aac_afh.c

   1 /*
   2  * Copyright (C) 2006-2011 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 <regex.h>
  14
  15 #include "para.h"
  16 #include "error.h"
  17 #include "afh.h"
  18 #include "string.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(const unsigned char *buf1, const char *buf2)
  46 {
  47         const 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 void read_tags(unsigned char *buf, size_t buflen, struct afh_info *afhi)
  95 {
  96         unsigned char *p = buf;
  97
  98         while (p + 32 < buf + buflen) {
  99                 unsigned char *q, type1[5], type2[5];
 100                 uint64_t size1, size2;
 101                 int ret, ret2;
 102
 103                 ret = read_atom_header(p, &size1, type1);
 104                 ret2 = read_atom_header(p + ret, &size2, type2);
 105
 106                 if (size2 <= 16 || atom_cmp(type2, "data")) {
 107                         p += size1;
 108                         continue;
 109                 }
 110                 size2 -= 16;
 111                 q = p + ret + ret2 + 8;
 112                 if (q + size2 > buf + buflen)
 113                         break;
 114                 if (!atom_cmp(type1, "©ART"))
 115                         afhi->tags.artist = get_tag(q, size2);
 116                 else if (!atom_cmp(type1, "©alb"))
 117                         afhi->tags.album = get_tag(q, size2);
 118                 else if (!atom_cmp(type1, "©nam"))
 119                         afhi->tags.title = get_tag(q, size2);
 120                 else if (!atom_cmp(type1, "©cmt"))
 121                         afhi->tags.comment = get_tag(q, size2);
 122                 else if (!atom_cmp(type1, "©day"))
 123                         afhi->tags.year = get_tag(q, size2);
 124                 p += size1;
 125         }
 126 }
 127
 128 static void read_meta(unsigned char *buf, size_t buflen, struct afh_info *afhi)
 129 {
 130         unsigned char *p = buf;
 131
 132         while (p + 4 < buf + buflen) {
 133
 134                 if (p[0] != 'i' || p[1] != 'l' || p[2] != 's' || p[3] != 't') {
 135                         p++;
 136                         continue;
 137                 }
 138                 p += 4;
 139                 return read_tags(p, buflen - (p - buf), afhi);
 140         }
 141 }
 142
 143 static void aac_get_taginfo(unsigned char *buf, size_t buflen,
 144                 struct afh_info *afhi)
 145 {
 146         int i;
 147         uint64_t subsize;
 148         unsigned char type[5];
 149
 150         for (i = 0; i + 24 < buflen; i++) {
 151                 unsigned char *p = buf + i;
 152                 if (p[0] != 'm' || p[1] != 'e' || p[2] != 't' || p[3] != 'a')
 153                         continue;
 154                 PARA_INFO_LOG("found metadata at offset %d\n", i);
 155                 i += 8;
 156                 p = buf + i;
 157                 i += read_atom_header(p, &subsize, type);
 158                 p = buf + i;
 159                 return read_meta(p, buflen - i, afhi);
 160         }
 161         PARA_INFO_LOG("no meta data\n");
 162 }
 163
 164 static ssize_t aac_compute_chunk_table(struct afh_info *afhi,
 165                 unsigned char *map, size_t numbytes)
 166 {
 167         int ret, i;
 168         size_t sum = 0;
 169         off_t skip;
 170
 171         ret = aac_find_stsz(map, numbytes, &skip);
 172         if (ret < 0)
 173                 return ret;
 174         afhi->chunks_total = ret;
 175         PARA_DEBUG_LOG("sz table has %lu entries\n", afhi->chunks_total);
 176         afhi->chunk_table = para_malloc((afhi->chunks_total + 1) * sizeof(size_t));
 177         for (i = 1; i <= afhi->chunks_total; i++) {
 178                 if (skip + 4 > numbytes)
 179                         break;
 180                 sum += aac_read_int32(map + skip);
 181                 afhi->chunk_table[i] = sum;
 182                 skip += 4;
 183 //              if (i < 10 || i + 10 > afhi->chunks_total)
 184 //                      PARA_DEBUG_LOG("offset #%d: %zu\n", i, afhi->chunk_table[i]);
 185         }
 186         return skip;
 187 }
 188
 189 static int aac_set_chunk_tv(struct afh_info *afhi,
 190                 mp4AudioSpecificConfig *mp4ASC, long unsigned *seconds)
 191 {
 192         float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023;
 193         struct timeval total;
 194         long unsigned ms = 1000.0 * afhi->chunks_total * tmp
 195                 / mp4ASC->samplingFrequency;
 196
 197         if (!mp4ASC->samplingFrequency)
 198                 return -E_MP4ASC;
 199         ms = 1000.0 * afhi->chunks_total * tmp / mp4ASC->samplingFrequency;
 200         ms2tv(ms, &total);
 201         tv_divide(afhi->chunks_total, &total, &afhi->chunk_tv);
 202         PARA_INFO_LOG("%luHz, %lus (%lu x %lums)\n",
 203                 mp4ASC->samplingFrequency, ms / 1000,
 204                 afhi->chunks_total, tv2ms(&afhi->chunk_tv));
 205         if (ms < 1000)
 206                 return -E_MP4ASC;
 207         *seconds = ms / 1000;
 208         return 1;
 209 }
 210
 211 /*
 212  * Init m4a file and write some tech data to given pointers.
 213  */
 214 static int aac_get_file_info(char *map, size_t numbytes, __a_unused int fd,
 215                 struct afh_info *afhi)
 216 {
 217         int i;
 218         size_t skip;
 219         ssize_t ret;
 220         unsigned long rate = 0, decoder_len;
 221         unsigned char channels = 0;
 222         mp4AudioSpecificConfig mp4ASC;
 223         NeAACDecHandle handle = NULL;
 224         unsigned char *umap = (unsigned char *) map;
 225
 226         ret = aac_find_esds(umap, numbytes, &skip, &decoder_len);
 227         if (ret < 0)
 228                 goto out;
 229         aac_get_taginfo(umap, numbytes, afhi);
 230         handle = aac_open();
 231         ret = -E_AAC_AFH_INIT;
 232         if (NeAACDecInit(handle, umap + skip, decoder_len, &rate, &channels))
 233                 goto out;
 234         if (!channels)
 235                 goto out;
 236         PARA_DEBUG_LOG("rate: %lu, channels: %d\n", rate, channels);
 237         ret = -E_MP4ASC;
 238         if (NeAACDecAudioSpecificConfig(umap + skip, numbytes - skip, &mp4ASC))
 239                 goto out;
 240         if (!mp4ASC.samplingFrequency)
 241                 goto out;
 242         ret = aac_compute_chunk_table(afhi, umap, numbytes);
 243         if (ret < 0)
 244                 goto out;
 245         skip = ret;
 246         ret = aac_set_chunk_tv(afhi, &mp4ASC, &afhi->seconds_total);
 247         if (ret < 0)
 248                 goto out;
 249         ret = aac_find_entry_point(umap + skip, numbytes - skip, &skip);
 250         if (ret < 0)
 251                 goto out;
 252         afhi->chunk_table[0] = ret;
 253         for (i = 1; i<= afhi->chunks_total; i++)
 254                 afhi->chunk_table[i] += ret;
 255         afhi->channels = channels;
 256         afhi->frequency = rate;
 257         ret = (afhi->chunk_table[afhi->chunks_total] - afhi->chunk_table[0]) * 8; /* bits */
 258         ret += (channels * afhi->seconds_total * 500); /* avoid rounding error */
 259         afhi->bitrate = ret / (channels * afhi->seconds_total * 1000);
 260         ret = 1;
 261 out:
 262         if (handle)
 263                 NeAACDecClose(handle);
 264         return ret;
 265 }
 266
 267 static const char* aac_suffixes[] = {"m4a", "mp4", NULL};
 268 /**
 269  * the init function of the aac audio format handler
 270  *
 271  * \param afh pointer to the struct to initialize
 272  */
 273 void aac_afh_init(struct audio_format_handler *afh)
 274 {
 275         afh->get_file_info = aac_get_file_info,
 276         afh->suffixes = aac_suffixes;
 277 }