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
|
/*
* Copyright (C) 2010 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package android.net.rtp;
import java.util.Arrays;
/**
* This class defines a collection of audio codecs to be used with
* {@link AudioStream}s. Their parameters are designed to be exchanged using
* Session Description Protocol (SDP). Most of the values listed here can be
* found in RFC 3551, while others are described in separated standards.
*
* <p>Few simple configurations are defined as public static instances for the
* convenience of direct uses. More complicated ones could be obtained using
* {@link #getCodec(int, String, String)}. For example, one can use the
* following snippet to create a mode-1-only AMR codec.</p>
* <pre>
* AudioCodec codec = AudioCodec.getCodec(100, "AMR/8000", "mode-set=1");
* </pre>
*
* @see AudioStream
*
* @deprecated {@link android.net.sip.SipManager} and associated classes are no longer
* supported and should not be used as the basis of future VOIP apps.
*/
public class AudioCodec {
/**
* The RTP payload type of the encoding.
*/
public final int type;
/**
* The encoding parameters to be used in the corresponding SDP attribute.
*/
public final String rtpmap;
/**
* The format parameters to be used in the corresponding SDP attribute.
*/
public final String fmtp;
/**
* G.711 u-law audio codec.
*/
public static final AudioCodec PCMU = new AudioCodec(0, "PCMU/8000", null);
/**
* G.711 a-law audio codec.
*/
public static final AudioCodec PCMA = new AudioCodec(8, "PCMA/8000", null);
/**
* GSM Full-Rate audio codec, also known as GSM-FR, GSM 06.10, GSM, or
* simply FR.
*/
public static final AudioCodec GSM = new AudioCodec(3, "GSM/8000", null);
/**
* GSM Enhanced Full-Rate audio codec, also known as GSM-EFR, GSM 06.60, or
* simply EFR.
*/
public static final AudioCodec GSM_EFR = new AudioCodec(96, "GSM-EFR/8000", null);
/**
* Adaptive Multi-Rate narrowband audio codec, also known as AMR or AMR-NB.
* Currently CRC, robust sorting, and interleaving are not supported. See
* more details about these features in RFC 4867.
*/
public static final AudioCodec AMR = new AudioCodec(97, "AMR/8000", null);
private static final AudioCodec[] sCodecs = {GSM_EFR, AMR, GSM, PCMU, PCMA};
private AudioCodec(int type, String rtpmap, String fmtp) {
this.type = type;
this.rtpmap = rtpmap;
this.fmtp = fmtp;
}
/**
* Returns system supported audio codecs.
*/
public static AudioCodec[] getCodecs() {
return Arrays.copyOf(sCodecs, sCodecs.length);
}
/**
* Creates an AudioCodec according to the given configuration.
*
* @param type The payload type of the encoding defined in RTP/AVP.
* @param rtpmap The encoding parameters specified in the corresponding SDP
* attribute, or null if it is not available.
* @param fmtp The format parameters specified in the corresponding SDP
* attribute, or null if it is not available.
* @return The configured AudioCodec or {@code null} if it is not supported.
*/
public static AudioCodec getCodec(int type, String rtpmap, String fmtp) {
if (type < 0 || type > 127) {
return null;
}
AudioCodec hint = null;
if (rtpmap != null) {
String clue = rtpmap.trim().toUpperCase();
for (AudioCodec codec : sCodecs) {
if (clue.startsWith(codec.rtpmap)) {
String channels = clue.substring(codec.rtpmap.length());
if (channels.length() == 0 || channels.equals("/1")) {
hint = codec;
}
break;
}
}
} else if (type < 96) {
for (AudioCodec codec : sCodecs) {
if (type == codec.type) {
hint = codec;
rtpmap = codec.rtpmap;
break;
}
}
}
if (hint == null) {
return null;
}
if (hint == AMR && fmtp != null) {
String clue = fmtp.toLowerCase();
if (clue.contains("crc=1") || clue.contains("robust-sorting=1") ||
clue.contains("interleaving=")) {
return null;
}
}
return new AudioCodec(type, rtpmap, fmtp);
}
}
|
