aac_afh.c

   1 /*
   2  * Copyright (C) 2006-2007 Andre Noll <maan@systemlinux.org>
   3  *
   4  *     This program is free software; you can redistribute it and/or modify
   5  *     it under the terms of the GNU General Public License as published by
   6  *     the Free Software Foundation; either version 2 of the License, or
   7  *     (at your option) any later version.
   8  *
   9  *     This program is distributed in the hope that it will be useful,
  10  *     but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *     GNU General Public License for more details.
  13  *
  14  *     You should have received a copy of the GNU General Public License
  15  *     along with this program; if not, write to the Free Software
  16  *     Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111, USA.
  17  */
  18 /*
  19  * based in parts on libfaad, Copyright (C) 2003-2005 M. Bakker,
  20  * Ahead Software AG
  21  */
  22
  23 /** \file aac_afh.c para_server's aac audio format handler */
  24
  25 #include "server.h"
  26 #include "error.h"
  27 #include "string.h"
  28 #include "aac.h"
  29 #include "fd.h"
  30
  31 static int aac_find_stsz(unsigned char *buf, off_t buflen, off_t *skip)
  32 {
  33         int i;
  34
  35         for (i = 0; i + 16 < buflen; i++) {
  36                 unsigned char *p = buf + i;
  37                 unsigned sample_count, sample_size;
  38
  39                 if (p[0] != 's' || p[1] != 't' || p[2] != 's' || p[3] != 'z')
  40                         continue;
  41                 PARA_INFO_LOG("found stsz@%d\n", i);
  42                 i += 8;
  43                 sample_size = aac_read_int32(buf + i);
  44                 PARA_INFO_LOG("sample size: %d\n", sample_size);
  45                 i += 4;
  46                 sample_count = aac_read_int32(buf + i);
  47                 i += 4;
  48                 PARA_INFO_LOG("sample count: %d\n", sample_count);
  49                 *skip = i;
  50                 return sample_count;
  51         }
  52         return -E_STSZ;
  53 }
  54
  55 static ssize_t aac_compute_chunk_table(struct audio_format_info *afi,
  56                 unsigned char *map, off_t numbytes)
  57 {
  58         int ret, i;
  59         size_t sum = 0;
  60         off_t skip;
  61
  62         ret = aac_find_stsz(map, numbytes, &skip);
  63         if (ret < 0)
  64                 return ret;
  65         afi->chunks_total = ret;
  66         PARA_INFO_LOG("sz table has %lu entries\n", afi->chunks_total);
  67         afi->chunk_table = para_malloc((afi->chunks_total + 1) * sizeof(size_t));
  68         for (i = 1; i <= afi->chunks_total; i++) {
  69                 if (skip + 4 > numbytes)
  70                         break;
  71                 sum += aac_read_int32(map + skip);
  72                 afi->chunk_table[i] = sum;
  73                 skip += 4;
  74 //              if (i < 10 || i + 10 > afi->chunks_total)
  75 //                      PARA_DEBUG_LOG("offset #%d: %zu\n", i, afi->chunk_table[i]);
  76         }
  77         return skip;
  78 }
  79
  80 static long unsigned aac_set_chunk_tv(struct audio_format_info *afi,
  81                 mp4AudioSpecificConfig *mp4ASC)
  82 {
  83         float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023,
  84                 ms = 1000.0 * afi->chunks_total * tmp / mp4ASC->samplingFrequency;
  85         struct timeval total;
  86
  87         ms2tv(ms, &total);
  88         tv_divide(afi->chunks_total, &total, &afi->chunk_tv);
  89         PARA_INFO_LOG("%luHz, %fs (%lu x %lums)\n",
  90                 mp4ASC->samplingFrequency, ms / 1000,
  91                 afi->chunks_total, tv2ms(&afi->chunk_tv));
  92         return ms < 1000? -E_MP4ASC : ms / 1000;
  93 }
  94
  95 /*
  96  * Init m4a file and write some tech data to given pointers.
  97  */
  98 static int aac_get_file_info(char *map, off_t numbytes,
  99                 struct audio_format_info *afi)
 100 {
 101         int i;
 102         size_t skip;
 103         ssize_t ret;
 104         unsigned long rate = 0, decoder_len;
 105         unsigned char channels = 0;
 106         mp4AudioSpecificConfig mp4ASC;
 107         NeAACDecHandle handle;
 108
 109         ret = aac_find_esds(map, numbytes, &skip);
 110         if (ret < 0)
 111                 goto out;
 112         decoder_len = ret;
 113         handle = aac_open();
 114         ret = -E_AACDEC_INIT;
 115         if (NeAACDecInit(handle, map + skip, decoder_len, &rate, &channels))
 116                 goto out;
 117         if (!channels)
 118                 goto out;
 119         PARA_INFO_LOG("rate: %lu, channels: %d\n", rate, channels);
 120         ret = -E_MP4ASC;
 121         if (NeAACDecAudioSpecificConfig(map + skip, numbytes - skip, &mp4ASC))
 122                 goto out;
 123         if (!mp4ASC.samplingFrequency)
 124                 goto out;
 125         ret = aac_compute_chunk_table(afi, map, numbytes);
 126         if (ret < 0)
 127                 goto out;
 128         skip = ret;
 129         afi->seconds_total = aac_set_chunk_tv(afi, &mp4ASC);
 130         ret = aac_find_entry_point(map + skip, numbytes - skip, &skip);
 131         if (ret < 0)
 132                 goto out;
 133         afi->chunk_table[0] = ret;
 134         for (i = 1; i<= afi->chunks_total; i++)
 135                 afi->chunk_table[i] += ret;
 136         afi->channels = channels;
 137         afi->frequency = rate;
 138         ret = (afi->chunk_table[afi->chunks_total] - afi->chunk_table[0]) * 8; /* bits */
 139         ret += (channels * afi->seconds_total * 500); /* avoid rounding error */
 140         afi->bitrate = ret / (channels * afi->seconds_total * 1000);
 141         sprintf(afi->info_string, "audio_file_info1:%lu x %lums, "
 142                 "%uHz, %d channel%s, %ukb/s\n"
 143                 "audio_file_info2:\n"
 144                 "audio_file_info3:\n",
 145                 afi->chunks_total, tv2ms(&afi->chunk_tv),
 146                 afi->frequency, channels, channels == 1? "" : "s", afi->bitrate
 147         );
 148         tv_scale(20, &afi->chunk_tv, &afi->eof_tv);
 149         ret = 1;
 150 out:
 151         return ret;
 152 }
 153
 154 static const char* aac_suffixes[] = {"m4a", "mp4", NULL};
 155 /**
 156  * the init function of the aac audio format handler
 157  *
 158  * \param afh pointer to the struct to initialize
 159  */
 160 void aac_afh_init(struct audio_format_handler *afh)
 161 {
 162         afh->get_file_info = aac_get_file_info,
 163         afh->suffixes = aac_suffixes;
 164 }