forked from python/cpython
-
Notifications
You must be signed in to change notification settings - Fork 0
/
Copy pathaudioop.c
1891 lines (1622 loc) · 56.2 KB
/
audioop.c
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
/* audioopmodule - Module to detect peak values in arrays */
#define PY_SSIZE_T_CLEAN
#include "Python.h"
typedef short PyInt16;
#if defined(__CHAR_UNSIGNED__)
#if defined(signed)
/* This module currently does not work on systems where only unsigned
characters are available. Take it out of Setup. Sorry. */
#endif
#endif
static const int maxvals[] = {0, 0x7F, 0x7FFF, 0x7FFFFF, 0x7FFFFFFF};
/* -1 trick is needed on Windows to support -0x80000000 without a warning */
static const int minvals[] = {0, -0x80, -0x8000, -0x800000, -0x7FFFFFFF-1};
static const unsigned int masks[] = {0, 0xFF, 0xFFFF, 0xFFFFFF, 0xFFFFFFFF};
static int
fbound(double val, double minval, double maxval)
{
if (val > maxval)
val = maxval;
else if (val < minval + 1)
val = minval;
return (int)val;
}
/* Code shamelessly stolen from sox, 12.17.7, g711.c
** (c) Craig Reese, Joe Campbell and Jeff Poskanzer 1989 */
/* From g711.c:
*
* December 30, 1994:
* Functions linear2alaw, linear2ulaw have been updated to correctly
* convert unquantized 16 bit values.
* Tables for direct u- to A-law and A- to u-law conversions have been
* corrected.
* Borge Lindberg, Center for PersonKommunikation, Aalborg University.
* bli@cpk.auc.dk
*
*/
#define BIAS 0x84 /* define the add-in bias for 16 bit samples */
#define CLIP 32635
#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
#define QUANT_MASK (0xf) /* Quantization field mask. */
#define SEG_SHIFT (4) /* Left shift for segment number. */
#define SEG_MASK (0x70) /* Segment field mask. */
static PyInt16 seg_aend[8] = {0x1F, 0x3F, 0x7F, 0xFF,
0x1FF, 0x3FF, 0x7FF, 0xFFF};
static PyInt16 seg_uend[8] = {0x3F, 0x7F, 0xFF, 0x1FF,
0x3FF, 0x7FF, 0xFFF, 0x1FFF};
static PyInt16
search(PyInt16 val, PyInt16 *table, int size)
{
int i;
for (i = 0; i < size; i++) {
if (val <= *table++)
return (i);
}
return (size);
}
#define st_ulaw2linear16(uc) (_st_ulaw2linear16[uc])
#define st_alaw2linear16(uc) (_st_alaw2linear16[uc])
static PyInt16 _st_ulaw2linear16[256] = {
-32124, -31100, -30076, -29052, -28028, -27004, -25980,
-24956, -23932, -22908, -21884, -20860, -19836, -18812,
-17788, -16764, -15996, -15484, -14972, -14460, -13948,
-13436, -12924, -12412, -11900, -11388, -10876, -10364,
-9852, -9340, -8828, -8316, -7932, -7676, -7420,
-7164, -6908, -6652, -6396, -6140, -5884, -5628,
-5372, -5116, -4860, -4604, -4348, -4092, -3900,
-3772, -3644, -3516, -3388, -3260, -3132, -3004,
-2876, -2748, -2620, -2492, -2364, -2236, -2108,
-1980, -1884, -1820, -1756, -1692, -1628, -1564,
-1500, -1436, -1372, -1308, -1244, -1180, -1116,
-1052, -988, -924, -876, -844, -812, -780,
-748, -716, -684, -652, -620, -588, -556,
-524, -492, -460, -428, -396, -372, -356,
-340, -324, -308, -292, -276, -260, -244,
-228, -212, -196, -180, -164, -148, -132,
-120, -112, -104, -96, -88, -80, -72,
-64, -56, -48, -40, -32, -24, -16,
-8, 0, 32124, 31100, 30076, 29052, 28028,
27004, 25980, 24956, 23932, 22908, 21884, 20860,
19836, 18812, 17788, 16764, 15996, 15484, 14972,
14460, 13948, 13436, 12924, 12412, 11900, 11388,
10876, 10364, 9852, 9340, 8828, 8316, 7932,
7676, 7420, 7164, 6908, 6652, 6396, 6140,
5884, 5628, 5372, 5116, 4860, 4604, 4348,
4092, 3900, 3772, 3644, 3516, 3388, 3260,
3132, 3004, 2876, 2748, 2620, 2492, 2364,
2236, 2108, 1980, 1884, 1820, 1756, 1692,
1628, 1564, 1500, 1436, 1372, 1308, 1244,
1180, 1116, 1052, 988, 924, 876, 844,
812, 780, 748, 716, 684, 652, 620,
588, 556, 524, 492, 460, 428, 396,
372, 356, 340, 324, 308, 292, 276,
260, 244, 228, 212, 196, 180, 164,
148, 132, 120, 112, 104, 96, 88,
80, 72, 64, 56, 48, 40, 32,
24, 16, 8, 0
};
/*
* linear2ulaw() accepts a 14-bit signed integer and encodes it as u-law data
* stored in a unsigned char. This function should only be called with
* the data shifted such that it only contains information in the lower
* 14-bits.
*
* In order to simplify the encoding process, the original linear magnitude
* is biased by adding 33 which shifts the encoding range from (0 - 8158) to
* (33 - 8191). The result can be seen in the following encoding table:
*
* Biased Linear Input Code Compressed Code
* ------------------------ ---------------
* 00000001wxyza 000wxyz
* 0000001wxyzab 001wxyz
* 000001wxyzabc 010wxyz
* 00001wxyzabcd 011wxyz
* 0001wxyzabcde 100wxyz
* 001wxyzabcdef 101wxyz
* 01wxyzabcdefg 110wxyz
* 1wxyzabcdefgh 111wxyz
*
* Each biased linear code has a leading 1 which identifies the segment
* number. The value of the segment number is equal to 7 minus the number
* of leading 0's. The quantization interval is directly available as the
* four bits wxyz. * The trailing bits (a - h) are ignored.
*
* Ordinarily the complement of the resulting code word is used for
* transmission, and so the code word is complemented before it is returned.
*
* For further information see John C. Bellamy's Digital Telephony, 1982,
* John Wiley & Sons, pps 98-111 and 472-476.
*/
static unsigned char
st_14linear2ulaw(PyInt16 pcm_val) /* 2's complement (14-bit range) */
{
PyInt16 mask;
PyInt16 seg;
unsigned char uval;
/* u-law inverts all bits */
/* Get the sign and the magnitude of the value. */
if (pcm_val < 0) {
pcm_val = -pcm_val;
mask = 0x7F;
} else {
mask = 0xFF;
}
if ( pcm_val > CLIP ) pcm_val = CLIP; /* clip the magnitude */
pcm_val += (BIAS >> 2);
/* Convert the scaled magnitude to segment number. */
seg = search(pcm_val, seg_uend, 8);
/*
* Combine the sign, segment, quantization bits;
* and complement the code word.
*/
if (seg >= 8) /* out of range, return maximum value. */
return (unsigned char) (0x7F ^ mask);
else {
uval = (unsigned char) (seg << 4) | ((pcm_val >> (seg + 1)) & 0xF);
return (uval ^ mask);
}
}
static PyInt16 _st_alaw2linear16[256] = {
-5504, -5248, -6016, -5760, -4480, -4224, -4992,
-4736, -7552, -7296, -8064, -7808, -6528, -6272,
-7040, -6784, -2752, -2624, -3008, -2880, -2240,
-2112, -2496, -2368, -3776, -3648, -4032, -3904,
-3264, -3136, -3520, -3392, -22016, -20992, -24064,
-23040, -17920, -16896, -19968, -18944, -30208, -29184,
-32256, -31232, -26112, -25088, -28160, -27136, -11008,
-10496, -12032, -11520, -8960, -8448, -9984, -9472,
-15104, -14592, -16128, -15616, -13056, -12544, -14080,
-13568, -344, -328, -376, -360, -280, -264,
-312, -296, -472, -456, -504, -488, -408,
-392, -440, -424, -88, -72, -120, -104,
-24, -8, -56, -40, -216, -200, -248,
-232, -152, -136, -184, -168, -1376, -1312,
-1504, -1440, -1120, -1056, -1248, -1184, -1888,
-1824, -2016, -1952, -1632, -1568, -1760, -1696,
-688, -656, -752, -720, -560, -528, -624,
-592, -944, -912, -1008, -976, -816, -784,
-880, -848, 5504, 5248, 6016, 5760, 4480,
4224, 4992, 4736, 7552, 7296, 8064, 7808,
6528, 6272, 7040, 6784, 2752, 2624, 3008,
2880, 2240, 2112, 2496, 2368, 3776, 3648,
4032, 3904, 3264, 3136, 3520, 3392, 22016,
20992, 24064, 23040, 17920, 16896, 19968, 18944,
30208, 29184, 32256, 31232, 26112, 25088, 28160,
27136, 11008, 10496, 12032, 11520, 8960, 8448,
9984, 9472, 15104, 14592, 16128, 15616, 13056,
12544, 14080, 13568, 344, 328, 376, 360,
280, 264, 312, 296, 472, 456, 504,
488, 408, 392, 440, 424, 88, 72,
120, 104, 24, 8, 56, 40, 216,
200, 248, 232, 152, 136, 184, 168,
1376, 1312, 1504, 1440, 1120, 1056, 1248,
1184, 1888, 1824, 2016, 1952, 1632, 1568,
1760, 1696, 688, 656, 752, 720, 560,
528, 624, 592, 944, 912, 1008, 976,
816, 784, 880, 848
};
/*
* linear2alaw() accepts an 13-bit signed integer and encodes it as A-law data
* stored in a unsigned char. This function should only be called with
* the data shifted such that it only contains information in the lower
* 13-bits.
*
* Linear Input Code Compressed Code
* ------------------------ ---------------
* 0000000wxyza 000wxyz
* 0000001wxyza 001wxyz
* 000001wxyzab 010wxyz
* 00001wxyzabc 011wxyz
* 0001wxyzabcd 100wxyz
* 001wxyzabcde 101wxyz
* 01wxyzabcdef 110wxyz
* 1wxyzabcdefg 111wxyz
*
* For further information see John C. Bellamy's Digital Telephony, 1982,
* John Wiley & Sons, pps 98-111 and 472-476.
*/
static unsigned char
st_linear2alaw(PyInt16 pcm_val) /* 2's complement (13-bit range) */
{
PyInt16 mask;
short seg;
unsigned char aval;
/* A-law using even bit inversion */
if (pcm_val >= 0) {
mask = 0xD5; /* sign (7th) bit = 1 */
} else {
mask = 0x55; /* sign bit = 0 */
pcm_val = -pcm_val - 1;
}
/* Convert the scaled magnitude to segment number. */
seg = search(pcm_val, seg_aend, 8);
/* Combine the sign, segment, and quantization bits. */
if (seg >= 8) /* out of range, return maximum value. */
return (unsigned char) (0x7F ^ mask);
else {
aval = (unsigned char) seg << SEG_SHIFT;
if (seg < 2)
aval |= (pcm_val >> 1) & QUANT_MASK;
else
aval |= (pcm_val >> seg) & QUANT_MASK;
return (aval ^ mask);
}
}
/* End of code taken from sox */
/* Intel ADPCM step variation table */
static int indexTable[16] = {
-1, -1, -1, -1, 2, 4, 6, 8,
-1, -1, -1, -1, 2, 4, 6, 8,
};
static int stepsizeTable[89] = {
7, 8, 9, 10, 11, 12, 13, 14, 16, 17,
19, 21, 23, 25, 28, 31, 34, 37, 41, 45,
50, 55, 60, 66, 73, 80, 88, 97, 107, 118,
130, 143, 157, 173, 190, 209, 230, 253, 279, 307,
337, 371, 408, 449, 494, 544, 598, 658, 724, 796,
876, 963, 1060, 1166, 1282, 1411, 1552, 1707, 1878, 2066,
2272, 2499, 2749, 3024, 3327, 3660, 4026, 4428, 4871, 5358,
5894, 6484, 7132, 7845, 8630, 9493, 10442, 11487, 12635, 13899,
15289, 16818, 18500, 20350, 22385, 24623, 27086, 29794, 32767
};
#define GETINTX(T, cp, i) (*(T *)((unsigned char *)(cp) + (i)))
#define SETINTX(T, cp, i, val) do { \
*(T *)((unsigned char *)(cp) + (i)) = (T)(val); \
} while (0)
#define GETINT8(cp, i) GETINTX(signed char, (cp), (i))
#define GETINT16(cp, i) GETINTX(short, (cp), (i))
#define GETINT32(cp, i) GETINTX(PY_INT32_T, (cp), (i))
#if WORDS_BIGENDIAN
#define GETINT24(cp, i) ( \
((unsigned char *)(cp) + (i))[2] + \
(((unsigned char *)(cp) + (i))[1] << 8) + \
(((signed char *)(cp) + (i))[0] << 16) )
#else
#define GETINT24(cp, i) ( \
((unsigned char *)(cp) + (i))[0] + \
(((unsigned char *)(cp) + (i))[1] << 8) + \
(((signed char *)(cp) + (i))[2] << 16) )
#endif
#define SETINT8(cp, i, val) SETINTX(signed char, (cp), (i), (val))
#define SETINT16(cp, i, val) SETINTX(short, (cp), (i), (val))
#define SETINT32(cp, i, val) SETINTX(PY_INT32_T, (cp), (i), (val))
#if WORDS_BIGENDIAN
#define SETINT24(cp, i, val) do { \
((unsigned char *)(cp) + (i))[2] = (int)(val); \
((unsigned char *)(cp) + (i))[1] = (int)(val) >> 8; \
((signed char *)(cp) + (i))[0] = (int)(val) >> 16; \
} while (0)
#else
#define SETINT24(cp, i, val) do { \
((unsigned char *)(cp) + (i))[0] = (int)(val); \
((unsigned char *)(cp) + (i))[1] = (int)(val) >> 8; \
((signed char *)(cp) + (i))[2] = (int)(val) >> 16; \
} while (0)
#endif
#define GETRAWSAMPLE(size, cp, i) ( \
(size == 1) ? (int)GETINT8((cp), (i)) : \
(size == 2) ? (int)GETINT16((cp), (i)) : \
(size == 3) ? (int)GETINT24((cp), (i)) : \
(int)GETINT32((cp), (i)))
#define SETRAWSAMPLE(size, cp, i, val) do { \
if (size == 1) \
SETINT8((cp), (i), (val)); \
else if (size == 2) \
SETINT16((cp), (i), (val)); \
else if (size == 3) \
SETINT24((cp), (i), (val)); \
else \
SETINT32((cp), (i), (val)); \
} while(0)
#define GETSAMPLE32(size, cp, i) ( \
(size == 1) ? (int)GETINT8((cp), (i)) << 24 : \
(size == 2) ? (int)GETINT16((cp), (i)) << 16 : \
(size == 3) ? (int)GETINT24((cp), (i)) << 8 : \
(int)GETINT32((cp), (i)))
#define SETSAMPLE32(size, cp, i, val) do { \
if (size == 1) \
SETINT8((cp), (i), (val) >> 24); \
else if (size == 2) \
SETINT16((cp), (i), (val) >> 16); \
else if (size == 3) \
SETINT24((cp), (i), (val) >> 8); \
else \
SETINT32((cp), (i), (val)); \
} while(0)
static PyObject *AudioopError;
static int
audioop_check_size(int size)
{
if (size < 1 || size > 4) {
PyErr_SetString(AudioopError, "Size should be 1, 2, 3 or 4");
return 0;
}
else
return 1;
}
static int
audioop_check_parameters(Py_ssize_t len, int size)
{
if (!audioop_check_size(size))
return 0;
if (len % size != 0) {
PyErr_SetString(AudioopError, "not a whole number of frames");
return 0;
}
return 1;
}
/*[clinic input]
module audioop
[clinic start generated code]*/
/*[clinic end generated code: output=da39a3ee5e6b4b0d input=8fa8f6611be3591a]*/
/*[clinic input]
audioop.getsample
fragment: Py_buffer
width: int
index: Py_ssize_t
/
Return the value of sample index from the fragment.
[clinic start generated code]*/
static PyObject *
audioop_getsample_impl(PyModuleDef *module, Py_buffer *fragment, int width,
Py_ssize_t index)
/*[clinic end generated code: output=3995e189fdc8ec16 input=88edbe2871393549]*/
{
int val;
if (!audioop_check_parameters(fragment->len, width))
return NULL;
if (index < 0 || index >= fragment->len/width) {
PyErr_SetString(AudioopError, "Index out of range");
return NULL;
}
val = GETRAWSAMPLE(width, fragment->buf, index*width);
return PyLong_FromLong(val);
}
/*[clinic input]
audioop.max
fragment: Py_buffer
width: int
/
Return the maximum of the absolute value of all samples in a fragment.
[clinic start generated code]*/
static PyObject *
audioop_max_impl(PyModuleDef *module, Py_buffer *fragment, int width)
/*[clinic end generated code: output=85047ee1001f2305 input=32bea5ea0ac8c223]*/
{
Py_ssize_t i;
unsigned int absval, max = 0;
if (!audioop_check_parameters(fragment->len, width))
return NULL;
for (i = 0; i < fragment->len; i += width) {
int val = GETRAWSAMPLE(width, fragment->buf, i);
if (val < 0) absval = (-val);
else absval = val;
if (absval > max) max = absval;
}
return PyLong_FromUnsignedLong(max);
}
/*[clinic input]
audioop.minmax
fragment: Py_buffer
width: int
/
Return the minimum and maximum values of all samples in the sound fragment.
[clinic start generated code]*/
static PyObject *
audioop_minmax_impl(PyModuleDef *module, Py_buffer *fragment, int width)
/*[clinic end generated code: output=ae8f5513c64fd569 input=89848e9b927a0696]*/
{
Py_ssize_t i;
/* -1 trick below is needed on Windows to support -0x80000000 without
a warning */
int min = 0x7fffffff, max = -0x7FFFFFFF-1;
if (!audioop_check_parameters(fragment->len, width))
return NULL;
for (i = 0; i < fragment->len; i += width) {
int val = GETRAWSAMPLE(width, fragment->buf, i);
if (val > max) max = val;
if (val < min) min = val;
}
return Py_BuildValue("(ii)", min, max);
}
/*[clinic input]
audioop.avg
fragment: Py_buffer
width: int
/
Return the average over all samples in the fragment.
[clinic start generated code]*/
static PyObject *
audioop_avg_impl(PyModuleDef *module, Py_buffer *fragment, int width)
/*[clinic end generated code: output=7fccd645c95f4860 input=1114493c7611334d]*/
{
Py_ssize_t i;
int avg;
double sum = 0.0;
if (!audioop_check_parameters(fragment->len, width))
return NULL;
for (i = 0; i < fragment->len; i += width)
sum += GETRAWSAMPLE(width, fragment->buf, i);
if (fragment->len == 0)
avg = 0;
else
avg = (int)floor(sum / (double)(fragment->len/width));
return PyLong_FromLong(avg);
}
/*[clinic input]
audioop.rms
fragment: Py_buffer
width: int
/
Return the root-mean-square of the fragment, i.e. sqrt(sum(S_i^2)/n).
[clinic start generated code]*/
static PyObject *
audioop_rms_impl(PyModuleDef *module, Py_buffer *fragment, int width)
/*[clinic end generated code: output=7b398702c81b709d input=4cc57c6c94219d78]*/
{
Py_ssize_t i;
unsigned int res;
double sum_squares = 0.0;
if (!audioop_check_parameters(fragment->len, width))
return NULL;
for (i = 0; i < fragment->len; i += width) {
double val = GETRAWSAMPLE(width, fragment->buf, i);
sum_squares += val*val;
}
if (fragment->len == 0)
res = 0;
else
res = (unsigned int)sqrt(sum_squares / (double)(fragment->len/width));
return PyLong_FromUnsignedLong(res);
}
static double _sum2(const short *a, const short *b, Py_ssize_t len)
{
Py_ssize_t i;
double sum = 0.0;
for( i=0; i<len; i++) {
sum = sum + (double)a[i]*(double)b[i];
}
return sum;
}
/*
** Findfit tries to locate a sample within another sample. Its main use
** is in echo-cancellation (to find the feedback of the output signal in
** the input signal).
** The method used is as follows:
**
** let R be the reference signal (length n) and A the input signal (length N)
** with N > n, and let all sums be over i from 0 to n-1.
**
** Now, for each j in {0..N-n} we compute a factor fj so that -fj*R matches A
** as good as possible, i.e. sum( (A[j+i]+fj*R[i])^2 ) is minimal. This
** equation gives fj = sum( A[j+i]R[i] ) / sum(R[i]^2).
**
** Next, we compute the relative distance between the original signal and
** the modified signal and minimize that over j:
** vj = sum( (A[j+i]-fj*R[i])^2 ) / sum( A[j+i]^2 ) =>
** vj = ( sum(A[j+i]^2)*sum(R[i]^2) - sum(A[j+i]R[i])^2 ) / sum( A[j+i]^2 )
**
** In the code variables correspond as follows:
** cp1 A
** cp2 R
** len1 N
** len2 n
** aj_m1 A[j-1]
** aj_lm1 A[j+n-1]
** sum_ri_2 sum(R[i]^2)
** sum_aij_2 sum(A[i+j]^2)
** sum_aij_ri sum(A[i+j]R[i])
**
** sum_ri is calculated once, sum_aij_2 is updated each step and sum_aij_ri
** is completely recalculated each step.
*/
/*[clinic input]
audioop.findfit
fragment: Py_buffer
reference: Py_buffer
/
Try to match reference as well as possible to a portion of fragment.
[clinic start generated code]*/
static PyObject *
audioop_findfit_impl(PyModuleDef *module, Py_buffer *fragment,
Py_buffer *reference)
/*[clinic end generated code: output=609eedf5d823d6dd input=62c305605e183c9a]*/
{
const short *cp1, *cp2;
Py_ssize_t len1, len2;
Py_ssize_t j, best_j;
double aj_m1, aj_lm1;
double sum_ri_2, sum_aij_2, sum_aij_ri, result, best_result, factor;
if (fragment->len & 1 || reference->len & 1) {
PyErr_SetString(AudioopError, "Strings should be even-sized");
return NULL;
}
cp1 = (const short *)fragment->buf;
len1 = fragment->len >> 1;
cp2 = (const short *)reference->buf;
len2 = reference->len >> 1;
if (len1 < len2) {
PyErr_SetString(AudioopError, "First sample should be longer");
return NULL;
}
sum_ri_2 = _sum2(cp2, cp2, len2);
sum_aij_2 = _sum2(cp1, cp1, len2);
sum_aij_ri = _sum2(cp1, cp2, len2);
result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri) / sum_aij_2;
best_result = result;
best_j = 0;
for ( j=1; j<=len1-len2; j++) {
aj_m1 = (double)cp1[j-1];
aj_lm1 = (double)cp1[j+len2-1];
sum_aij_2 = sum_aij_2 + aj_lm1*aj_lm1 - aj_m1*aj_m1;
sum_aij_ri = _sum2(cp1+j, cp2, len2);
result = (sum_ri_2*sum_aij_2 - sum_aij_ri*sum_aij_ri)
/ sum_aij_2;
if ( result < best_result ) {
best_result = result;
best_j = j;
}
}
factor = _sum2(cp1+best_j, cp2, len2) / sum_ri_2;
return Py_BuildValue("(nf)", best_j, factor);
}
/*
** findfactor finds a factor f so that the energy in A-fB is minimal.
** See the comment for findfit for details.
*/
/*[clinic input]
audioop.findfactor
fragment: Py_buffer
reference: Py_buffer
/
Return a factor F such that rms(add(fragment, mul(reference, -F))) is minimal.
[clinic start generated code]*/
static PyObject *
audioop_findfactor_impl(PyModuleDef *module, Py_buffer *fragment,
Py_buffer *reference)
/*[clinic end generated code: output=5566a8c55de54f99 input=816680301d012b21]*/
{
const short *cp1, *cp2;
Py_ssize_t len;
double sum_ri_2, sum_aij_ri, result;
if (fragment->len & 1 || reference->len & 1) {
PyErr_SetString(AudioopError, "Strings should be even-sized");
return NULL;
}
if (fragment->len != reference->len) {
PyErr_SetString(AudioopError, "Samples should be same size");
return NULL;
}
cp1 = (const short *)fragment->buf;
cp2 = (const short *)reference->buf;
len = fragment->len >> 1;
sum_ri_2 = _sum2(cp2, cp2, len);
sum_aij_ri = _sum2(cp1, cp2, len);
result = sum_aij_ri / sum_ri_2;
return PyFloat_FromDouble(result);
}
/*
** findmax returns the index of the n-sized segment of the input sample
** that contains the most energy.
*/
/*[clinic input]
audioop.findmax
fragment: Py_buffer
length: Py_ssize_t
/
Search fragment for a slice of specified number of samples with maximum energy.
[clinic start generated code]*/
static PyObject *
audioop_findmax_impl(PyModuleDef *module, Py_buffer *fragment,
Py_ssize_t length)
/*[clinic end generated code: output=01fe796fad2573bb input=2f304801ed42383c]*/
{
const short *cp1;
Py_ssize_t len1;
Py_ssize_t j, best_j;
double aj_m1, aj_lm1;
double result, best_result;
if (fragment->len & 1) {
PyErr_SetString(AudioopError, "Strings should be even-sized");
return NULL;
}
cp1 = (const short *)fragment->buf;
len1 = fragment->len >> 1;
if (length < 0 || len1 < length) {
PyErr_SetString(AudioopError, "Input sample should be longer");
return NULL;
}
result = _sum2(cp1, cp1, length);
best_result = result;
best_j = 0;
for ( j=1; j<=len1-length; j++) {
aj_m1 = (double)cp1[j-1];
aj_lm1 = (double)cp1[j+length-1];
result = result + aj_lm1*aj_lm1 - aj_m1*aj_m1;
if ( result > best_result ) {
best_result = result;
best_j = j;
}
}
return PyLong_FromSsize_t(best_j);
}
/*[clinic input]
audioop.avgpp
fragment: Py_buffer
width: int
/
Return the average peak-peak value over all samples in the fragment.
[clinic start generated code]*/
static PyObject *
audioop_avgpp_impl(PyModuleDef *module, Py_buffer *fragment, int width)
/*[clinic end generated code: output=06c8380fd6e34207 input=0b3cceeae420a7d9]*/
{
Py_ssize_t i;
int prevval, prevextremevalid = 0, prevextreme = 0;
double sum = 0.0;
unsigned int avg;
int diff, prevdiff, nextreme = 0;
if (!audioop_check_parameters(fragment->len, width))
return NULL;
if (fragment->len <= width)
return PyLong_FromLong(0);
prevval = GETRAWSAMPLE(width, fragment->buf, 0);
prevdiff = 17; /* Anything != 0, 1 */
for (i = width; i < fragment->len; i += width) {
int val = GETRAWSAMPLE(width, fragment->buf, i);
if (val != prevval) {
diff = val < prevval;
if (prevdiff == !diff) {
/* Derivative changed sign. Compute difference to last
** extreme value and remember.
*/
if (prevextremevalid) {
if (prevval < prevextreme)
sum += (double)((unsigned int)prevextreme -
(unsigned int)prevval);
else
sum += (double)((unsigned int)prevval -
(unsigned int)prevextreme);
nextreme++;
}
prevextremevalid = 1;
prevextreme = prevval;
}
prevval = val;
prevdiff = diff;
}
}
if ( nextreme == 0 )
avg = 0;
else
avg = (unsigned int)(sum / (double)nextreme);
return PyLong_FromUnsignedLong(avg);
}
/*[clinic input]
audioop.maxpp
fragment: Py_buffer
width: int
/
Return the maximum peak-peak value in the sound fragment.
[clinic start generated code]*/
static PyObject *
audioop_maxpp_impl(PyModuleDef *module, Py_buffer *fragment, int width)
/*[clinic end generated code: output=c300c0bd7e8535c0 input=671a13e1518f80a1]*/
{
Py_ssize_t i;
int prevval, prevextremevalid = 0, prevextreme = 0;
unsigned int max = 0, extremediff;
int diff, prevdiff;
if (!audioop_check_parameters(fragment->len, width))
return NULL;
if (fragment->len <= width)
return PyLong_FromLong(0);
prevval = GETRAWSAMPLE(width, fragment->buf, 0);
prevdiff = 17; /* Anything != 0, 1 */
for (i = width; i < fragment->len; i += width) {
int val = GETRAWSAMPLE(width, fragment->buf, i);
if (val != prevval) {
diff = val < prevval;
if (prevdiff == !diff) {
/* Derivative changed sign. Compute difference to
** last extreme value and remember.
*/
if (prevextremevalid) {
if (prevval < prevextreme)
extremediff = (unsigned int)prevextreme -
(unsigned int)prevval;
else
extremediff = (unsigned int)prevval -
(unsigned int)prevextreme;
if ( extremediff > max )
max = extremediff;
}
prevextremevalid = 1;
prevextreme = prevval;
}
prevval = val;
prevdiff = diff;
}
}
return PyLong_FromUnsignedLong(max);
}
/*[clinic input]
audioop.cross
fragment: Py_buffer
width: int
/
Return the number of zero crossings in the fragment passed as an argument.
[clinic start generated code]*/
static PyObject *
audioop_cross_impl(PyModuleDef *module, Py_buffer *fragment, int width)
/*[clinic end generated code: output=99e6572d7d7cdbf1 input=b1b3f15b83f6b41a]*/
{
Py_ssize_t i;
int prevval;
Py_ssize_t ncross;
if (!audioop_check_parameters(fragment->len, width))
return NULL;
ncross = -1;
prevval = 17; /* Anything <> 0,1 */
for (i = 0; i < fragment->len; i += width) {
int val = GETRAWSAMPLE(width, fragment->buf, i) < 0;
if (val != prevval) ncross++;
prevval = val;
}
return PyLong_FromSsize_t(ncross);
}
/*[clinic input]
audioop.mul
fragment: Py_buffer
width: int
factor: double
/
Return a fragment that has all samples in the original fragment multiplied by the floating-point value factor.
[clinic start generated code]*/
static PyObject *
audioop_mul_impl(PyModuleDef *module, Py_buffer *fragment, int width,
double factor)
/*[clinic end generated code: output=1c7c31191ac86b10 input=c726667baa157d3c]*/
{
signed char *ncp;
Py_ssize_t i;
double maxval, minval;
PyObject *rv;
if (!audioop_check_parameters(fragment->len, width))
return NULL;
maxval = (double) maxvals[width];
minval = (double) minvals[width];
rv = PyBytes_FromStringAndSize(NULL, fragment->len);
if (rv == NULL)
return NULL;
ncp = (signed char *)PyBytes_AsString(rv);
for (i = 0; i < fragment->len; i += width) {
double val = GETRAWSAMPLE(width, fragment->buf, i);
val *= factor;
val = floor(fbound(val, minval, maxval));
SETRAWSAMPLE(width, ncp, i, (int)val);
}
return rv;
}
/*[clinic input]
audioop.tomono
fragment: Py_buffer
width: int
lfactor: double
rfactor: double
/
Convert a stereo fragment to a mono fragment.
[clinic start generated code]*/
static PyObject *
audioop_tomono_impl(PyModuleDef *module, Py_buffer *fragment, int width,
double lfactor, double rfactor)
/*[clinic end generated code: output=553f547c5e29e3b6 input=c4ec949b3f4dddfa]*/
{
signed char *cp, *ncp;
Py_ssize_t len, i;
double maxval, minval;
PyObject *rv;
cp = fragment->buf;
len = fragment->len;
if (!audioop_check_parameters(len, width))
return NULL;
if (((len / width) & 1) != 0) {
PyErr_SetString(AudioopError, "not a whole number of frames");
return NULL;
}
maxval = (double) maxvals[width];
minval = (double) minvals[width];
rv = PyBytes_FromStringAndSize(NULL, len/2);
if (rv == NULL)
return NULL;
ncp = (signed char *)PyBytes_AsString(rv);
for (i = 0; i < len; i += width*2) {
double val1 = GETRAWSAMPLE(width, cp, i);
double val2 = GETRAWSAMPLE(width, cp, i + width);
double val = val1*lfactor + val2*rfactor;
val = floor(fbound(val, minval, maxval));
SETRAWSAMPLE(width, ncp, i/2, val);
}
return rv;
}
/*[clinic input]
audioop.tostereo
fragment: Py_buffer
width: int
lfactor: double
rfactor: double
/
Generate a stereo fragment from a mono fragment.
[clinic start generated code]*/
static PyObject *
audioop_tostereo_impl(PyModuleDef *module, Py_buffer *fragment, int width,
double lfactor, double rfactor)
/*[clinic end generated code: output=697bb6ba41e9dd2c input=27b6395ebfdff37a]*/
{
signed char *ncp;
Py_ssize_t i;
double maxval, minval;