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1 | /* |
2 | * Wavesynth pseudo-codec | |
3 | * Copyright (c) 2011 Nicolas George | |
4 | * | |
5 | * This file is part of FFmpeg. | |
6 | * | |
7 | * FFmpeg is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU Lesser General Public | |
9 | * License as published by the Free Software Foundation; either | |
10 | * version 2.1 of the License, or (at your option) any later version. | |
11 | * | |
12 | * FFmpeg is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * Lesser General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public | |
18 | * License along with FFmpeg; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
22 | #include "libavutil/intreadwrite.h" | |
23 | #include "libavutil/log.h" | |
24 | #include "avcodec.h" | |
25 | #include "internal.h" | |
26 | ||
27 | ||
28 | #define SIN_BITS 14 | |
29 | #define WS_MAX_CHANNELS 32 | |
30 | #define INF_TS 0x7FFFFFFFFFFFFFFF | |
31 | ||
32 | #define PINK_UNIT 128 | |
33 | ||
34 | /* | |
35 | Format of the extradata and packets | |
36 | ||
37 | THIS INFORMATION IS NOT PART OF THE PUBLIC API OR ABI. | |
38 | IT CAN CHANGE WITHOUT NOTIFICATION. | |
39 | ||
40 | All numbers are in little endian. | |
41 | ||
42 | The codec extradata define a set of intervals with uniform content. | |
43 | Overlapping intervals are added together. | |
44 | ||
45 | extradata: | |
46 | uint32 number of intervals | |
47 | ... intervals | |
48 | ||
49 | interval: | |
50 | int64 start timestamp; time_base must be 1/sample_rate; | |
51 | start timestamps must be in ascending order | |
52 | int64 end timestamp | |
53 | uint32 type | |
54 | uint32 channels mask | |
55 | ... additional information, depends on type | |
56 | ||
57 | sine interval (type fourcc "SINE"): | |
58 | int32 start frequency, in 1/(1<<16) Hz | |
59 | int32 end frequency | |
60 | int32 start amplitude, 1<<16 is the full amplitude | |
61 | int32 end amplitude | |
62 | uint32 start phase, 0 is sin(0), 0x20000000 is sin(pi/2), etc.; | |
63 | n | (1<<31) means to match the phase of previous channel #n | |
64 | ||
65 | pink noise interval (type fourcc "NOIS"): | |
66 | int32 start amplitude | |
67 | int32 end amplitude | |
68 | ||
69 | The input packets encode the time and duration of the requested segment. | |
70 | ||
71 | packet: | |
72 | int64 start timestamp | |
73 | int32 duration | |
74 | ||
75 | */ | |
76 | ||
77 | enum ws_interval_type { | |
78 | WS_SINE = MKTAG('S','I','N','E'), | |
79 | WS_NOISE = MKTAG('N','O','I','S'), | |
80 | }; | |
81 | ||
82 | struct ws_interval { | |
83 | int64_t ts_start, ts_end; | |
84 | uint64_t phi0, dphi0, ddphi; | |
85 | uint64_t amp0, damp; | |
86 | uint64_t phi, dphi, amp; | |
87 | uint32_t channels; | |
88 | enum ws_interval_type type; | |
89 | int next; | |
90 | }; | |
91 | ||
92 | struct wavesynth_context { | |
93 | int64_t cur_ts; | |
94 | int64_t next_ts; | |
95 | int32_t *sin; | |
96 | struct ws_interval *inter; | |
97 | uint32_t dither_state; | |
98 | uint32_t pink_state; | |
99 | int32_t pink_pool[PINK_UNIT]; | |
100 | unsigned pink_need, pink_pos; | |
101 | int nb_inter; | |
102 | int cur_inter; | |
103 | int next_inter; | |
104 | }; | |
105 | ||
106 | #define LCG_A 1284865837 | |
107 | #define LCG_C 4150755663 | |
108 | #define LCG_AI 849225893 /* A*AI = 1 [mod 1<<32] */ | |
109 | ||
110 | static uint32_t lcg_next(uint32_t *s) | |
111 | { | |
112 | *s = *s * LCG_A + LCG_C; | |
113 | return *s; | |
114 | } | |
115 | ||
116 | static void lcg_seek(uint32_t *s, int64_t dt) | |
117 | { | |
118 | uint32_t a, c, t = *s; | |
119 | ||
120 | if (dt >= 0) { | |
121 | a = LCG_A; | |
122 | c = LCG_C; | |
123 | } else { /* coefficients for a step backward */ | |
124 | a = LCG_AI; | |
125 | c = (uint32_t)(LCG_AI * LCG_C); | |
126 | dt = -dt; | |
127 | } | |
128 | while (dt) { | |
129 | if (dt & 1) | |
130 | t = a * t + c; | |
131 | c *= a + 1; /* coefficients for a double step */ | |
132 | a *= a; | |
133 | dt >>= 1; | |
134 | } | |
135 | *s = t; | |
136 | } | |
137 | ||
138 | /* Emulate pink noise by summing white noise at the sampling frequency, | |
139 | * white noise at half the sampling frequency (each value taken twice), | |
140 | * etc., with a total of 8 octaves. | |
141 | * This is known as the Voss-McCartney algorithm. */ | |
142 | ||
143 | static void pink_fill(struct wavesynth_context *ws) | |
144 | { | |
145 | int32_t vt[7] = { 0 }, v = 0; | |
146 | int i, j; | |
147 | ||
148 | ws->pink_pos = 0; | |
149 | if (!ws->pink_need) | |
150 | return; | |
151 | for (i = 0; i < PINK_UNIT; i++) { | |
152 | for (j = 0; j < 7; j++) { | |
153 | if ((i >> j) & 1) | |
154 | break; | |
155 | v -= vt[j]; | |
156 | vt[j] = (int32_t)lcg_next(&ws->pink_state) >> 3; | |
157 | v += vt[j]; | |
158 | } | |
159 | ws->pink_pool[i] = v + ((int32_t)lcg_next(&ws->pink_state) >> 3); | |
160 | } | |
161 | lcg_next(&ws->pink_state); /* so we use exactly 256 steps */ | |
162 | } | |
163 | ||
164 | /** | |
165 | * @return (1<<64) * a / b, without overflow, if a < b | |
166 | */ | |
167 | static uint64_t frac64(uint64_t a, uint64_t b) | |
168 | { | |
169 | uint64_t r = 0; | |
170 | int i; | |
171 | ||
172 | if (b < (uint64_t)1 << 32) { /* b small, use two 32-bits steps */ | |
173 | a <<= 32; | |
174 | return ((a / b) << 32) | ((a % b) << 32) / b; | |
175 | } | |
176 | if (b < (uint64_t)1 << 48) { /* b medium, use four 16-bits steps */ | |
177 | for (i = 0; i < 4; i++) { | |
178 | a <<= 16; | |
179 | r = (r << 16) | (a / b); | |
180 | a %= b; | |
181 | } | |
182 | return r; | |
183 | } | |
184 | for (i = 63; i >= 0; i--) { | |
185 | if (a >= (uint64_t)1 << 63 || a << 1 >= b) { | |
186 | r |= (uint64_t)1 << i; | |
187 | a = (a << 1) - b; | |
188 | } else { | |
189 | a <<= 1; | |
190 | } | |
191 | } | |
192 | return r; | |
193 | } | |
194 | ||
195 | static uint64_t phi_at(struct ws_interval *in, int64_t ts) | |
196 | { | |
197 | uint64_t dt = ts - in->ts_start; | |
198 | uint64_t dt2 = dt & 1 ? /* dt * (dt - 1) / 2 without overflow */ | |
199 | dt * ((dt - 1) >> 1) : (dt >> 1) * (dt - 1); | |
200 | return in->phi0 + dt * in->dphi0 + dt2 * in->ddphi; | |
201 | } | |
202 | ||
203 | static void wavesynth_seek(struct wavesynth_context *ws, int64_t ts) | |
204 | { | |
205 | int *last, i; | |
206 | struct ws_interval *in; | |
207 | ||
208 | last = &ws->cur_inter; | |
209 | for (i = 0; i < ws->nb_inter; i++) { | |
210 | in = &ws->inter[i]; | |
211 | if (ts < in->ts_start) | |
212 | break; | |
213 | if (ts >= in->ts_end) | |
214 | continue; | |
215 | *last = i; | |
216 | last = &in->next; | |
217 | in->phi = phi_at(in, ts); | |
218 | in->dphi = in->dphi0 + (ts - in->ts_start) * in->ddphi; | |
219 | in->amp = in->amp0 + (ts - in->ts_start) * in->damp; | |
220 | } | |
221 | ws->next_inter = i; | |
222 | ws->next_ts = i < ws->nb_inter ? ws->inter[i].ts_start : INF_TS; | |
223 | *last = -1; | |
224 | lcg_seek(&ws->dither_state, ts - ws->cur_ts); | |
225 | if (ws->pink_need) { | |
226 | int64_t pink_ts_cur = (ws->cur_ts + PINK_UNIT - 1) & ~(PINK_UNIT - 1); | |
227 | int64_t pink_ts_next = ts & ~(PINK_UNIT - 1); | |
228 | int pos = ts & (PINK_UNIT - 1); | |
229 | lcg_seek(&ws->pink_state, (pink_ts_next - pink_ts_cur) << 1); | |
230 | if (pos) { | |
231 | pink_fill(ws); | |
232 | ws->pink_pos = pos; | |
233 | } else { | |
234 | ws->pink_pos = PINK_UNIT; | |
235 | } | |
236 | } | |
237 | ws->cur_ts = ts; | |
238 | } | |
239 | ||
240 | static int wavesynth_parse_extradata(AVCodecContext *avc) | |
241 | { | |
242 | struct wavesynth_context *ws = avc->priv_data; | |
243 | struct ws_interval *in; | |
244 | uint8_t *edata, *edata_end; | |
245 | int32_t f1, f2, a1, a2; | |
246 | uint32_t phi; | |
247 | int64_t dphi1, dphi2, dt, cur_ts = -0x8000000000000000; | |
248 | int i; | |
249 | ||
250 | if (avc->extradata_size < 4) | |
251 | return AVERROR(EINVAL); | |
252 | edata = avc->extradata; | |
253 | edata_end = edata + avc->extradata_size; | |
254 | ws->nb_inter = AV_RL32(edata); | |
255 | edata += 4; | |
256 | if (ws->nb_inter < 0) | |
257 | return AVERROR(EINVAL); | |
258 | ws->inter = av_calloc(ws->nb_inter, sizeof(*ws->inter)); | |
259 | if (!ws->inter) | |
260 | return AVERROR(ENOMEM); | |
261 | for (i = 0; i < ws->nb_inter; i++) { | |
262 | in = &ws->inter[i]; | |
263 | if (edata_end - edata < 24) | |
264 | return AVERROR(EINVAL); | |
265 | in->ts_start = AV_RL64(edata + 0); | |
266 | in->ts_end = AV_RL64(edata + 8); | |
267 | in->type = AV_RL32(edata + 16); | |
268 | in->channels = AV_RL32(edata + 20); | |
269 | edata += 24; | |
270 | if (in->ts_start < cur_ts || in->ts_end <= in->ts_start) | |
271 | return AVERROR(EINVAL); | |
272 | cur_ts = in->ts_start; | |
273 | dt = in->ts_end - in->ts_start; | |
274 | switch (in->type) { | |
275 | case WS_SINE: | |
276 | if (edata_end - edata < 20) | |
277 | return AVERROR(EINVAL); | |
278 | f1 = AV_RL32(edata + 0); | |
279 | f2 = AV_RL32(edata + 4); | |
280 | a1 = AV_RL32(edata + 8); | |
281 | a2 = AV_RL32(edata + 12); | |
282 | phi = AV_RL32(edata + 16); | |
283 | edata += 20; | |
284 | dphi1 = frac64(f1, (int64_t)avc->sample_rate << 16); | |
285 | dphi2 = frac64(f2, (int64_t)avc->sample_rate << 16); | |
286 | in->dphi0 = dphi1; | |
287 | in->ddphi = (dphi2 - dphi1) / dt; | |
288 | if (phi & 0x80000000) { | |
289 | phi &= ~0x80000000; | |
290 | if (phi >= i) | |
291 | return AVERROR(EINVAL); | |
292 | in->phi0 = phi_at(&ws->inter[phi], in->ts_start); | |
293 | } else { | |
294 | in->phi0 = (uint64_t)phi << 33; | |
295 | } | |
296 | break; | |
297 | case WS_NOISE: | |
298 | if (edata_end - edata < 8) | |
299 | return AVERROR(EINVAL); | |
300 | a1 = AV_RL32(edata + 0); | |
301 | a2 = AV_RL32(edata + 4); | |
302 | edata += 8; | |
303 | break; | |
304 | default: | |
305 | return AVERROR(EINVAL); | |
306 | } | |
307 | in->amp0 = (int64_t)a1 << 32; | |
308 | in->damp = (((int64_t)a2 << 32) - ((int64_t)a1 << 32)) / dt; | |
309 | } | |
310 | if (edata != edata_end) | |
311 | return AVERROR(EINVAL); | |
312 | return 0; | |
313 | } | |
314 | ||
315 | static av_cold int wavesynth_init(AVCodecContext *avc) | |
316 | { | |
317 | struct wavesynth_context *ws = avc->priv_data; | |
318 | int i, r; | |
319 | ||
320 | if (avc->channels > WS_MAX_CHANNELS) { | |
321 | av_log(avc, AV_LOG_ERROR, | |
322 | "This implementation is limited to %d channels.\n", | |
323 | WS_MAX_CHANNELS); | |
324 | return AVERROR(EINVAL); | |
325 | } | |
326 | r = wavesynth_parse_extradata(avc); | |
327 | if (r < 0) { | |
328 | av_log(avc, AV_LOG_ERROR, "Invalid intervals definitions.\n"); | |
329 | goto fail; | |
330 | } | |
331 | ws->sin = av_malloc(sizeof(*ws->sin) << SIN_BITS); | |
332 | if (!ws->sin) { | |
333 | r = AVERROR(ENOMEM); | |
334 | goto fail; | |
335 | } | |
336 | for (i = 0; i < 1 << SIN_BITS; i++) | |
337 | ws->sin[i] = floor(32767 * sin(2 * M_PI * i / (1 << SIN_BITS))); | |
338 | ws->dither_state = MKTAG('D','I','T','H'); | |
339 | for (i = 0; i < ws->nb_inter; i++) | |
340 | ws->pink_need += ws->inter[i].type == WS_NOISE; | |
341 | ws->pink_state = MKTAG('P','I','N','K'); | |
342 | ws->pink_pos = PINK_UNIT; | |
343 | wavesynth_seek(ws, 0); | |
344 | avc->sample_fmt = AV_SAMPLE_FMT_S16; | |
345 | return 0; | |
346 | ||
347 | fail: | |
348 | av_free(ws->inter); | |
349 | av_free(ws->sin); | |
350 | return r; | |
351 | } | |
352 | ||
353 | static void wavesynth_synth_sample(struct wavesynth_context *ws, int64_t ts, | |
354 | int32_t *channels) | |
355 | { | |
356 | int32_t amp, val, *cv; | |
357 | struct ws_interval *in; | |
358 | int i, *last, pink; | |
359 | uint32_t c, all_ch = 0; | |
360 | ||
361 | i = ws->cur_inter; | |
362 | last = &ws->cur_inter; | |
363 | if (ws->pink_pos == PINK_UNIT) | |
364 | pink_fill(ws); | |
365 | pink = ws->pink_pool[ws->pink_pos++] >> 16; | |
366 | while (i >= 0) { | |
367 | in = &ws->inter[i]; | |
368 | i = in->next; | |
369 | if (ts >= in->ts_end) { | |
370 | *last = i; | |
371 | continue; | |
372 | } | |
373 | last = &in->next; | |
374 | amp = in->amp >> 32; | |
375 | in->amp += in->damp; | |
376 | switch (in->type) { | |
377 | case WS_SINE: | |
378 | val = amp * ws->sin[in->phi >> (64 - SIN_BITS)]; | |
379 | in->phi += in->dphi; | |
380 | in->dphi += in->ddphi; | |
381 | break; | |
382 | case WS_NOISE: | |
383 | val = amp * pink; | |
384 | break; | |
385 | default: | |
386 | val = 0; | |
387 | } | |
388 | all_ch |= in->channels; | |
389 | for (c = in->channels, cv = channels; c; c >>= 1, cv++) | |
390 | if (c & 1) | |
391 | *cv += val; | |
392 | } | |
393 | val = (int32_t)lcg_next(&ws->dither_state) >> 16; | |
394 | for (c = all_ch, cv = channels; c; c >>= 1, cv++) | |
395 | if (c & 1) | |
396 | *cv += val; | |
397 | } | |
398 | ||
399 | static void wavesynth_enter_intervals(struct wavesynth_context *ws, int64_t ts) | |
400 | { | |
401 | int *last, i; | |
402 | struct ws_interval *in; | |
403 | ||
404 | last = &ws->cur_inter; | |
405 | for (i = ws->cur_inter; i >= 0; i = ws->inter[i].next) | |
406 | last = &ws->inter[i].next; | |
407 | for (i = ws->next_inter; i < ws->nb_inter; i++) { | |
408 | in = &ws->inter[i]; | |
409 | if (ts < in->ts_start) | |
410 | break; | |
411 | if (ts >= in->ts_end) | |
412 | continue; | |
413 | *last = i; | |
414 | last = &in->next; | |
415 | in->phi = in->phi0; | |
416 | in->dphi = in->dphi0; | |
417 | in->amp = in->amp0; | |
418 | } | |
419 | ws->next_inter = i; | |
420 | ws->next_ts = i < ws->nb_inter ? ws->inter[i].ts_start : INF_TS; | |
421 | *last = -1; | |
422 | } | |
423 | ||
424 | static int wavesynth_decode(AVCodecContext *avc, void *rframe, int *rgot_frame, | |
425 | AVPacket *packet) | |
426 | { | |
427 | struct wavesynth_context *ws = avc->priv_data; | |
428 | AVFrame *frame = rframe; | |
429 | int64_t ts; | |
430 | int duration; | |
431 | int s, c, r; | |
432 | int16_t *pcm; | |
433 | int32_t channels[WS_MAX_CHANNELS]; | |
434 | ||
435 | *rgot_frame = 0; | |
436 | if (packet->size != 12) | |
437 | return AVERROR_INVALIDDATA; | |
438 | ts = AV_RL64(packet->data); | |
439 | if (ts != ws->cur_ts) | |
440 | wavesynth_seek(ws, ts); | |
441 | duration = AV_RL32(packet->data + 8); | |
442 | if (duration <= 0) | |
443 | return AVERROR(EINVAL); | |
444 | frame->nb_samples = duration; | |
445 | r = ff_get_buffer(avc, frame, 0); | |
446 | if (r < 0) | |
447 | return r; | |
448 | pcm = (int16_t *)frame->data[0]; | |
449 | for (s = 0; s < duration; s++, ts++) { | |
450 | memset(channels, 0, avc->channels * sizeof(*channels)); | |
451 | if (ts >= ws->next_ts) | |
452 | wavesynth_enter_intervals(ws, ts); | |
453 | wavesynth_synth_sample(ws, ts, channels); | |
454 | for (c = 0; c < avc->channels; c++) | |
455 | *(pcm++) = channels[c] >> 16; | |
456 | } | |
457 | ws->cur_ts += duration; | |
458 | *rgot_frame = 1; | |
459 | return packet->size; | |
460 | } | |
461 | ||
462 | static av_cold int wavesynth_close(AVCodecContext *avc) | |
463 | { | |
464 | struct wavesynth_context *ws = avc->priv_data; | |
465 | ||
466 | av_free(ws->sin); | |
467 | av_free(ws->inter); | |
468 | return 0; | |
469 | } | |
470 | ||
471 | AVCodec ff_ffwavesynth_decoder = { | |
472 | .name = "wavesynth", | |
473 | .long_name = NULL_IF_CONFIG_SMALL("Wave synthesis pseudo-codec"), | |
474 | .type = AVMEDIA_TYPE_AUDIO, | |
475 | .id = AV_CODEC_ID_FFWAVESYNTH, | |
476 | .priv_data_size = sizeof(struct wavesynth_context), | |
477 | .init = wavesynth_init, | |
478 | .close = wavesynth_close, | |
479 | .decode = wavesynth_decode, | |
480 | .capabilities = CODEC_CAP_DR1, | |
481 | }; |