a9d36fa16a93226d581105321a0ea79d09d804c8
[paraslash.git] / mp3_afh.c
1 /*
2 * Copyright (C) 2003-2008 Andre Noll <maan@systemlinux.org>
3 *
4 * Licensed under the GPL v2. For licencing details see COPYING.
5 */
6
7 /** \file mp3_afh.c para_server's mp3 audio format handler */
8
9 /*
10 * This file is based in part on mp3tech.c and mp3tech.h, Copyright (C)
11 * 2000-2001 Cedric Tefft <cedric@earthling.net>, which in turn is based
12 * in part on
13 *
14 * * MP3Info 0.5 by Ricardo Cerqueira <rmc@rccn.net>
15 * * MP3Stat 0.9 by Ed Sweetman <safemode@voicenet.com> and
16 * Johannes Overmann <overmann@iname.com>
17 */
18
19 #include "para.h"
20 #include "error.h"
21 #include "afh.h"
22 #include "string.h"
23 #include "afs.h"
24 #include "server.h"
25
26 /** \cond some defines and structs which are only used in this file */
27
28 /*
29 * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
30 * to see before we decide we are looking at a real MP3 file
31 */
32 #define MIN_CONSEC_GOOD_FRAMES 4
33 #define FRAME_HEADER_SIZE 4
34 #define MIN_FRAME_SIZE 21
35
36 struct mp3header {
37 unsigned long sync;
38 unsigned int version;
39 unsigned int layer;
40 unsigned int crc;
41 unsigned int bitrate;
42 unsigned int freq;
43 unsigned int padding;
44 unsigned int mode;
45 unsigned int copyright;
46 unsigned int original;
47 unsigned int emphasis;
48 };
49
50 struct id3tag {
51 char title[31];
52 char artist[31];
53 char album[31];
54 char year[5];
55 char comment[31];
56 };
57
58 struct mp3info {
59 int id3_isvalid;
60 struct id3tag id3;
61 int vbr;
62 };
63
64 /** \endcond */
65 static const int frequencies[3][4] = {
66 {22050,24000,16000,50000}, /* MPEG 2.0 */
67 {44100,48000,32000,50000}, /* MPEG 1.0 */
68 {11025,12000,8000,50000} /* MPEG 2.5 */
69 };
70
71 static const int mp3info_bitrate[2][3][14] = {
72 { /* MPEG 2.0 */
73 {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
74 {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
75 {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
76 },
77
78 { /* MPEG 1.0 */
79 {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
80 {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
81 {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
82 }
83 };
84
85 static const int frame_size_index[] = {24000, 72000, 72000};
86 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
87
88 static struct mp3info mp3;
89
90 static int header_frequency(struct mp3header *h)
91 {
92 if (h->version > 2 || h->freq > 3)
93 return -E_HEADER_FREQ;
94 return frequencies[h->version][h->freq];
95 }
96
97 static const char *header_mode(struct mp3header *h)
98 {
99 if (h->mode > 4)
100 h->mode = 4; /* invalid */
101 return mode_text[h->mode];
102 }
103
104 static int header_channels(struct mp3header *h)
105 {
106 if (h->mode > 3)
107 return 0;
108 if (h->mode < 3)
109 return 2;
110 return 1;
111 }
112
113 static int header_bitrate(struct mp3header *h)
114 {
115 if (!h->layer || h->layer > 3 || h->bitrate > 14 || !h->bitrate)
116 return -E_HEADER_BITRATE;
117 return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
118 }
119
120 static int frame_length(struct mp3header *header)
121 {
122 int hb, hf = header_frequency(header);
123
124 if (hf < 0)
125 return hf;
126 hb = header_bitrate(header);
127 if (hb < 0)
128 return hb;
129 if (header->sync != 0xFFE || header->layer > 3)
130 return -E_FRAME;
131 return frame_size_index[3 - header->layer] *
132 ((header->version & 1) + 1) * hb / hf
133 + header->padding;
134 }
135
136 static void write_info_str(struct afh_info *afhi, struct mp3header *header)
137 {
138 int v = mp3.id3_isvalid;
139
140 afhi->info_string = make_message(
141 "%s: %cbr, %s\n" /* audio file info*/
142 "%s: %s, by %s\n" /* taginfo1 */
143 "%s: A: %s, Y: %s, C: %s\n", /* taginfo 2*/
144 status_item_list[SI_AUDIO_FILE_INFO], mp3.vbr? 'v' : 'c',
145 header_mode(header),
146 status_item_list[SI_TAGINFO1], v && *mp3.id3.title?
147 mp3.id3.title : "(title tag not set)",
148 v && *mp3.id3.artist?
149 mp3.id3.artist : "(artist tag not set)",
150 status_item_list[SI_TAGINFO2],
151 v && *mp3.id3.album?
152 mp3.id3.album : "(album tag not set)",
153 v && *mp3.id3.year? mp3.id3.year : "????",
154 v && *mp3.id3.comment?
155 mp3.id3.comment : "(comment tag not set)"
156 );
157 }
158
159 /*
160 * Remove trailing whitespace from the end of a string
161 */
162 static char *unpad(char *string)
163 {
164 char *pos = string + strlen(string) - 1;
165 while (para_isspace(pos[0]))
166 (pos--)[0] = 0;
167 return string;
168 }
169
170 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
171 {
172 if ((*(uint*)h1) == (*(uint*)h2))
173 return 1;
174 if ((h1->version == h2->version) &&
175 (h1->layer == h2->layer) &&
176 (h1->crc == h2->crc) &&
177 (h1->freq == h2->freq) &&
178 (h1->mode == h2->mode) &&
179 (h1->copyright == h2->copyright) &&
180 (h1->original == h2->original) &&
181 (h1->emphasis == h2->emphasis))
182 return 1;
183 return 0;
184 }
185
186 /*
187 * get next MP3 frame header.
188 *
189 * On success, the header frame length is returned and the given header
190 * structure that is filled in. A return value of zero means that we did not
191 * retrieve a valid frame header, and a negative return value indicates an
192 * error.
193 */
194 static int get_header(unsigned char *map, size_t numbytes, off_t *fpos,
195 struct mp3header *header)
196 {
197 int fl, ret;
198
199 if (*fpos + FRAME_HEADER_SIZE > numbytes) {
200 *fpos = numbytes - 1;
201 header->sync = 0;
202 return 0;
203 }
204 header->layer = (map[*fpos + 1] >> 1) & 3;
205 header->sync = (((int)map[*fpos]<<4) | ((int)(map[*fpos + 1]&0xE0)>>4));
206 if (map[*fpos + 1] & 0x10)
207 header->version = (map[*fpos + 1] >> 3) & 1;
208 else
209 header->version = 2;
210 if ((header->sync != 0xFFE) || (header->layer != 1)) {
211 ret = 0;
212 header->sync = 0;
213 goto out;
214 }
215 header->crc = map[*fpos + 1] & 1;
216 header->bitrate = (map[*fpos + 2] >> 4) & 0x0F;
217 header->freq = (map[*fpos + 2] >> 2) & 0x3;
218 header->padding = (map[*fpos + 2] >>1) & 0x1;
219 header->mode = (map[*fpos + 3] >> 6) & 0x3;
220 fl = frame_length(header);
221 ret = (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
222 out:
223 *fpos += FRAME_HEADER_SIZE;
224 return ret;
225 }
226
227 /*
228 * find the next mp3 header
229 *
230 * Return the length of the next frame header or zero if the end of the file is
231 * reached.
232 */
233 static int mp3_seek_next_header(unsigned char *map, size_t numbytes, off_t *fpos,
234 struct mp3header *result)
235 {
236 int k, l = 0, first_len;
237 struct mp3header h, h2;
238 long valid_start = 0;
239
240 for (; *fpos < numbytes; (*fpos)++) {
241 if (map[*fpos] != 0xff)
242 continue;
243 valid_start = *fpos;
244 first_len = get_header(map, numbytes, fpos, &h);
245 if (first_len <= 0)
246 continue;
247 *fpos += first_len - FRAME_HEADER_SIZE;
248 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
249 if ((l = get_header(map, numbytes, fpos, &h2)) <= 0)
250 break;
251 if (!compare_headers(&h, &h2))
252 break;
253 *fpos += l - FRAME_HEADER_SIZE;
254 }
255 if (k == MIN_CONSEC_GOOD_FRAMES) {
256 *fpos = valid_start;
257 *result = h2;
258 return first_len;
259 }
260 }
261 return 0;
262 }
263
264 static void mp3_get_id3(unsigned char *map, size_t numbytes)
265 {
266 off_t fpos;
267
268 mp3.id3_isvalid = 0;
269 mp3.id3.title[0] = '\0';
270 mp3.id3.artist[0] = '\0';
271 mp3.id3.album[0] = '\0';
272 mp3.id3.comment[0] = '\0';
273 mp3.id3.year[0] = '\0';
274 if (numbytes < 128)
275 return;
276 fpos = numbytes - 128;
277 if (strncmp("TAG", (char *) map + fpos, 3)) {
278 PARA_DEBUG_LOG("no id3 tag\n");
279 return;
280 }
281 fpos = numbytes - 125;
282 memcpy(mp3.id3.title, map + fpos, 30);
283 fpos += 30;
284 mp3.id3.title[30] = '\0';
285 memcpy(mp3.id3.artist, map + fpos, 30);
286 fpos += 30;
287 mp3.id3.artist[30] = '\0';
288 memcpy(mp3.id3.album, map + fpos, 30);
289 fpos += 30;
290 mp3.id3.album[30] = '\0';
291 memcpy(mp3.id3.year, map + fpos, 4);
292 fpos += 4;
293 mp3.id3.year[4] = '\0';
294 memcpy(mp3.id3.comment, map + fpos, 30);
295 mp3.id3.comment[30] = '\0';
296 mp3.id3_isvalid = 1;
297 unpad(mp3.id3.title);
298 unpad(mp3.id3.artist);
299 unpad(mp3.id3.album);
300 unpad(mp3.id3.year);
301 unpad(mp3.id3.comment);
302 }
303
304 static int find_valid_start(unsigned char *map, size_t numbytes, off_t *fpos,
305 struct mp3header *header)
306 {
307 int frame_len;
308
309 frame_len = get_header(map, numbytes, fpos, header);
310 if (frame_len < 0)
311 return frame_len;
312 if (!frame_len) {
313 frame_len = mp3_seek_next_header(map, numbytes, fpos, header);
314 if (frame_len <= 0)
315 return frame_len;
316 } else
317 *fpos -= FRAME_HEADER_SIZE;
318 if (frame_len <= 1)
319 return -E_FRAME_LENGTH;
320 return frame_len;
321 }
322
323 static int mp3_read_info(unsigned char *map, size_t numbytes,
324 struct afh_info *afhi)
325 {
326 long freq_avg = 0, br_avg = 0;
327 int ret, len = 0, old_br = -1;
328 struct timeval total_time = {0, 0};
329 unsigned chunk_table_size = 1000; /* gets increased on demand */
330 off_t fpos = 0;
331 struct mp3header header;
332
333 afhi->chunks_total = 0;
334 afhi->chunk_table = para_malloc(chunk_table_size * sizeof(size_t));
335 mp3_get_id3(map, numbytes);
336 mp3.vbr = 0;
337 while (1) {
338 unsigned long freq, br, fl;
339 struct timeval tmp, cct; /* current chunk time */
340 fpos += len;
341 len = find_valid_start(map, numbytes, &fpos, &header);
342 if (len <= 0)
343 break;
344 ret = header_frequency(&header);
345 if (ret < 0)
346 continue;
347 freq = ret;
348 ret = header_bitrate(&header);
349 if (ret < 0)
350 continue;
351 br = ret;
352 ret = frame_length(&header);
353 if (ret < 0)
354 continue;
355 fl = ret;
356 tmp.tv_sec = fl;
357 tmp.tv_usec = 0;
358 tv_divide(br * 125, &tmp, &cct);
359 tv_add(&cct, &total_time, &tmp);
360 total_time = tmp;
361 //PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
362 if (afhi->chunks_total >= chunk_table_size) {
363 chunk_table_size *= 2;
364 afhi->chunk_table = para_realloc(afhi->chunk_table,
365 chunk_table_size * sizeof(size_t));
366 }
367 afhi->chunk_table[afhi->chunks_total] = fpos;
368 // if (afhi->chunks_total < 10 || !(afhi->chunks_total % 1000))
369 // PARA_INFO_LOG("chunk #%lu: %zd\n", afhi->chunks_total,
370 // afhi->chunk_table[afhi->chunks_total]);
371 afhi->chunks_total++;
372 if (afhi->chunks_total == 1) {
373 freq_avg = freq;
374 br_avg = br;
375 old_br = br;
376 continue;
377 }
378 freq_avg += ((long)freq - freq_avg) / ((long)afhi->chunks_total + 1);
379 br_avg += ((long)br - br_avg) / ((long)afhi->chunks_total + 1);
380 if (old_br != br)
381 mp3.vbr = 1;
382 old_br = br;
383 }
384 ret = -E_MP3_INFO;
385 if (!afhi->chunks_total || !freq_avg || !br_avg)
386 goto err_out;
387 afhi->chunk_table[afhi->chunks_total] = numbytes - 1;
388 afhi->bitrate = br_avg;
389 afhi->frequency = freq_avg;
390 afhi->channels = header_channels(&header);
391 afhi->seconds_total = (tv2ms(&total_time) + 500) / 1000;
392 tv_divide(afhi->chunks_total, &total_time, &afhi->chunk_tv);
393 PARA_DEBUG_LOG("%lu chunks, each %lums\n", afhi->chunks_total,
394 tv2ms(&afhi->chunk_tv));
395 tv_scale(3, &afhi->chunk_tv, &afhi->eof_tv);
396 PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&afhi->eof_tv));
397 write_info_str(afhi, &header);
398 return 1;
399 err_out:
400 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
401 free(afhi->chunk_table);
402 return ret;
403 }
404
405 /*
406 * Read mp3 information from audio file
407 */
408 int mp3_get_file_info(char *map, size_t numbytes,
409 struct afh_info *afhi)
410 {
411 int ret;
412
413 ret = mp3_read_info((unsigned char *)map, numbytes, afhi);
414 if (ret < 0)
415 return ret;
416 if (afhi->seconds_total < 2 || !afhi->chunks_total)
417 return -E_MP3_INFO;
418 return 1;
419 }
420
421 static const char* mp3_suffixes[] = {"mp3", NULL};
422
423 /**
424 * the init function of the mp3 audio format handler
425 *
426 * \param afh pointer to the struct to initialize
427 */
428 void mp3_init(struct audio_format_handler *afh)
429 {
430 afh->get_file_info = mp3_get_file_info;
431 afh->suffixes = mp3_suffixes;
432 }