1 |
3 |
xianfeng |
/*
|
2 |
|
|
* Rate conversion Plug-In
|
3 |
|
|
* Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz>
|
4 |
|
|
*
|
5 |
|
|
*
|
6 |
|
|
* This library is free software; you can redistribute it and/or modify
|
7 |
|
|
* it under the terms of the GNU Library General Public License as
|
8 |
|
|
* published by the Free Software Foundation; either version 2 of
|
9 |
|
|
* the License, or (at your option) any later version.
|
10 |
|
|
*
|
11 |
|
|
* This program is distributed in the hope that it will be useful,
|
12 |
|
|
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
13 |
|
|
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
14 |
|
|
* GNU Library General Public License for more details.
|
15 |
|
|
*
|
16 |
|
|
* You should have received a copy of the GNU Library General Public
|
17 |
|
|
* License along with this library; if not, write to the Free Software
|
18 |
|
|
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
|
19 |
|
|
*
|
20 |
|
|
*/
|
21 |
|
|
|
22 |
|
|
#include <sound/driver.h>
|
23 |
|
|
#include <linux/time.h>
|
24 |
|
|
#include <sound/core.h>
|
25 |
|
|
#include <sound/pcm.h>
|
26 |
|
|
#include "pcm_plugin.h"
|
27 |
|
|
|
28 |
|
|
#define SHIFT 11
|
29 |
|
|
#define BITS (1<<SHIFT)
|
30 |
|
|
#define R_MASK (BITS-1)
|
31 |
|
|
|
32 |
|
|
/*
|
33 |
|
|
* Basic rate conversion plugin
|
34 |
|
|
*/
|
35 |
|
|
|
36 |
|
|
struct rate_channel {
|
37 |
|
|
signed short last_S1;
|
38 |
|
|
signed short last_S2;
|
39 |
|
|
};
|
40 |
|
|
|
41 |
|
|
typedef void (*rate_f)(struct snd_pcm_plugin *plugin,
|
42 |
|
|
const struct snd_pcm_plugin_channel *src_channels,
|
43 |
|
|
struct snd_pcm_plugin_channel *dst_channels,
|
44 |
|
|
int src_frames, int dst_frames);
|
45 |
|
|
|
46 |
|
|
struct rate_priv {
|
47 |
|
|
unsigned int pitch;
|
48 |
|
|
unsigned int pos;
|
49 |
|
|
rate_f func;
|
50 |
|
|
snd_pcm_sframes_t old_src_frames, old_dst_frames;
|
51 |
|
|
struct rate_channel channels[0];
|
52 |
|
|
};
|
53 |
|
|
|
54 |
|
|
static void rate_init(struct snd_pcm_plugin *plugin)
|
55 |
|
|
{
|
56 |
|
|
unsigned int channel;
|
57 |
|
|
struct rate_priv *data = (struct rate_priv *)plugin->extra_data;
|
58 |
|
|
data->pos = 0;
|
59 |
|
|
for (channel = 0; channel < plugin->src_format.channels; channel++) {
|
60 |
|
|
data->channels[channel].last_S1 = 0;
|
61 |
|
|
data->channels[channel].last_S2 = 0;
|
62 |
|
|
}
|
63 |
|
|
}
|
64 |
|
|
|
65 |
|
|
static void resample_expand(struct snd_pcm_plugin *plugin,
|
66 |
|
|
const struct snd_pcm_plugin_channel *src_channels,
|
67 |
|
|
struct snd_pcm_plugin_channel *dst_channels,
|
68 |
|
|
int src_frames, int dst_frames)
|
69 |
|
|
{
|
70 |
|
|
unsigned int pos = 0;
|
71 |
|
|
signed int val;
|
72 |
|
|
signed short S1, S2;
|
73 |
|
|
signed short *src, *dst;
|
74 |
|
|
unsigned int channel;
|
75 |
|
|
int src_step, dst_step;
|
76 |
|
|
int src_frames1, dst_frames1;
|
77 |
|
|
struct rate_priv *data = (struct rate_priv *)plugin->extra_data;
|
78 |
|
|
struct rate_channel *rchannels = data->channels;
|
79 |
|
|
|
80 |
|
|
for (channel = 0; channel < plugin->src_format.channels; channel++) {
|
81 |
|
|
pos = data->pos;
|
82 |
|
|
S1 = rchannels->last_S1;
|
83 |
|
|
S2 = rchannels->last_S2;
|
84 |
|
|
if (!src_channels[channel].enabled) {
|
85 |
|
|
if (dst_channels[channel].wanted)
|
86 |
|
|
snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
|
87 |
|
|
dst_channels[channel].enabled = 0;
|
88 |
|
|
continue;
|
89 |
|
|
}
|
90 |
|
|
dst_channels[channel].enabled = 1;
|
91 |
|
|
src = (signed short *)src_channels[channel].area.addr +
|
92 |
|
|
src_channels[channel].area.first / 8 / 2;
|
93 |
|
|
dst = (signed short *)dst_channels[channel].area.addr +
|
94 |
|
|
dst_channels[channel].area.first / 8 / 2;
|
95 |
|
|
src_step = src_channels[channel].area.step / 8 / 2;
|
96 |
|
|
dst_step = dst_channels[channel].area.step / 8 / 2;
|
97 |
|
|
src_frames1 = src_frames;
|
98 |
|
|
dst_frames1 = dst_frames;
|
99 |
|
|
while (dst_frames1-- > 0) {
|
100 |
|
|
if (pos & ~R_MASK) {
|
101 |
|
|
pos &= R_MASK;
|
102 |
|
|
S1 = S2;
|
103 |
|
|
if (src_frames1-- > 0) {
|
104 |
|
|
S2 = *src;
|
105 |
|
|
src += src_step;
|
106 |
|
|
}
|
107 |
|
|
}
|
108 |
|
|
val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
|
109 |
|
|
if (val < -32768)
|
110 |
|
|
val = -32768;
|
111 |
|
|
else if (val > 32767)
|
112 |
|
|
val = 32767;
|
113 |
|
|
*dst = val;
|
114 |
|
|
dst += dst_step;
|
115 |
|
|
pos += data->pitch;
|
116 |
|
|
}
|
117 |
|
|
rchannels->last_S1 = S1;
|
118 |
|
|
rchannels->last_S2 = S2;
|
119 |
|
|
rchannels++;
|
120 |
|
|
}
|
121 |
|
|
data->pos = pos;
|
122 |
|
|
}
|
123 |
|
|
|
124 |
|
|
static void resample_shrink(struct snd_pcm_plugin *plugin,
|
125 |
|
|
const struct snd_pcm_plugin_channel *src_channels,
|
126 |
|
|
struct snd_pcm_plugin_channel *dst_channels,
|
127 |
|
|
int src_frames, int dst_frames)
|
128 |
|
|
{
|
129 |
|
|
unsigned int pos = 0;
|
130 |
|
|
signed int val;
|
131 |
|
|
signed short S1, S2;
|
132 |
|
|
signed short *src, *dst;
|
133 |
|
|
unsigned int channel;
|
134 |
|
|
int src_step, dst_step;
|
135 |
|
|
int src_frames1, dst_frames1;
|
136 |
|
|
struct rate_priv *data = (struct rate_priv *)plugin->extra_data;
|
137 |
|
|
struct rate_channel *rchannels = data->channels;
|
138 |
|
|
|
139 |
|
|
for (channel = 0; channel < plugin->src_format.channels; ++channel) {
|
140 |
|
|
pos = data->pos;
|
141 |
|
|
S1 = rchannels->last_S1;
|
142 |
|
|
S2 = rchannels->last_S2;
|
143 |
|
|
if (!src_channels[channel].enabled) {
|
144 |
|
|
if (dst_channels[channel].wanted)
|
145 |
|
|
snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
|
146 |
|
|
dst_channels[channel].enabled = 0;
|
147 |
|
|
continue;
|
148 |
|
|
}
|
149 |
|
|
dst_channels[channel].enabled = 1;
|
150 |
|
|
src = (signed short *)src_channels[channel].area.addr +
|
151 |
|
|
src_channels[channel].area.first / 8 / 2;
|
152 |
|
|
dst = (signed short *)dst_channels[channel].area.addr +
|
153 |
|
|
dst_channels[channel].area.first / 8 / 2;
|
154 |
|
|
src_step = src_channels[channel].area.step / 8 / 2;
|
155 |
|
|
dst_step = dst_channels[channel].area.step / 8 / 2;
|
156 |
|
|
src_frames1 = src_frames;
|
157 |
|
|
dst_frames1 = dst_frames;
|
158 |
|
|
while (dst_frames1 > 0) {
|
159 |
|
|
S1 = S2;
|
160 |
|
|
if (src_frames1-- > 0) {
|
161 |
|
|
S1 = *src;
|
162 |
|
|
src += src_step;
|
163 |
|
|
}
|
164 |
|
|
if (pos & ~R_MASK) {
|
165 |
|
|
pos &= R_MASK;
|
166 |
|
|
val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
|
167 |
|
|
if (val < -32768)
|
168 |
|
|
val = -32768;
|
169 |
|
|
else if (val > 32767)
|
170 |
|
|
val = 32767;
|
171 |
|
|
*dst = val;
|
172 |
|
|
dst += dst_step;
|
173 |
|
|
dst_frames1--;
|
174 |
|
|
}
|
175 |
|
|
pos += data->pitch;
|
176 |
|
|
}
|
177 |
|
|
rchannels->last_S1 = S1;
|
178 |
|
|
rchannels->last_S2 = S2;
|
179 |
|
|
rchannels++;
|
180 |
|
|
}
|
181 |
|
|
data->pos = pos;
|
182 |
|
|
}
|
183 |
|
|
|
184 |
|
|
static snd_pcm_sframes_t rate_src_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
|
185 |
|
|
{
|
186 |
|
|
struct rate_priv *data;
|
187 |
|
|
snd_pcm_sframes_t res;
|
188 |
|
|
|
189 |
|
|
snd_assert(plugin != NULL, return -ENXIO);
|
190 |
|
|
if (frames == 0)
|
191 |
|
|
return 0;
|
192 |
|
|
data = (struct rate_priv *)plugin->extra_data;
|
193 |
|
|
if (plugin->src_format.rate < plugin->dst_format.rate) {
|
194 |
|
|
res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
|
195 |
|
|
} else {
|
196 |
|
|
res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);
|
197 |
|
|
}
|
198 |
|
|
if (data->old_src_frames > 0) {
|
199 |
|
|
snd_pcm_sframes_t frames1 = frames, res1 = data->old_dst_frames;
|
200 |
|
|
while (data->old_src_frames < frames1) {
|
201 |
|
|
frames1 >>= 1;
|
202 |
|
|
res1 <<= 1;
|
203 |
|
|
}
|
204 |
|
|
while (data->old_src_frames > frames1) {
|
205 |
|
|
frames1 <<= 1;
|
206 |
|
|
res1 >>= 1;
|
207 |
|
|
}
|
208 |
|
|
if (data->old_src_frames == frames1)
|
209 |
|
|
return res1;
|
210 |
|
|
}
|
211 |
|
|
data->old_src_frames = frames;
|
212 |
|
|
data->old_dst_frames = res;
|
213 |
|
|
return res;
|
214 |
|
|
}
|
215 |
|
|
|
216 |
|
|
static snd_pcm_sframes_t rate_dst_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames)
|
217 |
|
|
{
|
218 |
|
|
struct rate_priv *data;
|
219 |
|
|
snd_pcm_sframes_t res;
|
220 |
|
|
|
221 |
|
|
snd_assert(plugin != NULL, return -ENXIO);
|
222 |
|
|
if (frames == 0)
|
223 |
|
|
return 0;
|
224 |
|
|
data = (struct rate_priv *)plugin->extra_data;
|
225 |
|
|
if (plugin->src_format.rate < plugin->dst_format.rate) {
|
226 |
|
|
res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);
|
227 |
|
|
} else {
|
228 |
|
|
res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
|
229 |
|
|
}
|
230 |
|
|
if (data->old_dst_frames > 0) {
|
231 |
|
|
snd_pcm_sframes_t frames1 = frames, res1 = data->old_src_frames;
|
232 |
|
|
while (data->old_dst_frames < frames1) {
|
233 |
|
|
frames1 >>= 1;
|
234 |
|
|
res1 <<= 1;
|
235 |
|
|
}
|
236 |
|
|
while (data->old_dst_frames > frames1) {
|
237 |
|
|
frames1 <<= 1;
|
238 |
|
|
res1 >>= 1;
|
239 |
|
|
}
|
240 |
|
|
if (data->old_dst_frames == frames1)
|
241 |
|
|
return res1;
|
242 |
|
|
}
|
243 |
|
|
data->old_dst_frames = frames;
|
244 |
|
|
data->old_src_frames = res;
|
245 |
|
|
return res;
|
246 |
|
|
}
|
247 |
|
|
|
248 |
|
|
static snd_pcm_sframes_t rate_transfer(struct snd_pcm_plugin *plugin,
|
249 |
|
|
const struct snd_pcm_plugin_channel *src_channels,
|
250 |
|
|
struct snd_pcm_plugin_channel *dst_channels,
|
251 |
|
|
snd_pcm_uframes_t frames)
|
252 |
|
|
{
|
253 |
|
|
snd_pcm_uframes_t dst_frames;
|
254 |
|
|
struct rate_priv *data;
|
255 |
|
|
|
256 |
|
|
snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
|
257 |
|
|
if (frames == 0)
|
258 |
|
|
return 0;
|
259 |
|
|
#ifdef CONFIG_SND_DEBUG
|
260 |
|
|
{
|
261 |
|
|
unsigned int channel;
|
262 |
|
|
for (channel = 0; channel < plugin->src_format.channels; channel++) {
|
263 |
|
|
snd_assert(src_channels[channel].area.first % 8 == 0 &&
|
264 |
|
|
src_channels[channel].area.step % 8 == 0,
|
265 |
|
|
return -ENXIO);
|
266 |
|
|
snd_assert(dst_channels[channel].area.first % 8 == 0 &&
|
267 |
|
|
dst_channels[channel].area.step % 8 == 0,
|
268 |
|
|
return -ENXIO);
|
269 |
|
|
}
|
270 |
|
|
}
|
271 |
|
|
#endif
|
272 |
|
|
|
273 |
|
|
dst_frames = rate_dst_frames(plugin, frames);
|
274 |
|
|
if (dst_frames > dst_channels[0].frames)
|
275 |
|
|
dst_frames = dst_channels[0].frames;
|
276 |
|
|
data = (struct rate_priv *)plugin->extra_data;
|
277 |
|
|
data->func(plugin, src_channels, dst_channels, frames, dst_frames);
|
278 |
|
|
return dst_frames;
|
279 |
|
|
}
|
280 |
|
|
|
281 |
|
|
static int rate_action(struct snd_pcm_plugin *plugin,
|
282 |
|
|
enum snd_pcm_plugin_action action,
|
283 |
|
|
unsigned long udata)
|
284 |
|
|
{
|
285 |
|
|
snd_assert(plugin != NULL, return -ENXIO);
|
286 |
|
|
switch (action) {
|
287 |
|
|
case INIT:
|
288 |
|
|
case PREPARE:
|
289 |
|
|
rate_init(plugin);
|
290 |
|
|
break;
|
291 |
|
|
default:
|
292 |
|
|
break;
|
293 |
|
|
}
|
294 |
|
|
return 0; /* silenty ignore other actions */
|
295 |
|
|
}
|
296 |
|
|
|
297 |
|
|
int snd_pcm_plugin_build_rate(struct snd_pcm_substream *plug,
|
298 |
|
|
struct snd_pcm_plugin_format *src_format,
|
299 |
|
|
struct snd_pcm_plugin_format *dst_format,
|
300 |
|
|
struct snd_pcm_plugin **r_plugin)
|
301 |
|
|
{
|
302 |
|
|
int err;
|
303 |
|
|
struct rate_priv *data;
|
304 |
|
|
struct snd_pcm_plugin *plugin;
|
305 |
|
|
|
306 |
|
|
snd_assert(r_plugin != NULL, return -ENXIO);
|
307 |
|
|
*r_plugin = NULL;
|
308 |
|
|
|
309 |
|
|
snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
|
310 |
|
|
snd_assert(src_format->channels > 0, return -ENXIO);
|
311 |
|
|
snd_assert(src_format->format == SNDRV_PCM_FORMAT_S16, return -ENXIO);
|
312 |
|
|
snd_assert(dst_format->format == SNDRV_PCM_FORMAT_S16, return -ENXIO);
|
313 |
|
|
snd_assert(src_format->rate != dst_format->rate, return -ENXIO);
|
314 |
|
|
|
315 |
|
|
err = snd_pcm_plugin_build(plug, "rate conversion",
|
316 |
|
|
src_format, dst_format,
|
317 |
|
|
sizeof(struct rate_priv) +
|
318 |
|
|
src_format->channels * sizeof(struct rate_channel),
|
319 |
|
|
&plugin);
|
320 |
|
|
if (err < 0)
|
321 |
|
|
return err;
|
322 |
|
|
data = (struct rate_priv *)plugin->extra_data;
|
323 |
|
|
if (src_format->rate < dst_format->rate) {
|
324 |
|
|
data->pitch = ((src_format->rate << SHIFT) + (dst_format->rate >> 1)) / dst_format->rate;
|
325 |
|
|
data->func = resample_expand;
|
326 |
|
|
} else {
|
327 |
|
|
data->pitch = ((dst_format->rate << SHIFT) + (src_format->rate >> 1)) / src_format->rate;
|
328 |
|
|
data->func = resample_shrink;
|
329 |
|
|
}
|
330 |
|
|
data->pos = 0;
|
331 |
|
|
rate_init(plugin);
|
332 |
|
|
data->old_src_frames = data->old_dst_frames = 0;
|
333 |
|
|
plugin->transfer = rate_transfer;
|
334 |
|
|
plugin->src_frames = rate_src_frames;
|
335 |
|
|
plugin->dst_frames = rate_dst_frames;
|
336 |
|
|
plugin->action = rate_action;
|
337 |
|
|
*r_plugin = plugin;
|
338 |
|
|
return 0;
|
339 |
|
|
}
|