_mulaw_ops = {
.close = snd_pcm_generic_close,
.info = snd_pcm_generic_info,
.hw_refine = snd_pcm_mulaw_hw_refine,
.hw_params = snd_pcm_mulaw_hw_params,
.hw_free = snd_pcm_generic_hw_free,
.sw_params = snd_pcm_generic_sw_params,
.channel_info = snd_pcm_generic_channel_info,
.dump = snd_pcm_mulaw_dump,
.nonblock = snd_pcm_generic_nonblock,
.async = snd_pcm_generic_async,
.mmap = snd_pcm_generic_mmap,
.munmap = snd_pcm_generic_munmap,
.get_chmap = snd_pcm_generic_get_chmap,
.set_chmap = snd_pcm_generic_set_chmap,
};
/**
* \brief Creates a new Mu-Law 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_mulaw_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_mulaw_t *mulaw;
int err;
assert(pcmp && slave);
if (snd_pcm_format_linear(sformat) != 1 &&
sformat != SND_PCM_FORMAT_MU_LAW)
return -EINVAL;
mulaw = calloc(1, sizeof(snd_pcm_mulaw_t));
if (!mulaw) {
return -ENOMEM;
}
snd_pcm_plugin_init(&mulaw->plug);
mulaw->sformat = sformat;
mulaw->plug.read = snd_pcm_mulaw_read_areas;
mulaw->plug.write = snd_pcm_mulaw_write_areas;
mulaw->plug.undo_read = snd_pcm_plugin_undo_read_generic;
mulaw->plug.undo_write = snd_pcm_plugin_undo_write_generic;
mulaw->plug.gen.slave = slave;
mulaw->plug.gen.close_slave = close_slave;
err = snd_pcm_new(&pcm, SND_PCM_TYPE_MULAW, name, slave->stream, slave->mode);
if (err < 0) {
free(mulaw);
return err;
}
pcm->ops = &snd_pcm_mulaw_ops;
pcm->fast_ops = &snd_pcm_plugin_fast_ops;
pcm->private_data = mulaw;
pcm->poll_fd = slave->poll_fd;
pcm->poll_events = slave->poll_events;
pcm->tstamp_type = slave->tstamp_type;
snd_pcm_set_hw_ptr(pcm, &mulaw->plug.hw_ptr, -1, 0);
snd_pcm_set_appl_ptr(pcm, &mulaw->plug.appl_ptr, -1, 0);
*pcmp = pcm;
return 0;
}
/*! \page pcm_plugins
\section pcm_plugins_mulaw Plugin: Mu-Law
This plugin converts Mu-Law samples to linear or linear to Mu-Law samples
from master Mu-Law conversion PCM to given slave PCM. The channel count,
format and rate must match for both of them.
\code
pcm.name {
type mulaw # Mu-Law 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_mulaw_funcref Function reference
<UL>
<LI>snd_pcm_mulaw_open()
<LI>_snd_pcm_mulaw_open()
</UL>
*/
/**
* \brief Creates a new Mu-Law 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_mulaw_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_MU_LAW) {
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_mulaw_open(pcmp, name, sformat, spcm, 1);
if (err < 0)
snd_pcm_close(spcm);
return err;
}
#ifndef DOC_HIDDEN
SND_DLSYM_BUILD_VERSION(_snd_pcm_mulaw_open, SND_PCM_DLSYM_VERSION);
#endif