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/libavformat/rtpenc_vp8.c

http://github.com/FFmpeg/FFmpeg
C | 55 lines | 21 code | 7 blank | 27 comment | 2 complexity | 9bcc6314ba65eaa9293b265a64e084a0 MD5 | raw file
 1/*
 2 * RTP VP8 Packetizer
 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 "rtpenc.h"
23
24/* Based on a draft spec for VP8 RTP.
25 * ( http://tools.ietf.org/html/draft-ietf-payload-vp8-05 ) */
26void ff_rtp_send_vp8(AVFormatContext *s1, const uint8_t *buf, int size)
27{
28    RTPMuxContext *s = s1->priv_data;
29    int len, max_packet_size, header_size;
30
31    s->buf_ptr      = s->buf;
32    s->timestamp    = s->cur_timestamp;
33
34    // extended control bit set, reference frame, start of partition,
35    // partition id 0
36    *s->buf_ptr++ = 0x90;
37    *s->buf_ptr++ = 0x80; // Picture id present
38    *s->buf_ptr++ = s->frame_count++ & 0x7f;
39    // Calculate the number of remaining bytes
40    header_size     = s->buf_ptr - s->buf;
41    max_packet_size = s->max_payload_size - header_size;
42
43    while (size > 0) {
44        len = FFMIN(size, max_packet_size);
45
46        memcpy(s->buf_ptr, buf, len);
47        // marker bit is last packet in frame
48        ff_rtp_send_data(s1, s->buf, len + header_size, size == len);
49
50        size         -= len;
51        buf          += len;
52        // Clear the partition start bit, keep the rest of the header untouched
53        s->buf[0]    &= ~0x10;
54    }
55}