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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 "libavutil/intreadwrite.h"
22 
23 #include "avformat.h"
24 #include "rtpenc.h"
25 
26 
27 void ff_rtp_send_aac(AVFormatContext *s1, const uint8_t *buff, int size)
28 {
29  RTPMuxContext *s = s1->priv_data;
30  AVStream *st = s1->streams[0];
31  const int max_au_headers_size = 2 + 2 * s->max_frames_per_packet;
32  int len, max_packet_size = s->max_payload_size - max_au_headers_size;
33  uint8_t *p;
34 
35  /* skip ADTS header, if present */
36  if ((s1->streams[0]->codec->extradata_size) == 0) {
37  size -= 7;
38  buff += 7;
39  }
40 
41  /* test if the packet must be sent */
42  len = (s->buf_ptr - s->buf);
43  if (s->num_frames &&
45  (len + size) > s->max_payload_size ||
47  s1->max_delay, AV_TIME_BASE_Q) >= 0)) {
48  int au_size = s->num_frames * 2;
49 
50  p = s->buf + max_au_headers_size - au_size - 2;
51  if (p != s->buf) {
52  memmove(p + 2, s->buf + 2, au_size);
53  }
54  /* Write the AU header size */
55  AV_WB16(p, au_size * 8);
56 
57  ff_rtp_send_data(s1, p, s->buf_ptr - p, 1);
58 
59  s->num_frames = 0;
60  }
61  if (s->num_frames == 0) {
62  s->buf_ptr = s->buf + max_au_headers_size;
63  s->timestamp = s->cur_timestamp;
64  }
65 
66  if (size <= max_packet_size) {
67  p = s->buf + s->num_frames++ * 2 + 2;
68  AV_WB16(p, size * 8);
69  memcpy(s->buf_ptr, buff, size);
70  s->buf_ptr += size;
71  } else {
72  int au_size = size;
73 
74  max_packet_size = s->max_payload_size - 4;
75  p = s->buf;
76  AV_WB16(p, 2 * 8);
77  while (size > 0) {
78  len = FFMIN(size, max_packet_size);
79  AV_WB16(&p[2], au_size * 8);
80  memcpy(p + 4, buff, len);
81  ff_rtp_send_data(s1, p, len + 4, len == size);
82  size -= len;
83  buff += len;
84  }
85  }
86 }