libavformat/rtp_aac.c

   1 /*
   2  * copyright (c) 2007 Luca Abeni
   3  *
   4  * This file is part of FFmpeg.
   5  *
   6  * FFmpeg is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU Lesser General Public
   8  * License as published by the Free Software Foundation; either
   9  * version 2.1 of the License, or (at your option) any later version.
  10  *
  11  * FFmpeg is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  14  * Lesser General Public License for more details.
  15  *
  16  * You should have received a copy of the GNU Lesser General Public
  17  * License along with FFmpeg; if not, write to the Free Software
  18  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  19  */
  20
  21 #include "avformat.h"
  22 #include "rtp_aac.h"
  23 #include "rtp_internal.h"
  24
  25 #define MAX_FRAMES_PER_PACKET (s->max_frames_per_packet ? s->max_frames_per_packet : 5)
  26 #define MAX_AU_HEADERS_SIZE (2 + 2 * MAX_FRAMES_PER_PACKET)
  27
  28 void ff_rtp_send_aac(AVFormatContext *s1, const uint8_t *buff, int size)
  29 {
  30     RTPDemuxContext *s = s1->priv_data;
  31     int len, max_packet_size;
  32     uint8_t *p;
  33
  34     /* skip ADTS header, if present */
  35     if ((s1->streams[0]->codec->extradata_size) == 0) {
  36         size -= 7;
  37         buff += 7;
  38     }
  39     max_packet_size = s->max_payload_size - MAX_AU_HEADERS_SIZE;
  40
  41     /* test if the packet must be sent */
  42     len = (s->buf_ptr - s->buf);
  43     if ((s->read_buf_index == MAX_FRAMES_PER_PACKET) || (len && (len + size) > max_packet_size)) {
  44         int au_size = s->read_buf_index * 2;
  45
  46         p = s->buf + MAX_AU_HEADERS_SIZE - au_size - 2;
  47         if (p != s->buf) {
  48             memmove(p + 2, s->buf + 2, au_size);
  49         }
  50         /* Write the AU header size */
  51         p[0] = ((au_size * 8) & 0xFF) >> 8;
  52         p[1] = (au_size * 8) & 0xFF;
  53
  54         ff_rtp_send_data(s1, p, s->buf_ptr - p, 1);
  55
  56         s->read_buf_index = 0;
  57     }
  58     if (s->read_buf_index == 0) {
  59         s->buf_ptr = s->buf + MAX_AU_HEADERS_SIZE;
  60         s->timestamp = s->cur_timestamp;
  61     }
  62
  63     if (size < max_packet_size) {
  64         p = s->buf + s->read_buf_index++ * 2 + 2;
  65         *p++ = size >> 5;
  66         *p = (size & 0x1F) << 3;
  67         memcpy(s->buf_ptr, buff, size);
  68         s->buf_ptr += size;
  69     } else {
  70         if (s->buf_ptr != s->buf + MAX_AU_HEADERS_SIZE) {
  71             av_log(s1, AV_LOG_ERROR, "Strange...\n");
  72             av_abort();
  73         }
  74         max_packet_size = s->max_payload_size - 4;
  75         p = s->buf;
  76         p[0] = 0;
  77         p[1] = 16;
  78         while (size > 0) {
  79             len = FFMIN(size, max_packet_size);
  80             p[2] = len >> 5;
  81             p[3] = (size & 0x1F) << 3;
  82             memcpy(p + 4, buff, len);
  83             ff_rtp_send_data(s1, p, len + 4, len == size);
  84             size -= len;
  85             buff += len;
  86         }
  87     }
  88 }