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source: vbox/trunk/src/VBox/Devices/Audio/rate_template.h@ 41757

最後變更 在這個檔案從41757是 1,由 vboxsync 提交於 55 年 前

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  • 屬性 svn:keywords 設為 Author Date Id Revision
檔案大小: 3.2 KB
 
1/*
2 * QEMU Mixing engine
3 *
4 * Copyright (c) 2004-2005 Vassili Karpov (malc)
5 * Copyright (c) 1998 Fabrice Bellard
6 *
7 * Permission is hereby granted, free of charge, to any person obtaining a copy
8 * of this software and associated documentation files (the "Software"), to deal
9 * in the Software without restriction, including without limitation the rights
10 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
11 * copies of the Software, and to permit persons to whom the Software is
12 * furnished to do so, subject to the following conditions:
13 *
14 * The above copyright notice and this permission notice shall be included in
15 * all copies or substantial portions of the Software.
16 *
17 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
18 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
19 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
20 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
21 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
22 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
23 * THE SOFTWARE.
24 */
25
26/*
27 * Processed signed long samples from ibuf to obuf.
28 * Return number of samples processed.
29 */
30void NAME (void *opaque, st_sample_t *ibuf, st_sample_t *obuf,
31 int *isamp, int *osamp)
32{
33 struct rate *rate = opaque;
34 st_sample_t *istart, *iend;
35 st_sample_t *ostart, *oend;
36 st_sample_t ilast, icur, out;
37#ifdef FLOAT_MIXENG
38 real_t t;
39#else
40 int64_t t;
41#endif
42
43 ilast = rate->ilast;
44
45 istart = ibuf;
46 iend = ibuf + *isamp;
47
48 ostart = obuf;
49 oend = obuf + *osamp;
50
51 if (rate->opos_inc == (1ULL + UINT_MAX)) {
52 int i, n = *isamp > *osamp ? *osamp : *isamp;
53 for (i = 0; i < n; i++) {
54 OP (obuf[i].l, ibuf[i].l);
55 OP (obuf[i].r, ibuf[i].r);
56 }
57 *isamp = n;
58 *osamp = n;
59 return;
60 }
61
62 while (obuf < oend) {
63
64 /* Safety catch to make sure we have input samples. */
65 if (ibuf >= iend) {
66 break;
67 }
68
69 /* read as many input samples so that ipos > opos */
70
71 while (rate->ipos <= (rate->opos >> 32)) {
72 ilast = *ibuf++;
73 rate->ipos++;
74 /* See if we finished the input buffer yet */
75 if (ibuf >= iend) {
76 goto the_end;
77 }
78 }
79
80 icur = *ibuf;
81
82 /* interpolate */
83#ifdef FLOAT_MIXENG
84#ifdef RECIPROCAL
85 t = (rate->opos & UINT_MAX) * (1.f / UINT_MAX);
86#else
87 t = (rate->opos & UINT_MAX) / (real_t) UINT_MAX;
88#endif
89 out.l = (ilast.l * (1.0 - t)) + icur.l * t;
90 out.r = (ilast.r * (1.0 - t)) + icur.r * t;
91#else
92 t = rate->opos & 0xffffffff;
93 out.l = (ilast.l * ((int64_t) UINT_MAX - t) + icur.l * t) >> 32;
94 out.r = (ilast.r * ((int64_t) UINT_MAX - t) + icur.r * t) >> 32;
95#endif
96
97 /* output sample & increment position */
98 OP (obuf->l, out.l);
99 OP (obuf->r, out.r);
100 obuf += 1;
101 rate->opos += rate->opos_inc;
102 }
103
104the_end:
105 *isamp = ibuf - istart;
106 *osamp = obuf - ostart;
107 rate->ilast = ilast;
108}
109
110#undef NAME
111#undef OP
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