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
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
|
/*
* RTP VP8 Depacketizer
* 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
*/
/**
* @file
* @brief RTP support for the VP8 payload
* @author Josh Allmann <joshua.allmann@gmail.com>
* @see http://www.webmproject.org/code/specs/rtp/
*/
#include "libavcodec/bytestream.h"
#include "rtpdec_formats.h"
struct PayloadContext {
AVIOContext *data;
uint32_t timestamp;
int is_keyframe;
};
static void prepare_packet(AVPacket *pkt, PayloadContext *vp8, int stream)
{
av_init_packet(pkt);
pkt->stream_index = stream;
pkt->flags = vp8->is_keyframe ? AV_PKT_FLAG_KEY : 0;
pkt->size = avio_close_dyn_buf(vp8->data, &pkt->data);
pkt->destruct = av_destruct_packet;
vp8->data = NULL;
}
static int vp8_handle_packet(AVFormatContext *ctx,
PayloadContext *vp8,
AVStream *st,
AVPacket *pkt,
uint32_t *timestamp,
const uint8_t *buf,
int len, int flags)
{
int start_packet, end_packet, has_au, ret = AVERROR(EAGAIN);
if (!buf) {
// only called when vp8_handle_packet returns 1
if (!vp8->data) {
av_log(ctx, AV_LOG_ERROR, "Invalid VP8 data passed\n");
return AVERROR_INVALIDDATA;
}
prepare_packet(pkt, vp8, st->index);
*timestamp = vp8->timestamp;
return 0;
}
start_packet = *buf & 1;
end_packet = flags & RTP_FLAG_MARKER;
has_au = *buf & 2;
buf++;
len--;
if (start_packet) {
int res;
uint32_t ts = *timestamp;
if (vp8->data) {
// missing end marker; return old frame anyway. untested
prepare_packet(pkt, vp8, st->index);
*timestamp = vp8->timestamp; // reset timestamp from old frame
// if current frame fits into one rtp packet, need to hold
// that for the next av_get_packet call
ret = end_packet ? 1 : 0;
}
if ((res = avio_open_dyn_buf(&vp8->data)) < 0)
return res;
vp8->is_keyframe = *buf & 1;
vp8->timestamp = ts;
}
if (!vp8->data || vp8->timestamp != *timestamp && ret == AVERROR(EAGAIN)) {
av_log(ctx, AV_LOG_WARNING,
"Received no start marker; dropping frame\n");
return AVERROR(EAGAIN);
}
// cycle through VP8AU headers if needed
// not tested with actual VP8AUs
while (len) {
int au_len = len;
if (has_au && len > 2) {
au_len = AV_RB16(buf);
buf += 2;
len -= 2;
if (buf + au_len > buf + len) {
av_log(ctx, AV_LOG_ERROR, "Invalid VP8AU length\n");
return AVERROR_INVALIDDATA;
}
}
avio_write(vp8->data, buf, au_len);
buf += au_len;
len -= au_len;
}
if (ret != AVERROR(EAGAIN)) // did we miss a end marker?
return ret;
if (end_packet) {
prepare_packet(pkt, vp8, st->index);
return 0;
}
return AVERROR(EAGAIN);
}
static PayloadContext *vp8_new_context(void)
{
av_log(NULL, AV_LOG_ERROR, "RTP VP8 payload implementation is incompatible "
"with the latest spec drafts.\n");
return av_mallocz(sizeof(PayloadContext));
}
static void vp8_free_context(PayloadContext *vp8)
{
if (vp8->data) {
uint8_t *tmp;
avio_close_dyn_buf(vp8->data, &tmp);
av_free(tmp);
}
av_free(vp8);
}
RTPDynamicProtocolHandler ff_vp8_dynamic_handler = {
.enc_name = "VP8",
.codec_type = AVMEDIA_TYPE_VIDEO,
.codec_id = CODEC_ID_VP8,
.alloc = vp8_new_context,
.free = vp8_free_context,
.parse_packet = vp8_handle_packet,
};
|
