d8ec8bec3b592d75419c02e275d9f23ac7b8674c
[paraslash.git] / mp3.c
1 /*
2 * Copyright (C) 2003-2006 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 /** \file mp3.c para_server's mp3 audio format handler */
20
21 /*
22 * This file is based in part on mp3tech.c and mp3tech.h, Copyright (C)
23 * 2000-2001 Cedric Tefft <cedric@earthling.net>, which in turn is based
24 * in part on
25 *
26 * * MP3Info 0.5 by Ricardo Cerqueira <rmc@rccn.net>
27 * * MP3Stat 0.9 by Ed Sweetman <safemode@voicenet.com> and
28 * Johannes Overmann <overmann@iname.com>
29 */
30
31 #include "server.cmdline.h"
32 #include "server.h"
33 #include "afs.h"
34 #include "error.h"
35 #include "fd.h"
36
37 /** \cond some defines and structs which are only used in this file */
38
39 /*
40 * MIN_CONSEC_GOOD_FRAMES defines how many consecutive valid MP3 frames we need
41 * to see before we decide we are looking at a real MP3 file
42 */
43 #define MIN_CONSEC_GOOD_FRAMES 3
44
45 #define FRAME_HEADER_SIZE 4
46 #define MIN_FRAME_SIZE 21
47
48 struct mp3header {
49 unsigned long sync;
50 unsigned int version;
51 unsigned int layer;
52 unsigned int crc;
53 unsigned int bitrate;
54 unsigned int freq;
55 unsigned int padding;
56 unsigned int mode;
57 unsigned int copyright;
58 unsigned int original;
59 unsigned int emphasis;
60 };
61
62 struct id3tag {
63 char title[31];
64 char artist[31];
65 char album[31];
66 char year[5];
67 char comment[31];
68 };
69
70 struct mp3info {
71 char *filename;
72 FILE *file;
73 struct mp3header header;
74 int id3_isvalid;
75 struct id3tag id3;
76 int vbr;
77 long unsigned br_average;
78 long unsigned seconds;
79 int frames;
80 int freq;
81 };
82
83 /** \endcond */
84 static int frequencies[3][4] = {
85 {22050,24000,16000,50000}, /* MPEG 2.0 */
86 {44100,48000,32000,50000}, /* MPEG 1.0 */
87 {11025,12000,8000,50000} /* MPEG 2.5 */
88 };
89
90 static int mp3info_bitrate[2][3][14] = {
91 { /* MPEG 2.0 */
92 {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
93 {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
94 {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
95 },
96
97 { /* MPEG 1.0 */
98 {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
99 {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
100 {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
101 }
102 };
103
104 static int frame_size_index[] = {24000, 72000, 72000};
105 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
106
107 static struct mp3info mp3;
108 static char mp3buf[8192];
109 static int chunk_size;
110 static struct audio_format_handler *af;
111
112 static int header_frequency(struct mp3header *h)
113 {
114 if (h->version > 2 || h->freq > 3)
115 return -E_HEADER_FREQ;
116 return frequencies[h->version][h->freq];
117 }
118
119 static const char *header_mode(struct mp3header *h)
120 {
121 if (h->mode > 4)
122 h->mode = 4; /* invalid */
123 return mode_text[h->mode];
124 }
125 static int header_bitrate(struct mp3header *h)
126 {
127 if (h->layer > 3 || h->bitrate > 14)
128 return -E_HEADER_BITRATE;
129 return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
130 }
131
132 static int frame_length(struct mp3header *header)
133 {
134 int hb, hf = header_frequency(header);
135
136 if (hf < 0)
137 return hf;
138 hb = header_bitrate(header);
139 if (hb < 0)
140 return hb;
141 if (header->sync != 0xFFE || header->layer > 3)
142 return -E_FRAME;
143 return frame_size_index[3 - header->layer] *
144 ((header->version & 1) + 1) * hb / hf
145 + header->padding;
146 }
147
148 static void write_info_str(char *info_str)
149 {
150 int v = mp3.id3_isvalid;
151
152 snprintf(info_str, MMD_INFO_SIZE,
153 "audio_file_info1:%d x %lums, %lu kbit/s (%cbr) %i KHz %s\n"
154 "audio_file_info2:%s, by %s\n"
155 "audio_file_info3:A: %s, Y: %s, C: %s\n",
156 mp3.frames,
157 tv2ms(&af->chunk_tv),
158 mp3.br_average,
159 mp3.vbr? 'v' : 'c',
160 mp3.freq / 1000,
161 header_mode(&mp3.header),
162 v && *mp3.id3.title? mp3.id3.title : "(title tag not set)",
163 v && *mp3.id3.artist? mp3.id3.artist : "(artist tag not set)",
164 v && *mp3.id3.album? mp3.id3.album : "(album tag not set)",
165 v && *mp3.id3.year? mp3.id3.year : "????",
166 v && *mp3.id3.comment? mp3.id3.comment : "(comment tag not set)"
167 );
168 }
169
170 /*
171 * Remove trailing whitespace from the end of a string
172 */
173 static char *unpad(char *string)
174 {
175 char *pos = string + strlen(string) - 1;
176 while (isspace(pos[0]))
177 (pos--)[0] = 0;
178 return string;
179 }
180
181 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
182 {
183 if ((*(uint*)h1) == (*(uint*)h2))
184 return 1;
185 if ((h1->version == h2->version) &&
186 (h1->layer == h2->layer) &&
187 (h1->crc == h2->crc) &&
188 (h1->freq == h2->freq) &&
189 (h1->mode == h2->mode) &&
190 (h1->copyright == h2->copyright) &&
191 (h1->original == h2->original) &&
192 (h1->emphasis == h2->emphasis))
193 return 1;
194 else
195 return 0;
196 }
197
198 /**
199 * get next MP3 frame header.
200 *
201 * \param stream to read the header from
202 * \param header structure that gets filled in by get_header()
203 *
204 * \return On success, the header frame length is returned. A return value of
205 * zero means that we did not retrieve a valid frame header, and a negative
206 * return value indicates an error.
207 */
208 static int get_header(FILE *file, struct mp3header *header)
209 {
210 unsigned char buffer[FRAME_HEADER_SIZE];
211 int fl, ret;
212
213 if (!file || !header)
214 return -E_MP3_NO_FILE;
215 ret = para_fread(buffer, FRAME_HEADER_SIZE, 1, file);
216 if (ret < FRAME_HEADER_SIZE) {
217 header->sync = 0;
218 return ret < 0? ret : 0;
219 }
220 header->layer = (buffer[1] >> 1) & 3;
221 header->sync = (((int)buffer[0]<<4) | ((int)(buffer[1]&0xE0)>>4));
222 if (buffer[1] & 0x10)
223 header->version = (buffer[1] >> 3) & 1;
224 else
225 header->version = 2;
226 if ((header->sync != 0xFFE) || (header->layer != 1)) {
227 header->sync = 0;
228 // PARA_DEBUG_LOG("%s: header not found\n", __func__);
229 return 0;
230 }
231 header->crc = buffer[1] & 1;
232 header->bitrate = (buffer[2] >> 4) & 0x0F;
233 // PARA_DEBUG_LOG("%s: found header, bitrate: %u\n", __func__,
234 // header->bitrate);
235 header->freq = (buffer[2] >> 2) & 0x3;
236 header->padding = (buffer[2] >>1) & 0x1;
237 header->mode = (buffer[3] >> 6) & 0x3;
238 fl = frame_length(header);
239 return (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
240 }
241
242 /**
243 * find the next mp3 header
244 *
245 * \return On success, the length of the next frame header. If the end of the
246 * file was reached, the function returns zero. On errors, a negative value is
247 * returned.
248 *
249 */
250 static int mp3_seek_next_header(void)
251 {
252 int k, l = 0, c, first_len;
253 struct mp3header h, h2;
254 long valid_start = 0;
255
256 while (1) {
257 while ((c = fgetc(mp3.file)) != 255 && (c != EOF))
258 ; /* nothing */
259 if (c != 255)
260 return 0;
261 ungetc(c, mp3.file);
262 valid_start = ftell(mp3.file);
263 first_len = get_header(mp3.file, &h);
264 if (first_len <= 0)
265 continue;
266 if (fseek(mp3.file, first_len - FRAME_HEADER_SIZE, SEEK_CUR) < 0)
267 return -E_FSEEK;
268 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
269 if ((l = get_header(mp3.file, &h2)) <= 0)
270 break;
271 if (!compare_headers(&h, &h2))
272 break;
273 fseek(mp3.file, l - FRAME_HEADER_SIZE, SEEK_CUR);
274 }
275 if (k == MIN_CONSEC_GOOD_FRAMES) {
276 fseek(mp3.file, valid_start, SEEK_SET);
277 memcpy(&(mp3.header), &h2, sizeof(struct mp3header));
278 return first_len;
279 }
280 }
281 }
282
283 static int mp3_get_id3(void)
284 {
285 char fbuf[4];
286
287 mp3.id3_isvalid = 0;
288 mp3.id3.title[0] = '\0';
289 mp3.id3.artist[0] = '\0';
290 mp3.id3.album[0] = '\0';
291 mp3.id3.comment[0] = '\0';
292 mp3.id3.year[0] = '\0';
293 if (fseek(mp3.file, -128, SEEK_END))
294 return -E_FSEEK;
295 if (para_fread(fbuf, 1, 3, mp3.file) < 0)
296 return -E_FREAD;
297 fbuf[3] = '\0';
298 if (strcmp("TAG", fbuf)) {
299 PARA_INFO_LOG("%s", "no id3 tag\n");
300 return 0;
301 }
302 if (fseek(mp3.file, -125, SEEK_END) < 0)
303 return -E_FSEEK;
304 if (para_fread(mp3.id3.title, 1, 30, mp3.file) != 30)
305 return -E_FREAD;
306 mp3.id3.title[30] = '\0';
307 if (para_fread(mp3.id3.artist, 1, 30, mp3.file) != 30)
308 return -E_FREAD;
309 mp3.id3.artist[30] = '\0';
310 if (para_fread(mp3.id3.album, 1, 30, mp3.file) != 30)
311 return -E_FREAD;
312 mp3.id3.album[30] = '\0';
313 if (para_fread(mp3.id3.year, 1, 4, mp3.file) != 4)
314 return -E_FREAD;
315 mp3.id3.year[4] = '\0';
316 if (para_fread(mp3.id3.comment, 1, 30, mp3.file) != 30)
317 return -E_FREAD;
318 mp3.id3.comment[30] = '\0';
319 mp3.id3_isvalid = 1;
320 unpad(mp3.id3.title);
321 unpad(mp3.id3.artist);
322 unpad(mp3.id3.album);
323 unpad(mp3.id3.year);
324 unpad(mp3.id3.comment);
325 return 1;
326 }
327
328 static int find_valid_start(void)
329 {
330 int frame_len;
331
332 if (!mp3.file)
333 return -E_MP3_NO_FILE;
334 frame_len = get_header(mp3.file, &mp3.header);
335 if (frame_len < 0)
336 return frame_len;
337 if (!frame_len) {
338 frame_len = mp3_seek_next_header();
339 if (frame_len <= 0)
340 return frame_len;
341 } else
342 if (fseek(mp3.file, -FRAME_HEADER_SIZE, SEEK_CUR) < 0)
343 return -E_FSEEK;
344 if (frame_len <= 1) /* FRAME_HEADER_SIZE? */
345 return -E_FRAME_LENGTH;
346 return frame_len;
347 }
348
349 static int mp3_read_info(void)
350 {
351 long fl_avg = 0, freq_avg = 0, br_avg = 0, fcount = 0;
352 int ret, len = 0, old_br = -1;
353 struct timeval total_time = {0, 0};
354
355 ret = mp3_get_id3();
356 if (ret < 0)
357 return ret;
358 rewind(mp3.file);
359 mp3.vbr = 0;
360 mp3.freq = 0;
361 while (1) {
362 int freq, br, fl;
363 struct timeval tmp, cct; /* current chunk time */
364 if (len > 0)
365 if (fseek(mp3.file, len, SEEK_CUR) < 0)
366 return -E_FSEEK;
367 len = find_valid_start();
368 if (len <= 0)
369 break;
370 freq = header_frequency(&mp3.header);
371 br = header_bitrate(&mp3.header);
372 fl = frame_length(&mp3.header);
373 if (freq < 0 || br < 0 || fl < 0)
374 continue;
375 tmp.tv_sec = fl;
376 tmp.tv_usec = 0;
377 tv_divide(br * 125, &tmp, &cct);
378 tv_add(&cct, &total_time, &tmp);
379 total_time = tmp;
380 // PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
381 fcount++;
382 if (fcount == 1) {
383 freq_avg = freq;
384 br_avg = br;
385 old_br = br;
386 fl_avg = fl;
387 continue;
388 }
389 freq_avg += (freq - freq_avg) / (fcount + 1);
390 fl_avg += (fl - fl_avg) / (fcount + 1);
391 br_avg += (br - br_avg) / (fcount + 1);
392 if (old_br != br)
393 mp3.vbr = 1;
394 old_br = br;
395 }
396 if (!fcount || !freq_avg || !br_avg)
397 return -E_MP3_INFO;
398 mp3.br_average = br_avg;
399 mp3.freq = freq_avg;
400 mp3.frames = fcount;
401 mp3.seconds = (tv2ms(&total_time) + 500) / 1000;
402 tv_divide(fcount, &total_time, &af->chunk_tv);
403 rewind(mp3.file);
404 PARA_DEBUG_LOG("chunk_time: %lums\n", tv2ms(&af->chunk_tv));
405 tv_scale(30, &af->chunk_tv, &af->eof_tv);
406 PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&af->eof_tv));
407 return 1;
408 }
409
410 /*
411 * Read mp3 information from audio file
412 */
413 static int mp3_get_file_info(FILE *audio_file, char *info_str,
414 long unsigned *frames, int *seconds)
415 {
416 int ret;
417
418 if (!audio_file)
419 return -E_MP3_NO_FILE;
420 mp3.file = audio_file;
421 ret = mp3_read_info();
422 if (ret < 0) {
423 mp3.file = NULL;
424 return ret;
425 }
426 write_info_str(info_str);
427 *frames = mp3.frames;
428 *seconds = mp3.seconds;
429 if (*seconds < 2 || !*frames)
430 return -E_MP3_INFO;
431 return 1;
432 }
433
434 static int mp3_reposition_stream(long unsigned new_frame)
435 {
436 int count = 0, len;
437
438 PARA_DEBUG_LOG("jmp to frame %lu/%i\n", new_frame, mp3.frames);
439 rewind(mp3.file);
440 while (count < new_frame && (len = find_valid_start()) > 0) {
441 // PARA_DEBUG_LOG("%s: jmp to frame %d\n", __func__, count);
442 if (fseek(mp3.file, len, SEEK_CUR) < 0)
443 return -E_FSEEK;
444 count++;
445 }
446 if (count != new_frame) {
447 rewind(mp3.file);
448 return -E_MP3_REPOS;
449 }
450 return 1;
451 }
452
453 static int mp3_read_next_chunk(void)
454 {
455 int len = find_valid_start();
456
457 if (len <= 0) {
458 if (len < 0)
459 PARA_ERROR_LOG("invalid frame len (%d)\n", len);
460 return len;
461 }
462 chunk_size = para_fread(mp3buf, len, 1, mp3.file);
463 if (len != chunk_size)
464 PARA_DEBUG_LOG("short read (%d/%d)\n", chunk_size, len);
465 return chunk_size;
466 }
467
468 static char *mp3_read_chunk(__a_unused long unsigned chunk_num, ssize_t *len)
469 {
470 *len = mp3_read_next_chunk();
471 if (*len <= 0)
472 return NULL;
473 return mp3buf;
474 }
475
476 static void mp3_close_audio_file(void)
477 {
478 if (!mp3.file)
479 return;
480 fclose(mp3.file);
481 mp3.file = NULL;
482 }
483
484 static const char* mp3_suffixes[] = {"mp3", NULL};
485 void mp3_init(struct audio_format_handler *p)
486 {
487 af = p;
488 af->get_file_info = mp3_get_file_info;
489 af->reposition_stream = mp3_reposition_stream;
490 af->read_chunk = mp3_read_chunk;
491 af->close_audio_file = mp3_close_audio_file;
492 af->get_header_info = NULL;
493 /* eof_tv gets overwritten in mp3_get_file_info() */
494 af->eof_tv.tv_sec = 0;
495 af->eof_tv.tv_usec = 100 * 1000;
496 af->suffixes = mp3_suffixes;
497 }