aac_afh.c

   1 /*
   2  * Copyright (C) 2006 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 "afs.h"
  28 #include "afh.h"
  29 #include "error.h"
  30 #include "string.h"
  31 #include "aac.h"
  32 #include "fd.h"
  33
  34 /* 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 struct audio_format_handler *af;
  42 static size_t num_chunks;
  43 static size_t entry;
  44
  45 static size_t *chunk_table;
  46 NeAACDecHandle handle;
  47
  48 static void aac_close_audio_file(void)
  49 {
  50         if (!infile)
  51                 return;
  52         fclose(infile);
  53         infile = NULL;
  54 }
  55
  56 static int aac_find_stsz(unsigned char *buf, unsigned buflen, size_t *skip)
  57 {
  58         int i;
  59
  60         for (i = 0; i + 16 < buflen; i++) {
  61                 unsigned char *p = buf + i;
  62                 unsigned sample_count, sample_size;
  63
  64                 if (p[0] != 's' || p[1] != 't' || p[2] != 's' || p[3] != 'z')
  65                         continue;
  66                 PARA_INFO_LOG("found stsz@%d\n", i);
  67                 i += 8;
  68                 sample_size = aac_read_int32(buf + i);
  69                 PARA_INFO_LOG("sample size: %d\n", sample_size);
  70                 i += 4;
  71                 sample_count = aac_read_int32(buf + i);
  72                 i += 4;
  73                 PARA_INFO_LOG("sample count: %d\n", sample_count);
  74                 *skip = i;
  75                 return sample_count;
  76         }
  77         PARA_WARNING_LOG("stsz not found, buflen: %d\n", buflen);
  78         return -E_STSZ;
  79 }
  80
  81 static int read_chunk_table(size_t skip)
  82 {
  83         int ret, i;
  84         size_t sum = 0;
  85
  86         for (;;) {
  87                 ret = aac_find_stsz(inbuf, inbuf_len, &skip);
  88                 if (ret >= 0)
  89                         break;
  90                 ret = read(fileno(infile), inbuf, inbuf_size);
  91                 if (ret <= 0)
  92                         return -E_AAC_READ;
  93                 PARA_INFO_LOG("next buffer: %d bytes\n", ret);
  94         }
  95         num_chunks = ret;
  96         PARA_INFO_LOG("sz table has %zu entries\n", num_chunks);
  97         free(chunk_table);
  98         chunk_table = para_malloc(num_chunks * sizeof(size_t));
  99         for (i = 0; i < num_chunks; i++) {
 100                 if (skip + 4 > inbuf_len) {
 101                         skip = inbuf_len - skip;
 102                         memmove(inbuf, inbuf + inbuf_len - skip, skip);
 103                         ret = read(fileno(infile), inbuf + skip, inbuf_size - skip);
 104                         if (ret <= 0)
 105                                 return -E_AAC_READ;
 106                         inbuf_len = ret + skip;
 107                         skip = 0;
 108                         PARA_INFO_LOG("next buffer: %zu bytes\n", inbuf_len);
 109                 }
 110                 sum += aac_read_int32(inbuf + skip);
 111                 chunk_table[i] = sum;
 112                 skip += 4;
 113                 if (i < 10 || i + 10 > num_chunks)
 114                         PARA_DEBUG_LOG("offset #%d: %zu\n", i, chunk_table[i]);
 115         }
 116         return 1;
 117
 118 }
 119
 120 long unsigned aac_set_chunk_tv(mp4AudioSpecificConfig *mp4ASC)
 121 {
 122         float tmp = mp4ASC->sbr_present_flag == 1? 2047 : 1023,
 123                 ms = 1000.0 * num_chunks * tmp / mp4ASC->samplingFrequency;
 124         struct timeval total;
 125
 126         ms2tv(ms, &total);
 127         tv_divide(num_chunks, &total, &af->chunk_tv);
 128         PARA_INFO_LOG("%luHz, %fs (%zd x %lums)\n",
 129                 mp4ASC->samplingFrequency, ms / 1000,
 130                 num_chunks, tv2ms(&af->chunk_tv));
 131         return ms / 1000;
 132 }
 133
 134 /*
 135  * Init m4a file and write some tech data to given pointers.
 136  */
 137 static int aac_get_file_info(FILE *file, char *info_str, long unsigned *frames,
 138         int *seconds)
 139 {
 140         int ret, decoder_len;
 141         size_t skip;
 142         unsigned long rate = 0;
 143         unsigned char channels = 0;
 144         mp4AudioSpecificConfig mp4ASC;
 145
 146         free(inbuf);
 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         entry = ret;
 185         sprintf(info_str, "audio_file_info1:%zu x %lums\n"
 186                 "audio_file_info2:\n"
 187                 "audio_file_info3:\n",
 188                 num_chunks,
 189                 tv2ms(&af->chunk_tv));
 190         tv_scale(20, &af->chunk_tv, &af->eof_tv);
 191         return 1;
 192 }
 193
 194 /*
 195  * nothing to do as we'll seek to the correct offset in aac read_chunk() anyway
 196  */
 197 static int aac_reposition_stream(__a_unused long unsigned request)
 198 {
 199         return 1;
 200 }
 201
 202 static char *aac_read_chunk(long unsigned current_chunk, ssize_t *len)
 203 {
 204         int ret;
 205         size_t pos;
 206
 207         *len = 0;
 208         if (current_chunk >= num_chunks)
 209                 return NULL;
 210         if (!current_chunk) {
 211                 *len = chunk_table[0];
 212                 pos = entry;
 213         } else {
 214                 *len = chunk_table[current_chunk] - chunk_table[current_chunk - 1];
 215                 pos = entry + chunk_table[current_chunk - 1];
 216         }
 217         if (inbuf_size < *len) {
 218                 inbuf = para_realloc(inbuf, *len);
 219                 inbuf_size = *len;
 220         }
 221 //      PARA_DEBUG_LOG("reading chunk #%lu@%zd (%zd bytes)\n", current_chunk,
 222 //              pos, *len);
 223         ret = fseek(infile, pos, SEEK_SET);
 224         if (ret < 0)
 225                 return NULL;
 226         ret = para_fread(inbuf, *len, 1, infile);
 227         if (ret != *len)
 228                 return NULL;
 229 //      PARA_DEBUG_LOG("ret: %d, inbuf[0]: %lx - %lx\n", ret, (long unsigned) inbuf[0],
 230 //              (long unsigned) inbuf[4]);
 231         return (char *)inbuf;
 232 }
 233
 234 static const char* aac_suffixes[] = {"m4a", 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 }