1 /*
2 * TwoLAME: an optimized MPEG Audio Layer Two encoder
3 *
4 * Copyright (C) 2001-2004 Michael Cheng
5 * Copyright (C) 2004-2006 The TwoLAME Project
6 *
7 * This library 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 * This library 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 this library; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 *
21 * $Id$
22 *
23 */
24
25
26 #include <stdio.h>
27 #include <string.h>
28
29 #include "twolame.h"
30 #include "common.h"
31 #include "dab.h"
32
33
34 void
dab_crc_calc(twolame_options * glopts,unsigned int bit_alloc[2][SBLIMIT],unsigned int scfsi[2][SBLIMIT],unsigned int scalar[2][3][SBLIMIT],unsigned int * crc,int packed)35 dab_crc_calc(twolame_options * glopts,
36 unsigned int bit_alloc[2][SBLIMIT],
37 unsigned int scfsi[2][SBLIMIT],
38 unsigned int scalar[2][3][SBLIMIT], unsigned int *crc, int packed)
39 {
40 int i, j, k;
41 int nch = glopts->num_channels_out;
42 int nb_scalar;
43 int f[5] = { 0, 4, 8, 16, 30 };
44 int first, last;
45
46 first = f[packed];
47 last = f[packed + 1];
48 if (last > glopts->sblimit)
49 last = glopts->sblimit;
50
51 nb_scalar = 0;
52 *crc = 0x0;
53 for (i = first; i < last; i++)
54 for (k = 0; k < nch; k++)
55 if (bit_alloc[k][i]) /* above jsbound, bit_alloc[0][i] == ba[1][i] */
56 switch (scfsi[k][i]) {
57 case 0:
58 for (j = 0; j < 3; j++) {
59 nb_scalar++;
60 dab_crc_update(scalar[k][j][i] >> 3, 3, crc);
61 }
62 break;
63 case 1:
64 case 3:
65 nb_scalar += 2;
66 dab_crc_update(scalar[k][0][i] >> 3, 3, crc);
67 dab_crc_update(scalar[k][2][i] >> 3, 3, crc);
68 break;
69 case 2:
70 nb_scalar++;
71 dab_crc_update(scalar[k][0][i] >> 3, 3, crc);
72 }
73 }
74
dab_crc_update(unsigned int data,unsigned int length,unsigned int * crc)75 void dab_crc_update(unsigned int data, unsigned int length, unsigned int *crc)
76 {
77 unsigned int masking, carry;
78
79 masking = 1 << length;
80
81 while ((masking >>= 1)) {
82 carry = *crc & 0x80;
83 *crc <<= 1;
84 if (!carry ^ !(data & masking))
85 *crc ^= CRC8_POLYNOMIAL;
86 }
87 *crc &= 0xff;
88 }
89
90
91 #ifdef OLD_BROKEN_DAB_STUFF
92 // Leaving these here while DAB is reimplemented properly
93
94 #define MINIMUM 4 /* Minimum size of the buffer in bytes */
95 #define MAX_LENGTH 32 /* Maximum length of word written */
96
97
98 /*
99 19 Jul 03
100 DAB stuff got broken in the update to 02m
101 Not sure who uses this. I would like to get it working again eventually.
102 */
103
104 /*
105 Just after the available bits calculation in twolame,
106 allocated some bits for the DAB stuff
107 */
108
109 if (header.dab_extension) {
110 /* in 24 kHz we always have 4 bytes */
111 if (header.sampling_frequency == 1)
112 header.dab_extension = 4;
113 /* You must have one frame in memory if you are in DAB mode */
114 /* in conformity of the norme ETS 300 401 http://www.etsi.org */
115 /* see bitstream.c */
116 if (frameNum == 1)
117 minimum = lg_frame + MINIMUM;
118 adb -= header.dab_extension * 8 + header.dab_length * 8 + 16;
119 }
120
121
122 /*
123 Just after we finishing padding up to the number of ADB
124 Put the extension stuff in (ancillary data, right at the end)
125 */
126 if (header.dab_extension) {
127 /* Reserve some bytes for X-PAD in DAB mode */
128 putbits(mybs, 0, header.dab_length * 8);
129
130 for (i = header.dab_extension - 1; i >= 0; i--) {
131 CRC_calcDAB(&frame, bit_alloc, scfsi, scalar, &crc, i);
132 /* this crc is for the previous frame in DAB mode */
133 if (mybs->buf_byte_idx + lg_frame < mybs->buf_size)
134 mybs->buf[mybs->buf_byte_idx + lg_frame] = crc;
135 /* reserved 2 bytes for F-PAD in DAB mode */
136 putbits(mybs, crc, 8);
137 }
138 putbits(mybs, 0, 16);
139 }
140 #endif
141
142
143 // vim:ts=4:sw=4:nowrap:
144