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1/***************************************************************************
2 * __________ __ ___.
3 * Open \______ \ ____ ____ | | _\_ |__ _______ ___
4 * Source | _// _ \_/ ___\| |/ /| __ \ / _ \ \/ /
5 * Jukebox | | ( <_> ) \___| < | \_\ ( <_> > < <
6 * Firmware |____|_ /\____/ \___ >__|_ \|___ /\____/__/\_ \
7 * \/ \/ \/ \/ \/
8 * $Id$
9 *
10 * Copyright (C) 2005 Dave Chapman
11 *
12 * All files in this archive are subject to the GNU General Public License.
13 * See the file COPYING in the source tree root for full license agreement.
14 *
15 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY
16 * KIND, either express or implied.
17 *
18 ****************************************************************************/
19#include <stdio.h>
20#include <string.h>
21#include <stdlib.h>
22#include <ctype.h>
23#include <inttypes.h>
24
25#include "system.h"
26#include "id3.h"
27#include "metadata_common.h"
28#include "logf.h"
29
30/* A simple parser to read vital metadata from an Ogg Speex file. Returns
31 * false if metadata needed by the Speex codec couldn't be read.
32 */
33
34bool get_speex_metadata(int fd, struct mp3entry* id3)
35{
36 /* An Ogg File is split into pages, each starting with the string
37 * "OggS". Each page has a timestamp (in PCM samples) referred to as
38 * the "granule position".
39 *
40 * An Ogg Speex has the following structure:
41 * 1) Identification header (containing samplerate, numchannels, etc)
42 Described in this page: (http://www.speex.org/manual2/node7.html)
43 * 2) Comment header - containing the Vorbis Comments
44 * 3) Many audio packets...
45 */
46
47 /* Use the path name of the id3 structure as a temporary buffer. */
48 unsigned char* buf = (unsigned char*)id3->path;
49 long comment_size;
50 long remaining = 0;
51 long last_serial = 0;
52 long serial, r;
53 int segments;
54 int i;
55 bool eof = false;
56
57 if ((lseek(fd, 0, SEEK_SET) < 0) || (read(fd, buf, 58) < 33))
58 {
59 return false;
60 }
61
62 if ((memcmp(buf, "OggS", 4) != 0) || (memcmp(&buf[28], "Speex", 5) != 0))
63 {
64 return false;
65 }
66
67 /* We need to ensure the serial number from this page is the same as the
68 * one from the last page (since we only support a single bitstream).
69 */
70 serial = get_long_le(&buf[14]);
71 if ((lseek(fd, 33, SEEK_SET) < 0)||(read(fd, buf, 58) < 4))
72 {
73 return false;
74 }
75
76 id3->frequency = get_slong(&buf[31]);
77 last_serial = get_long_le(&buf[27]);/*temporary, header size*/
78 id3->bitrate = get_long_le(&buf[47]);
79 id3->vbr = get_long_le(&buf[55]);
80 id3->filesize = filesize(fd);
81 /* Comments are in second Ogg page */
82 if (lseek(fd, 28+last_serial/*(temporary for header size)*/, SEEK_SET) < 0)
83 {
84 return false;
85 }
86
87 /* Minimum header length for Ogg pages is 27. */
88 if (read(fd, buf, 27) < 27)
89 {
90 return false;
91 }
92
93 if (memcmp(buf, "OggS", 4) !=0 )
94 {
95 return false;
96 }
97
98 segments = buf[26];
99 /* read in segment table */
100 if (read(fd, buf, segments) < segments)
101 {
102 return false;
103 }
104
105 /* The second packet in a vorbis stream is the comment packet. It *may*
106 * extend beyond the second page, but usually does not. Here we find the
107 * length of the comment packet (or the rest of the page if the comment
108 * packet extends to the third page).
109 */
110 for (i = 0; i < segments; i++)
111 {
112 remaining += buf[i];
113 /* The last segment of a packet is always < 255 bytes */
114 if (buf[i] < 255)
115 {
116 break;
117 }
118 }
119
120 comment_size = remaining;
121
122 /* Failure to read the tags isn't fatal. */
123 read_vorbis_tags(fd, id3, remaining);
124
125 /* We now need to search for the last page in the file - identified by
126 * by ('O','g','g','S',0) and retrieve totalsamples.
127 */
128
129 /* A page is always < 64 kB */
130 if (lseek(fd, -(MIN(64 * 1024, id3->filesize)), SEEK_END) < 0)
131 {
132 return false;
133 }
134
135 remaining = 0;
136
137 while (!eof)
138 {
139 r = read(fd, &buf[remaining], MAX_PATH - remaining);
140
141 if (r <= 0)
142 {
143 eof = true;
144 }
145 else
146 {
147 remaining += r;
148 }
149
150 /* Inefficient (but simple) search */
151 i = 0;
152
153 while (i < (remaining - 3))
154 {
155 if ((buf[i] == 'O') && (memcmp(&buf[i], "OggS", 4) == 0))
156 {
157 if (i < (remaining - 17))
158 {
159 /* Note that this only reads the low 32 bits of a
160 * 64 bit value.
161 */
162 id3->samples = get_long_le(&buf[i + 6]);
163 last_serial = get_long_le(&buf[i + 14]);
164
165 /* If this page is very small the beginning of the next
166 * header could be in buffer. Jump near end of this header
167 * and continue */
168 i += 27;
169 }
170 else
171 {
172 break;
173 }
174 }
175 else
176 {
177 i++;
178 }
179 }
180
181 if (i < remaining)
182 {
183 /* Move the remaining bytes to start of buffer.
184 * Reuse var 'segments' as it is no longer needed */
185 segments = 0;
186 while (i < remaining)
187 {
188 buf[segments++] = buf[i++];
189 }
190 remaining = segments;
191 }
192 else
193 {
194 /* Discard the rest of the buffer */
195 remaining = 0;
196 }
197 }
198
199 /* This file has mutiple vorbis bitstreams (or is corrupt). */
200 /* FIXME we should display an error here. */
201 if (serial != last_serial)
202 {
203 logf("serialno mismatch");
204 logf("%ld", serial);
205 logf("%ld", last_serial);
206 return false;
207 }
208
209 id3->length = (id3->samples / id3->frequency) * 1000;
210 id3->bitrate = (((int64_t) id3->filesize - comment_size) * 8) / id3->length;
211 return true;
212}