libmpdemux/demux_aac.c

   1 /*
   2  * This file is part of MPlayer.
   3  *
   4  * MPlayer 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  * MPlayer 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 along
  15  * with MPlayer; if not, write to the Free Software Foundation, Inc.,
  16  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  17  */
  18
  19 #include <stdio.h>
  20 #include <stdlib.h>
  21 #include <string.h>
  22
  23 #include "config.h"
  24 #include "mp_msg.h"
  25 #include "help_mp.h"
  26
  27 #include "stream/stream.h"
  28 #include "demuxer.h"
  29 #include "parse_es.h"
  30 #include "stheader.h"
  31
  32 #include "ms_hdr.h"
  33
  34 typedef struct {
  35         uint8_t *buf;
  36         uint64_t size;  /// amount of time of data packets pushed to demuxer->audio (in bytes)
  37         float time;     /// amount of time elapsed based upon samples_per_frame/sample_rate (in milliseconds)
  38         float last_pts; /// last pts seen
  39         int bitrate;    /// bitrate computed as size/time
  40 } aac_priv_t;
  41
  42 /// \param srate (out) sample rate
  43 /// \param num (out) number of audio frames in this ADTS frame
  44 /// \return size of the ADTS frame in bytes
  45 /// aac_parse_frames needs a buffer at least 8 bytes long
  46 int aac_parse_frame(uint8_t *buf, int *srate, int *num);
  47
  48 static int demux_aac_init(demuxer_t *demuxer)
  49 {
  50         aac_priv_t *priv;
  51
  52         priv = calloc(1, sizeof(aac_priv_t));
  53         if(!priv)
  54                 return 0;
  55
  56         priv->buf = (uint8_t*) malloc(8);
  57         if(!priv->buf)
  58         {
  59                 free(priv);
  60                 return 0;
  61         }
  62
  63         demuxer->priv = priv;
  64         return 1;
  65 }
  66
  67 static void demux_close_aac(demuxer_t *demuxer)
  68 {
  69         aac_priv_t *priv = (aac_priv_t *) demuxer->priv;
  70
  71         if(!priv)
  72                 return;
  73
  74         if(priv->buf)
  75                 free(priv->buf);
  76
  77         free(demuxer->priv);
  78
  79         return;
  80 }
  81
  82 /// returns DEMUXER_TYPE_AAC if it finds 8 ADTS frames in 32768 bytes, 0 otherwise
  83 static int demux_aac_probe(demuxer_t *demuxer)
  84 {
  85         int cnt = 0, c, len, srate, num;
  86         off_t init, probed;
  87         aac_priv_t *priv;
  88
  89         if(! demux_aac_init(demuxer))
  90         {
  91                 mp_msg(MSGT_DEMUX, MSGL_ERR, "COULDN'T INIT aac_demux, exit\n");
  92                 return 0;
  93         }
  94
  95         priv = (aac_priv_t *) demuxer->priv;
  96
  97         init = probed = stream_tell(demuxer->stream);
  98         while(probed-init <= 32768 && cnt < 8)
  99         {
 100                 c = 0;
 101                 while(c != 0xFF)
 102                 {
 103                         c = stream_read_char(demuxer->stream);
 104                         if(c < 0)
 105                                 goto fail;
 106                 }
 107                 priv->buf[0] = 0xFF;
 108                 if(stream_read(demuxer->stream, &(priv->buf[1]), 7) < 7)
 109                         goto fail;
 110
 111                 len = aac_parse_frame(priv->buf, &srate, &num);
 112                 if(len > 0)
 113                 {
 114                         cnt++;
 115                         stream_skip(demuxer->stream, len - 8);
 116                 }
 117                 probed = stream_tell(demuxer->stream);
 118         }
 119
 120         stream_seek(demuxer->stream, init);
 121         if(cnt < 8)
 122                 goto fail;
 123
 124         mp_msg(MSGT_DEMUX, MSGL_V, "demux_aac_probe, INIT: %"PRIu64", PROBED: %"PRIu64", cnt: %d\n", init, probed, cnt);
 125         return DEMUXER_TYPE_AAC;
 126
 127 fail:
 128         mp_msg(MSGT_DEMUX, MSGL_V, "demux_aac_probe, failed to detect an AAC stream\n");
 129         return 0;
 130 }
 131
 132 static demuxer_t* demux_aac_open(demuxer_t *demuxer)
 133 {
 134         sh_audio_t *sh;
 135
 136         sh = new_sh_audio(demuxer, 0);
 137         sh->ds = demuxer->audio;
 138         sh->format = mmioFOURCC('M', 'P', '4', 'A');
 139         demuxer->audio->id = 0;
 140         demuxer->audio->sh = sh;
 141
 142         demuxer->filepos = stream_tell(demuxer->stream);
 143
 144         return demuxer;
 145 }
 146
 147 static int demux_aac_fill_buffer(demuxer_t *demuxer, demux_stream_t *ds)
 148 {
 149         aac_priv_t *priv = (aac_priv_t *) demuxer->priv;
 150         demux_packet_t *dp;
 151         int c1, c2, len, srate, num;
 152         float tm = 0;
 153
 154         if(demuxer->stream->eof || (demuxer->movi_end && stream_tell(demuxer->stream) >= demuxer->movi_end))
 155                 return 0;
 156
 157         while(! demuxer->stream->eof)
 158         {
 159                 c1 = c2 = 0;
 160                 while(c1 != 0xFF)
 161                 {
 162                         c1 = stream_read_char(demuxer->stream);
 163                         if(c1 < 0)
 164                                 return 0;
 165                 }
 166                 c2 = stream_read_char(demuxer->stream);
 167                 if(c2 < 0)
 168                         return 0;
 169                 if((c2 & 0xF6) != 0xF0)
 170                         continue;
 171
 172                 priv->buf[0] = (unsigned char) c1;
 173                 priv->buf[1] = (unsigned char) c2;
 174                 if(stream_read(demuxer->stream, &(priv->buf[2]), 6) < 6)
 175                         return 0;
 176
 177                 len = aac_parse_frame(priv->buf, &srate, &num);
 178                 if(len > 0)
 179                 {
 180                         dp = new_demux_packet(len);
 181                         if(! dp)
 182                         {
 183                                 mp_msg(MSGT_DEMUX, MSGL_ERR, "fill_buffer, NEW_ADD_PACKET(%d)FAILED\n", len);
 184                                 return 0;
 185                         }
 186
 187
 188                         memcpy(dp->buffer, priv->buf, 8);
 189                         stream_read(demuxer->stream, &(dp->buffer[8]), len-8);
 190                         if(srate)
 191                                 tm = (float) (num * 1024.0/srate);
 192                         priv->last_pts += tm;
 193                         dp->pts = priv->last_pts;
 194                         //fprintf(stderr, "\nPTS: %.3f\n", dp->pts);
 195                         ds_add_packet(demuxer->audio, dp);
 196                         priv->size += len;
 197                         priv->time += tm;
 198
 199                         priv->bitrate = (int) (priv->size / priv->time);
 200                         demuxer->filepos = stream_tell(demuxer->stream);
 201
 202                         return len;
 203                 }
 204                 else
 205                         stream_skip(demuxer->stream, -6);
 206         }
 207
 208         return 0;
 209 }
 210
 211
 212 //This is an almost verbatim copy of high_res_mp3_seek(), from demux_audio.c
 213 static void demux_aac_seek(demuxer_t *demuxer, float rel_seek_secs, float audio_delay, int flags)
 214 {
 215         aac_priv_t *priv = (aac_priv_t *) demuxer->priv;
 216         demux_stream_t *d_audio=demuxer->audio;
 217         sh_audio_t *sh_audio=d_audio->sh;
 218         float time;
 219
 220         ds_free_packs(d_audio);
 221
 222         time = (flags & SEEK_ABSOLUTE) ? rel_seek_secs - priv->last_pts : rel_seek_secs;
 223         if(time < 0)
 224         {
 225                 stream_seek(demuxer->stream, demuxer->movi_start);
 226                 time = priv->last_pts + time;
 227                 priv->last_pts = 0;
 228         }
 229
 230         if(time > 0)
 231         {
 232                 int len, nf, srate, num;
 233
 234                 nf = time * sh_audio->samplerate/1024;
 235
 236                 while(nf > 0)
 237                 {
 238                         if(stream_read(demuxer->stream,priv->buf, 8) < 8)
 239                                 break;
 240                         len = aac_parse_frame(priv->buf, &srate, &num);
 241                         if(len <= 0)
 242                         {
 243                                 stream_skip(demuxer->stream, -7);
 244                                 continue;
 245                         }
 246                         stream_skip(demuxer->stream, len - 8);
 247                         priv->last_pts += (float) (num*1024.0/srate);
 248                         nf -= num;
 249                 }
 250         }
 251 }
 252
 253
 254 const demuxer_desc_t demuxer_desc_aac = {
 255   "AAC demuxer",
 256   "aac",
 257   "AAC",
 258   "Nico Sabbi",
 259   "Raw AAC files ",
 260   DEMUXER_TYPE_AAC,
 261   0, // unsafe autodetect
 262   demux_aac_probe,
 263   demux_aac_fill_buffer,
 264   demux_aac_open,
 265   demux_close_aac,
 266   demux_aac_seek,
 267   NULL
 268 };