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1da177e4 LT |
1 | /* |
2 | * Rate conversion Plug-In | |
c1017a4c | 3 | * Copyright (c) 1999 by Jaroslav Kysela <perex@perex.cz> |
1da177e4 LT |
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 | ||
1da177e4 LT |
22 | #include <linux/time.h> |
23 | #include <sound/core.h> | |
24 | #include <sound/pcm.h> | |
25 | #include "pcm_plugin.h" | |
26 | ||
27 | #define SHIFT 11 | |
28 | #define BITS (1<<SHIFT) | |
29 | #define R_MASK (BITS-1) | |
30 | ||
31 | /* | |
32 | * Basic rate conversion plugin | |
33 | */ | |
34 | ||
6ac77bc1 | 35 | struct rate_channel { |
1da177e4 LT |
36 | signed short last_S1; |
37 | signed short last_S2; | |
6ac77bc1 | 38 | }; |
1da177e4 | 39 | |
6ac77bc1 TI |
40 | typedef void (*rate_f)(struct snd_pcm_plugin *plugin, |
41 | const struct snd_pcm_plugin_channel *src_channels, | |
42 | struct snd_pcm_plugin_channel *dst_channels, | |
1da177e4 LT |
43 | int src_frames, int dst_frames); |
44 | ||
6ac77bc1 | 45 | struct rate_priv { |
1da177e4 LT |
46 | unsigned int pitch; |
47 | unsigned int pos; | |
48 | rate_f func; | |
1da177e4 | 49 | snd_pcm_sframes_t old_src_frames, old_dst_frames; |
6ac77bc1 TI |
50 | struct rate_channel channels[0]; |
51 | }; | |
1da177e4 | 52 | |
6ac77bc1 | 53 | static void rate_init(struct snd_pcm_plugin *plugin) |
1da177e4 LT |
54 | { |
55 | unsigned int channel; | |
6ac77bc1 | 56 | struct rate_priv *data = (struct rate_priv *)plugin->extra_data; |
1da177e4 LT |
57 | data->pos = 0; |
58 | for (channel = 0; channel < plugin->src_format.channels; channel++) { | |
59 | data->channels[channel].last_S1 = 0; | |
60 | data->channels[channel].last_S2 = 0; | |
61 | } | |
62 | } | |
63 | ||
6ac77bc1 TI |
64 | static void resample_expand(struct snd_pcm_plugin *plugin, |
65 | const struct snd_pcm_plugin_channel *src_channels, | |
66 | struct snd_pcm_plugin_channel *dst_channels, | |
1da177e4 LT |
67 | int src_frames, int dst_frames) |
68 | { | |
69 | unsigned int pos = 0; | |
70 | signed int val; | |
71 | signed short S1, S2; | |
0534ab42 | 72 | signed short *src, *dst; |
1da177e4 LT |
73 | unsigned int channel; |
74 | int src_step, dst_step; | |
75 | int src_frames1, dst_frames1; | |
6ac77bc1 TI |
76 | struct rate_priv *data = (struct rate_priv *)plugin->extra_data; |
77 | struct rate_channel *rchannels = data->channels; | |
1da177e4 LT |
78 | |
79 | for (channel = 0; channel < plugin->src_format.channels; channel++) { | |
80 | pos = data->pos; | |
81 | S1 = rchannels->last_S1; | |
82 | S2 = rchannels->last_S2; | |
83 | if (!src_channels[channel].enabled) { | |
84 | if (dst_channels[channel].wanted) | |
85 | snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format); | |
86 | dst_channels[channel].enabled = 0; | |
87 | continue; | |
88 | } | |
89 | dst_channels[channel].enabled = 1; | |
0534ab42 TI |
90 | src = (signed short *)src_channels[channel].area.addr + |
91 | src_channels[channel].area.first / 8 / 2; | |
92 | dst = (signed short *)dst_channels[channel].area.addr + | |
93 | dst_channels[channel].area.first / 8 / 2; | |
94 | src_step = src_channels[channel].area.step / 8 / 2; | |
95 | dst_step = dst_channels[channel].area.step / 8 / 2; | |
1da177e4 LT |
96 | src_frames1 = src_frames; |
97 | dst_frames1 = dst_frames; | |
98 | while (dst_frames1-- > 0) { | |
99 | if (pos & ~R_MASK) { | |
100 | pos &= R_MASK; | |
101 | S1 = S2; | |
102 | if (src_frames1-- > 0) { | |
0534ab42 | 103 | S2 = *src; |
1da177e4 LT |
104 | src += src_step; |
105 | } | |
106 | } | |
107 | val = S1 + ((S2 - S1) * (signed int)pos) / BITS; | |
108 | if (val < -32768) | |
109 | val = -32768; | |
110 | else if (val > 32767) | |
111 | val = 32767; | |
0534ab42 | 112 | *dst = val; |
1da177e4 LT |
113 | dst += dst_step; |
114 | pos += data->pitch; | |
115 | } | |
116 | rchannels->last_S1 = S1; | |
117 | rchannels->last_S2 = S2; | |
118 | rchannels++; | |
119 | } | |
120 | data->pos = pos; | |
121 | } | |
122 | ||
6ac77bc1 TI |
123 | static void resample_shrink(struct snd_pcm_plugin *plugin, |
124 | const struct snd_pcm_plugin_channel *src_channels, | |
125 | struct snd_pcm_plugin_channel *dst_channels, | |
1da177e4 LT |
126 | int src_frames, int dst_frames) |
127 | { | |
128 | unsigned int pos = 0; | |
129 | signed int val; | |
130 | signed short S1, S2; | |
0534ab42 | 131 | signed short *src, *dst; |
1da177e4 LT |
132 | unsigned int channel; |
133 | int src_step, dst_step; | |
134 | int src_frames1, dst_frames1; | |
6ac77bc1 TI |
135 | struct rate_priv *data = (struct rate_priv *)plugin->extra_data; |
136 | struct rate_channel *rchannels = data->channels; | |
1da177e4 LT |
137 | |
138 | for (channel = 0; channel < plugin->src_format.channels; ++channel) { | |
139 | pos = data->pos; | |
140 | S1 = rchannels->last_S1; | |
141 | S2 = rchannels->last_S2; | |
142 | if (!src_channels[channel].enabled) { | |
143 | if (dst_channels[channel].wanted) | |
144 | snd_pcm_area_silence(&dst_channels[channel].area, 0, dst_frames, plugin->dst_format.format); | |
145 | dst_channels[channel].enabled = 0; | |
146 | continue; | |
147 | } | |
148 | dst_channels[channel].enabled = 1; | |
0534ab42 TI |
149 | src = (signed short *)src_channels[channel].area.addr + |
150 | src_channels[channel].area.first / 8 / 2; | |
151 | dst = (signed short *)dst_channels[channel].area.addr + | |
152 | dst_channels[channel].area.first / 8 / 2; | |
153 | src_step = src_channels[channel].area.step / 8 / 2; | |
154 | dst_step = dst_channels[channel].area.step / 8 / 2; | |
1da177e4 LT |
155 | src_frames1 = src_frames; |
156 | dst_frames1 = dst_frames; | |
157 | while (dst_frames1 > 0) { | |
158 | S1 = S2; | |
159 | if (src_frames1-- > 0) { | |
5370d96f | 160 | S2 = *src; |
1da177e4 LT |
161 | src += src_step; |
162 | } | |
163 | if (pos & ~R_MASK) { | |
164 | pos &= R_MASK; | |
165 | val = S1 + ((S2 - S1) * (signed int)pos) / BITS; | |
166 | if (val < -32768) | |
167 | val = -32768; | |
168 | else if (val > 32767) | |
169 | val = 32767; | |
0534ab42 | 170 | *dst = val; |
1da177e4 LT |
171 | dst += dst_step; |
172 | dst_frames1--; | |
173 | } | |
174 | pos += data->pitch; | |
175 | } | |
176 | rchannels->last_S1 = S1; | |
177 | rchannels->last_S2 = S2; | |
178 | rchannels++; | |
179 | } | |
180 | data->pos = pos; | |
181 | } | |
182 | ||
6ac77bc1 | 183 | static snd_pcm_sframes_t rate_src_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames) |
1da177e4 | 184 | { |
6ac77bc1 | 185 | struct rate_priv *data; |
1da177e4 LT |
186 | snd_pcm_sframes_t res; |
187 | ||
7eaa943c TI |
188 | if (snd_BUG_ON(!plugin)) |
189 | return -ENXIO; | |
1da177e4 LT |
190 | if (frames == 0) |
191 | return 0; | |
6ac77bc1 | 192 | data = (struct rate_priv *)plugin->extra_data; |
1da177e4 LT |
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 | ||
6ac77bc1 | 216 | static snd_pcm_sframes_t rate_dst_frames(struct snd_pcm_plugin *plugin, snd_pcm_uframes_t frames) |
1da177e4 | 217 | { |
6ac77bc1 | 218 | struct rate_priv *data; |
1da177e4 LT |
219 | snd_pcm_sframes_t res; |
220 | ||
7eaa943c TI |
221 | if (snd_BUG_ON(!plugin)) |
222 | return -ENXIO; | |
1da177e4 LT |
223 | if (frames == 0) |
224 | return 0; | |
6ac77bc1 | 225 | data = (struct rate_priv *)plugin->extra_data; |
1da177e4 LT |
226 | if (plugin->src_format.rate < plugin->dst_format.rate) { |
227 | res = (((frames << SHIFT) + (data->pitch / 2)) / data->pitch); | |
228 | } else { | |
229 | res = (((frames * data->pitch) + (BITS/2)) >> SHIFT); | |
230 | } | |
231 | if (data->old_dst_frames > 0) { | |
232 | snd_pcm_sframes_t frames1 = frames, res1 = data->old_src_frames; | |
233 | while (data->old_dst_frames < frames1) { | |
234 | frames1 >>= 1; | |
235 | res1 <<= 1; | |
236 | } | |
237 | while (data->old_dst_frames > frames1) { | |
238 | frames1 <<= 1; | |
239 | res1 >>= 1; | |
240 | } | |
241 | if (data->old_dst_frames == frames1) | |
242 | return res1; | |
243 | } | |
244 | data->old_dst_frames = frames; | |
245 | data->old_src_frames = res; | |
246 | return res; | |
247 | } | |
248 | ||
6ac77bc1 TI |
249 | static snd_pcm_sframes_t rate_transfer(struct snd_pcm_plugin *plugin, |
250 | const struct snd_pcm_plugin_channel *src_channels, | |
251 | struct snd_pcm_plugin_channel *dst_channels, | |
1da177e4 LT |
252 | snd_pcm_uframes_t frames) |
253 | { | |
254 | snd_pcm_uframes_t dst_frames; | |
6ac77bc1 | 255 | struct rate_priv *data; |
1da177e4 | 256 | |
7eaa943c TI |
257 | if (snd_BUG_ON(!plugin || !src_channels || !dst_channels)) |
258 | return -ENXIO; | |
1da177e4 LT |
259 | if (frames == 0) |
260 | return 0; | |
261 | #ifdef CONFIG_SND_DEBUG | |
262 | { | |
263 | unsigned int channel; | |
264 | for (channel = 0; channel < plugin->src_format.channels; channel++) { | |
7eaa943c TI |
265 | if (snd_BUG_ON(src_channels[channel].area.first % 8 || |
266 | src_channels[channel].area.step % 8)) | |
267 | return -ENXIO; | |
268 | if (snd_BUG_ON(dst_channels[channel].area.first % 8 || | |
269 | dst_channels[channel].area.step % 8)) | |
270 | return -ENXIO; | |
1da177e4 LT |
271 | } |
272 | } | |
273 | #endif | |
274 | ||
275 | dst_frames = rate_dst_frames(plugin, frames); | |
276 | if (dst_frames > dst_channels[0].frames) | |
277 | dst_frames = dst_channels[0].frames; | |
6ac77bc1 | 278 | data = (struct rate_priv *)plugin->extra_data; |
1da177e4 LT |
279 | data->func(plugin, src_channels, dst_channels, frames, dst_frames); |
280 | return dst_frames; | |
281 | } | |
282 | ||
6ac77bc1 TI |
283 | static int rate_action(struct snd_pcm_plugin *plugin, |
284 | enum snd_pcm_plugin_action action, | |
47eaebfd | 285 | unsigned long udata) |
1da177e4 | 286 | { |
7eaa943c TI |
287 | if (snd_BUG_ON(!plugin)) |
288 | return -ENXIO; | |
1da177e4 LT |
289 | switch (action) { |
290 | case INIT: | |
291 | case PREPARE: | |
292 | rate_init(plugin); | |
293 | break; | |
294 | default: | |
295 | break; | |
296 | } | |
297 | return 0; /* silenty ignore other actions */ | |
298 | } | |
299 | ||
6ac77bc1 TI |
300 | int snd_pcm_plugin_build_rate(struct snd_pcm_substream *plug, |
301 | struct snd_pcm_plugin_format *src_format, | |
302 | struct snd_pcm_plugin_format *dst_format, | |
303 | struct snd_pcm_plugin **r_plugin) | |
1da177e4 LT |
304 | { |
305 | int err; | |
6ac77bc1 TI |
306 | struct rate_priv *data; |
307 | struct snd_pcm_plugin *plugin; | |
1da177e4 | 308 | |
7eaa943c TI |
309 | if (snd_BUG_ON(!r_plugin)) |
310 | return -ENXIO; | |
1da177e4 LT |
311 | *r_plugin = NULL; |
312 | ||
7eaa943c TI |
313 | if (snd_BUG_ON(src_format->channels != dst_format->channels)) |
314 | return -ENXIO; | |
315 | if (snd_BUG_ON(src_format->channels <= 0)) | |
316 | return -ENXIO; | |
317 | if (snd_BUG_ON(src_format->format != SNDRV_PCM_FORMAT_S16)) | |
318 | return -ENXIO; | |
319 | if (snd_BUG_ON(dst_format->format != SNDRV_PCM_FORMAT_S16)) | |
320 | return -ENXIO; | |
321 | if (snd_BUG_ON(src_format->rate == dst_format->rate)) | |
322 | return -ENXIO; | |
1da177e4 LT |
323 | |
324 | err = snd_pcm_plugin_build(plug, "rate conversion", | |
325 | src_format, dst_format, | |
92bfa664 GS |
326 | struct_size(data, channels, |
327 | src_format->channels), | |
1da177e4 LT |
328 | &plugin); |
329 | if (err < 0) | |
330 | return err; | |
6ac77bc1 | 331 | data = (struct rate_priv *)plugin->extra_data; |
1da177e4 LT |
332 | if (src_format->rate < dst_format->rate) { |
333 | data->pitch = ((src_format->rate << SHIFT) + (dst_format->rate >> 1)) / dst_format->rate; | |
334 | data->func = resample_expand; | |
335 | } else { | |
336 | data->pitch = ((dst_format->rate << SHIFT) + (src_format->rate >> 1)) / src_format->rate; | |
337 | data->func = resample_shrink; | |
338 | } | |
339 | data->pos = 0; | |
340 | rate_init(plugin); | |
341 | data->old_src_frames = data->old_dst_frames = 0; | |
342 | plugin->transfer = rate_transfer; | |
343 | plugin->src_frames = rate_src_frames; | |
344 | plugin->dst_frames = rate_dst_frames; | |
345 | plugin->action = rate_action; | |
346 | *r_plugin = plugin; | |
347 | return 0; | |
348 | } |