Merge branch 'refs/heads/t/server_cmds'
[paraslash.git] / aac_common.c
1 /*
2 * Copyright (C) 2006-2014 Andre Noll <maan@tuebingen.mpg.de>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6 /*
7 * based in parts on libfaad, Copyright (C) 2003-2005 M. Bakker,
8 * Ahead Software AG
9 */
10
11 /** \file aac_common.c Common functions of aac_afh and aadcec. */
12
13 #include "para.h"
14 #include "aac.h"
15 #include "error.h"
16
17 /**
18 * Get a new libfaad decoder handle.
19 *
20 * \return The handle returned by NeAACDecOpen().
21 */
22 NeAACDecHandle aac_open(void)
23 {
24 NeAACDecHandle h = NeAACDecOpen();
25 NeAACDecConfigurationPtr c = NeAACDecGetCurrentConfiguration(h);
26
27 c->defObjectType = LC;
28 c->outputFormat = FAAD_FMT_16BIT;
29 c->downMatrix = 0;
30 NeAACDecSetConfiguration(h, c);
31 return h;
32 }
33
34 static unsigned long aac_read_decoder_length(unsigned char *buf, int *description_len)
35 {
36 uint8_t b;
37 uint8_t numBytes = 0;
38 unsigned long length = 0;
39
40 do {
41 b = buf[numBytes];
42 numBytes++;
43 length = (length << 7) | (b & 0x7F);
44 } while
45 ((b & 0x80) && numBytes < 4);
46 *description_len = numBytes;
47 return length;
48 }
49
50 /**
51 * search for the position and the length of the decoder configuration
52 *
53 * \param buf buffer to seach
54 * \param buflen length of \a buf
55 * \param skip Upon succesful return, this contains the offset in \a buf where
56 * the decoder config starts.
57 * \param decoder_length result pointer that is filled in with the length of
58 * the decoder configuration on success.
59 *
60 * \return positive on success, negative on errors
61 */
62 int aac_find_esds(unsigned char *buf, size_t buflen, size_t *skip,
63 unsigned long *decoder_length)
64 {
65 size_t i;
66
67 for (i = 0; i + 4 < buflen; i++) {
68 unsigned char *p = buf + i;
69 int description_len;
70
71 if (p[0] != 'e' || p[1] != 's' || p[2] != 'd' || p[3] != 's')
72 continue;
73 i += 8;
74 p = buf + i;
75 PARA_INFO_LOG("found esds@%zu, next: %x\n", i, *p);
76 if (*p == 3)
77 i += 8;
78 else
79 i += 6;
80 p = buf + i;
81 PARA_INFO_LOG("next: %x\n", *p);
82 if (*p != 4)
83 continue;
84 i += 18;
85 p = buf + i;
86 PARA_INFO_LOG("next: %x\n", *p);
87 if (*p != 5)
88 continue;
89 i++;
90 p = buf + i;
91 *decoder_length = aac_read_decoder_length(p, &description_len);
92 PARA_INFO_LOG("decoder length: %lu\n", *decoder_length);
93 i += description_len;
94 *skip = i;
95 return 1;
96 }
97 return -E_ESDS;
98 }
99
100 /**
101 * search for the first entry in the stco table
102 *
103 * \param buf buffer to seach
104 * \param buflen length of \a buf
105 * \param skip Upon succesful return, this contains the number
106 * of bytes to skip from the input buffer.
107 *
108 * \return the position of the first entry in the table on success,
109 * -E_STCO on errors.
110 */
111 ssize_t aac_find_entry_point(unsigned char *buf, size_t buflen, size_t *skip)
112 {
113 ssize_t ret;
114 size_t i;
115
116 for (i = 0; i + 20 < buflen; i++) {
117 unsigned char *p = buf + i;
118
119 if (p[0] != 's' || p[1] != 't' || p[2] != 'c' || p[3] != 'o')
120 continue;
121 PARA_INFO_LOG("found stco@%zu\n", i);
122 i += 12;
123 ret = aac_read_int32(buf + i); /* first offset */
124 i += 4;
125 PARA_INFO_LOG("entry point: %zd\n", ret);
126 *skip = i;
127 return ret;
128 }
129 PARA_WARNING_LOG("stco not found, buflen: %zu\n", buflen);
130 return -E_STCO;
131 }