Keep the audio file open when mmapping.
[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 /** \endcond */
51 static const int frequencies[3][4] = {
52 {22050,24000,16000,50000}, /* MPEG 2.0 */
53 {44100,48000,32000,50000}, /* MPEG 1.0 */
54 {11025,12000,8000,50000} /* MPEG 2.5 */
55 };
56
57 static const int mp3info_bitrate[2][3][14] = {
58 { /* MPEG 2.0 */
59 {32,48,56,64,80,96,112,128,144,160,176,192,224,256}, /* layer 1 */
60 {8,16,24,32,40,48,56,64,80,96,112,128,144,160}, /* layer 2 */
61 {8,16,24,32,40,48,56,64,80,96,112,128,144,160} /* layer 3 */
62 },
63
64 { /* MPEG 1.0 */
65 {32,64,96,128,160,192,224,256,288,320,352,384,416,448}, /* layer 1 */
66 {32,48,56,64,80,96,112,128,160,192,224,256,320,384}, /* layer 2 */
67 {32,40,48,56,64,80,96,112,128,160,192,224,256,320} /* layer 3 */
68 }
69 };
70
71 static const int frame_size_index[] = {24000, 72000, 72000};
72 static const char *mode_text[] = {"stereo", "joint stereo", "dual channel", "mono", "invalid"};
73
74 /*
75 * Remove trailing whitespace from the end of a string
76 */
77 static char *unpad(char *string)
78 {
79 char *pos = string + strlen(string) - 1;
80 while (para_isspace(pos[0]))
81 (pos--)[0] = 0;
82 return string;
83 }
84
85 static char *mp3_get_id3(unsigned char *map, size_t numbytes)
86 {
87 char title[31], artist[31], album[31], year[5], comment[31];
88 off_t fpos;
89
90 if (numbytes < 128 || strncmp("TAG", (char *)map + numbytes - 128, 3)) {
91 PARA_DEBUG_LOG("no id3 v1 tag\n");
92 return make_message("%s: (no id3 v1 tag)\n%s:\n",
93 status_item_list[SI_TAGINFO1],
94 status_item_list[SI_TAGINFO2]);
95 }
96 fpos = numbytes - 125;
97 memcpy(title, map + fpos, 30);
98 fpos += 30;
99 title[30] = '\0';
100 memcpy(artist, map + fpos, 30);
101 fpos += 30;
102 artist[30] = '\0';
103 memcpy(album, map + fpos, 30);
104 fpos += 30;
105 album[30] = '\0';
106 memcpy(year, map + fpos, 4);
107 fpos += 4;
108 year[4] = '\0';
109 memcpy(comment, map + fpos, 30);
110 comment[30] = '\0';
111 unpad(title);
112 unpad(artist);
113 unpad(album);
114 unpad(year);
115 unpad(comment);
116 return make_message("%s: %s, by %s\n" /* taginfo1 */
117 "%s: A: %s, Y: %s, C: %s\n", /* taginfo 2*/
118 status_item_list[SI_TAGINFO1],
119 *title? title : "(title tag not set)",
120 *artist? artist : "(artist tag not set)",
121 status_item_list[SI_TAGINFO2],
122 *album? album : "(album tag not set)",
123 *year? year : "????",
124 *comment? comment : "(comment tag not set)"
125 );
126 }
127
128 static int header_frequency(struct mp3header *h)
129 {
130 if (h->version > 2 || h->freq > 3)
131 return -E_HEADER_FREQ;
132 return frequencies[h->version][h->freq];
133 }
134
135 static const char *header_mode(struct mp3header *h)
136 {
137 if (h->mode > 4)
138 h->mode = 4; /* invalid */
139 return mode_text[h->mode];
140 }
141
142 static int header_channels(struct mp3header *h)
143 {
144 if (h->mode > 3)
145 return 0;
146 if (h->mode < 3)
147 return 2;
148 return 1;
149 }
150
151 static int header_bitrate(struct mp3header *h)
152 {
153 if (!h->layer || h->layer > 3 || h->bitrate > 14 || !h->bitrate)
154 return -E_HEADER_BITRATE;
155 return mp3info_bitrate[h->version & 1][3 - h->layer][h->bitrate - 1];
156 }
157
158 static int frame_length(struct mp3header *header)
159 {
160 int hb, hf = header_frequency(header);
161
162 if (hf < 0)
163 return hf;
164 hb = header_bitrate(header);
165 if (hb < 0)
166 return hb;
167 if (header->sync != 0xFFE || header->layer > 3)
168 return -E_FRAME;
169 return frame_size_index[3 - header->layer] *
170 ((header->version & 1) + 1) * hb / hf
171 + header->padding;
172 }
173
174 static int compare_headers(struct mp3header *h1,struct mp3header *h2)
175 {
176 if ((*(uint*)h1) == (*(uint*)h2))
177 return 1;
178 if ((h1->version == h2->version) &&
179 (h1->layer == h2->layer) &&
180 (h1->crc == h2->crc) &&
181 (h1->freq == h2->freq) &&
182 (h1->mode == h2->mode) &&
183 (h1->copyright == h2->copyright) &&
184 (h1->original == h2->original) &&
185 (h1->emphasis == h2->emphasis))
186 return 1;
187 return 0;
188 }
189
190 /*
191 * get next MP3 frame header.
192 *
193 * On success, the header frame length is returned and the given header
194 * structure that is filled in. A return value of zero means that we did not
195 * retrieve a valid frame header, and a negative return value indicates an
196 * error.
197 */
198 static int get_header(unsigned char *map, size_t numbytes, off_t *fpos,
199 struct mp3header *header)
200 {
201 int fl, ret;
202
203 if (*fpos + FRAME_HEADER_SIZE > numbytes) {
204 *fpos = numbytes - 1;
205 header->sync = 0;
206 return 0;
207 }
208 header->layer = (map[*fpos + 1] >> 1) & 3;
209 header->sync = (((int)map[*fpos]<<4) | ((int)(map[*fpos + 1]&0xE0)>>4));
210 if (map[*fpos + 1] & 0x10)
211 header->version = (map[*fpos + 1] >> 3) & 1;
212 else
213 header->version = 2;
214 if ((header->sync != 0xFFE) || (header->layer != 1)) {
215 ret = 0;
216 header->sync = 0;
217 goto out;
218 }
219 header->crc = map[*fpos + 1] & 1;
220 header->bitrate = (map[*fpos + 2] >> 4) & 0x0F;
221 header->freq = (map[*fpos + 2] >> 2) & 0x3;
222 header->padding = (map[*fpos + 2] >>1) & 0x1;
223 header->mode = (map[*fpos + 3] >> 6) & 0x3;
224 fl = frame_length(header);
225 ret = (fl >= MIN_FRAME_SIZE)? fl : -E_FRAME_LENGTH;
226 out:
227 *fpos += FRAME_HEADER_SIZE;
228 return ret;
229 }
230
231 /*
232 * find the next mp3 header
233 *
234 * Return the length of the next frame header or zero if the end of the file is
235 * reached.
236 */
237 static int mp3_seek_next_header(unsigned char *map, size_t numbytes, off_t *fpos,
238 struct mp3header *result)
239 {
240 int k, l = 0, first_len;
241 struct mp3header h, h2;
242 long valid_start = 0;
243
244 for (; *fpos < numbytes; (*fpos)++) {
245 if (map[*fpos] != 0xff)
246 continue;
247 valid_start = *fpos;
248 first_len = get_header(map, numbytes, fpos, &h);
249 if (first_len <= 0)
250 continue;
251 *fpos += first_len - FRAME_HEADER_SIZE;
252 for (k = 1; k < MIN_CONSEC_GOOD_FRAMES; k++) {
253 if ((l = get_header(map, numbytes, fpos, &h2)) <= 0)
254 break;
255 if (!compare_headers(&h, &h2))
256 break;
257 *fpos += l - FRAME_HEADER_SIZE;
258 }
259 if (k == MIN_CONSEC_GOOD_FRAMES) {
260 *fpos = valid_start;
261 *result = h2;
262 return first_len;
263 }
264 }
265 return 0;
266 }
267
268 static int find_valid_start(unsigned char *map, size_t numbytes, off_t *fpos,
269 struct mp3header *header)
270 {
271 int frame_len;
272
273 frame_len = get_header(map, numbytes, fpos, header);
274 if (frame_len < 0)
275 return frame_len;
276 if (!frame_len) {
277 frame_len = mp3_seek_next_header(map, numbytes, fpos, header);
278 if (frame_len <= 0)
279 return frame_len;
280 } else
281 *fpos -= FRAME_HEADER_SIZE;
282 if (frame_len <= 1)
283 return -E_FRAME_LENGTH;
284 return frame_len;
285 }
286
287 static int mp3_read_info(unsigned char *map, size_t numbytes,
288 struct afh_info *afhi)
289 {
290 long freq_avg = 0, br_avg = 0;
291 int ret, len = 0, old_br = -1, vbr = 0;
292 struct timeval total_time = {0, 0};
293 unsigned chunk_table_size = 1000; /* gets increased on demand */
294 off_t fpos = 0;
295 struct mp3header header;
296 char *taginfo;
297
298 afhi->chunks_total = 0;
299 afhi->chunk_table = para_malloc(chunk_table_size * sizeof(size_t));
300 taginfo = mp3_get_id3(map, numbytes);
301 while (1) {
302 unsigned long freq, br, fl;
303 struct timeval tmp, cct; /* current chunk time */
304 fpos += len;
305 len = find_valid_start(map, numbytes, &fpos, &header);
306 if (len <= 0)
307 break;
308 ret = header_frequency(&header);
309 if (ret < 0)
310 continue;
311 freq = ret;
312 ret = header_bitrate(&header);
313 if (ret < 0)
314 continue;
315 br = ret;
316 ret = frame_length(&header);
317 if (ret < 0)
318 continue;
319 fl = ret;
320 tmp.tv_sec = fl;
321 tmp.tv_usec = 0;
322 tv_divide(br * 125, &tmp, &cct);
323 tv_add(&cct, &total_time, &tmp);
324 total_time = tmp;
325 //PARA_DEBUG_LOG("%s: br: %d, freq: %d, fl: %d, cct: %lu\n", __func__, br, freq, fl, cct.tv_usec);
326 if (afhi->chunks_total >= chunk_table_size) {
327 chunk_table_size *= 2;
328 afhi->chunk_table = para_realloc(afhi->chunk_table,
329 chunk_table_size * sizeof(size_t));
330 }
331 afhi->chunk_table[afhi->chunks_total] = fpos;
332 // if (afhi->chunks_total < 10 || !(afhi->chunks_total % 1000))
333 // PARA_INFO_LOG("chunk #%lu: %zd\n", afhi->chunks_total,
334 // afhi->chunk_table[afhi->chunks_total]);
335 afhi->chunks_total++;
336 if (afhi->chunks_total == 1) {
337 freq_avg = freq;
338 br_avg = br;
339 old_br = br;
340 continue;
341 }
342 freq_avg += ((long)freq - freq_avg) / ((long)afhi->chunks_total + 1);
343 br_avg += ((long)br - br_avg) / ((long)afhi->chunks_total + 1);
344 if (old_br != br)
345 vbr = 1;
346 old_br = br;
347 }
348 ret = -E_MP3_INFO;
349 if (!afhi->chunks_total || !freq_avg || !br_avg)
350 goto err_out;
351 afhi->chunk_table[afhi->chunks_total] = numbytes - 1;
352 afhi->bitrate = br_avg;
353 afhi->frequency = freq_avg;
354 afhi->channels = header_channels(&header);
355 afhi->seconds_total = (tv2ms(&total_time) + 500) / 1000;
356 tv_divide(afhi->chunks_total, &total_time, &afhi->chunk_tv);
357 PARA_DEBUG_LOG("%lu chunks, each %lums\n", afhi->chunks_total,
358 tv2ms(&afhi->chunk_tv));
359 tv_scale(3, &afhi->chunk_tv, &afhi->eof_tv);
360 PARA_DEBUG_LOG("eof timeout: %lu\n", tv2ms(&afhi->eof_tv));
361 afhi->info_string = make_message("%s: %cbr, %s\n%s",
362 status_item_list[SI_AUDIO_FILE_INFO], vbr? 'v' : 'c',
363 header_mode(&header), taginfo);
364 free(taginfo);
365 return 1;
366 err_out:
367 free(taginfo);
368 PARA_ERROR_LOG("%s\n", para_strerror(-ret));
369 free(afhi->chunk_table);
370 return ret;
371 }
372
373 /*
374 * Read mp3 information from audio file
375 */
376 static int mp3_get_file_info(char *map, size_t numbytes, int fd,
377 struct afh_info *afhi)
378 {
379 int ret;
380
381 ret = mp3_read_info((unsigned char *)map, numbytes, afhi);
382 if (ret < 0)
383 return ret;
384 if (afhi->seconds_total < 2 || !afhi->chunks_total)
385 return -E_MP3_INFO;
386 return 1;
387 }
388
389 static const char* mp3_suffixes[] = {"mp3", NULL};
390
391 /**
392 * the init function of the mp3 audio format handler
393 *
394 * \param afh pointer to the struct to initialize
395 */
396 void mp3_init(struct audio_format_handler *afh)
397 {
398 afh->get_file_info = mp3_get_file_info;
399 afh->suffixes = mp3_suffixes;
400 }