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 <osl.h>
  14 #include "para.h"
  15 #include "error.h"
  16 #include "string.h"
  17 #include "afh.h"
  18 #include "afs.h"
  19 #include "server.h"
  20 #include "aac.h"
  21
  22 static int aac_find_stsz(unsigned char *buf, size_t buflen, off_t *skip)
  23 {
  24         int i;
  25
  26         for (i = 0; i + 16 < buflen; i++) {
  27                 unsigned char *p = buf + i;
  28                 unsigned sample_count, sample_size;
  29
  30                 if (p[0] != 's' || p[1] != 't' || p[2] != 's' || p[3] != 'z')
  31                         continue;
  32                 PARA_DEBUG_LOG("found stsz@%d\n", i);
  33                 i += 8;
  34                 sample_size = aac_read_int32(buf + i);
  35                 PARA_DEBUG_LOG("sample size: %d\n", sample_size);
  36                 i += 4;
  37                 sample_count = aac_read_int32(buf + i);
  38                 i += 4;
  39                 PARA_DEBUG_LOG("sample count: %d\n", sample_count);
  40                 *skip = i;
  41                 return sample_count;
  42         }
  43         return -E_STSZ;
  44 }
  45
  46 static int atom_cmp(unsigned char *buf1, char *buf2)
  47 {
  48         unsigned char *b2 = (unsigned char *)buf2;
  49
  50         if (buf1[0] != b2[0])
  51                 return 1;
  52         if (buf1[1] != b2[1])
  53                 return 1;
  54         if (buf1[2] != b2[2])
  55                 return 1;
  56         if (buf1[3] != b2[3])
  57                 return 1;
  58         return 0;
  59 }
  60
  61 static int read_atom_header(unsigned char *buf, uint64_t *subsize, unsigned char type[5])
  62 {
  63         int i;
  64         uint64_t size = (buf[0] << 24) + (buf[1] << 16) + (buf[2] << 8) + buf[3];
  65
  66         memcpy(type, buf + 4, 4);
  67         type[4] = '\0';
  68
  69         PARA_DEBUG_LOG("size: %llu, type: %s\n", (long long unsigned)size, type);
  70         if (size != 1) {
  71                 *subsize = size;
  72                 return 8;
  73         }
  74         buf += 4;
  75         size = 0;
  76         for (i = 0; i < 8; i++)
  77                 size |= ((uint64_t)buf[i]) << ((7 - i) * 8);
  78         *subsize = size;
  79         return 16;
  80 }
  81
  82 static char *get_tag(unsigned char *p, int size)
  83 {
  84         char *buf;
  85
  86         assert(size > 0);
  87         buf = para_malloc(size + 1);
  88
  89         memcpy(buf, p, size);
  90         buf[size] = '\0';
  91         PARA_DEBUG_LOG("size: %d: %s\n", size, buf);
  92         return buf;
  93 }
  94
  95 static char *read_tags(unsigned char *buf, size_t buflen)
  96 {
  97         unsigned char *p = buf;
  98         char *title = NULL, *artist = NULL, *album = NULL, *year = NULL,
  99                 *comment = NULL, *result;
 100
 101         while (p + 32 < buf + buflen) {
 102                 unsigned char *q, type1[5], type2[5];
 103                 uint64_t size1, size2;
 104                 int ret, ret2;
 105
 106                 ret = read_atom_header(p, &size1, type1);
 107                 ret2 = read_atom_header(p + ret, &size2, type2);
 108
 109                 if (size2 <= 16 || atom_cmp(type2, "data")) {
 110                         p += size1;
 111                         continue;
 112                 }
 113                 size2 -= 16;
 114                 q = p + ret + ret2 + 8;
 115                 if (q + size2 > buf + buflen)
 116                         break;
 117                 if (!atom_cmp(type1, "©ART"))
 118                         artist = get_tag(q, size2);
 119                 else if (!atom_cmp(type1, "©alb"))
 120                         album = get_tag(q, size2);
 121                 else if (!atom_cmp(type1, "©nam"))
 122                         title = get_tag(q, size2);
 123                 else if (!atom_cmp(type1, "©cmt"))
 124                         comment = get_tag(q, size2);
 125                 else if (!atom_cmp(type1, "©day"))
 126                         year = get_tag(q, size2);
 127                 p += size1;
 128         }
 129         result = make_taginfo(title, artist, album, year, comment);
 130         free(title);
 131         free(artist);
 132         free(album);
 133         free(year);
 134         free(comment);
 135         return result;
 136 }
 137
 138 static char *read_meta(unsigned char *buf, size_t buflen)
 139 {
 140         unsigned char *p = buf;
 141
 142         while (p + 4 < buf + buflen) {
 143
 144                 if (p[0] != 'i' || p[1] != 'l' || p[2] != 's' || p[3] != 't') {
 145                         p++;
 146                         continue;
 147                 }
 148                 p += 4;
 149                 return read_tags(p, buflen - (p - buf));
 150         }
 151         return make_taginfo(NULL, NULL, NULL, NULL, NULL);
 152 }
 153
 154 static char *aac_get_taginfo(unsigned char *buf, size_t buflen)
 155 {
 156         int i;
 157         uint64_t subsize;
 158         unsigned char type[5];
 159
 160         for (i = 0; i + 24 < buflen; i++) {
 161                 unsigned char *p = buf + i;
 162                 if (p[0] != 'm' || p[1] != 'e' || p[2] != 't' || p[3] != 'a')
 163                         continue;
 164                 PARA_INFO_LOG("found metadata at offset %d\n", i);
 165                 i += 8;
 166                 p = buf + i;
 167                 i += read_atom_header(p, &subsize, type);
 168                 p = buf + i;
 169                 return read_meta(p, buflen - i);
 170         }
 171         PARA_INFO_LOG("no meta data\n");
 172         return make_taginfo(NULL, NULL, NULL, NULL, NULL);
 173 }
 174
 175 static ssize_t aac_compute_chunk_table(struct afh_info *afhi,
 176                 unsigned char *map, size_t numbytes)
 177 {
 178         int ret, i;
 179         size_t sum = 0;
 180         off_t skip;
 181
 182         ret = aac_find_stsz(map, numbytes, &skip);
 183         if (ret < 0)
 184                 return ret;
 185         afhi->chunks_total = ret;
 186         PARA_DEBUG_LOG("sz table has %lu entries\n", afhi->chunks_total);
 187         afhi->chunk_table = para_malloc((afhi->chunks_total + 1) * sizeof(size_t));
 188         for (i = 1; i <= afhi->chunks_total; i++) {
 189                 if (skip + 4 > numbytes)
 190                         break;
 191                 sum += aac_read_int32(map + skip);
 192                 afhi->chunk_table[i] = sum;
 193                 skip += 4;
 194 //              if (i < 10 || i + 10 > afhi->chunks_total)
 195 //                      PARA_DEBUG_LOG("offset #%d: %zu\n", i, afhi->chunk_table[i]);
 196         }
 197         return skip;
 198 }
 199
 200 static int aac_set_chunk_tv(struct afh_info *afhi,
 201                 mp4AudioSpecificConfig *mp4ASC, long unsigned *seconds)
 202 {
 203         float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023;
 204         struct timeval total;
 205         long unsigned ms = 1000.0 * afhi->chunks_total * tmp
 206                 / mp4ASC->samplingFrequency;
 207
 208         if (!mp4ASC->samplingFrequency)
 209                 return -E_MP4ASC;
 210         ms = 1000.0 * afhi->chunks_total * tmp / mp4ASC->samplingFrequency;
 211         ms2tv(ms, &total);
 212         tv_divide(afhi->chunks_total, &total, &afhi->chunk_tv);
 213         PARA_INFO_LOG("%luHz, %lus (%lu x %lums)\n",
 214                 mp4ASC->samplingFrequency, ms / 1000,
 215                 afhi->chunks_total, tv2ms(&afhi->chunk_tv));
 216         if (ms < 1000)
 217                 return -E_MP4ASC;
 218         *seconds = ms / 1000;
 219         return 1;
 220 }
 221
 222 /*
 223  * Init m4a file and write some tech data to given pointers.
 224  */
 225 static int aac_get_file_info(char *map, size_t numbytes, __a_unused int fd,
 226                 struct afh_info *afhi)
 227 {
 228         int i;
 229         size_t skip;
 230         ssize_t ret;
 231         unsigned long rate = 0, decoder_len;
 232         unsigned char channels = 0;
 233         mp4AudioSpecificConfig mp4ASC;
 234         NeAACDecHandle handle = NULL;
 235         unsigned char *umap = (unsigned char *) map;
 236         char *taginfo;
 237
 238         ret = aac_find_esds(umap, numbytes, &skip, &decoder_len);
 239         if (ret < 0)
 240                 goto out;
 241         taginfo = aac_get_taginfo(umap, numbytes);
 242         handle = aac_open();
 243         ret = -E_AAC_AFH_INIT;
 244         if (NeAACDecInit(handle, umap + skip, decoder_len, &rate, &channels))
 245                 goto out;
 246         if (!channels)
 247                 goto out;
 248         PARA_DEBUG_LOG("rate: %lu, channels: %d\n", rate, channels);
 249         ret = -E_MP4ASC;
 250         if (NeAACDecAudioSpecificConfig(umap + skip, numbytes - skip, &mp4ASC))
 251                 goto out;
 252         if (!mp4ASC.samplingFrequency)
 253                 goto out;
 254         ret = aac_compute_chunk_table(afhi, umap, numbytes);
 255         if (ret < 0)
 256                 goto out;
 257         skip = ret;
 258         ret = aac_set_chunk_tv(afhi, &mp4ASC, &afhi->seconds_total);
 259         if (ret < 0)
 260                 goto out;
 261         ret = aac_find_entry_point(umap + skip, numbytes - skip, &skip);
 262         if (ret < 0)
 263                 goto out;
 264         afhi->chunk_table[0] = ret;
 265         for (i = 1; i<= afhi->chunks_total; i++)
 266                 afhi->chunk_table[i] += ret;
 267         afhi->channels = channels;
 268         afhi->frequency = rate;
 269         ret = (afhi->chunk_table[afhi->chunks_total] - afhi->chunk_table[0]) * 8; /* bits */
 270         ret += (channels * afhi->seconds_total * 500); /* avoid rounding error */
 271         afhi->bitrate = ret / (channels * afhi->seconds_total * 1000);
 272         afhi->info_string = make_message("%s:\n%s",
 273                 status_item_list[SI_AUDIO_FILE_INFO],
 274                 taginfo);
 275         free(taginfo);
 276         tv_scale(20, &afhi->chunk_tv, &afhi->eof_tv);
 277         ret = 1;
 278 out:
 279         if (handle)
 280                 NeAACDecClose(handle);
 281         return ret;
 282 }
 283
 284 static const char* aac_suffixes[] = {"m4a", "mp4", NULL};
 285 /**
 286  * the init function of the aac audio format handler
 287  *
 288  * \param afh pointer to the struct to initialize
 289  */
 290 void aac_afh_init(struct audio_format_handler *afh)
 291 {
 292         afh->get_file_info = aac_get_file_info,
 293         afh->suffixes = aac_suffixes;
 294 }