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.cmdline.h"
  26 #include "server.h"
  27 #include "vss.h"
  28 #include "afh.h"
  29 #include "error.h"
  30 #include "string.h"
  31 #include "aac.h"
  32 #include "fd.h"
  33
  34 /** size of the input buffer, must be big enough to hold header */
  35 #define DEFAULT_INBUF_SIZE 65536
  36
  37 static struct audio_format_handler *af;
  38 static FILE *infile;
  39 static unsigned char *inbuf;
  40 static size_t inbuf_size, inbuf_len, *chunk_table, num_chunks;
  41
  42 static void aac_close_audio_file(void)
  43 {
  44         if (!infile)
  45                 return;
  46         fclose(infile);
  47         infile = NULL;
  48         free(inbuf);
  49         inbuf = NULL;
  50         free(chunk_table);
  51         chunk_table = NULL;
  52 }
  53
  54 static int aac_find_stsz(unsigned char *buf, unsigned buflen, size_t *skip)
  55 {
  56         int i;
  57
  58         for (i = 0; i + 16 < buflen; i++) {
  59                 unsigned char *p = buf + i;
  60                 unsigned sample_count, sample_size;
  61
  62                 if (p[0] != 's' || p[1] != 't' || p[2] != 's' || p[3] != 'z')
  63                         continue;
  64                 PARA_INFO_LOG("found stsz@%d\n", i);
  65                 i += 8;
  66                 sample_size = aac_read_int32(buf + i);
  67                 PARA_INFO_LOG("sample size: %d\n", sample_size);
  68                 i += 4;
  69                 sample_count = aac_read_int32(buf + i);
  70                 i += 4;
  71                 PARA_INFO_LOG("sample count: %d\n", sample_count);
  72                 *skip = i;
  73                 return sample_count;
  74         }
  75         PARA_WARNING_LOG("stsz not found, buflen: %d\n", buflen);
  76         return -E_STSZ;
  77 }
  78
  79 static int read_chunk_table(size_t skip)
  80 {
  81         int ret, i;
  82         size_t sum = 0;
  83
  84         for (;;) {
  85                 ret = aac_find_stsz(inbuf, inbuf_len, &skip);
  86                 if (ret >= 0)
  87                         break;
  88                 ret = read(fileno(infile), inbuf, inbuf_size);
  89                 if (ret <= 0)
  90                         return -E_AAC_READ;
  91                 PARA_INFO_LOG("next buffer: %d bytes\n", ret);
  92         }
  93         num_chunks = ret;
  94         PARA_INFO_LOG("sz table has %zu entries\n", num_chunks);
  95         chunk_table = para_malloc((num_chunks + 1) * sizeof(size_t));
  96         for (i = 1; i <= num_chunks; i++) {
  97                 if (skip + 4 > inbuf_len) {
  98                         skip = inbuf_len - skip;
  99                         memmove(inbuf, inbuf + inbuf_len - skip, skip);
 100                         ret = read(fileno(infile), inbuf + skip, inbuf_size - skip);
 101                         if (ret <= 0)
 102                                 return -E_AAC_READ;
 103                         inbuf_len = ret + skip;
 104                         skip = 0;
 105                         PARA_INFO_LOG("next buffer: %zu bytes\n", inbuf_len);
 106                 }
 107                 sum += aac_read_int32(inbuf + skip);
 108                 chunk_table[i] = sum;
 109                 skip += 4;
 110                 if (i < 10 || i + 10 > num_chunks)
 111                         PARA_DEBUG_LOG("offset #%d: %zu\n", i, chunk_table[i]);
 112         }
 113         return 1;
 114 }
 115
 116 static long unsigned aac_set_chunk_tv(mp4AudioSpecificConfig *mp4ASC)
 117 {
 118         float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023,
 119                 ms = 1000.0 * num_chunks * tmp / mp4ASC->samplingFrequency;
 120         struct timeval total;
 121
 122         ms2tv(ms, &total);
 123         tv_divide(num_chunks, &total, &af->chunk_tv);
 124         PARA_INFO_LOG("%luHz, %fs (%zd x %lums)\n",
 125                 mp4ASC->samplingFrequency, ms / 1000,
 126                 num_chunks, tv2ms(&af->chunk_tv));
 127         return ms / 1000;
 128 }
 129
 130 /*
 131  * Init m4a file and write some tech data to given pointers.
 132  */
 133 static int aac_get_file_info(FILE *file, char *info_str, long unsigned *frames,
 134         int *seconds, size_t **vss_chunk_table)
 135 {
 136         int i, ret, decoder_len;
 137         size_t skip;
 138         unsigned long rate = 0;
 139         unsigned char channels = 0;
 140         mp4AudioSpecificConfig mp4ASC;
 141         NeAACDecHandle handle;
 142
 143         inbuf_size = DEFAULT_INBUF_SIZE;
 144         inbuf = para_malloc(inbuf_size);
 145         infile = file;
 146
 147         ret = read(fileno(infile), inbuf, inbuf_size);
 148         if (ret <= 0)
 149                 return -E_AAC_READ;
 150         inbuf_len = ret;
 151         ret = aac_find_esds(inbuf, inbuf_len, &skip);
 152         if (ret < 0)
 153                 return ret;
 154         decoder_len = ret;
 155         handle = aac_open();
 156         ret = NeAACDecInit(handle, inbuf + skip,
 157                 decoder_len, &rate, &channels);
 158         if (ret < 0)
 159                 return -E_AACDEC_INIT;
 160         skip += ret;
 161         PARA_INFO_LOG("rate: %lu, channels: %d\n", rate, channels);
 162         ret = NeAACDecAudioSpecificConfig(inbuf + skip, inbuf_len - skip,
 163                 &mp4ASC);
 164         if (ret < 0)
 165                 return -E_MP4ASC;
 166         ret = read_chunk_table(skip);
 167         if (ret < 0)
 168                 return ret;
 169         *frames = num_chunks;
 170         *seconds = aac_set_chunk_tv(&mp4ASC);
 171         *vss_chunk_table = chunk_table;
 172         for (;;) {
 173                 ret = aac_find_entry_point(inbuf, inbuf_len, &skip);
 174                 if (ret >= 0)
 175                         break;
 176                 ret = read(fileno(infile), inbuf, inbuf_size);
 177                 if (ret <= 0)
 178                         return -E_AAC_READ;
 179                 PARA_INFO_LOG("next buffer: %d bytes\n", ret);
 180         }
 181         chunk_table[0] = ret;
 182         for (i = 1; i<= num_chunks; i++)
 183                 chunk_table[i] += ret;
 184         sprintf(info_str, "audio_file_info1:%zu x %lums\n"
 185                 "audio_file_info2:\n"
 186                 "audio_file_info3:\n",
 187                 num_chunks,
 188                 tv2ms(&af->chunk_tv));
 189         tv_scale(20, &af->chunk_tv, &af->eof_tv);
 190         return 1;
 191 }
 192
 193 static const char* aac_suffixes[] = {"m4a", "mp4", NULL};
 194 /** the init function of the aac audio format handler */
 195 void aac_afh_init(struct audio_format_handler *p)
 196 {
 197         af = p;
 198         af->get_file_info = aac_get_file_info,
 199         af->close_audio_file = aac_close_audio_file;
 200         af->get_header_info = NULL;
 201         af->suffixes = aac_suffixes;
 202 }