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 FILE *infile;
  38 static int inbuf_size;
  39 static unsigned char *inbuf;
  40 static size_t inbuf_len;
  41 static struct audio_format_handler *af;
  42 static size_t num_chunks;
  43
  44 static size_t *chunk_table;
  45 static NeAACDecHandle handle;
  46
  47 static void aac_close_audio_file(void)
  48 {
  49         if (!infile)
  50                 return;
  51         fclose(infile);
  52         infile = NULL;
  53         free(inbuf);
  54         inbuf = NULL;
  55         free(chunk_table);
  56         chunk_table = NULL;
  57 }
  58
  59 static int aac_find_stsz(unsigned char *buf, unsigned buflen, size_t *skip)
  60 {
  61         int i;
  62
  63         for (i = 0; i + 16 < buflen; i++) {
  64                 unsigned char *p = buf + i;
  65                 unsigned sample_count, sample_size;
  66
  67                 if (p[0] != 's' || p[1] != 't' || p[2] != 's' || p[3] != 'z')
  68                         continue;
  69                 PARA_INFO_LOG("found stsz@%d\n", i);
  70                 i += 8;
  71                 sample_size = aac_read_int32(buf + i);
  72                 PARA_INFO_LOG("sample size: %d\n", sample_size);
  73                 i += 4;
  74                 sample_count = aac_read_int32(buf + i);
  75                 i += 4;
  76                 PARA_INFO_LOG("sample count: %d\n", sample_count);
  77                 *skip = i;
  78                 return sample_count;
  79         }
  80         PARA_WARNING_LOG("stsz not found, buflen: %d\n", buflen);
  81         return -E_STSZ;
  82 }
  83
  84 static int read_chunk_table(size_t skip)
  85 {
  86         int ret, i;
  87         size_t sum = 0;
  88
  89         for (;;) {
  90                 ret = aac_find_stsz(inbuf, inbuf_len, &skip);
  91                 if (ret >= 0)
  92                         break;
  93                 ret = read(fileno(infile), inbuf, inbuf_size);
  94                 if (ret <= 0)
  95                         return -E_AAC_READ;
  96                 PARA_INFO_LOG("next buffer: %d bytes\n", ret);
  97         }
  98         num_chunks = ret;
  99         PARA_INFO_LOG("sz table has %zu entries\n", num_chunks);
 100         chunk_table = para_malloc((num_chunks + 1) * sizeof(size_t));
 101         for (i = 1; i <= num_chunks; i++) {
 102                 if (skip + 4 > inbuf_len) {
 103                         skip = inbuf_len - skip;
 104                         memmove(inbuf, inbuf + inbuf_len - skip, skip);
 105                         ret = read(fileno(infile), inbuf + skip, inbuf_size - skip);
 106                         if (ret <= 0)
 107                                 return -E_AAC_READ;
 108                         inbuf_len = ret + skip;
 109                         skip = 0;
 110                         PARA_INFO_LOG("next buffer: %zu bytes\n", inbuf_len);
 111                 }
 112                 sum += aac_read_int32(inbuf + skip);
 113                 chunk_table[i] = sum;
 114                 skip += 4;
 115                 if (i < 10 || i + 10 > num_chunks)
 116                         PARA_DEBUG_LOG("offset #%d: %zu\n", i, chunk_table[i]);
 117         }
 118         return 1;
 119 }
 120
 121 static long unsigned aac_set_chunk_tv(mp4AudioSpecificConfig *mp4ASC)
 122 {
 123         float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023,
 124                 ms = 1000.0 * num_chunks * tmp / mp4ASC->samplingFrequency;
 125         struct timeval total;
 126
 127         ms2tv(ms, &total);
 128         tv_divide(num_chunks, &total, &af->chunk_tv);
 129         PARA_INFO_LOG("%luHz, %fs (%zd x %lums)\n",
 130                 mp4ASC->samplingFrequency, ms / 1000,
 131                 num_chunks, tv2ms(&af->chunk_tv));
 132         return ms / 1000;
 133 }
 134
 135 /*
 136  * Init m4a file and write some tech data to given pointers.
 137  */
 138 static int aac_get_file_info(FILE *file, char *info_str, long unsigned *frames,
 139         int *seconds)
 140 {
 141         int i, ret, decoder_len;
 142         size_t skip;
 143         unsigned long rate = 0;
 144         unsigned char channels = 0;
 145         mp4AudioSpecificConfig mp4ASC;
 146
 147         inbuf_size = DEFAULT_INBUF_SIZE;
 148         inbuf = para_malloc(inbuf_size);
 149         infile = file;
 150
 151         ret = read(fileno(infile), inbuf, inbuf_size);
 152         if (ret <= 0)
 153                 return -E_AAC_READ;
 154         inbuf_len = ret;
 155         ret = aac_find_esds(inbuf, inbuf_len, &skip);
 156         if (ret < 0)
 157                 return ret;
 158         decoder_len = ret;
 159         handle = aac_open();
 160         ret = NeAACDecInit(handle, inbuf + skip,
 161                 decoder_len, &rate, &channels);
 162         if (ret < 0)
 163                 return -E_AACDEC_INIT;
 164         skip += ret;
 165         PARA_INFO_LOG("rate: %lu, channels: %d\n", rate, channels);
 166         ret = NeAACDecAudioSpecificConfig(inbuf + skip, inbuf_len - skip,
 167                 &mp4ASC);
 168         if (ret < 0)
 169                 return -E_MP4ASC;
 170         ret = read_chunk_table(skip);
 171         if (ret < 0)
 172                 return ret;
 173         *frames = num_chunks;
 174         *seconds = aac_set_chunk_tv(&mp4ASC);
 175         for (;;) {
 176                 ret = aac_find_entry_point(inbuf, inbuf_len, &skip);
 177                 if (ret >= 0)
 178                         break;
 179                 ret = read(fileno(infile), inbuf, inbuf_size);
 180                 if (ret <= 0)
 181                         return -E_AAC_READ;
 182                 PARA_INFO_LOG("next buffer: %d bytes\n", ret);
 183         }
 184         chunk_table[0] = ret;
 185         for (i = 1; i<= num_chunks; i++)
 186                 chunk_table[i] += ret;
 187         sprintf(info_str, "audio_file_info1:%zu x %lums\n"
 188                 "audio_file_info2:\n"
 189                 "audio_file_info3:\n",
 190                 num_chunks,
 191                 tv2ms(&af->chunk_tv));
 192         tv_scale(20, &af->chunk_tv, &af->eof_tv);
 193         return 1;
 194 }
 195
 196 /*
 197  * nothing to do as we'll seek to the correct offset in aac read_chunk() anyway
 198  */
 199 static int aac_reposition_stream(__a_unused long unsigned request)
 200 {
 201         return 1;
 202 }
 203
 204 static char *aac_read_chunk(long unsigned current_chunk, ssize_t *len)
 205 {
 206         int ret;
 207         size_t pos;
 208
 209         *len = 0;
 210         if (current_chunk >= num_chunks)
 211                 return NULL;
 212         pos = chunk_table[current_chunk];
 213         *len = chunk_table[current_chunk + 1] - chunk_table[current_chunk];
 214         if (inbuf_size < *len) {
 215                 PARA_INFO_LOG("increasing inbuf for chunk #%lu/%zu to %zd bytes\n",
 216                         current_chunk, num_chunks, *len);
 217                 inbuf = para_realloc(inbuf, *len);
 218                 inbuf_size = *len;
 219         }
 220 //      PARA_DEBUG_LOG("reading chunk #%lu@%zd (%zd bytes)\n", current_chunk,
 221 //              pos, *len);
 222         ret = fseek(infile, pos, SEEK_SET);
 223         if (ret < 0)
 224                 return NULL;
 225         ret = para_fread(inbuf, *len, 1, infile);
 226         if (ret != *len)
 227                 return NULL;
 228 //      PARA_DEBUG_LOG("ret: %d, inbuf[0]: %lx - %lx\n", ret, (long unsigned) inbuf[0],
 229 //              (long unsigned) inbuf[4]);
 230         return (char *)inbuf;
 231 }
 232
 233
 234 static const char* aac_suffixes[] = {"m4a", "mp4", NULL};
 235 /** the init function of the aac audio format handler */
 236 void aac_afh_init(struct audio_format_handler *p)
 237 {
 238         af = p;
 239         af->reposition_stream = aac_reposition_stream;
 240         af->get_file_info = aac_get_file_info,
 241         af->read_chunk = aac_read_chunk;
 242         af->close_audio_file = aac_close_audio_file;
 243         af->get_header_info = NULL;
 244         af->suffixes = aac_suffixes;
 245 }