2 * RTP packetization for Xiph audio and video
3 * Copyright (c) 2010 Josh Allmann
5 * This file is part of FFmpeg.
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.
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.
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
22 #include "libavutil/avassert.h"
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)
31 void ff_rtp_send_xiph(AVFormatContext
*s1
, const uint8_t *buff
, int size
)
33 RTPMuxContext
*s
= s1
->priv_data
;
34 int max_pkt_size
, xdt
, frag
;
37 max_pkt_size
= s
->max_payload_size
;
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
47 case 0x03: // vorbis comments
48 case 0x81: // theora comments
49 xdt
= 2; // comment payload
52 xdt
= 0; // raw data payload
57 // Probably need a non-fixed way of generating
58 // this, but it has to be done in SDP and passed in from there.
60 *q
++ = (RTP_XIPH_IDENT
>> 16) & 0xff;
61 *q
++ = (RTP_XIPH_IDENT
>> 8) & 0xff;
62 *q
++ = (RTP_XIPH_IDENT
) & 0xff;
65 // 0 - whole frame (possibly multiple frames)
67 // 2 - fragment continuation
68 // 3 - last fragmement
69 frag
= size
<= max_pkt_size
? 0 : 1;
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
;
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);
84 // buffer current frame to send later
85 if (0 == s
->num_frames
) s
->timestamp
= s
->cur_timestamp
;
88 // Set packet header. Normally, this is OR'd with frag and xdt,
89 // but those are zero, so omitted here
92 if (s
->num_frames
> 1) q
= s
->buf_ptr
; // jump ahead if needed
93 *q
++ = (size
>> 8) & 0xff;
95 memcpy(q
, buff
, size
);
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);
106 s
->timestamp
= s
->cur_timestamp
;
110 int len
= (!frag
|| frag
== 3) ? size
: max_pkt_size
;
113 // set packet headers
114 *q
++ = (frag
<< 6) | (xdt
<< 4); // num_frames = 0
115 *q
++ = (len
>> 8) & 0xff;
118 memcpy(q
, buff
, len
);
123 ff_rtp_send_data(s1
, s
->buf
, q
- s
->buf
, 0);
125 frag
= size
<= max_pkt_size
? 3 : 2;