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 */
ff_rtp_send_xiph(AVFormatContext * s1,const uint8_t * buff,int size)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 }
128