1 /*
2  * SpanDSP - a series of DSP components for telephony
3  *
4  * g722_decode.c - The ITU G.722 codec, decode part.
5  *
6  * Written by Steve Underwood <steveu@coppice.org>
7  *
8  * Copyright (C) 2005 Steve Underwood
9  *
10  *  Despite my general liking of the GPL, I place my own contributions
11  *  to this code in the public domain for the benefit of all mankind -
12  *  even the slimy ones who might try to proprietize my work and use it
13  *  to my detriment.
14  *
15  * Based in part on a single channel G.722 codec which is:
16  *
17  * Copyright (c) CMU 1993
18  * Computer Science, Speech Group
19  * Chengxiang Lu and Alex Hauptmann
20  *
21  * $Id: g722_decode.c,v 1.15 2006/07/07 16:37:49 steveu Exp $
22  *
23  * Modifications for WebRtc, 2011/04/28, by tlegrand:
24  * -Removed usage of inttypes.h and tgmath.h
25  * -Changed to use WebRtc types
26  * -Changed __inline__ to __inline
27  * -Added saturation check on output
28  */
29 
30 /*! \file */
31 
32 
33 #ifdef HAVE_CONFIG_H
34 #include <config.h>
35 #endif
36 
37 #include <memory.h>
38 #include <stdio.h>
39 #include <stdlib.h>
40 
41 #include "g722_enc_dec.h"
42 #include "webrtc/typedefs.h"
43 
44 #if !defined(FALSE)
45 #define FALSE 0
46 #endif
47 #if !defined(TRUE)
48 #define TRUE (!FALSE)
49 #endif
50 
saturate(int32_t amp)51 static __inline int16_t saturate(int32_t amp)
52 {
53     int16_t amp16;
54 
55     /* Hopefully this is optimised for the common case - not clipping */
56     amp16 = (int16_t) amp;
57     if (amp == amp16)
58         return amp16;
59     if (amp > WEBRTC_INT16_MAX)
60         return  WEBRTC_INT16_MAX;
61     return  WEBRTC_INT16_MIN;
62 }
63 /*- End of function --------------------------------------------------------*/
64 
65 static void block4(G722DecoderState *s, int band, int d);
66 
block4(G722DecoderState * s,int band,int d)67 static void block4(G722DecoderState *s, int band, int d)
68 {
69     int wd1;
70     int wd2;
71     int wd3;
72     int i;
73 
74     /* Block 4, RECONS */
75     s->band[band].d[0] = d;
76     s->band[band].r[0] = saturate(s->band[band].s + d);
77 
78     /* Block 4, PARREC */
79     s->band[band].p[0] = saturate(s->band[band].sz + d);
80 
81     /* Block 4, UPPOL2 */
82     for (i = 0;  i < 3;  i++)
83         s->band[band].sg[i] = s->band[band].p[i] >> 15;
84     wd1 = saturate(s->band[band].a[1] << 2);
85 
86     wd2 = (s->band[band].sg[0] == s->band[band].sg[1])  ?  -wd1  :  wd1;
87     if (wd2 > 32767)
88         wd2 = 32767;
89     wd3 = (s->band[band].sg[0] == s->band[band].sg[2])  ?  128  :  -128;
90     wd3 += (wd2 >> 7);
91     wd3 += (s->band[band].a[2]*32512) >> 15;
92     if (wd3 > 12288)
93         wd3 = 12288;
94     else if (wd3 < -12288)
95         wd3 = -12288;
96     s->band[band].ap[2] = wd3;
97 
98     /* Block 4, UPPOL1 */
99     s->band[band].sg[0] = s->band[band].p[0] >> 15;
100     s->band[band].sg[1] = s->band[band].p[1] >> 15;
101     wd1 = (s->band[band].sg[0] == s->band[band].sg[1])  ?  192  :  -192;
102     wd2 = (s->band[band].a[1]*32640) >> 15;
103 
104     s->band[band].ap[1] = saturate(wd1 + wd2);
105     wd3 = saturate(15360 - s->band[band].ap[2]);
106     if (s->band[band].ap[1] > wd3)
107         s->band[band].ap[1] = wd3;
108     else if (s->band[band].ap[1] < -wd3)
109         s->band[band].ap[1] = -wd3;
110 
111     /* Block 4, UPZERO */
112     wd1 = (d == 0)  ?  0  :  128;
113     s->band[band].sg[0] = d >> 15;
114     for (i = 1;  i < 7;  i++)
115     {
116         s->band[band].sg[i] = s->band[band].d[i] >> 15;
117         wd2 = (s->band[band].sg[i] == s->band[band].sg[0])  ?  wd1  :  -wd1;
118         wd3 = (s->band[band].b[i]*32640) >> 15;
119         s->band[band].bp[i] = saturate(wd2 + wd3);
120     }
121 
122     /* Block 4, DELAYA */
123     for (i = 6;  i > 0;  i--)
124     {
125         s->band[band].d[i] = s->band[band].d[i - 1];
126         s->band[band].b[i] = s->band[band].bp[i];
127     }
128 
129     for (i = 2;  i > 0;  i--)
130     {
131         s->band[band].r[i] = s->band[band].r[i - 1];
132         s->band[band].p[i] = s->band[band].p[i - 1];
133         s->band[band].a[i] = s->band[band].ap[i];
134     }
135 
136     /* Block 4, FILTEP */
137     wd1 = saturate(s->band[band].r[1] + s->band[band].r[1]);
138     wd1 = (s->band[band].a[1]*wd1) >> 15;
139     wd2 = saturate(s->band[band].r[2] + s->band[band].r[2]);
140     wd2 = (s->band[band].a[2]*wd2) >> 15;
141     s->band[band].sp = saturate(wd1 + wd2);
142 
143     /* Block 4, FILTEZ */
144     s->band[band].sz = 0;
145     for (i = 6;  i > 0;  i--)
146     {
147         wd1 = saturate(s->band[band].d[i] + s->band[band].d[i]);
148         s->band[band].sz += (s->band[band].b[i]*wd1) >> 15;
149     }
150     s->band[band].sz = saturate(s->band[band].sz);
151 
152     /* Block 4, PREDIC */
153     s->band[band].s = saturate(s->band[band].sp + s->band[band].sz);
154 }
155 /*- End of function --------------------------------------------------------*/
156 
WebRtc_g722_decode_init(G722DecoderState * s,int rate,int options)157 G722DecoderState* WebRtc_g722_decode_init(G722DecoderState* s,
158                                           int rate,
159                                           int options) {
160     s = s ? s : malloc(sizeof(*s));
161     memset(s, 0, sizeof(*s));
162     if (rate == 48000)
163         s->bits_per_sample = 6;
164     else if (rate == 56000)
165         s->bits_per_sample = 7;
166     else
167         s->bits_per_sample = 8;
168     if ((options & G722_SAMPLE_RATE_8000))
169         s->eight_k = TRUE;
170     if ((options & G722_PACKED)  &&  s->bits_per_sample != 8)
171         s->packed = TRUE;
172     else
173         s->packed = FALSE;
174     s->band[0].det = 32;
175     s->band[1].det = 8;
176     return s;
177 }
178 /*- End of function --------------------------------------------------------*/
179 
WebRtc_g722_decode_release(G722DecoderState * s)180 int WebRtc_g722_decode_release(G722DecoderState *s)
181 {
182     free(s);
183     return 0;
184 }
185 /*- End of function --------------------------------------------------------*/
186 
WebRtc_g722_decode(G722DecoderState * s,int16_t amp[],const uint8_t g722_data[],size_t len)187 size_t WebRtc_g722_decode(G722DecoderState *s, int16_t amp[],
188                           const uint8_t g722_data[], size_t len)
189 {
190     static const int wl[8] = {-60, -30, 58, 172, 334, 538, 1198, 3042 };
191     static const int rl42[16] = {0, 7, 6, 5, 4, 3, 2, 1,
192                                  7, 6, 5, 4, 3,  2, 1, 0 };
193     static const int ilb[32] =
194     {
195         2048, 2093, 2139, 2186, 2233, 2282, 2332,
196         2383, 2435, 2489, 2543, 2599, 2656, 2714,
197         2774, 2834, 2896, 2960, 3025, 3091, 3158,
198         3228, 3298, 3371, 3444, 3520, 3597, 3676,
199         3756, 3838, 3922, 4008
200     };
201     static const int wh[3] = {0, -214, 798};
202     static const int rh2[4] = {2, 1, 2, 1};
203     static const int qm2[4] = {-7408, -1616,  7408,   1616};
204     static const int qm4[16] =
205     {
206               0, -20456, -12896,  -8968,
207           -6288,  -4240,  -2584,  -1200,
208           20456,  12896,   8968,   6288,
209            4240,   2584,   1200,      0
210     };
211     static const int qm5[32] =
212     {
213            -280,   -280, -23352, -17560,
214          -14120, -11664,  -9752,  -8184,
215           -6864,  -5712,  -4696,  -3784,
216           -2960,  -2208,  -1520,   -880,
217           23352,  17560,  14120,  11664,
218            9752,   8184,   6864,   5712,
219            4696,   3784,   2960,   2208,
220            1520,    880,    280,   -280
221     };
222     static const int qm6[64] =
223     {
224            -136,   -136,   -136,   -136,
225          -24808, -21904, -19008, -16704,
226          -14984, -13512, -12280, -11192,
227          -10232,  -9360,  -8576,  -7856,
228           -7192,  -6576,  -6000,  -5456,
229           -4944,  -4464,  -4008,  -3576,
230           -3168,  -2776,  -2400,  -2032,
231           -1688,  -1360,  -1040,   -728,
232           24808,  21904,  19008,  16704,
233           14984,  13512,  12280,  11192,
234           10232,   9360,   8576,   7856,
235            7192,   6576,   6000,   5456,
236            4944,   4464,   4008,   3576,
237            3168,   2776,   2400,   2032,
238            1688,   1360,   1040,    728,
239             432,    136,   -432,   -136
240     };
241     static const int qmf_coeffs[12] =
242     {
243            3,  -11,   12,   32, -210,  951, 3876, -805,  362, -156,   53,  -11,
244     };
245 
246     int dlowt;
247     int rlow;
248     int ihigh;
249     int dhigh;
250     int rhigh;
251     int xout1;
252     int xout2;
253     int wd1;
254     int wd2;
255     int wd3;
256     int code;
257     size_t outlen;
258     int i;
259     size_t j;
260 
261     outlen = 0;
262     rhigh = 0;
263     for (j = 0;  j < len;  )
264     {
265         if (s->packed)
266         {
267             /* Unpack the code bits */
268             if (s->in_bits < s->bits_per_sample)
269             {
270                 s->in_buffer |= (g722_data[j++] << s->in_bits);
271                 s->in_bits += 8;
272             }
273             code = s->in_buffer & ((1 << s->bits_per_sample) - 1);
274             s->in_buffer >>= s->bits_per_sample;
275             s->in_bits -= s->bits_per_sample;
276         }
277         else
278         {
279             code = g722_data[j++];
280         }
281 
282         switch (s->bits_per_sample)
283         {
284         default:
285         case 8:
286             wd1 = code & 0x3F;
287             ihigh = (code >> 6) & 0x03;
288             wd2 = qm6[wd1];
289             wd1 >>= 2;
290             break;
291         case 7:
292             wd1 = code & 0x1F;
293             ihigh = (code >> 5) & 0x03;
294             wd2 = qm5[wd1];
295             wd1 >>= 1;
296             break;
297         case 6:
298             wd1 = code & 0x0F;
299             ihigh = (code >> 4) & 0x03;
300             wd2 = qm4[wd1];
301             break;
302         }
303         /* Block 5L, LOW BAND INVQBL */
304         wd2 = (s->band[0].det*wd2) >> 15;
305         /* Block 5L, RECONS */
306         rlow = s->band[0].s + wd2;
307         /* Block 6L, LIMIT */
308         if (rlow > 16383)
309             rlow = 16383;
310         else if (rlow < -16384)
311             rlow = -16384;
312 
313         /* Block 2L, INVQAL */
314         wd2 = qm4[wd1];
315         dlowt = (s->band[0].det*wd2) >> 15;
316 
317         /* Block 3L, LOGSCL */
318         wd2 = rl42[wd1];
319         wd1 = (s->band[0].nb*127) >> 7;
320         wd1 += wl[wd2];
321         if (wd1 < 0)
322             wd1 = 0;
323         else if (wd1 > 18432)
324             wd1 = 18432;
325         s->band[0].nb = wd1;
326 
327         /* Block 3L, SCALEL */
328         wd1 = (s->band[0].nb >> 6) & 31;
329         wd2 = 8 - (s->band[0].nb >> 11);
330         wd3 = (wd2 < 0)  ?  (ilb[wd1] << -wd2)  :  (ilb[wd1] >> wd2);
331         s->band[0].det = wd3 << 2;
332 
333         block4(s, 0, dlowt);
334 
335         if (!s->eight_k)
336         {
337             /* Block 2H, INVQAH */
338             wd2 = qm2[ihigh];
339             dhigh = (s->band[1].det*wd2) >> 15;
340             /* Block 5H, RECONS */
341             rhigh = dhigh + s->band[1].s;
342             /* Block 6H, LIMIT */
343             if (rhigh > 16383)
344                 rhigh = 16383;
345             else if (rhigh < -16384)
346                 rhigh = -16384;
347 
348             /* Block 2H, INVQAH */
349             wd2 = rh2[ihigh];
350             wd1 = (s->band[1].nb*127) >> 7;
351             wd1 += wh[wd2];
352             if (wd1 < 0)
353                 wd1 = 0;
354             else if (wd1 > 22528)
355                 wd1 = 22528;
356             s->band[1].nb = wd1;
357 
358             /* Block 3H, SCALEH */
359             wd1 = (s->band[1].nb >> 6) & 31;
360             wd2 = 10 - (s->band[1].nb >> 11);
361             wd3 = (wd2 < 0)  ?  (ilb[wd1] << -wd2)  :  (ilb[wd1] >> wd2);
362             s->band[1].det = wd3 << 2;
363 
364             block4(s, 1, dhigh);
365         }
366 
367         if (s->itu_test_mode)
368         {
369             amp[outlen++] = (int16_t) (rlow << 1);
370             amp[outlen++] = (int16_t) (rhigh << 1);
371         }
372         else
373         {
374             if (s->eight_k)
375             {
376                 amp[outlen++] = (int16_t) (rlow << 1);
377             }
378             else
379             {
380                 /* Apply the receive QMF */
381                 for (i = 0;  i < 22;  i++)
382                     s->x[i] = s->x[i + 2];
383                 s->x[22] = rlow + rhigh;
384                 s->x[23] = rlow - rhigh;
385 
386                 xout1 = 0;
387                 xout2 = 0;
388                 for (i = 0;  i < 12;  i++)
389                 {
390                     xout2 += s->x[2*i]*qmf_coeffs[i];
391                     xout1 += s->x[2*i + 1]*qmf_coeffs[11 - i];
392                 }
393                 /* We shift by 12 to allow for the QMF filters (DC gain = 4096), less 1
394                    to allow for the 15 bit input to the G.722 algorithm. */
395                 /* WebRtc, tlegrand: added saturation */
396                 amp[outlen++] = saturate(xout1 >> 11);
397                 amp[outlen++] = saturate(xout2 >> 11);
398             }
399         }
400     }
401     return outlen;
402 }
403 /*- End of function --------------------------------------------------------*/
404 /*- End of file ------------------------------------------------------------*/
405