FFmpeg coverage


Directory: ../../../ffmpeg/
File: src/libavcodec/ffwavesynth.c
Date: 2021-09-22 05:58:22
Exec Total Coverage
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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, uint32_t dt)
117 {
118 uint32_t a, c, t = *s;
119
120 a = LCG_A;
121 c = LCG_C;
122 while (dt) {
123 if (dt & 1)
124 t = a * t + c;
125 c *= a + 1; /* coefficients for a double step */
126 a *= a;
127 dt >>= 1;
128 }
129 *s = t;
130 }
131
132 /* Emulate pink noise by summing white noise at the sampling frequency,
133 * white noise at half the sampling frequency (each value taken twice),
134 * etc., with a total of 8 octaves.
135 * This is known as the Voss-McCartney algorithm. */
136
137 static void pink_fill(struct wavesynth_context *ws)
138 {
139 int32_t vt[7] = { 0 }, v = 0;
140 int i, j;
141
142 ws->pink_pos = 0;
143 if (!ws->pink_need)
144 return;
145 for (i = 0; i < PINK_UNIT; i++) {
146 for (j = 0; j < 7; j++) {
147 if ((i >> j) & 1)
148 break;
149 v -= vt[j];
150 vt[j] = (int32_t)lcg_next(&ws->pink_state) >> 3;
151 v += vt[j];
152 }
153 ws->pink_pool[i] = v + ((int32_t)lcg_next(&ws->pink_state) >> 3);
154 }
155 lcg_next(&ws->pink_state); /* so we use exactly 256 steps */
156 }
157
158 /**
159 * @return (1<<64) * a / b, without overflow, if a < b
160 */
161 static uint64_t frac64(uint64_t a, uint64_t b)
162 {
163 uint64_t r = 0;
164 int i;
165
166 if (b < (uint64_t)1 << 32) { /* b small, use two 32-bits steps */
167 a <<= 32;
168 return ((a / b) << 32) | ((a % b) << 32) / b;
169 }
170 if (b < (uint64_t)1 << 48) { /* b medium, use four 16-bits steps */
171 for (i = 0; i < 4; i++) {
172 a <<= 16;
173 r = (r << 16) | (a / b);
174 a %= b;
175 }
176 return r;
177 }
178 for (i = 63; i >= 0; i--) {
179 if (a >= (uint64_t)1 << 63 || a << 1 >= b) {
180 r |= (uint64_t)1 << i;
181 a = (a << 1) - b;
182 } else {
183 a <<= 1;
184 }
185 }
186 return r;
187 }
188
189 static uint64_t phi_at(struct ws_interval *in, int64_t ts)
190 {
191 uint64_t dt = ts - (uint64_t)in->ts_start;
192 uint64_t dt2 = dt & 1 ? /* dt * (dt - 1) / 2 without overflow */
193 dt * ((dt - 1) >> 1) : (dt >> 1) * (dt - 1);
194 return in->phi0 + dt * in->dphi0 + dt2 * in->ddphi;
195 }
196
197 static void wavesynth_seek(struct wavesynth_context *ws, int64_t ts)
198 {
199 int *last, i;
200 struct ws_interval *in;
201
202 last = &ws->cur_inter;
203 for (i = 0; i < ws->nb_inter; i++) {
204 in = &ws->inter[i];
205 if (ts < in->ts_start)
206 break;
207 if (ts >= in->ts_end)
208 continue;
209 *last = i;
210 last = &in->next;
211 in->phi = phi_at(in, ts);
212 in->dphi = in->dphi0 + (ts - in->ts_start) * in->ddphi;
213 in->amp = in->amp0 + (ts - in->ts_start) * in->damp;
214 }
215 ws->next_inter = i;
216 ws->next_ts = i < ws->nb_inter ? ws->inter[i].ts_start : INF_TS;
217 *last = -1;
218 lcg_seek(&ws->dither_state, (uint32_t)ts - (uint32_t)ws->cur_ts);
219 if (ws->pink_need) {
220 uint64_t pink_ts_cur = (ws->cur_ts + (uint64_t)PINK_UNIT - 1) & ~(PINK_UNIT - 1);
221 uint64_t pink_ts_next = ts & ~(PINK_UNIT - 1);
222 int pos = ts & (PINK_UNIT - 1);
223 lcg_seek(&ws->pink_state, (uint32_t)(pink_ts_next - pink_ts_cur) * 2);
224 if (pos) {
225 pink_fill(ws);
226 ws->pink_pos = pos;
227 } else {
228 ws->pink_pos = PINK_UNIT;
229 }
230 }
231 ws->cur_ts = ts;
232 }
233
234 static int wavesynth_parse_extradata(AVCodecContext *avc)
235 {
236 struct wavesynth_context *ws = avc->priv_data;
237 struct ws_interval *in;
238 uint8_t *edata, *edata_end;
239 int32_t f1, f2, a1, a2;
240 uint32_t phi;
241 int64_t dphi1, dphi2, dt, cur_ts = -0x8000000000000000;
242 int i;
243
244 if (avc->extradata_size < 4)
245 return AVERROR(EINVAL);
246 edata = avc->extradata;
247 edata_end = edata + avc->extradata_size;
248 ws->nb_inter = AV_RL32(edata);
249 edata += 4;
250 if (ws->nb_inter < 0 || (edata_end - edata) / 24 < ws->nb_inter)
251 return AVERROR(EINVAL);
252 ws->inter = av_calloc(ws->nb_inter, sizeof(*ws->inter));
253 if (!ws->inter)
254 return AVERROR(ENOMEM);
255 for (i = 0; i < ws->nb_inter; i++) {
256 in = &ws->inter[i];
257 if (edata_end - edata < 24)
258 return AVERROR(EINVAL);
259 in->ts_start = AV_RL64(edata + 0);
260 in->ts_end = AV_RL64(edata + 8);
261 in->type = AV_RL32(edata + 16);
262 in->channels = AV_RL32(edata + 20);
263 edata += 24;
264 if (in->ts_start < cur_ts ||
265 in->ts_end <= in->ts_start ||
266 (uint64_t)in->ts_end - in->ts_start > INT64_MAX
267 )
268 return AVERROR(EINVAL);
269 cur_ts = in->ts_start;
270 dt = in->ts_end - in->ts_start;
271 switch (in->type) {
272 case WS_SINE:
273 if (edata_end - edata < 20 || avc->sample_rate <= 0)
274 return AVERROR(EINVAL);
275 f1 = AV_RL32(edata + 0);
276 f2 = AV_RL32(edata + 4);
277 a1 = AV_RL32(edata + 8);
278 a2 = AV_RL32(edata + 12);
279 phi = AV_RL32(edata + 16);
280 edata += 20;
281 dphi1 = frac64(f1, (int64_t)avc->sample_rate << 16);
282 dphi2 = frac64(f2, (int64_t)avc->sample_rate << 16);
283 in->dphi0 = dphi1;
284 in->ddphi = (int64_t)(dphi2 - (uint64_t)dphi1) / dt;
285 if (phi & 0x80000000) {
286 phi &= ~0x80000000;
287 if (phi >= i)
288 return AVERROR(EINVAL);
289 in->phi0 = phi_at(&ws->inter[phi], in->ts_start);
290 } else {
291 in->phi0 = (uint64_t)phi << 33;
292 }
293 break;
294 case WS_NOISE:
295 if (edata_end - edata < 8)
296 return AVERROR(EINVAL);
297 a1 = AV_RL32(edata + 0);
298 a2 = AV_RL32(edata + 4);
299 edata += 8;
300 break;
301 default:
302 return AVERROR(EINVAL);
303 }
304 in->amp0 = (uint64_t)a1 << 32;
305 in->damp = (int64_t)(((uint64_t)a2 << 32) - ((uint64_t)a1 << 32)) / dt;
306 }
307 if (edata != edata_end)
308 return AVERROR(EINVAL);
309 return 0;
310 }
311
312 static av_cold int wavesynth_init(AVCodecContext *avc)
313 {
314 struct wavesynth_context *ws = avc->priv_data;
315 int i, r;
316
317 if (avc->channels > WS_MAX_CHANNELS) {
318 av_log(avc, AV_LOG_ERROR,
319 "This implementation is limited to %d channels.\n",
320 WS_MAX_CHANNELS);
321 return AVERROR(EINVAL);
322 }
323 r = wavesynth_parse_extradata(avc);
324 if (r < 0) {
325 av_log(avc, AV_LOG_ERROR, "Invalid intervals definitions.\n");
326 return r;
327 }
328 ws->sin = av_malloc(sizeof(*ws->sin) << SIN_BITS);
329 if (!ws->sin)
330 return AVERROR(ENOMEM);
331 for (i = 0; i < 1 << SIN_BITS; i++)
332 ws->sin[i] = floor(32767 * sin(2 * M_PI * i / (1 << SIN_BITS)));
333 ws->dither_state = MKTAG('D','I','T','H');
334 for (i = 0; i < ws->nb_inter; i++)
335 ws->pink_need += ws->inter[i].type == WS_NOISE;
336 ws->pink_state = MKTAG('P','I','N','K');
337 ws->pink_pos = PINK_UNIT;
338 wavesynth_seek(ws, 0);
339 avc->sample_fmt = AV_SAMPLE_FMT_S16;
340 return 0;
341 }
342
343 static void wavesynth_synth_sample(struct wavesynth_context *ws, int64_t ts,
344 int32_t *channels)
345 {
346 int32_t amp, *cv;
347 unsigned val;
348 struct ws_interval *in;
349 int i, *last, pink;
350 uint32_t c, all_ch = 0;
351
352 i = ws->cur_inter;
353 last = &ws->cur_inter;
354 if (ws->pink_pos == PINK_UNIT)
355 pink_fill(ws);
356 pink = ws->pink_pool[ws->pink_pos++] >> 16;
357 while (i >= 0) {
358 in = &ws->inter[i];
359 i = in->next;
360 if (ts >= in->ts_end) {
361 *last = i;
362 continue;
363 }
364 last = &in->next;
365 amp = in->amp >> 32;
366 in->amp += in->damp;
367 switch (in->type) {
368 case WS_SINE:
369 val = amp * (unsigned)ws->sin[in->phi >> (64 - SIN_BITS)];
370 in->phi += in->dphi;
371 in->dphi += in->ddphi;
372 break;
373 case WS_NOISE:
374 val = amp * (unsigned)pink;
375 break;
376 default:
377 val = 0;
378 }
379 all_ch |= in->channels;
380 for (c = in->channels, cv = channels; c; c >>= 1, cv++)
381 if (c & 1)
382 *cv += (unsigned)val;
383 }
384 val = (int32_t)lcg_next(&ws->dither_state) >> 16;
385 for (c = all_ch, cv = channels; c; c >>= 1, cv++)
386 if (c & 1)
387 *cv += val;
388 }
389
390 static void wavesynth_enter_intervals(struct wavesynth_context *ws, int64_t ts)
391 {
392 int *last, i;
393 struct ws_interval *in;
394
395 last = &ws->cur_inter;
396 for (i = ws->cur_inter; i >= 0; i = ws->inter[i].next)
397 last = &ws->inter[i].next;
398 for (i = ws->next_inter; i < ws->nb_inter; i++) {
399 in = &ws->inter[i];
400 if (ts < in->ts_start)
401 break;
402 if (ts >= in->ts_end)
403 continue;
404 *last = i;
405 last = &in->next;
406 in->phi = in->phi0;
407 in->dphi = in->dphi0;
408 in->amp = in->amp0;
409 }
410 ws->next_inter = i;
411 ws->next_ts = i < ws->nb_inter ? ws->inter[i].ts_start : INF_TS;
412 *last = -1;
413 }
414
415 static int wavesynth_decode(AVCodecContext *avc, void *rframe, int *rgot_frame,
416 AVPacket *packet)
417 {
418 struct wavesynth_context *ws = avc->priv_data;
419 AVFrame *frame = rframe;
420 int64_t ts;
421 int duration;
422 int s, c, r;
423 int16_t *pcm;
424 int32_t channels[WS_MAX_CHANNELS];
425
426 *rgot_frame = 0;
427 if (packet->size != 12)
428 return AVERROR_INVALIDDATA;
429 ts = AV_RL64(packet->data);
430 if (ts != ws->cur_ts)
431 wavesynth_seek(ws, ts);
432 duration = AV_RL32(packet->data + 8);
433 if (duration <= 0)
434 return AVERROR(EINVAL);
435 frame->nb_samples = duration;
436 r = ff_get_buffer(avc, frame, 0);
437 if (r < 0)
438 return r;
439 pcm = (int16_t *)frame->data[0];
440 for (s = 0; s < duration; s++, ts+=(uint64_t)1) {
441 memset(channels, 0, avc->channels * sizeof(*channels));
442 if (ts >= ws->next_ts)
443 wavesynth_enter_intervals(ws, ts);
444 wavesynth_synth_sample(ws, ts, channels);
445 for (c = 0; c < avc->channels; c++)
446 *(pcm++) = channels[c] >> 16;
447 }
448 ws->cur_ts += (uint64_t)duration;
449 *rgot_frame = 1;
450 return packet->size;
451 }
452
453 static av_cold int wavesynth_close(AVCodecContext *avc)
454 {
455 struct wavesynth_context *ws = avc->priv_data;
456
457 av_freep(&ws->sin);
458 av_freep(&ws->inter);
459 return 0;
460 }
461
462 const AVCodec ff_ffwavesynth_decoder = {
463 .name = "wavesynth",
464 .long_name = NULL_IF_CONFIG_SMALL("Wave synthesis pseudo-codec"),
465 .type = AVMEDIA_TYPE_AUDIO,
466 .id = AV_CODEC_ID_FFWAVESYNTH,
467 .priv_data_size = sizeof(struct wavesynth_context),
468 .init = wavesynth_init,
469 .close = wavesynth_close,
470 .decode = wavesynth_decode,
471 .capabilities = AV_CODEC_CAP_DR1,
472 .caps_internal = FF_CODEC_CAP_INIT_THREADSAFE | FF_CODEC_CAP_INIT_CLEANUP,
473 };
474