blob: 9d055e40195d2ecffd99094fa3271f9f30dd6924
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_freep(&ws->inter); |
349 | av_freep(&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_freep(&ws->sin); |
467 | av_freep(&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 = AV_CODEC_CAP_DR1, |
481 | }; |
482 |