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rtpenc_h263.c
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1 /*
2  * RTP packetization for H.263 video
3  * Copyright (c) 2009 Luca Abeni
4  * Copyright (c) 2009 Martin Storsjo
5  *
6  * This file is part of FFmpeg.
7  *
8  * FFmpeg is free software; you can redistribute it and/or
9  * modify it under the terms of the GNU Lesser General Public
10  * License as published by the Free Software Foundation; either
11  * version 2.1 of the License, or (at your option) any later version.
12  *
13  * FFmpeg is distributed in the hope that it will be useful,
14  * but WITHOUT ANY WARRANTY; without even the implied warranty of
15  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16  * Lesser General Public License for more details.
17  *
18  * You should have received a copy of the GNU Lesser General Public
19  * License along with FFmpeg; if not, write to the Free Software
20  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21  */
22 
23 #include "avformat.h"
24 #include "rtpenc.h"
25 
27  const uint8_t *av_restrict end)
28 {
29  const uint8_t *p = end - 1;
30  start += 1; /* Make sure we never return the original start. */
31  for (; p > start; p -= 2) {
32  if (!*p) {
33  if (!p[ 1] && p[2]) return p;
34  else if (!p[-1] && p[1]) return p - 1;
35  }
36  }
37  return end;
38 }
39 
40 /**
41  * Packetize H.263 frames into RTP packets according to RFC 4629
42  */
44 {
45  RTPMuxContext *s = s1->priv_data;
46  int len, max_packet_size;
47  uint8_t *q;
48 
49  max_packet_size = s->max_payload_size;
50 
51  while (size > 0) {
52  q = s->buf;
53  if (size >= 2 && (buf1[0] == 0) && (buf1[1] == 0)) {
54  *q++ = 0x04;
55  buf1 += 2;
56  size -= 2;
57  } else {
58  *q++ = 0;
59  }
60  *q++ = 0;
61 
62  len = FFMIN(max_packet_size - 2, size);
63 
64  /* Look for a better place to split the frame into packets. */
65  if (len < size) {
67  buf1 + len);
68  len = end - buf1;
69  }
70 
71  memcpy(q, buf1, len);
72  q += len;
73 
74  /* 90 KHz time stamp */
75  s->timestamp = s->cur_timestamp;
76  ff_rtp_send_data(s1, s->buf, q - s->buf, (len == size));
77 
78  buf1 += len;
79  size -= len;
80  }
81 }