706e18a61057ba04be92a474b77014498fb9f992
[paraslash.git] / aac_afh.c
1 /*
2 * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111, USA.
17 */
18 /*
19 * based in parts on libfaad, Copyright (C) 2003-2005 M. Bakker,
20 * Ahead Software AG
21 */
22
23 /** \file aac_afh.c para_server's aac audio format handler */
24
25 #include "server.h"
26 #include "error.h"
27 #include "string.h"
28 #include "aac.h"
29 #include "fd.h"
30
31 static int aac_find_stsz(unsigned char *buf, off_t buflen, off_t *skip)
32 {
33 int i;
34
35 for (i = 0; i + 16 < buflen; i++) {
36 unsigned char *p = buf + i;
37 unsigned sample_count, sample_size;
38
39 if (p[0] != 's' || p[1] != 't' || p[2] != 's' || p[3] != 'z')
40 continue;
41 PARA_INFO_LOG("found stsz@%d\n", i);
42 i += 8;
43 sample_size = aac_read_int32(buf + i);
44 PARA_INFO_LOG("sample size: %d\n", sample_size);
45 i += 4;
46 sample_count = aac_read_int32(buf + i);
47 i += 4;
48 PARA_INFO_LOG("sample count: %d\n", sample_count);
49 *skip = i;
50 return sample_count;
51 }
52 return -E_STSZ;
53 }
54
55 static ssize_t aac_compute_chunk_table(struct audio_format_info *afi,
56 unsigned char *map, off_t numbytes)
57 {
58 int ret, i;
59 size_t sum = 0;
60 off_t skip;
61
62 ret = aac_find_stsz(map, numbytes, &skip);
63 if (ret < 0)
64 return ret;
65 afi->chunks_total = ret;
66 PARA_INFO_LOG("sz table has %lu entries\n", afi->chunks_total);
67 afi->chunk_table = para_malloc((afi->chunks_total + 1) * sizeof(size_t));
68 for (i = 1; i <= afi->chunks_total; i++) {
69 if (skip + 4 > numbytes)
70 break;
71 sum += aac_read_int32(map + skip);
72 afi->chunk_table[i] = sum;
73 skip += 4;
74 // if (i < 10 || i + 10 > afi->chunks_total)
75 // PARA_DEBUG_LOG("offset #%d: %zu\n", i, afi->chunk_table[i]);
76 }
77 return skip;
78 }
79
80 static long unsigned aac_set_chunk_tv(struct audio_format_info *afi,
81 mp4AudioSpecificConfig *mp4ASC)
82 {
83 float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023,
84 ms = 1000.0 * afi->chunks_total * tmp / mp4ASC->samplingFrequency;
85 struct timeval total;
86
87 ms2tv(ms, &total);
88 tv_divide(afi->chunks_total, &total, &afi->chunk_tv);
89 PARA_INFO_LOG("%luHz, %fs (%lu x %lums)\n",
90 mp4ASC->samplingFrequency, ms / 1000,
91 afi->chunks_total, tv2ms(&afi->chunk_tv));
92 return ms < 1000? -E_MP4ASC : ms / 1000;
93 }
94
95 /*
96 * Init m4a file and write some tech data to given pointers.
97 */
98 static int aac_get_file_info(char *map, off_t numbytes,
99 struct audio_format_info *afi)
100 {
101 int i;
102 size_t skip;
103 ssize_t ret;
104 unsigned long rate = 0, decoder_len;
105 unsigned char channels = 0;
106 mp4AudioSpecificConfig mp4ASC;
107 NeAACDecHandle handle;
108
109 ret = aac_find_esds(map, numbytes, &skip);
110 if (ret < 0)
111 goto out;
112 decoder_len = ret;
113 handle = aac_open();
114 ret = -E_AACDEC_INIT;
115 if (NeAACDecInit(handle, map + skip, decoder_len, &rate, &channels))
116 goto out;
117 if (!channels)
118 goto out;
119 PARA_INFO_LOG("rate: %lu, channels: %d\n", rate, channels);
120 ret = -E_MP4ASC;
121 if (NeAACDecAudioSpecificConfig(map + skip, numbytes - skip, &mp4ASC))
122 goto out;
123 if (!mp4ASC.samplingFrequency)
124 goto out;
125 ret = aac_compute_chunk_table(afi, map, numbytes);
126 if (ret < 0)
127 goto out;
128 skip = ret;
129 afi->seconds_total = aac_set_chunk_tv(afi, &mp4ASC);
130 ret = aac_find_entry_point(map + skip, numbytes - skip, &skip);
131 if (ret < 0)
132 goto out;
133 afi->chunk_table[0] = ret;
134 for (i = 1; i<= afi->chunks_total; i++)
135 afi->chunk_table[i] += ret;
136 afi->channels = channels;
137 afi->frequency = rate;
138 ret = (afi->chunk_table[afi->chunks_total] - afi->chunk_table[0]) * 8; /* bits */
139 ret += (channels * afi->seconds_total * 500); /* avoid rounding error */
140 afi->bitrate = ret / (channels * afi->seconds_total * 1000);
141 sprintf(afi->info_string, "audio_file_info1:%lu x %lums, "
142 "%uHz, %d channel%s, %ukb/s\n"
143 "audio_file_info2:\n"
144 "audio_file_info3:\n",
145 afi->chunks_total, tv2ms(&afi->chunk_tv),
146 afi->frequency, channels, channels == 1? "" : "s", afi->bitrate
147 );
148 tv_scale(20, &afi->chunk_tv, &afi->eof_tv);
149 ret = 1;
150 out:
151 return ret;
152 }
153
154 static const char* aac_suffixes[] = {"m4a", "mp4", NULL};
155 /**
156 * the init function of the aac audio format handler
157 *
158 * \param afh pointer to the struct to initialize
159 */
160 void aac_afh_init(struct audio_format_handler *afh)
161 {
162 afh->get_file_info = aac_get_file_info,
163 afh->suffixes = aac_suffixes;
164 }