Linux kernel mirror (for testing)
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kernel
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linux
1/*
2 * Rate conversion Plug-In
3 * Copyright (c) 1999 by Jaroslav Kysela <perex@suse.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
36typedef struct {
37 signed short last_S1;
38 signed short last_S2;
39} rate_channel_t;
40
41typedef void (*rate_f)(snd_pcm_plugin_t *plugin,
42 const snd_pcm_plugin_channel_t *src_channels,
43 snd_pcm_plugin_channel_t *dst_channels,
44 int src_frames, int dst_frames);
45
46typedef struct rate_private_data {
47 unsigned int pitch;
48 unsigned int pos;
49 rate_f func;
50 int get, put;
51 snd_pcm_sframes_t old_src_frames, old_dst_frames;
52 rate_channel_t channels[0];
53} rate_t;
54
55static void rate_init(snd_pcm_plugin_t *plugin)
56{
57 unsigned int channel;
58 rate_t *data = (rate_t *)plugin->extra_data;
59 data->pos = 0;
60 for (channel = 0; channel < plugin->src_format.channels; channel++) {
61 data->channels[channel].last_S1 = 0;
62 data->channels[channel].last_S2 = 0;
63 }
64}
65
66static void resample_expand(snd_pcm_plugin_t *plugin,
67 const snd_pcm_plugin_channel_t *src_channels,
68 snd_pcm_plugin_channel_t *dst_channels,
69 int src_frames, int dst_frames)
70{
71 unsigned int pos = 0;
72 signed int val;
73 signed short S1, S2;
74 char *src, *dst;
75 unsigned int channel;
76 int src_step, dst_step;
77 int src_frames1, dst_frames1;
78 rate_t *data = (rate_t *)plugin->extra_data;
79 rate_channel_t *rchannels = data->channels;
80
81#define GET_S16_LABELS
82#define PUT_S16_LABELS
83#include "plugin_ops.h"
84#undef GET_S16_LABELS
85#undef PUT_S16_LABELS
86 void *get = get_s16_labels[data->get];
87 void *put = put_s16_labels[data->put];
88 signed short sample = 0;
89
90 for (channel = 0; channel < plugin->src_format.channels; channel++) {
91 pos = data->pos;
92 S1 = rchannels->last_S1;
93 S2 = rchannels->last_S2;
94 if (!src_channels[channel].enabled) {
95 if (dst_channels[channel].wanted)
96 snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
97 dst_channels[channel].enabled = 0;
98 continue;
99 }
100 dst_channels[channel].enabled = 1;
101 src = (char *)src_channels[channel].area.addr + src_channels[channel].area.first / 8;
102 dst = (char *)dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
103 src_step = src_channels[channel].area.step / 8;
104 dst_step = dst_channels[channel].area.step / 8;
105 src_frames1 = src_frames;
106 dst_frames1 = dst_frames;
107 while (dst_frames1-- > 0) {
108 if (pos & ~R_MASK) {
109 pos &= R_MASK;
110 S1 = S2;
111 if (src_frames1-- > 0) {
112 goto *get;
113#define GET_S16_END after_get
114#include "plugin_ops.h"
115#undef GET_S16_END
116 after_get:
117 S2 = sample;
118 src += src_step;
119 }
120 }
121 val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
122 if (val < -32768)
123 val = -32768;
124 else if (val > 32767)
125 val = 32767;
126 sample = val;
127 goto *put;
128#define PUT_S16_END after_put
129#include "plugin_ops.h"
130#undef PUT_S16_END
131 after_put:
132 dst += dst_step;
133 pos += data->pitch;
134 }
135 rchannels->last_S1 = S1;
136 rchannels->last_S2 = S2;
137 rchannels++;
138 }
139 data->pos = pos;
140}
141
142static void resample_shrink(snd_pcm_plugin_t *plugin,
143 const snd_pcm_plugin_channel_t *src_channels,
144 snd_pcm_plugin_channel_t *dst_channels,
145 int src_frames, int dst_frames)
146{
147 unsigned int pos = 0;
148 signed int val;
149 signed short S1, S2;
150 char *src, *dst;
151 unsigned int channel;
152 int src_step, dst_step;
153 int src_frames1, dst_frames1;
154 rate_t *data = (rate_t *)plugin->extra_data;
155 rate_channel_t *rchannels = data->channels;
156
157#define GET_S16_LABELS
158#define PUT_S16_LABELS
159#include "plugin_ops.h"
160#undef GET_S16_LABELS
161#undef PUT_S16_LABELS
162 void *get = get_s16_labels[data->get];
163 void *put = put_s16_labels[data->put];
164 signed short sample = 0;
165
166 for (channel = 0; channel < plugin->src_format.channels; ++channel) {
167 pos = data->pos;
168 S1 = rchannels->last_S1;
169 S2 = rchannels->last_S2;
170 if (!src_channels[channel].enabled) {
171 if (dst_channels[channel].wanted)
172 snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format);
173 dst_channels[channel].enabled = 0;
174 continue;
175 }
176 dst_channels[channel].enabled = 1;
177 src = (char *)src_channels[channel].area.addr + src_channels[channel].area.first / 8;
178 dst = (char *)dst_channels[channel].area.addr + dst_channels[channel].area.first / 8;
179 src_step = src_channels[channel].area.step / 8;
180 dst_step = dst_channels[channel].area.step / 8;
181 src_frames1 = src_frames;
182 dst_frames1 = dst_frames;
183 while (dst_frames1 > 0) {
184 S1 = S2;
185 if (src_frames1-- > 0) {
186 goto *get;
187#define GET_S16_END after_get
188#include "plugin_ops.h"
189#undef GET_S16_END
190 after_get:
191 S2 = sample;
192 src += src_step;
193 }
194 if (pos & ~R_MASK) {
195 pos &= R_MASK;
196 val = S1 + ((S2 - S1) * (signed int)pos) / BITS;
197 if (val < -32768)
198 val = -32768;
199 else if (val > 32767)
200 val = 32767;
201 sample = val;
202 goto *put;
203#define PUT_S16_END after_put
204#include "plugin_ops.h"
205#undef PUT_S16_END
206 after_put:
207 dst += dst_step;
208 dst_frames1--;
209 }
210 pos += data->pitch;
211 }
212 rchannels->last_S1 = S1;
213 rchannels->last_S2 = S2;
214 rchannels++;
215 }
216 data->pos = pos;
217}
218
219static snd_pcm_sframes_t rate_src_frames(snd_pcm_plugin_t *plugin, snd_pcm_uframes_t frames)
220{
221 rate_t *data;
222 snd_pcm_sframes_t res;
223
224 snd_assert(plugin != NULL, return -ENXIO);
225 if (frames == 0)
226 return 0;
227 data = (rate_t *)plugin->extra_data;
228 if (plugin->src_format.rate < plugin->dst_format.rate) {
229 res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
230 } else {
231 res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);
232 }
233 if (data->old_src_frames > 0) {
234 snd_pcm_sframes_t frames1 = frames, res1 = data->old_dst_frames;
235 while (data->old_src_frames < frames1) {
236 frames1 >>= 1;
237 res1 <<= 1;
238 }
239 while (data->old_src_frames > frames1) {
240 frames1 <<= 1;
241 res1 >>= 1;
242 }
243 if (data->old_src_frames == frames1)
244 return res1;
245 }
246 data->old_src_frames = frames;
247 data->old_dst_frames = res;
248 return res;
249}
250
251static snd_pcm_sframes_t rate_dst_frames(snd_pcm_plugin_t *plugin, snd_pcm_uframes_t frames)
252{
253 rate_t *data;
254 snd_pcm_sframes_t res;
255
256 snd_assert(plugin != NULL, return -ENXIO);
257 if (frames == 0)
258 return 0;
259 data = (rate_t *)plugin->extra_data;
260 if (plugin->src_format.rate < plugin->dst_format.rate) {
261 res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch);
262 } else {
263 res = (((frames * data->pitch) + (BITS/2)) >> SHIFT);
264 }
265 if (data->old_dst_frames > 0) {
266 snd_pcm_sframes_t frames1 = frames, res1 = data->old_src_frames;
267 while (data->old_dst_frames < frames1) {
268 frames1 >>= 1;
269 res1 <<= 1;
270 }
271 while (data->old_dst_frames > frames1) {
272 frames1 <<= 1;
273 res1 >>= 1;
274 }
275 if (data->old_dst_frames == frames1)
276 return res1;
277 }
278 data->old_dst_frames = frames;
279 data->old_src_frames = res;
280 return res;
281}
282
283static snd_pcm_sframes_t rate_transfer(snd_pcm_plugin_t *plugin,
284 const snd_pcm_plugin_channel_t *src_channels,
285 snd_pcm_plugin_channel_t *dst_channels,
286 snd_pcm_uframes_t frames)
287{
288 snd_pcm_uframes_t dst_frames;
289 rate_t *data;
290
291 snd_assert(plugin != NULL && src_channels != NULL && dst_channels != NULL, return -ENXIO);
292 if (frames == 0)
293 return 0;
294#ifdef CONFIG_SND_DEBUG
295 {
296 unsigned int channel;
297 for (channel = 0; channel < plugin->src_format.channels; channel++) {
298 snd_assert(src_channels[channel].area.first % 8 == 0 &&
299 src_channels[channel].area.step % 8 == 0,
300 return -ENXIO);
301 snd_assert(dst_channels[channel].area.first % 8 == 0 &&
302 dst_channels[channel].area.step % 8 == 0,
303 return -ENXIO);
304 }
305 }
306#endif
307
308 dst_frames = rate_dst_frames(plugin, frames);
309 if (dst_frames > dst_channels[0].frames)
310 dst_frames = dst_channels[0].frames;
311 data = (rate_t *)plugin->extra_data;
312 data->func(plugin, src_channels, dst_channels, frames, dst_frames);
313 return dst_frames;
314}
315
316static int rate_action(snd_pcm_plugin_t *plugin,
317 snd_pcm_plugin_action_t action,
318 unsigned long udata ATTRIBUTE_UNUSED)
319{
320 snd_assert(plugin != NULL, return -ENXIO);
321 switch (action) {
322 case INIT:
323 case PREPARE:
324 rate_init(plugin);
325 break;
326 default:
327 break;
328 }
329 return 0; /* silenty ignore other actions */
330}
331
332int snd_pcm_plugin_build_rate(snd_pcm_plug_t *plug,
333 snd_pcm_plugin_format_t *src_format,
334 snd_pcm_plugin_format_t *dst_format,
335 snd_pcm_plugin_t **r_plugin)
336{
337 int err;
338 rate_t *data;
339 snd_pcm_plugin_t *plugin;
340
341 snd_assert(r_plugin != NULL, return -ENXIO);
342 *r_plugin = NULL;
343
344 snd_assert(src_format->channels == dst_format->channels, return -ENXIO);
345 snd_assert(src_format->channels > 0, return -ENXIO);
346 snd_assert(snd_pcm_format_linear(src_format->format) != 0, return -ENXIO);
347 snd_assert(snd_pcm_format_linear(dst_format->format) != 0, return -ENXIO);
348 snd_assert(src_format->rate != dst_format->rate, return -ENXIO);
349
350 err = snd_pcm_plugin_build(plug, "rate conversion",
351 src_format, dst_format,
352 sizeof(rate_t) + src_format->channels * sizeof(rate_channel_t),
353 &plugin);
354 if (err < 0)
355 return err;
356 data = (rate_t *)plugin->extra_data;
357 data->get = getput_index(src_format->format);
358 snd_assert(data->get >= 0 && data->get < 4*2*2, return -EINVAL);
359 data->put = getput_index(dst_format->format);
360 snd_assert(data->put >= 0 && data->put < 4*2*2, return -EINVAL);
361
362 if (src_format->rate < dst_format->rate) {
363 data->pitch = ((src_format->rate << SHIFT) + (dst_format->rate >> 1)) / dst_format->rate;
364 data->func = resample_expand;
365 } else {
366 data->pitch = ((dst_format->rate << SHIFT) + (src_format->rate >> 1)) / src_format->rate;
367 data->func = resample_shrink;
368 }
369 data->pos = 0;
370 rate_init(plugin);
371 data->old_src_frames = data->old_dst_frames = 0;
372 plugin->transfer = rate_transfer;
373 plugin->src_frames = rate_src_frames;
374 plugin->dst_frames = rate_dst_frames;
375 plugin->action = rate_action;
376 *r_plugin = plugin;
377 return 0;
378}