swr: reorder/redesign operations to avoid integer overflow.
[ffmpeg.git] / libswresample / resample_template.c
1 /*
2  * audio resampling
3  * Copyright (c) 2004-2012 Michael Niedermayer <michaelni@gmx.at>
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 /**
23  * @file
24  * audio resampling
25  * @author Michael Niedermayer <michaelni@gmx.at>
26  */
27
28 int RENAME(swri_resample)(ResampleContext *c, DELEM *dst, const DELEM *src, int *consumed, int src_size, int dst_size, int update_ctx){
29     int dst_index, i;
30     int index= c->index;
31     int frac= c->frac;
32     int dst_incr_frac= c->dst_incr % c->src_incr;
33     int dst_incr=      c->dst_incr / c->src_incr;
34     int compensation_distance= c->compensation_distance;
35
36     av_assert1(c->filter_shift == FILTER_SHIFT);
37     av_assert1(c->felem_size == sizeof(FELEM));
38
39     if(compensation_distance == 0 && c->filter_length == 1 && c->phase_shift==0){
40         int64_t index2= ((int64_t)index)<<32;
41         int64_t incr= (1LL<<32) * c->dst_incr / c->src_incr;
42         dst_size= FFMIN(dst_size, (src_size-1-index) * (int64_t)c->src_incr / c->dst_incr);
43
44         for(dst_index=0; dst_index < dst_size; dst_index++){
45             dst[dst_index] = src[index2>>32];
46             index2 += incr;
47         }
48         index += dst_index * dst_incr;
49         index += (frac + dst_index * (int64_t)dst_incr_frac) / c->src_incr;
50         frac   = (frac + dst_index * (int64_t)dst_incr_frac) % c->src_incr;
51         av_assert2(index >= 0);
52         *consumed= index >> c->phase_shift;
53         index &= c->phase_mask;
54     }else if(compensation_distance == 0 && !c->linear && index >= 0){
55         int sample_index = 0;
56         for(dst_index=0; dst_index < dst_size; dst_index++){
57             FELEM *filter;
58             sample_index += index >> c->phase_shift;
59             index &= c->phase_mask;
60             filter= ((FELEM*)c->filter_bank) + c->filter_alloc*index;
61
62             if(sample_index + c->filter_length > src_size){
63                 break;
64             }else{
65 #ifdef COMMON_CORE
66                 COMMON_CORE
67 #else
68                 FELEM2 val=0;
69                 for(i=0; i<c->filter_length; i++){
70                     val += src[sample_index + i] * (FELEM2)filter[i];
71                 }
72                 OUT(dst[dst_index], val);
73 #endif
74             }
75
76             frac += dst_incr_frac;
77             index += dst_incr;
78             if(frac >= c->src_incr){
79                 frac -= c->src_incr;
80                 index++;
81             }
82         }
83         *consumed = sample_index;
84     }else{
85         int sample_index = 0;
86         for(dst_index=0; dst_index < dst_size; dst_index++){
87             FELEM *filter;
88             FELEM2 val=0;
89
90             sample_index += index >> c->phase_shift;
91             index &= c->phase_mask;
92             filter = ((FELEM*)c->filter_bank) + c->filter_alloc*index;
93
94             if(sample_index + c->filter_length > src_size || -sample_index >= src_size){
95                 break;
96             }else if(sample_index < 0){
97                 for(i=0; i<c->filter_length; i++)
98                     val += src[FFABS(sample_index + i)] * filter[i];
99             }else if(c->linear){
100                 FELEM2 v2=0;
101                 for(i=0; i<c->filter_length; i++){
102                     val += src[sample_index + i] * (FELEM2)filter[i];
103                     v2  += src[sample_index + i] * (FELEM2)filter[i + c->filter_alloc];
104                 }
105                 val+=(v2-val)*(FELEML)frac / c->src_incr;
106             }else{
107                 for(i=0; i<c->filter_length; i++){
108                     val += src[sample_index + i] * (FELEM2)filter[i];
109                 }
110             }
111
112             OUT(dst[dst_index], val);
113
114             frac += dst_incr_frac;
115             index += dst_incr;
116             if(frac >= c->src_incr){
117                 frac -= c->src_incr;
118                 index++;
119             }
120
121             if(dst_index + 1 == compensation_distance){
122                 compensation_distance= 0;
123                 dst_incr_frac= c->ideal_dst_incr % c->src_incr;
124                 dst_incr=      c->ideal_dst_incr / c->src_incr;
125             }
126         }
127         *consumed= FFMAX(sample_index, 0);
128         index += FFMIN(sample_index, 0) << c->phase_shift;
129     }
130
131     if(compensation_distance){
132         compensation_distance -= dst_index;
133         av_assert1(compensation_distance > 0);
134     }
135     if(update_ctx){
136         c->frac= frac;
137         c->index= index;
138         c->dst_incr= dst_incr_frac + c->src_incr*dst_incr;
139         c->compensation_distance= compensation_distance;
140     }
141 #if 0
142     if(update_ctx && !c->compensation_distance){
143 #undef rand
144         av_resample_compensate(c, rand() % (8000*2) - 8000, 8000*2);
145 av_log(NULL, AV_LOG_DEBUG, "%d %d %d\n", c->dst_incr, c->ideal_dst_incr, c->compensation_distance);
146     }
147 #endif
148
149     return dst_index;
150 }