libavformat/rtpenc_latm.c

   1 /*
   2  * RTP Packetization of MPEG-4 Audio (RFC 3016)
   3  * Copyright (c) 2011 Juan Carlos Rodriguez <ing.juancarlosrodriguez@hotmail.com>
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * Libav is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with Libav; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 #include "avformat.h"
  23 #include "rtpenc.h"
  24
  25 void ff_rtp_send_latm(AVFormatContext *s1, const uint8_t *buff, int size)
  26 {
  27     /* MP4A-LATM
  28      * The RTP payload format specification is described in RFC 3016
  29      * The encoding specifications are provided in ISO/IEC 14496-3 */
  30
  31     RTPMuxContext *s = s1->priv_data;
  32     int header_size;
  33     int offset = 0;
  34     int len    = 0;
  35
  36     /* skip ADTS header, if present */
  37     if ((s1->streams[0]->codec->extradata_size) == 0) {
  38         size -= 7;
  39         buff += 7;
  40     }
  41
  42     /* PayloadLengthInfo() */
  43     header_size = size/0xFF + 1;
  44     memset(s->buf, 0xFF, header_size - 1);
  45     s->buf[header_size - 1] = size % 0xFF;
  46
  47     s->timestamp = s->cur_timestamp;
  48
  49     /* PayloadMux() */
  50     while (size > 0) {
  51         len   = FFMIN(size, s->max_payload_size - (!offset ? header_size : 0));
  52         size -= len;
  53         if (!offset) {
  54             memcpy(s->buf + header_size, buff, len);
  55             ff_rtp_send_data(s1, s->buf, header_size + len, !size);
  56         } else {
  57             ff_rtp_send_data(s1, buff + offset, len, !size);
  58         }
  59         offset += len;
  60     }
  61 }