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
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
|
/*
* RTP H.263 Depacketizer, RFC 2190
* Copyright (c) 2012 Martin Storsjo
* Based on the GStreamer H.263 Depayloder:
* Copyright 2005 Wim Taymans
* Copyright 2007 Edward Hervey
* Copyright 2007 Nokia Corporation
* Copyright 2007 Collabora Ltd, Philippe Kalaf
* Copyright 2010 Mark Nauwelaerts
*
* This file is part of Libav.
*
* Libav 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.
*
* Libav 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 Libav; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#include "avformat.h"
#include "rtpdec_formats.h"
#include "libavutil/attributes.h"
#include "libavutil/intreadwrite.h"
#include "libavcodec/get_bits.h"
struct PayloadContext {
AVIOContext *buf;
uint8_t endbyte;
int endbyte_bits;
uint32_t timestamp;
int newformat;
};
static PayloadContext *h263_new_context(void)
{
return av_mallocz(sizeof(PayloadContext));
}
static void h263_free_context(PayloadContext *data)
{
if (!data)
return;
if (data->buf) {
uint8_t *p;
avio_close_dyn_buf(data->buf, &p);
av_free(p);
}
av_free(data);
}
static av_cold int h263_init(AVFormatContext *ctx, int st_index, PayloadContext *data)
{
if (st_index < 0)
return 0;
ctx->streams[st_index]->need_parsing = AVSTREAM_PARSE_FULL;
return 0;
}
static int h263_handle_packet(AVFormatContext *ctx, PayloadContext *data,
AVStream *st, AVPacket *pkt, uint32_t *timestamp,
const uint8_t *buf, int len, uint16_t seq,
int flags)
{
/* Corresponding to header fields in the RFC */
int f, p, i, sbit, ebit, src, r;
int header_size, ret;
if (data->newformat)
return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf, len,
seq, flags);
if (data->buf && data->timestamp != *timestamp) {
/* Dropping old buffered, unfinished data */
uint8_t *p;
avio_close_dyn_buf(data->buf, &p);
av_free(p);
data->buf = NULL;
}
if (len < 4) {
av_log(ctx, AV_LOG_ERROR, "Too short H.263 RTP packet: %d\n", len);
return AVERROR_INVALIDDATA;
}
f = buf[0] & 0x80;
p = buf[0] & 0x40;
if (!f) {
/* Mode A */
header_size = 4;
i = buf[1] & 0x10;
r = ((buf[1] & 0x01) << 3) | ((buf[2] & 0xe0) >> 5);
} else if (!p) {
/* Mode B */
header_size = 8;
if (len < header_size) {
av_log(ctx, AV_LOG_ERROR,
"Too short H.263 RTP packet: %d bytes, %d header bytes\n",
len, header_size);
return AVERROR_INVALIDDATA;
}
r = buf[3] & 0x03;
i = buf[4] & 0x80;
} else {
/* Mode C */
header_size = 12;
if (len < header_size) {
av_log(ctx, AV_LOG_ERROR,
"Too short H.263 RTP packet: %d bytes, %d header bytes\n",
len, header_size);
return AVERROR_INVALIDDATA;
}
r = buf[3] & 0x03;
i = buf[4] & 0x80;
}
sbit = (buf[0] >> 3) & 0x7;
ebit = buf[0] & 0x7;
src = (buf[1] & 0xe0) >> 5;
if (!(buf[0] & 0xf8)) { /* Reserved bits in RFC 2429/4629 are zero */
if ((src == 0 || src >= 6) && r) {
/* Invalid src for this format, and bits that should be zero
* according to RFC 2190 aren't zero. */
av_log(ctx, AV_LOG_WARNING,
"Interpreting H263 RTP data as RFC 2429/4629 even though "
"signalled with a static payload type.\n");
data->newformat = 1;
return ff_h263_handle_packet(ctx, data, st, pkt, timestamp, buf,
len, seq, flags);
}
}
buf += header_size;
len -= header_size;
if (!data->buf) {
/* Check the picture start code, only start buffering a new frame
* if this is correct */
if (len > 4 && AV_RB32(buf) >> 10 == 0x20) {
ret = avio_open_dyn_buf(&data->buf);
if (ret < 0)
return ret;
data->timestamp = *timestamp;
} else {
/* Frame not started yet, skipping */
return AVERROR(EAGAIN);
}
}
if (data->endbyte_bits || sbit) {
if (data->endbyte_bits == sbit) {
data->endbyte |= buf[0] & (0xff >> sbit);
data->endbyte_bits = 0;
buf++;
len--;
avio_w8(data->buf, data->endbyte);
} else {
/* Start/end skip bits not matching - missed packets? */
GetBitContext gb;
init_get_bits(&gb, buf, len*8 - ebit);
skip_bits(&gb, sbit);
if (data->endbyte_bits) {
data->endbyte |= get_bits(&gb, 8 - data->endbyte_bits);
avio_w8(data->buf, data->endbyte);
}
while (get_bits_left(&gb) >= 8)
avio_w8(data->buf, get_bits(&gb, 8));
data->endbyte_bits = get_bits_left(&gb);
if (data->endbyte_bits)
data->endbyte = get_bits(&gb, data->endbyte_bits) <<
(8 - data->endbyte_bits);
ebit = 0;
len = 0;
}
}
if (ebit) {
if (len > 0)
avio_write(data->buf, buf, len - 1);
data->endbyte_bits = 8 - ebit;
data->endbyte = buf[len - 1] & (0xff << ebit);
} else {
avio_write(data->buf, buf, len);
}
if (!(flags & RTP_FLAG_MARKER))
return AVERROR(EAGAIN);
if (data->endbyte_bits)
avio_w8(data->buf, data->endbyte);
data->endbyte_bits = 0;
ret = ff_rtp_finalize_packet(pkt, &data->buf, st->index);
if (ret < 0)
return ret;
if (!i)
pkt->flags |= AV_PKT_FLAG_KEY;
return 0;
}
RTPDynamicProtocolHandler ff_h263_rfc2190_dynamic_handler = {
.codec_type = AVMEDIA_TYPE_VIDEO,
.codec_id = AV_CODEC_ID_H263,
.init = h263_init,
.parse_packet = h263_handle_packet,
.alloc = h263_new_context,
.free = h263_free_context,
.static_payload_id = 34,
};
|
