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2ba45a60 DM |
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 | ||
26 | const uint8_t *ff_h263_find_resync_marker_reverse(const uint8_t *av_restrict start, | |
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 | */ | |
43 | void ff_rtp_send_h263(AVFormatContext *s1, const uint8_t *buf1, int size) | |
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) { | |
66 | const uint8_t *end = ff_h263_find_resync_marker_reverse(buf1, | |
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 | } |