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
|
/*
* RTP packetization for H.263 video
* Copyright (c) 2012 Martin Storsjo
*
* 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 "avformat.h"
#include "rtpenc.h"
#include "libavcodec/put_bits.h"
#include "libavcodec/get_bits.h"
struct H263Info {
int src;
int i;
int u;
int s;
int a;
int pb;
int tr;
};
struct H263State {
int gobn;
int mba;
int hmv1, vmv1, hmv2, vmv2;
int quant;
};
static void send_mode_a(AVFormatContext *s1, const struct H263Info *info,
const uint8_t *buf, int len, int ebits, int m)
{
RTPMuxContext *s = s1->priv_data;
PutBitContext pb;
init_put_bits(&pb, s->buf, 32);
put_bits(&pb, 1, 0); /* F - 0, mode A */
put_bits(&pb, 1, 0); /* P - 0, normal I/P */
put_bits(&pb, 3, 0); /* SBIT - 0 bits */
put_bits(&pb, 3, ebits); /* EBIT */
put_bits(&pb, 3, info->src); /* SRC - source format */
put_bits(&pb, 1, info->i); /* I - inter/intra */
put_bits(&pb, 1, info->u); /* U - unrestricted motion vector */
put_bits(&pb, 1, info->s); /* S - syntax-baesd arithmetic coding */
put_bits(&pb, 1, info->a); /* A - advanced prediction */
put_bits(&pb, 4, 0); /* R - reserved */
put_bits(&pb, 2, 0); /* DBQ - 0 */
put_bits(&pb, 3, 0); /* TRB - 0 */
put_bits(&pb, 8, info->tr); /* TR */
flush_put_bits(&pb);
memcpy(s->buf + 4, buf, len);
ff_rtp_send_data(s1, s->buf, len + 4, m);
}
static void send_mode_b(AVFormatContext *s1, const struct H263Info *info,
const struct H263State *state, const uint8_t *buf,
int len, int sbits, int ebits, int m)
{
RTPMuxContext *s = s1->priv_data;
PutBitContext pb;
init_put_bits(&pb, s->buf, 64);
put_bits(&pb, 1, 1); /* F - 1, mode B */
put_bits(&pb, 1, 0); /* P - 0, mode B */
put_bits(&pb, 3, sbits); /* SBIT - 0 bits */
put_bits(&pb, 3, ebits); /* EBIT - 0 bits */
put_bits(&pb, 3, info->src); /* SRC - source format */
put_bits(&pb, 5, state->quant); /* QUANT - quantizer for the first MB */
put_bits(&pb, 5, state->gobn); /* GOBN - GOB number */
put_bits(&pb, 9, state->mba); /* MBA - MB address */
put_bits(&pb, 2, 0); /* R - reserved */
put_bits(&pb, 1, info->i); /* I - inter/intra */
put_bits(&pb, 1, info->u); /* U - unrestricted motion vector */
put_bits(&pb, 1, info->s); /* S - syntax-baesd arithmetic coding */
put_bits(&pb, 1, info->a); /* A - advanced prediction */
put_bits(&pb, 7, state->hmv1); /* HVM1 - horizontal motion vector 1 */
put_bits(&pb, 7, state->vmv1); /* VMV1 - vertical motion vector 1 */
put_bits(&pb, 7, state->hmv2); /* HVM2 - horizontal motion vector 2 */
put_bits(&pb, 7, state->vmv2); /* VMV2 - vertical motion vector 2 */
flush_put_bits(&pb);
memcpy(s->buf + 8, buf, len);
ff_rtp_send_data(s1, s->buf, len + 8, m);
}
void ff_rtp_send_h263_rfc2190(AVFormatContext *s1, const uint8_t *buf, int size,
const uint8_t *mb_info, int mb_info_size)
{
RTPMuxContext *s = s1->priv_data;
int len, sbits = 0, ebits = 0;
GetBitContext gb;
struct H263Info info = { 0 };
struct H263State state = { 0 };
int mb_info_pos = 0, mb_info_count = mb_info_size / 12;
const uint8_t *buf_base = buf;
s->timestamp = s->cur_timestamp;
init_get_bits(&gb, buf, size*8);
if (get_bits(&gb, 22) == 0x20) { /* Picture Start Code */
info.tr = get_bits(&gb, 8);
skip_bits(&gb, 2); /* PTYPE start, H261 disambiguation */
skip_bits(&gb, 3); /* Split screen, document camera, freeze picture release */
info.src = get_bits(&gb, 3);
info.i = get_bits(&gb, 1);
info.u = get_bits(&gb, 1);
info.s = get_bits(&gb, 1);
info.a = get_bits(&gb, 1);
info.pb = get_bits(&gb, 1);
}
while (size > 0) {
struct H263State packet_start_state = state;
len = FFMIN(s->max_payload_size - 8, size);
/* Look for a better place to split the frame into packets. */
if (len < size) {
const uint8_t *end = ff_h263_find_resync_marker_reverse(buf,
buf + len);
len = end - buf;
if (len == s->max_payload_size - 8) {
/* Skip mb info prior to the start of the current ptr */
while (mb_info_pos < mb_info_count) {
uint32_t pos = AV_RL32(&mb_info[12*mb_info_pos])/8;
if (pos >= buf - buf_base)
break;
mb_info_pos++;
}
/* Find the first mb info past the end pointer */
while (mb_info_pos + 1 < mb_info_count) {
uint32_t pos = AV_RL32(&mb_info[12*(mb_info_pos + 1)])/8;
if (pos >= end - buf_base)
break;
mb_info_pos++;
}
if (mb_info_pos < mb_info_count) {
const uint8_t *ptr = &mb_info[12*mb_info_pos];
/* get position in bits in the input packet at which the next info block should be used */
uint32_t bit_pos = AV_RL32(ptr);
/* get position in bytes */
uint32_t pos_next_mb_info = (bit_pos + 7)/8;
/* check if data from the next MB info block should be used */
if (pos_next_mb_info <= end - buf_base) {
state.quant = ptr[4];
state.gobn = ptr[5];
state.mba = AV_RL16(&ptr[6]);
state.hmv1 = (int8_t) ptr[8];
state.vmv1 = (int8_t) ptr[9];
state.hmv2 = (int8_t) ptr[10];
state.vmv2 = (int8_t) ptr[11];
ebits = 8 * pos_next_mb_info - bit_pos;
len = pos_next_mb_info - (buf - buf_base);
mb_info_pos++;
}
} else {
av_log(s1, AV_LOG_ERROR, "Unable to split H263 packet, "
"use -mb_info %d or -ps 1.\n",
s->max_payload_size - 8);
}
}
}
if (size > 2 && !buf[0] && !buf[1])
send_mode_a(s1, &info, buf, len, ebits, len == size);
else
send_mode_b(s1, &info, &packet_start_state, buf, len, sbits,
ebits, len == size);
if (ebits) {
sbits = 8 - ebits;
len--;
} else {
sbits = 0;
}
buf += len;
size -= len;
ebits = 0;
}
}
|
