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 <regex.h>
  14 #include <osl.h>
  15
  16 #include "para.h"
  17 #include "error.h"
  18 #include "afh.h"
  19 #include "string.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 void read_tags(unsigned char *buf, size_t buflen, struct afh_info *afhi)
  96 {
  97         unsigned char *p = buf;
  98
  99         while (p + 32 < buf + buflen) {
 100                 unsigned char *q, type1[5], type2[5];
 101                 uint64_t size1, size2;
 102                 int ret, ret2;
 103
 104                 ret = read_atom_header(p, &size1, type1);
 105                 ret2 = read_atom_header(p + ret, &size2, type2);
 106
 107                 if (size2 <= 16 || atom_cmp(type2, "data")) {
 108                         p += size1;
 109                         continue;
 110                 }
 111                 size2 -= 16;
 112                 q = p + ret + ret2 + 8;
 113                 if (q + size2 > buf + buflen)
 114                         break;
 115                 if (!atom_cmp(type1, "©ART"))
 116                         afhi->tags.artist = get_tag(q, size2);
 117                 else if (!atom_cmp(type1, "©alb"))
 118                         afhi->tags.album = get_tag(q, size2);
 119                 else if (!atom_cmp(type1, "©nam"))
 120                         afhi->tags.title = get_tag(q, size2);
 121                 else if (!atom_cmp(type1, "©cmt"))
 122                         afhi->tags.comment = get_tag(q, size2);
 123                 else if (!atom_cmp(type1, "©day"))
 124                         afhi->tags.year = get_tag(q, size2);
 125                 p += size1;
 126         }
 127 }
 128
 129 static void read_meta(unsigned char *buf, size_t buflen, struct afh_info *afhi)
 130 {
 131         unsigned char *p = buf;
 132
 133         while (p + 4 < buf + buflen) {
 134
 135                 if (p[0] != 'i' || p[1] != 'l' || p[2] != 's' || p[3] != 't') {
 136                         p++;
 137                         continue;
 138                 }
 139                 p += 4;
 140                 return read_tags(p, buflen - (p - buf), afhi);
 141         }
 142 }
 143
 144 static void aac_get_taginfo(unsigned char *buf, size_t buflen,
 145                 struct afh_info *afhi)
 146 {
 147         int i;
 148         uint64_t subsize;
 149         unsigned char type[5];
 150
 151         for (i = 0; i + 24 < buflen; i++) {
 152                 unsigned char *p = buf + i;
 153                 if (p[0] != 'm' || p[1] != 'e' || p[2] != 't' || p[3] != 'a')
 154                         continue;
 155                 PARA_INFO_LOG("found metadata at offset %d\n", i);
 156                 i += 8;
 157                 p = buf + i;
 158                 i += read_atom_header(p, &subsize, type);
 159                 p = buf + i;
 160                 return read_meta(p, buflen - i, afhi);
 161         }
 162         PARA_INFO_LOG("no meta data\n");
 163 }
 164
 165 static ssize_t aac_compute_chunk_table(struct afh_info *afhi,
 166                 unsigned char *map, size_t numbytes)
 167 {
 168         int ret, i;
 169         size_t sum = 0;
 170         off_t skip;
 171
 172         ret = aac_find_stsz(map, numbytes, &skip);
 173         if (ret < 0)
 174                 return ret;
 175         afhi->chunks_total = ret;
 176         PARA_DEBUG_LOG("sz table has %lu entries\n", afhi->chunks_total);
 177         afhi->chunk_table = para_malloc((afhi->chunks_total + 1) * sizeof(size_t));
 178         for (i = 1; i <= afhi->chunks_total; i++) {
 179                 if (skip + 4 > numbytes)
 180                         break;
 181                 sum += aac_read_int32(map + skip);
 182                 afhi->chunk_table[i] = sum;
 183                 skip += 4;
 184 //              if (i < 10 || i + 10 > afhi->chunks_total)
 185 //                      PARA_DEBUG_LOG("offset #%d: %zu\n", i, afhi->chunk_table[i]);
 186         }
 187         return skip;
 188 }
 189
 190 static int aac_set_chunk_tv(struct afh_info *afhi,
 191                 mp4AudioSpecificConfig *mp4ASC, long unsigned *seconds)
 192 {
 193         float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023;
 194         struct timeval total;
 195         long unsigned ms = 1000.0 * afhi->chunks_total * tmp
 196                 / mp4ASC->samplingFrequency;
 197
 198         if (!mp4ASC->samplingFrequency)
 199                 return -E_MP4ASC;
 200         ms = 1000.0 * afhi->chunks_total * tmp / mp4ASC->samplingFrequency;
 201         ms2tv(ms, &total);
 202         tv_divide(afhi->chunks_total, &total, &afhi->chunk_tv);
 203         PARA_INFO_LOG("%luHz, %lus (%lu x %lums)\n",
 204                 mp4ASC->samplingFrequency, ms / 1000,
 205                 afhi->chunks_total, tv2ms(&afhi->chunk_tv));
 206         if (ms < 1000)
 207                 return -E_MP4ASC;
 208         *seconds = ms / 1000;
 209         return 1;
 210 }
 211
 212 /*
 213  * Init m4a file and write some tech data to given pointers.
 214  */
 215 static int aac_get_file_info(char *map, size_t numbytes, __a_unused int fd,
 216                 struct afh_info *afhi)
 217 {
 218         int i;
 219         size_t skip;
 220         ssize_t ret;
 221         unsigned long rate = 0, decoder_len;
 222         unsigned char channels = 0;
 223         mp4AudioSpecificConfig mp4ASC;
 224         NeAACDecHandle handle = NULL;
 225         unsigned char *umap = (unsigned char *) map;
 226
 227         ret = aac_find_esds(umap, numbytes, &skip, &decoder_len);
 228         if (ret < 0)
 229                 goto out;
 230         aac_get_taginfo(umap, numbytes, afhi);
 231         handle = aac_open();
 232         ret = -E_AAC_AFH_INIT;
 233         if (NeAACDecInit(handle, umap + skip, decoder_len, &rate, &channels))
 234                 goto out;
 235         if (!channels)
 236                 goto out;
 237         PARA_DEBUG_LOG("rate: %lu, channels: %d\n", rate, channels);
 238         ret = -E_MP4ASC;
 239         if (NeAACDecAudioSpecificConfig(umap + skip, numbytes - skip, &mp4ASC))
 240                 goto out;
 241         if (!mp4ASC.samplingFrequency)
 242                 goto out;
 243         ret = aac_compute_chunk_table(afhi, umap, numbytes);
 244         if (ret < 0)
 245                 goto out;
 246         skip = ret;
 247         ret = aac_set_chunk_tv(afhi, &mp4ASC, &afhi->seconds_total);
 248         if (ret < 0)
 249                 goto out;
 250         ret = aac_find_entry_point(umap + skip, numbytes - skip, &skip);
 251         if (ret < 0)
 252                 goto out;
 253         afhi->chunk_table[0] = ret;
 254         for (i = 1; i<= afhi->chunks_total; i++)
 255                 afhi->chunk_table[i] += ret;
 256         afhi->channels = channels;
 257         afhi->frequency = rate;
 258         ret = (afhi->chunk_table[afhi->chunks_total] - afhi->chunk_table[0]) * 8; /* bits */
 259         ret += (channels * afhi->seconds_total * 500); /* avoid rounding error */
 260         afhi->bitrate = ret / (channels * afhi->seconds_total * 1000);
 261         ret = 1;
 262 out:
 263         if (handle)
 264                 NeAACDecClose(handle);
 265         return ret;
 266 }
 267
 268 static const char* aac_suffixes[] = {"m4a", "mp4", NULL};
 269 /**
 270  * the init function of the aac audio format handler
 271  *
 272  * \param afh pointer to the struct to initialize
 273  */
 274 void aac_afh_init(struct audio_format_handler *afh)
 275 {
 276         afh->get_file_info = aac_get_file_info,
 277         afh->suffixes = aac_suffixes;
 278 }