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rtp.h
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1 /*
2  * RTP definitions
3  * Copyright (c) 2002 Fabrice Bellard
4  *
5  * This file is part of FFmpeg.
6  *
7  * FFmpeg is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU Lesser General Public
9  * License as published by the Free Software Foundation; either
10  * version 2.1 of the License, or (at your option) any later version.
11  *
12  * FFmpeg is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15  * Lesser General Public License for more details.
16  *
17  * You should have received a copy of the GNU Lesser General Public
18  * License along with FFmpeg; if not, write to the Free Software
19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
20  */
21 #ifndef AVFORMAT_RTP_H
22 #define AVFORMAT_RTP_H
23 
24 #include "libavformat/avformat.h"
25 #include "libavcodec/avcodec.h"
26 
27 /**
28  * Return the payload type for a given stream used in the given format context.
29  * Static payload types are derived from the codec.
30  * Dynamic payload type are derived from the id field in AVStream.
31  * The format context private option payload_type overrides both.
32  *
33  * @param fmt The context of the format
34  * @param codec The context of the codec
35  * @param idx The stream index
36  * @return The payload type (the 'PT' field in the RTP header).
37  */
39  int idx);
40 
41 /**
42  * Initialize a codec context based on the payload type.
43  *
44  * Fill the codec_type and codec_id fields of a codec context with
45  * information depending on the payload type; for audio codecs, the
46  * channels and sample_rate fields are also filled.
47  *
48  * @param codec The context of the codec
49  * @param payload_type The payload type (the 'PT' field in the RTP header)
50  * @return In case of unknown payload type or dynamic payload type, a
51  * negative value is returned; otherwise, 0 is returned
52  */
53 int ff_rtp_get_codec_info(AVCodecContext *codec, int payload_type);
54 
55 /**
56  * Return the encoding name (as defined in
57  * http://www.iana.org/assignments/rtp-parameters) for a given payload type.
58  *
59  * @param payload_type The payload type (the 'PT' field in the RTP header)
60  * @return In case of unknown payload type or dynamic payload type, a pointer
61  * to an empty string is returned; otherwise, a pointer to a string containing
62  * the encoding name is returned
63  */
64 const char *ff_rtp_enc_name(int payload_type);
65 
66 /**
67  * Return the codec id for the given encoding name and codec type.
68  *
69  * @param buf A pointer to the string containing the encoding name
70  * @param codec_type The codec type
71  * @return In case of unknown encoding name, AV_CODEC_ID_NONE is returned;
72  * otherwise, the codec id is returned
73  */
74 enum AVCodecID ff_rtp_codec_id(const char *buf, enum AVMediaType codec_type);
75 
76 #define RTP_PT_PRIVATE 96
77 #define RTP_VERSION 2
78 #define RTP_MAX_SDES 256 /**< maximum text length for SDES */
79 
80 /* RTCP packets use 0.5% of the bandwidth */
81 #define RTCP_TX_RATIO_NUM 5
82 #define RTCP_TX_RATIO_DEN 1000
83 
84 /* An arbitrary id value for RTP Xiph streams - only relevant to indicate
85  * that the configuration has changed within a stream (by changing the
86  * ident value sent).
87  */
88 #define RTP_XIPH_IDENT 0xfecdba
89 
90 /* RTCP packet types */
91 enum RTCPType {
92  RTCP_FIR = 192,
93  RTCP_NACK, // 193
94  RTCP_SMPTETC,// 194
95  RTCP_IJ, // 195
96  RTCP_SR = 200,
97  RTCP_RR, // 201
98  RTCP_SDES, // 202
99  RTCP_BYE, // 203
100  RTCP_APP, // 204
101  RTCP_RTPFB,// 205
102  RTCP_PSFB, // 206
103  RTCP_XR, // 207
104  RTCP_AVB, // 208
105  RTCP_RSI, // 209
106  RTCP_TOKEN,// 210
107 };
108 
109 #define RTP_PT_IS_RTCP(x) (((x) >= RTCP_FIR && (x) <= RTCP_IJ) || \
110  ((x) >= RTCP_SR && (x) <= RTCP_TOKEN))
111 
112 #endif /* AVFORMAT_RTP_H */