Statistics
| Branch: | Revision:

ffmpeg / libavcodec / vorbis.c @ 9106a698

History | View | Annotate | Download (5.12 KB)

1
/**
2
 * @file libavcodec/vorbis.c
3
 * Common code for Vorbis I encoder and decoder
4
 * @author Denes Balatoni  ( dbalatoni programozo hu )
5

6
 * This file is part of FFmpeg.
7
 *
8
 * FFmpeg is free software; you can redistribute it and/or
9
 * modify it under the terms of the GNU Lesser General Public
10
 * License as published by the Free Software Foundation; either
11
 * version 2.1 of the License, or (at your option) any later version.
12
 *
13
 * FFmpeg is distributed in the hope that it will be useful,
14
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
16
 * Lesser General Public License for more details.
17
 *
18
 * You should have received a copy of the GNU Lesser General Public
19
 * License along with FFmpeg; if not, write to the Free Software
20
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21
 */
22

    
23
#undef V_DEBUG
24
//#define V_DEBUG
25

    
26
#define ALT_BITSTREAM_READER_LE
27
#include "avcodec.h"
28
#include "get_bits.h"
29

    
30
#include "vorbis.h"
31

    
32

    
33
/* Helper functions */
34

    
35
unsigned int ff_vorbis_nth_root(unsigned int x, unsigned int n) {   // x^(1/n)
36
    unsigned int ret=0, i, j;
37

    
38
    do {
39
        ++ret;
40
        for(i=0,j=ret;i<n-1;i++) j*=ret;
41
    } while (j<=x);
42

    
43
    return ret - 1;
44
}
45

    
46
// Generate vlc codes from vorbis huffman code lengths
47

    
48
int ff_vorbis_len2vlc(uint8_t *bits, uint32_t *codes, uint_fast32_t num) {
49
    uint_fast32_t exit_at_level[33]={404,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,
50
        0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0};
51

    
52
    uint_fast8_t i,j;
53
    uint_fast32_t code,p;
54

    
55
#ifdef V_DEBUG
56
    GetBitContext gb;
57
#endif
58

    
59
    for(p=0;(bits[p]==0) && (p<num);++p);
60
    if (p==num) {
61
//        av_log(vc->avccontext, AV_LOG_INFO, "An empty codebook. Heh?! \n");
62
        return 0;
63
    }
64

    
65
    codes[p]=0;
66
    for(i=0;i<bits[p];++i) {
67
        exit_at_level[i+1]=1<<i;
68
    }
69

    
70
#ifdef V_DEBUG
71
    av_log(NULL, AV_LOG_INFO, " %d. of %d code len %d code %d - ", p, num, bits[p], codes[p]);
72
    init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);
73
    for(i=0;i<bits[p];++i) {
74
        av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
75
    }
76
    av_log(NULL, AV_LOG_INFO, "\n");
77
#endif
78

    
79
    ++p;
80

    
81
    for(;p<num;++p) {
82
        if (bits[p]==0) continue;
83
        // find corresponding exit(node which the tree can grow further from)
84
        for(i=bits[p];i>0;--i) {
85
            if (exit_at_level[i]) break;
86
        }
87
        if (!i) return 1; // overspecified tree
88
        code=exit_at_level[i];
89
        exit_at_level[i]=0;
90
        // construct code (append 0s to end) and introduce new exits
91
        for(j=i+1;j<=bits[p];++j) {
92
            exit_at_level[j]=code+(1<<(j-1));
93
        }
94
        codes[p]=code;
95

    
96
#ifdef V_DEBUG
97
        av_log(NULL, AV_LOG_INFO, " %d. code len %d code %d - ", p, bits[p], codes[p]);
98
        init_get_bits(&gb, (uint_fast8_t *)&codes[p], bits[p]);
99
        for(i=0;i<bits[p];++i) {
100
            av_log(NULL, AV_LOG_INFO, "%s", get_bits1(&gb) ? "1" : "0");
101
        }
102
        av_log(NULL, AV_LOG_INFO, "\n");
103
#endif
104

    
105
    }
106

    
107
    //no exits should be left (underspecified tree - ie. unused valid vlcs - not allowed by SPEC)
108
    for (p=1; p<33; p++)
109
        if (exit_at_level[p]) return 1;
110

    
111
    return 0;
112
}
113

    
114
void ff_vorbis_ready_floor1_list(vorbis_floor1_entry * list, int values) {
115
    int i;
116
    list[0].sort = 0;
117
    list[1].sort = 1;
118
    for (i = 2; i < values; i++) {
119
        int j;
120
        list[i].low = 0;
121
        list[i].high = 1;
122
        list[i].sort = i;
123
        for (j = 2; j < i; j++) {
124
            int tmp = list[j].x;
125
            if (tmp < list[i].x) {
126
                if (tmp > list[list[i].low].x) list[i].low = j;
127
            } else {
128
                if (tmp < list[list[i].high].x) list[i].high = j;
129
            }
130
        }
131
    }
132
    for (i = 0; i < values - 1; i++) {
133
        int j;
134
        for (j = i + 1; j < values; j++) {
135
            if (list[list[i].sort].x > list[list[j].sort].x) {
136
                int tmp = list[i].sort;
137
                list[i].sort = list[j].sort;
138
                list[j].sort = tmp;
139
            }
140
        }
141
    }
142
}
143

    
144
static void render_line(int x0, int y0, int x1, int y1, float * buf) {
145
    int dy = y1 - y0;
146
    int adx = x1 - x0;
147
    int base = dy / adx;
148
    int ady = FFABS(dy) - FFABS(base) * adx;
149
    int x = x0;
150
    int y = y0;
151
    int err = 0;
152
    int sy = dy<0 ? -1 : 1;
153
    buf[x] = ff_vorbis_floor1_inverse_db_table[y];
154
    while (++x < x1) {
155
        err += ady;
156
        if (err >= adx) {
157
            err -= adx;
158
            y += sy;
159
        }
160
        y += base;
161
        buf[x] = ff_vorbis_floor1_inverse_db_table[y];
162
    }
163
}
164

    
165
void ff_vorbis_floor1_render_list(vorbis_floor1_entry * list, int values, uint_fast16_t * y_list, int * flag, int multiplier, float * out, int samples) {
166
    int lx, ly, i;
167
    lx = 0;
168
    ly = y_list[0] * multiplier;
169
    for (i = 1; i < values; i++) {
170
        int pos = list[i].sort;
171
        if (flag[pos]) {
172
            int x1 = list[pos].x;
173
            int y1 = y_list[pos] * multiplier;
174
            if (lx < samples)
175
                render_line(lx, ly, FFMIN(x1,samples), y1, out);
176
            lx = x1;
177
            ly = y1;
178
        }
179
        if (lx >= samples) break;
180
    }
181
    if (lx < samples) render_line(lx, ly, samples, ly, out);
182
}