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rtpenc_aac.c
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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 "rtpenc.h"
23 
24 
25 void ff_rtp_send_aac(AVFormatContext *s1, const uint8_t *buff, int size)
26 {
27  RTPMuxContext *s = s1->priv_data;
28  int len, max_packet_size;
29  uint8_t *p;
31  const int max_au_headers_size = 2 + 2 * max_frames_per_packet;
32 
33  /* skip ADTS header, if present */
34  if ((s1->streams[0]->codec->extradata_size) == 0) {
35  size -= 7;
36  buff += 7;
37  }
38  max_packet_size = s->max_payload_size - max_au_headers_size;
39 
40  /* test if the packet must be sent */
41  len = (s->buf_ptr - s->buf);
42  if ((s->num_frames == max_frames_per_packet) || (len && (len + size) > s->max_payload_size)) {
43  int au_size = s->num_frames * 2;
44 
45  p = s->buf + max_au_headers_size - au_size - 2;
46  if (p != s->buf) {
47  memmove(p + 2, s->buf + 2, au_size);
48  }
49  /* Write the AU header size */
50  p[0] = au_size >> 5;
51  p[1] = (au_size & 0x1F) << 3;
52 
53  ff_rtp_send_data(s1, p, s->buf_ptr - p, 1);
54 
55  s->num_frames = 0;
56  }
57  if (s->num_frames == 0) {
58  s->buf_ptr = s->buf + max_au_headers_size;
59  s->timestamp = s->cur_timestamp;
60  }
61 
62  if (size <= max_packet_size) {
63  p = s->buf + s->num_frames++ * 2 + 2;
64  *p++ = size >> 5;
65  *p = (size & 0x1F) << 3;
66  memcpy(s->buf_ptr, buff, size);
67  s->buf_ptr += size;
68  } else {
69  int au_size = size;
70 
71  max_packet_size = s->max_payload_size - 4;
72  p = s->buf;
73  p[0] = 0;
74  p[1] = 16;
75  while (size > 0) {
76  len = FFMIN(size, max_packet_size);
77  p[2] = au_size >> 5;
78  p[3] = (au_size & 0x1F) << 3;
79  memcpy(p + 4, buff, len);
80  ff_rtp_send_data(s1, p, len + 4, len == size);
81  size -= len;
82  buff += len;
83  }
84  }
85 }