blob: 00c29a7d02b211dcae86f35433d1f396bf214dca
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 "libavutil/intreadwrite.h" |
24 | |
25 | #include "avformat.h" |
26 | #include "rtpenc.h" |
27 | |
28 | /** |
29 | * Packetize Xiph frames into RTP according to |
30 | * RFC 5215 (Vorbis) and the Theora RFC draft. |
31 | * (http://svn.xiph.org/trunk/theora/doc/draft-ietf-avt-rtp-theora-00.txt) |
32 | */ |
33 | void ff_rtp_send_xiph(AVFormatContext *s1, const uint8_t *buff, int size) |
34 | { |
35 | RTPMuxContext *s = s1->priv_data; |
36 | AVStream *st = s1->streams[0]; |
37 | int max_pkt_size, xdt, frag; |
38 | uint8_t *q; |
39 | |
40 | max_pkt_size = s->max_payload_size - 6; // ident+frag+tdt/vdt+pkt_num+pkt_length |
41 | |
42 | // set xiph data type |
43 | switch (*buff) { |
44 | case 0x01: // vorbis id |
45 | case 0x05: // vorbis setup |
46 | case 0x80: // theora header |
47 | case 0x82: // theora tables |
48 | xdt = 1; // packed config payload |
49 | break; |
50 | case 0x03: // vorbis comments |
51 | case 0x81: // theora comments |
52 | xdt = 2; // comment payload |
53 | break; |
54 | default: |
55 | xdt = 0; // raw data payload |
56 | break; |
57 | } |
58 | |
59 | // Set ident. |
60 | // Probably need a non-fixed way of generating |
61 | // this, but it has to be done in SDP and passed in from there. |
62 | q = s->buf; |
63 | *q++ = (RTP_XIPH_IDENT >> 16) & 0xff; |
64 | *q++ = (RTP_XIPH_IDENT >> 8) & 0xff; |
65 | *q++ = (RTP_XIPH_IDENT ) & 0xff; |
66 | |
67 | // set fragment |
68 | // 0 - whole frame (possibly multiple frames) |
69 | // 1 - first fragment |
70 | // 2 - fragment continuation |
71 | // 3 - last fragment |
72 | frag = size <= max_pkt_size ? 0 : 1; |
73 | |
74 | if (!frag && !xdt) { // do we have a whole frame of raw data? |
75 | uint8_t *end_ptr = s->buf + 6 + max_pkt_size; // what we're allowed to write |
76 | uint8_t *ptr = s->buf_ptr + 2 + size; // what we're going to write |
77 | int remaining = end_ptr - ptr; |
78 | |
79 | av_assert1(s->num_frames <= s->max_frames_per_packet); |
80 | if (s->num_frames > 0 && |
81 | (remaining < 0 || |
82 | s->num_frames == s->max_frames_per_packet || |
83 | av_compare_ts(s->cur_timestamp - s->timestamp, st->time_base, |
84 | s1->max_delay, AV_TIME_BASE_Q) >= 0)) { |
85 | // send previous packets now; no room for new data, or too much delay |
86 | ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0); |
87 | s->num_frames = 0; |
88 | } |
89 | |
90 | // buffer current frame to send later |
91 | if (0 == s->num_frames) |
92 | s->timestamp = s->cur_timestamp; |
93 | s->num_frames++; |
94 | |
95 | // Set packet header. Normally, this is OR'd with frag and xdt, |
96 | // but those are zero, so omitted here |
97 | *q++ = s->num_frames; |
98 | |
99 | if (s->num_frames > 1) |
100 | q = s->buf_ptr; // jump ahead if needed |
101 | AV_WB16(q, size); |
102 | q += 2; |
103 | memcpy(q, buff, size); |
104 | q += size; |
105 | s->buf_ptr = q; |
106 | |
107 | return; |
108 | } else if (s->num_frames) { |
109 | // immediately send buffered frames if buffer is not raw data, |
110 | // or if current frame is fragmented. |
111 | ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0); |
112 | } |
113 | |
114 | s->timestamp = s->cur_timestamp; |
115 | s->num_frames = 0; |
116 | s->buf_ptr = q; |
117 | while (size > 0) { |
118 | int len = (!frag || frag == 3) ? size : max_pkt_size; |
119 | q = s->buf_ptr; |
120 | |
121 | // set packet headers |
122 | *q++ = (frag << 6) | (xdt << 4); // num_frames = 0 |
123 | AV_WB16(q, len); |
124 | q += 2; |
125 | // set packet body |
126 | memcpy(q, buff, len); |
127 | q += len; |
128 | buff += len; |
129 | size -= len; |
130 | |
131 | ff_rtp_send_data(s1, s->buf, q - s->buf, 0); |
132 | |
133 | frag = size <= max_pkt_size ? 3 : 2; |
134 | } |
135 | } |
136 |