summaryrefslogtreecommitdiff
path: root/libavformat/rtpenc_xiph.c
blob: b4d950b91d76ff6634de9084ce0ca32fc450ce91 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
/*
 * RTP packetization for Xiph audio and video
 * Copyright (c) 2010 Josh Allmann
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include "libavutil/avassert.h"
#include "libavutil/intreadwrite.h"

#include "avformat.h"
#include "rtpenc.h"

/**
 * Packetize Xiph frames into RTP according to
 * RFC 5215 (Vorbis) and the Theora RFC draft.
 * (http://svn.xiph.org/trunk/theora/doc/draft-ietf-avt-rtp-theora-00.txt)
 */
void ff_rtp_send_xiph(AVFormatContext *s1, const uint8_t *buff, int size)
{
    RTPMuxContext *s = s1->priv_data;
    AVStream *st = s1->streams[0];
    int max_pkt_size, xdt, frag;
    uint8_t *q;

    max_pkt_size = s->max_payload_size - 6; // ident+frag+tdt/vdt+pkt_num+pkt_length

    // set xiph data type
    switch (*buff) {
    case 0x01:   // vorbis id
    case 0x05:   // vorbis setup
    case 0x80:   // theora header
    case 0x82:   // theora tables
        xdt = 1; // packed config payload
        break;
    case 0x03:   // vorbis comments
    case 0x81:   // theora comments
        xdt = 2; // comment payload
        break;
    default:
        xdt = 0; // raw data payload
        break;
    }

    // Set ident.
    // Probably need a non-fixed way of generating
    // this, but it has to be done in SDP and passed in from there.
    q = s->buf;
    *q++ = (RTP_XIPH_IDENT >> 16) & 0xff;
    *q++ = (RTP_XIPH_IDENT >>  8) & 0xff;
    *q++ = (RTP_XIPH_IDENT      ) & 0xff;

    // set fragment
    // 0 - whole frame (possibly multiple frames)
    // 1 - first fragment
    // 2 - fragment continuation
    // 3 - last fragmement
    frag = size <= max_pkt_size ? 0 : 1;

    if (!frag && !xdt) { // do we have a whole frame of raw data?
        uint8_t *end_ptr = s->buf + 6 + max_pkt_size; // what we're allowed to write
        uint8_t *ptr     = s->buf_ptr + 2 + size; // what we're going to write
        int remaining    = end_ptr - ptr;

        av_assert1(s->num_frames <= s->max_frames_per_packet);
        if (s->num_frames > 0 &&
            (remaining < 0 ||
             s->num_frames == s->max_frames_per_packet ||
             av_compare_ts(s->cur_timestamp - s->timestamp, st->time_base,
                           s1->max_delay, AV_TIME_BASE_Q) >= 0)) {
            // send previous packets now; no room for new data, or too much delay
            ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
            s->num_frames = 0;
        }

        // buffer current frame to send later
        if (0 == s->num_frames)
            s->timestamp = s->cur_timestamp;
        s->num_frames++;

        // Set packet header. Normally, this is OR'd with frag and xdt,
        // but those are zero, so omitted here
        *q++ = s->num_frames;

        if (s->num_frames > 1)
            q = s->buf_ptr; // jump ahead if needed
        AV_WB16(q, size);
        q += 2;
        memcpy(q, buff, size);
        q += size;
        s->buf_ptr = q;

        return;
    } else if (s->num_frames) {
        // immediately send buffered frames if buffer is not raw data,
        // or if current frame is fragmented.
        ff_rtp_send_data(s1, s->buf, s->buf_ptr - s->buf, 0);
    }

    s->timestamp = s->cur_timestamp;
    s->num_frames = 0;
    s->buf_ptr = q;
    while (size > 0) {
        int len = (!frag || frag == 3) ? size : max_pkt_size;
        q = s->buf_ptr;

        // set packet headers
        *q++ = (frag << 6) | (xdt << 4); // num_frames = 0
        AV_WB16(q, len);
        q += 2;
        // set packet body
        memcpy(q, buff, len);
        q += len;
        buff += len;
        size -= len;

        ff_rtp_send_data(s1, s->buf, q - s->buf, 0);

        frag = size <= max_pkt_size ? 3 : 2;
    }
}