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1 | /* |
2 | * RTP packetization for Xiph audio and video | |
3 | * Copyright (c) 2010 Josh Allmann | |
4 | * | |
5 | * This file is part of FFmpeg. | |
6 | * | |
7 | * FFmpeg is free software; you can redistribute it and/or | |
8 | * modify it under the terms of the GNU Lesser General Public | |
9 | * License as published by the Free Software Foundation; either | |
10 | * version 2.1 of the License, or (at your option) any later version. | |
11 | * | |
12 | * FFmpeg is distributed in the hope that it will be useful, | |
13 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
15 | * Lesser General Public License for more details. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public | |
18 | * License along with FFmpeg; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
22 | #include "libavutil/avassert.h" | |
23 | #include "avformat.h" | |
24 | #include "rtpenc.h" | |
25 | ||
26 | /** | |
27 | * Packetize Xiph frames into RTP according to | |
28 | * RFC 5215 (Vorbis) and the Theora RFC draft. | |
29 | * (http://svn.xiph.org/trunk/theora/doc/draft-ietf-avt-rtp-theora-00.txt) | |
30 | */ | |
31 | void ff_rtp_send_xiph(AVFormatContext *s1, const uint8_t *buff, int size) | |
32 | { | |
33 | RTPMuxContext *s = s1->priv_data; | |
34 | int max_pkt_size, xdt, frag; | |
35 | uint8_t *q; | |
36 | ||
37 | max_pkt_size = s->max_payload_size; | |
38 | ||
39 | // set xiph data type | |
40 | switch (*buff) { | |
41 | case 0x01: // vorbis id | |
42 | case 0x05: // vorbis setup | |
43 | case 0x80: // theora header | |
44 | case 0x82: // theora tables | |
45 | xdt = 1; // packed config payload | |
46 | break; | |
47 | case 0x03: // vorbis comments | |
48 | case 0x81: // theora comments | |
49 | xdt = 2; // comment payload | |
50 | break; | |
51 | default: | |
52 | xdt = 0; // raw data payload | |
53 | break; | |
54 | } | |
55 | ||
56 | // Set ident. | |
57 | // Probably need a non-fixed way of generating | |
58 | // this, but it has to be done in SDP and passed in from there. | |
59 | q = s->buf; | |
60 | *q++ = (RTP_XIPH_IDENT >> 16) & 0xff; | |
61 | *q++ = (RTP_XIPH_IDENT >> 8) & 0xff; | |
62 | *q++ = (RTP_XIPH_IDENT ) & 0xff; | |
63 | ||
64 | // set fragment | |
65 | // 0 - whole frame (possibly multiple frames) | |
66 | // 1 - first fragment | |
67 | // 2 - fragment continuation | |
68 | // 3 - last fragmement | |
69 | frag = size <= max_pkt_size ? 0 : 1; | |
70 | ||
71 | if (!frag && !xdt) { // do we have a whole frame of raw data? | |
72 | uint8_t *end_ptr = s->buf + 6 + max_pkt_size; // what we're allowed to write | |
73 | uint8_t *ptr = s->buf_ptr + 2 + size; // what we're going to write | |
74 | int remaining = end_ptr - ptr; | |
75 | ||
76 | av_assert1(s->num_frames <= s->max_frames_per_packet); | |
77 | if ((s->num_frames > 0 && remaining < 0) || | |
78 | s->num_frames == s->max_frames_per_packet) { | |
79 | // send previous packets now; no room for new data | |
80 | ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0); | |
81 | s->num_frames = 0; | |
82 | } | |
83 | ||
84 | // buffer current frame to send later | |
85 | if (0 == s->num_frames) s->timestamp = s->cur_timestamp; | |
86 | s->num_frames++; | |
87 | ||
88 | // Set packet header. Normally, this is OR'd with frag and xdt, | |
89 | // but those are zero, so omitted here | |
90 | *q++ = s->num_frames; | |
91 | ||
92 | if (s->num_frames > 1) q = s->buf_ptr; // jump ahead if needed | |
93 | *q++ = (size >> 8) & 0xff; | |
94 | *q++ = size & 0xff; | |
95 | memcpy(q, buff, size); | |
96 | q += size; | |
97 | s->buf_ptr = q; | |
98 | ||
99 | return; | |
100 | } else if (s->num_frames) { | |
101 | // immediately send buffered frames if buffer is not raw data, | |
102 | // or if current frame is fragmented. | |
103 | ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0); | |
104 | } | |
105 | ||
106 | s->timestamp = s->cur_timestamp; | |
107 | s->num_frames = 0; | |
108 | s->buf_ptr = q; | |
109 | while (size > 0) { | |
110 | int len = (!frag || frag == 3) ? size : max_pkt_size; | |
111 | q = s->buf_ptr; | |
112 | ||
113 | // set packet headers | |
114 | *q++ = (frag << 6) | (xdt << 4); // num_frames = 0 | |
115 | *q++ = (len >> 8) & 0xff; | |
116 | *q++ = len & 0xff; | |
117 | // set packet body | |
118 | memcpy(q, buff, len); | |
119 | q += len; | |
120 | buff += len; | |
121 | size -= len; | |
122 | ||
123 | ff_rtp_send_data(s1, s->buf, q - s->buf, 0); | |
124 | ||
125 | frag = size <= max_pkt_size ? 3 : 2; | |
126 | } | |
127 | } |