aac_afh.c

   1 /*
   2  * Copyright (C) 2006-2008 Andre Noll <maan@systemlinux.org>
   3  *
   4  * Licensed under the GPL v2. For licencing details see COPYING.
   5  */
   6 /*
   7  * based in parts on libfaad, Copyright (C) 2003-2005 M. Bakker,
   8  * Ahead Software AG
   9  */
  10
  11 /** \file aac_afh.c para_server's aac audio format handler */
  12
  13 #include "para.h"
  14 #include "error.h"
  15 #include "string.h"
  16 #include "afh.h"
  17 #include "afs.h"
  18 #include "server.h"
  19 #include "aac.h"
  20
  21 static int aac_find_stsz(unsigned char *buf, size_t buflen, off_t *skip)
  22 {
  23         int i;
  24
  25         for (i = 0; i + 16 < buflen; i++) {
  26                 unsigned char *p = buf + i;
  27                 unsigned sample_count, sample_size;
  28
  29                 if (p[0] != 's' || p[1] != 't' || p[2] != 's' || p[3] != 'z')
  30                         continue;
  31                 PARA_DEBUG_LOG("found stsz@%d\n", i);
  32                 i += 8;
  33                 sample_size = aac_read_int32(buf + i);
  34                 PARA_DEBUG_LOG("sample size: %d\n", sample_size);
  35                 i += 4;
  36                 sample_count = aac_read_int32(buf + i);
  37                 i += 4;
  38                 PARA_DEBUG_LOG("sample count: %d\n", sample_count);
  39                 *skip = i;
  40                 return sample_count;
  41         }
  42         return -E_STSZ;
  43 }
  44
  45 static int atom_cmp(unsigned char *buf1, char *buf2)
  46 {
  47         unsigned char *b2 = (unsigned char *)buf2;
  48
  49         if (buf1[0] != b2[0])
  50                 return 1;
  51         if (buf1[1] != b2[1])
  52                 return 1;
  53         if (buf1[2] != b2[2])
  54                 return 1;
  55         if (buf1[3] != b2[3])
  56                 return 1;
  57         return 0;
  58 }
  59
  60 static int read_atom_header(unsigned char *buf, uint64_t *subsize, unsigned char type[5])
  61 {
  62         int i;
  63         uint64_t size = (buf[0] << 24) + (buf[1] << 16) + (buf[2] << 8) + buf[3];
  64
  65         memcpy(type, buf + 4, 4);
  66         type[4] = '\0';
  67
  68         PARA_DEBUG_LOG("size: %llu, type: %s\n", (long long unsigned)size, type);
  69         if (size != 1) {
  70                 *subsize = size;
  71                 return 8;
  72         }
  73         buf += 4;
  74         size = 0;
  75         for (i = 0; i < 8; i++)
  76                 size |= ((uint64_t)buf[i]) << ((7 - i) * 8);
  77         *subsize = size;
  78         return 16;
  79 }
  80
  81 static char *get_tag(unsigned char *p, int size)
  82 {
  83         char *buf;
  84
  85         assert(size > 0);
  86         buf = para_malloc(size + 1);
  87
  88         memcpy(buf, p, size);
  89         buf[size] = '\0';
  90         PARA_DEBUG_LOG("size: %d: %s\n", size, buf);
  91         return buf;
  92 }
  93
  94 static char *read_tags(unsigned char *buf, size_t buflen)
  95 {
  96         unsigned char *p = buf;
  97         char *title = NULL, *artist = NULL, *album = NULL, *year = NULL,
  98                 *comment = NULL, *result;
  99
 100         while (p + 32 < buf + buflen) {
 101                 unsigned char *q, type1[5], type2[5];
 102                 uint64_t size1, size2;
 103                 int ret, ret2;
 104
 105                 ret = read_atom_header(p, &size1, type1);
 106                 ret2 = read_atom_header(p + ret, &size2, type2);
 107
 108                 if (size2 <= 16 || atom_cmp(type2, "data")) {
 109                         p += size1;
 110                         continue;
 111                 }
 112                 size2 -= 16;
 113                 q = p + ret + ret2 + 8;
 114                 if (q + size2 > buf + buflen)
 115                         break;
 116                 if (!atom_cmp(type1, "©ART"))
 117                         artist = get_tag(q, size2);
 118                 else if (!atom_cmp(type1, "©alb"))
 119                         album = get_tag(q, size2);
 120                 else if (!atom_cmp(type1, "©nam"))
 121                         title = get_tag(q, size2);
 122                 else if (!atom_cmp(type1, "©cmt"))
 123                         comment = get_tag(q, size2);
 124                 else if (!atom_cmp(type1, "©day"))
 125                         year = get_tag(q, size2);
 126                 p += size1;
 127         }
 128         result = make_taginfo(title, artist, album, year, comment);
 129         free(title);
 130         free(artist);
 131         free(album);
 132         free(year);
 133         free(comment);
 134         return result;
 135 }
 136
 137 static char *read_meta(unsigned char *buf, size_t buflen)
 138 {
 139         unsigned char *p = buf;
 140
 141         while (p + 4 < buf + buflen) {
 142
 143                 if (p[0] != 'i' || p[1] != 'l' || p[2] != 's' || p[3] != 't') {
 144                         p++;
 145                         continue;
 146                 }
 147                 p += 4;
 148                 return read_tags(p, buflen - (p - buf));
 149         }
 150         return make_taginfo(NULL, NULL, NULL, NULL, NULL);
 151 }
 152
 153 static char *aac_get_taginfo(unsigned char *buf, size_t buflen)
 154 {
 155         int i;
 156         uint64_t subsize;
 157         unsigned char type[5];
 158
 159         for (i = 0; i + 24 < buflen; i++) {
 160                 unsigned char *p = buf + i;
 161                 if (p[0] != 'm' || p[1] != 'e' || p[2] != 't' || p[3] != 'a')
 162                         continue;
 163                 PARA_INFO_LOG("found metadata at offset %d\n", i);
 164                 i += 8;
 165                 p = buf + i;
 166                 i += read_atom_header(p, &subsize, type);
 167                 p = buf + i;
 168                 return read_meta(p, buflen - i);
 169         }
 170         PARA_INFO_LOG("no meta data\n");
 171         return make_taginfo(NULL, NULL, NULL, NULL, NULL);
 172 }
 173
 174 static ssize_t aac_compute_chunk_table(struct afh_info *afhi,
 175                 unsigned char *map, size_t numbytes)
 176 {
 177         int ret, i;
 178         size_t sum = 0;
 179         off_t skip;
 180
 181         ret = aac_find_stsz(map, numbytes, &skip);
 182         if (ret < 0)
 183                 return ret;
 184         afhi->chunks_total = ret;
 185         PARA_DEBUG_LOG("sz table has %lu entries\n", afhi->chunks_total);
 186         afhi->chunk_table = para_malloc((afhi->chunks_total + 1) * sizeof(size_t));
 187         for (i = 1; i <= afhi->chunks_total; i++) {
 188                 if (skip + 4 > numbytes)
 189                         break;
 190                 sum += aac_read_int32(map + skip);
 191                 afhi->chunk_table[i] = sum;
 192                 skip += 4;
 193 //              if (i < 10 || i + 10 > afhi->chunks_total)
 194 //                      PARA_DEBUG_LOG("offset #%d: %zu\n", i, afhi->chunk_table[i]);
 195         }
 196         return skip;
 197 }
 198
 199 static int aac_set_chunk_tv(struct afh_info *afhi,
 200                 mp4AudioSpecificConfig *mp4ASC, long unsigned *seconds)
 201 {
 202         float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023;
 203         struct timeval total;
 204         long unsigned ms = 1000.0 * afhi->chunks_total * tmp
 205                 / mp4ASC->samplingFrequency;
 206
 207         if (!mp4ASC->samplingFrequency)
 208                 return -E_MP4ASC;
 209         ms = 1000.0 * afhi->chunks_total * tmp / mp4ASC->samplingFrequency;
 210         ms2tv(ms, &total);
 211         tv_divide(afhi->chunks_total, &total, &afhi->chunk_tv);
 212         PARA_INFO_LOG("%luHz, %lus (%lu x %lums)\n",
 213                 mp4ASC->samplingFrequency, ms / 1000,
 214                 afhi->chunks_total, tv2ms(&afhi->chunk_tv));
 215         if (ms < 1000)
 216                 return -E_MP4ASC;
 217         *seconds = ms / 1000;
 218         return 1;
 219 }
 220
 221 /*
 222  * Init m4a file and write some tech data to given pointers.
 223  */
 224 static int aac_get_file_info(char *map, size_t numbytes, __a_unused int fd,
 225                 struct afh_info *afhi)
 226 {
 227         int i;
 228         size_t skip;
 229         ssize_t ret;
 230         unsigned long rate = 0, decoder_len;
 231         unsigned char channels = 0;
 232         mp4AudioSpecificConfig mp4ASC;
 233         NeAACDecHandle handle = NULL;
 234         unsigned char *umap = (unsigned char *) map;
 235         char *taginfo;
 236
 237         ret = aac_find_esds(umap, numbytes, &skip, &decoder_len);
 238         if (ret < 0)
 239                 goto out;
 240         taginfo = aac_get_taginfo(umap, numbytes);
 241         handle = aac_open();
 242         ret = -E_AAC_AFH_INIT;
 243         if (NeAACDecInit(handle, umap + skip, decoder_len, &rate, &channels))
 244                 goto out;
 245         if (!channels)
 246                 goto out;
 247         PARA_DEBUG_LOG("rate: %lu, channels: %d\n", rate, channels);
 248         ret = -E_MP4ASC;
 249         if (NeAACDecAudioSpecificConfig(umap + skip, numbytes - skip, &mp4ASC))
 250                 goto out;
 251         if (!mp4ASC.samplingFrequency)
 252                 goto out;
 253         ret = aac_compute_chunk_table(afhi, umap, numbytes);
 254         if (ret < 0)
 255                 goto out;
 256         skip = ret;
 257         ret = aac_set_chunk_tv(afhi, &mp4ASC, &afhi->seconds_total);
 258         if (ret < 0)
 259                 goto out;
 260         ret = aac_find_entry_point(umap + skip, numbytes - skip, &skip);
 261         if (ret < 0)
 262                 goto out;
 263         afhi->chunk_table[0] = ret;
 264         for (i = 1; i<= afhi->chunks_total; i++)
 265                 afhi->chunk_table[i] += ret;
 266         afhi->channels = channels;
 267         afhi->frequency = rate;
 268         ret = (afhi->chunk_table[afhi->chunks_total] - afhi->chunk_table[0]) * 8; /* bits */
 269         ret += (channels * afhi->seconds_total * 500); /* avoid rounding error */
 270         afhi->bitrate = ret / (channels * afhi->seconds_total * 1000);
 271         afhi->info_string = make_message("%s:\n%s",
 272                 status_item_list[SI_AUDIO_FILE_INFO],
 273                 taginfo);
 274         free(taginfo);
 275         tv_scale(20, &afhi->chunk_tv, &afhi->eof_tv);
 276         ret = 1;
 277 out:
 278         if (handle)
 279                 NeAACDecClose(handle);
 280         return ret;
 281 }
 282
 283 static const char* aac_suffixes[] = {"m4a", "mp4", NULL};
 284 /**
 285  * the init function of the aac audio format handler
 286  *
 287  * \param afh pointer to the struct to initialize
 288  */
 289 void aac_afh_init(struct audio_format_handler *afh)
 290 {
 291         afh->get_file_info = aac_get_file_info,
 292         afh->suffixes = aac_suffixes;
 293 }