forked from luck/tmp_suning_uos_patched
6ac77bc180
Modules: ALSA<-OSS emulation Remove xxx_t typedefs from the core PCM OSS-emulation codes. Signed-off-by: Takashi Iwai <tiwai@suse.de>
309 lines
9.0 KiB
C
309 lines
9.0 KiB
C
/*
|
|
* Mu-Law conversion Plug-In Interface
|
|
* Copyright (c) 1999 by Jaroslav Kysela <perex@suse.cz>
|
|
* Uros Bizjak <uros@kss-loka.si>
|
|
*
|
|
* Based on reference implementation by Sun Microsystems, Inc.
|
|
*
|
|
* This library is free software; you can redistribute it and/or modify
|
|
* it under the terms of the GNU Library General Public License as
|
|
* published by the Free Software Foundation; either version 2 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 Library General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Library General Public
|
|
* License along with this library; if not, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
|
*
|
|
*/
|
|
|
|
#include <sound/driver.h>
|
|
#include <linux/time.h>
|
|
#include <sound/core.h>
|
|
#include <sound/pcm.h>
|
|
#include "pcm_plugin.h"
|
|
|
|
#define SIGN_BIT (0x80) /* Sign bit for a u-law byte. */
|
|
#define QUANT_MASK (0xf) /* Quantization field mask. */
|
|
#define NSEGS (8) /* Number of u-law segments. */
|
|
#define SEG_SHIFT (4) /* Left shift for segment number. */
|
|
#define SEG_MASK (0x70) /* Segment field mask. */
|
|
|
|
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;
|
|
}
|
|
|
|
#define BIAS (0x84) /* Bias for linear code. */
|
|
|
|
/*
|
|
* linear2ulaw() - 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 linear2ulaw(int pcm_val) /* 2's complement (16-bit range) */
|
|
{
|
|
int mask;
|
|
int seg;
|
|
unsigned char uval;
|
|
|
|
/* Get the sign and the magnitude of the value. */
|
|
if (pcm_val < 0) {
|
|
pcm_val = BIAS - pcm_val;
|
|
mask = 0x7F;
|
|
} else {
|
|
pcm_val += BIAS;
|
|
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)) & 0xF);
|
|
return uval ^ mask;
|
|
}
|
|
|
|
/*
|
|
* ulaw2linear() - 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 ulaw2linear(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 & QUANT_MASK) << 3) + BIAS;
|
|
t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
|
|
|
|
return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
|
|
}
|
|
|
|
/*
|
|
* Basic Mu-Law plugin
|
|
*/
|
|
|
|
typedef void (*mulaw_f)(struct snd_pcm_plugin *plugin,
|
|
const struct snd_pcm_plugin_channel *src_channels,
|
|
struct snd_pcm_plugin_channel *dst_channels,
|
|
snd_pcm_uframes_t frames);
|
|
|
|
struct mulaw_priv {
|
|
mulaw_f func;
|
|
int conv;
|
|
};
|
|
|
|
static void mulaw_decode(struct snd_pcm_plugin *plugin,
|
|
const struct snd_pcm_plugin_channel *src_channels,
|
|
struct snd_pcm_plugin_channel *dst_channels,
|
|
snd_pcm_uframes_t frames)
|
|
{
|
|
#define PUT_S16_LABELS
|
|
#include "plugin_ops.h"
|
|
#undef PUT_S16_LABELS
|
|
struct mulaw_priv *data = (struct mulaw_priv *)plugin->extra_data;
|
|
void *put = put_s16_labels[data->conv];
|
|
int channel;
|
|
int nchannels = plugin->src_format.channels;
|
|
for (channel = 0; channel < nchannels; ++channel) {
|
|
char *src;
|
|
char *dst;
|
|
int src_step, dst_step;
|
|
snd_pcm_uframes_t frames1;
|
|
if (!src_channels[channel].enabled) {
|
|
if (dst_channels[channel].wanted)
|
|
snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
|
|
dst_channels[channel].enabled = 0;
|
|
continue;
|
|
}
|
|
dst_channels[channel].enabled = 1;
|
|
src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
|
|
dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
|
|
src_step = src_channels[channel].area.step / 8;
|
|
dst_step = dst_channels[channel].area.step / 8;
|
|
frames1 = frames;
|
|
while (frames1-- > 0) {
|
|
signed short sample = ulaw2linear(*src);
|
|
goto *put;
|
|
#define PUT_S16_END after
|
|
#include "plugin_ops.h"
|
|
#undef PUT_S16_END
|
|
after:
|
|
src += src_step;
|
|
dst += dst_step;
|
|
}
|
|
}
|
|
}
|
|
|
|
static void mulaw_encode(struct snd_pcm_plugin *plugin,
|
|
const struct snd_pcm_plugin_channel *src_channels,
|
|
struct snd_pcm_plugin_channel *dst_channels,
|
|
snd_pcm_uframes_t frames)
|
|
{
|
|
#define GET_S16_LABELS
|
|
#include "plugin_ops.h"
|
|
#undef GET_S16_LABELS
|
|
struct mulaw_priv *data = (struct mulaw_priv *)plugin->extra_data;
|
|
void *get = get_s16_labels[data->conv];
|
|
int channel;
|
|
int nchannels = plugin->src_format.channels;
|
|
signed short sample = 0;
|
|
for (channel = 0; channel < nchannels; ++channel) {
|
|
char *src;
|
|
char *dst;
|
|
int src_step, dst_step;
|
|
snd_pcm_uframes_t frames1;
|
|
if (!src_channels[channel].enabled) {
|
|
if (dst_channels[channel].wanted)
|
|
snd_pcm_area_silence(&dst_channels[channel].area, 0, frames, plugin->dst_format.format);
|
|
dst_channels[channel].enabled = 0;
|
|
continue;
|
|
}
|
|
dst_channels[channel].enabled = 1;
|
|
src = src_channels[channel].area.addr + src_channels[channel].area.first / 8;
|
|
dst = dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
|
|
src_step = src_channels[channel].area.step / 8;
|
|
dst_step = dst_channels[channel].area.step / 8;
|
|
frames1 = frames;
|
|
while (frames1-- > 0) {
|
|
goto *get;
|
|
#define GET_S16_END after
|
|
#include "plugin_ops.h"
|
|
#undef GET_S16_END
|
|
after:
|
|
*dst = linear2ulaw(sample);
|
|
src += src_step;
|
|
dst += dst_step;
|
|
}
|
|
}
|
|
}
|
|
|
|
static snd_pcm_sframes_t mulaw_transfer(struct snd_pcm_plugin *plugin,
|
|
const struct snd_pcm_plugin_channel *src_channels,
|
|
struct snd_pcm_plugin_channel *dst_channels,
|
|
snd_pcm_uframes_t frames)
|
|
{
|
|
struct mulaw_priv *data;
|
|
|
|
snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
|
|
if (frames == 0)
|
|
return 0;
|
|
#ifdef CONFIG_SND_DEBUG
|
|
{
|
|
unsigned int channel;
|
|
for (channel = 0; channel < plugin->src_format.channels; channel++) {
|
|
snd_assert(src_channels[channel].area.first % 8 == 0 &&
|
|
src_channels[channel].area.step % 8 == 0,
|
|
return -ENXIO);
|
|
snd_assert(dst_channels[channel].area.first % 8 == 0 &&
|
|
dst_channels[channel].area.step % 8 == 0,
|
|
return -ENXIO);
|
|
}
|
|
}
|
|
#endif
|
|
data = (struct mulaw_priv *)plugin->extra_data;
|
|
data->func(plugin, src_channels, dst_channels, frames);
|
|
return frames;
|
|
}
|
|
|
|
int snd_pcm_plugin_build_mulaw(struct snd_pcm_substream *plug,
|
|
struct snd_pcm_plugin_format *src_format,
|
|
struct snd_pcm_plugin_format *dst_format,
|
|
struct snd_pcm_plugin **r_plugin)
|
|
{
|
|
int err;
|
|
struct mulaw_priv *data;
|
|
struct snd_pcm_plugin *plugin;
|
|
struct snd_pcm_plugin_format *format;
|
|
mulaw_f func;
|
|
|
|
snd_assert(r_plugin != NULL, return -ENXIO);
|
|
*r_plugin = NULL;
|
|
|
|
snd_assert(src_format->rate == dst_format->rate, return -ENXIO);
|
|
snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
|
|
|
|
if (dst_format->format == SNDRV_PCM_FORMAT_MU_LAW) {
|
|
format = src_format;
|
|
func = mulaw_encode;
|
|
}
|
|
else if (src_format->format == SNDRV_PCM_FORMAT_MU_LAW) {
|
|
format = dst_format;
|
|
func = mulaw_decode;
|
|
}
|
|
else {
|
|
snd_BUG();
|
|
return -EINVAL;
|
|
}
|
|
snd_assert(snd_pcm_format_linear(format->format) != 0, return -ENXIO);
|
|
|
|
err = snd_pcm_plugin_build(plug, "Mu-Law<->linear conversion",
|
|
src_format, dst_format,
|
|
sizeof(struct mulaw_priv), &plugin);
|
|
if (err < 0)
|
|
return err;
|
|
data = (struct mulaw_priv *)plugin->extra_data;
|
|
data->func = func;
|
|
data->conv = getput_index(format->format);
|
|
snd_assert(data->conv >= 0 && data->conv < 4*2*2, return -EINVAL);
|
|
plugin->transfer = mulaw_transfer;
|
|
*r_plugin = plugin;
|
|
return 0;
|
|
}
|