aac_afh.c

   1 /*
   2  * Copyright (C) 2006-2007 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 ssize_t aac_compute_chunk_table(struct afh_info *afhi,
  46                 unsigned char *map, size_t numbytes)
  47 {
  48         int ret, i;
  49         size_t sum = 0;
  50         off_t skip;
  51
  52         ret = aac_find_stsz(map, numbytes, &skip);
  53         if (ret < 0)
  54                 return ret;
  55         afhi->chunks_total = ret;
  56         PARA_DEBUG_LOG("sz table has %lu entries\n", afhi->chunks_total);
  57         afhi->chunk_table = para_malloc((afhi->chunks_total + 1) * sizeof(size_t));
  58         for (i = 1; i <= afhi->chunks_total; i++) {
  59                 if (skip + 4 > numbytes)
  60                         break;
  61                 sum += aac_read_int32(map + skip);
  62                 afhi->chunk_table[i] = sum;
  63                 skip += 4;
  64 //              if (i < 10 || i + 10 > afhi->chunks_total)
  65 //                      PARA_DEBUG_LOG("offset #%d: %zu\n", i, afhi->chunk_table[i]);
  66         }
  67         return skip;
  68 }
  69
  70 static int aac_set_chunk_tv(struct afh_info *afhi,
  71                 mp4AudioSpecificConfig *mp4ASC, long unsigned *seconds)
  72 {
  73         float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023;
  74         struct timeval total;
  75         long unsigned ms = 1000.0 * afhi->chunks_total * tmp
  76                 / mp4ASC->samplingFrequency;
  77
  78         if (!mp4ASC->samplingFrequency)
  79                 return -E_MP4ASC;
  80         ms = 1000.0 * afhi->chunks_total * tmp / mp4ASC->samplingFrequency;
  81         ms2tv(ms, &total);
  82         tv_divide(afhi->chunks_total, &total, &afhi->chunk_tv);
  83         PARA_INFO_LOG("%luHz, %lus (%lu x %lums)\n",
  84                 mp4ASC->samplingFrequency, ms / 1000,
  85                 afhi->chunks_total, tv2ms(&afhi->chunk_tv));
  86         if (ms < 1000)
  87                 return -E_MP4ASC;
  88         *seconds = ms / 1000;
  89         return 1;
  90 }
  91
  92 /*
  93  * Init m4a file and write some tech data to given pointers.
  94  */
  95 static int aac_get_file_info(char *map, size_t numbytes,
  96                 struct afh_info *afhi)
  97 {
  98         int i;
  99         size_t skip;
 100         ssize_t ret;
 101         unsigned long rate = 0, decoder_len;
 102         unsigned char channels = 0;
 103         mp4AudioSpecificConfig mp4ASC;
 104         NeAACDecHandle handle = NULL;
 105         unsigned char *umap = (unsigned char *) map;
 106
 107         ret = aac_find_esds(umap, numbytes, &skip, &decoder_len);
 108         if (ret < 0)
 109                 goto out;
 110         handle = aac_open();
 111         ret = -E_AAC_AFH_INIT;
 112         if (NeAACDecInit(handle, umap + skip, decoder_len, &rate, &channels))
 113                 goto out;
 114         if (!channels)
 115                 goto out;
 116         PARA_DEBUG_LOG("rate: %lu, channels: %d\n", rate, channels);
 117         ret = -E_MP4ASC;
 118         if (NeAACDecAudioSpecificConfig(umap + skip, numbytes - skip, &mp4ASC))
 119                 goto out;
 120         if (!mp4ASC.samplingFrequency)
 121                 goto out;
 122         ret = aac_compute_chunk_table(afhi, umap, numbytes);
 123         if (ret < 0)
 124                 goto out;
 125         skip = ret;
 126         ret = aac_set_chunk_tv(afhi, &mp4ASC, &afhi->seconds_total);
 127         if (ret < 0)
 128                 goto out;
 129         ret = aac_find_entry_point(umap + skip, numbytes - skip, &skip);
 130         if (ret < 0)
 131                 goto out;
 132         afhi->chunk_table[0] = ret;
 133         for (i = 1; i<= afhi->chunks_total; i++)
 134                 afhi->chunk_table[i] += ret;
 135         afhi->channels = channels;
 136         afhi->frequency = rate;
 137         ret = (afhi->chunk_table[afhi->chunks_total] - afhi->chunk_table[0]) * 8; /* bits */
 138         ret += (channels * afhi->seconds_total * 500); /* avoid rounding error */
 139         afhi->bitrate = ret / (channels * afhi->seconds_total * 1000);
 140         sprintf(afhi->info_string, "audio_file_info1:%lu x %lums, "
 141                 "%uHz, %d channel%s, %ukb/s\n"
 142                 "audio_file_info2:\n"
 143                 "audio_file_info3:\n",
 144                 afhi->chunks_total, tv2ms(&afhi->chunk_tv),
 145                 afhi->frequency, channels, channels == 1? "" : "s", afhi->bitrate
 146         );
 147         tv_scale(20, &afhi->chunk_tv, &afhi->eof_tv);
 148         ret = 1;
 149 out:
 150         if (handle)
 151                 NeAACDecClose(handle);
 152         return ret;
 153 }
 154
 155 static const char* aac_suffixes[] = {"m4a", "mp4", NULL};
 156 /**
 157  * the init function of the aac audio format handler
 158  *
 159  * \param afh pointer to the struct to initialize
 160  */
 161 void aac_afh_init(struct audio_format_handler *afh)
 162 {
 163         afh->get_file_info = aac_get_file_info,
 164         afh->suffixes = aac_suffixes;
 165 }