-
Notifications
You must be signed in to change notification settings - Fork 180
/
decoder.go
242 lines (201 loc) · 6.58 KB
/
decoder.go
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
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
package rtpmjpeg
import (
"errors"
"fmt"
"time"
"github.com/pion/rtp"
"github.com/aler9/gortsplib/v2/pkg/codecs/jpeg"
"github.com/aler9/gortsplib/v2/pkg/formatdecenc/rtpmjpeg/headers"
"github.com/aler9/gortsplib/v2/pkg/rtptime"
)
// ErrMorePacketsNeeded is returned when more packets are needed.
var ErrMorePacketsNeeded = errors.New("need more packets")
// ErrNonStartingPacketAndNoPrevious is returned when we received a non-starting
// fragment of an image and we didn't received anything before.
// It's normal to receive this when we are decoding a stream that has been already
// running for some time.
var ErrNonStartingPacketAndNoPrevious = errors.New(
"received a non-starting fragment without any previous starting fragment")
var lumDcCodeLens = []byte{
0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0,
}
var lumDcSymbols = []byte{
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
}
var lumAcCodelens = []byte{
0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d,
}
var lumAcSymbols = []byte{ //nolint:dupl
0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa,
}
var chmDcCodelens = []byte{
0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0,
}
var chmDcSymbols = []byte{
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11,
}
var chmAcCodelens = []byte{
0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77,
}
var chmAcSymbols = []byte{ //nolint:dupl
0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
0xf9, 0xfa,
}
// Decoder is a RTP/M-JPEG decoder.
type Decoder struct {
timeDecoder *rtptime.Decoder
firstPacketReceived bool
fragmentedSize int
fragments [][]byte
firstJpegHeader *headers.JPEG
firstQTHeader *headers.QuantizationTable
}
// Init initializes the decoder.
func (d *Decoder) Init() {
d.timeDecoder = rtptime.NewDecoder(rtpClockRate)
}
// Decode decodes an image from a RTP/M-JPEG packet.
func (d *Decoder) Decode(pkt *rtp.Packet) ([]byte, time.Duration, error) {
byts := pkt.Payload
var jh headers.JPEG
n, err := jh.Unmarshal(byts)
if err != nil {
return nil, 0, err
}
byts = byts[n:]
if jh.Width > maxDimension {
return nil, 0, fmt.Errorf("Width of %d is not supported", jh.Width)
}
if jh.Height > maxDimension {
return nil, 0, fmt.Errorf("Height of %d is not supported", jh.Height)
}
if jh.FragmentOffset == 0 {
if jh.Quantization >= 128 {
d.firstQTHeader = &headers.QuantizationTable{}
n, err := d.firstQTHeader.Unmarshal(byts)
if err != nil {
return nil, 0, err
}
byts = byts[n:]
} else {
d.firstQTHeader = nil
}
d.fragments = d.fragments[:0] // discard pending fragmented packets
d.fragmentedSize = len(byts)
d.fragments = append(d.fragments, byts)
d.firstJpegHeader = &jh
d.firstPacketReceived = true
} else {
if len(d.fragments) == 0 {
if !d.firstPacketReceived {
return nil, 0, ErrNonStartingPacketAndNoPrevious
}
return nil, 0, fmt.Errorf("received a non-starting fragment")
}
if int(jh.FragmentOffset) != d.fragmentedSize {
d.fragments = d.fragments[:0] // discard pending fragmented packets
return nil, 0, fmt.Errorf("received wrong fragment")
}
d.fragmentedSize += len(byts)
d.fragments = append(d.fragments, byts)
}
if !pkt.Marker {
return nil, 0, ErrMorePacketsNeeded
}
if d.fragmentedSize < 2 {
return nil, 0, fmt.Errorf("invalid data")
}
data := make([]byte, d.fragmentedSize)
pos := 0
for _, frag := range d.fragments {
pos += copy(data[pos:], frag)
}
d.fragments = d.fragments[:0]
var buf []byte
buf = jpeg.StartOfImage{}.Marshal(buf)
var dqt jpeg.DefineQuantizationTable
id := uint8(0)
for i := 0; i < len(d.firstQTHeader.Tables); i += 64 {
dqt.Tables = append(dqt.Tables, jpeg.QuantizationTable{
ID: id,
Data: d.firstQTHeader.Tables[i : i+64],
})
id++
}
buf = dqt.Marshal(buf)
buf = jpeg.StartOfFrame1{
Type: d.firstJpegHeader.Type,
Width: d.firstJpegHeader.Width,
Height: d.firstJpegHeader.Height,
QuantizationTableCount: id,
}.Marshal(buf)
buf = jpeg.DefineHuffmanTable{
Codes: lumDcCodeLens,
Symbols: lumDcSymbols,
TableNumber: 0,
TableClass: 0,
}.Marshal(buf)
buf = jpeg.DefineHuffmanTable{
Codes: lumAcCodelens,
Symbols: lumAcSymbols,
TableNumber: 0,
TableClass: 1,
}.Marshal(buf)
buf = jpeg.DefineHuffmanTable{
Codes: chmDcCodelens,
Symbols: chmDcSymbols,
TableNumber: 1,
TableClass: 0,
}.Marshal(buf)
buf = jpeg.DefineHuffmanTable{
Codes: chmAcCodelens,
Symbols: chmAcSymbols,
TableNumber: 1,
TableClass: 1,
}.Marshal(buf)
buf = jpeg.StartOfScan{}.Marshal(buf)
buf = append(buf, data...)
if data[len(data)-2] != 0xFF || data[len(data)-1] != jpeg.MarkerEndOfImage {
buf = append(buf, []byte{0xFF, jpeg.MarkerEndOfImage}...)
}
return buf, d.timeDecoder.Decode(pkt.Timestamp), nil
}