[go: up one dir, main page]

rtp 0.4.0

A pure Rust implementation of RTP
Documentation 
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

#[cfg(test)]
mod packetizer_test;

use crate::{extension::abs_send_time_extension::*, header::*, packet::*, sequence::*};
use util::marshal::{Marshal, MarshalSize};

use anyhow::Result;
use bytes::{Bytes, BytesMut};
use std::fmt;
use std::sync::Arc;
use std::time::SystemTime;

/// Payloader payloads a byte array for use as rtp.Packet payloads
pub trait Payloader: fmt::Debug {
    fn payload(&mut self, mtu: usize, b: &Bytes) -> Result<Vec<Bytes>>;
    fn clone_to(&self) -> Box<dyn Payloader + Send + Sync>;
}

impl Clone for Box<dyn Payloader + Send + Sync> {
    fn clone(&self) -> Box<dyn Payloader + Send + Sync> {
        self.clone_to()
    }
}

/// Packetizer packetizes a payload
pub trait Packetizer: fmt::Debug {
    fn enable_abs_send_time(&mut self, value: u8);
    fn packetize(&mut self, payload: &Bytes, samples: u32) -> Result<Vec<Packet>>;
    fn skip_samples(&mut self, skipped_samples: u32);
    fn clone_to(&self) -> Box<dyn Packetizer + Send + Sync>;
}

impl Clone for Box<dyn Packetizer + Send + Sync> {
    fn clone(&self) -> Box<dyn Packetizer + Send + Sync> {
        self.clone_to()
    }
}

/// Depacketizer depacketizes a RTP payload, removing any RTP specific data from the payload
pub trait Depacketizer {
    fn depacketize(&mut self, b: &Bytes) -> Result<()>;
}

pub type FnTimeGen = Arc<dyn (Fn() -> SystemTime) + Send + Sync>;

#[derive(Clone)]
pub(crate) struct PacketizerImpl {
    pub(crate) mtu: usize,
    pub(crate) payload_type: u8,
    pub(crate) ssrc: u32,
    pub(crate) payloader: Box<dyn Payloader + Send + Sync>,
    pub(crate) sequencer: Box<dyn Sequencer + Send + Sync>,
    pub(crate) timestamp: u32,
    pub(crate) clock_rate: u32,
    pub(crate) abs_send_time: u8, //http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
    pub(crate) time_gen: Option<FnTimeGen>,
}

impl fmt::Debug for PacketizerImpl {
    fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result {
        f.debug_struct("PacketizerImpl")
            .field("mtu", &self.mtu)
            .field("payload_type", &self.payload_type)
            .field("ssrc", &self.ssrc)
            .field("timestamp", &self.timestamp)
            .field("clock_rate", &self.clock_rate)
            .field("abs_send_time", &self.abs_send_time)
            .finish()
    }
}

pub fn new_packetizer(
    mtu: usize,
    payload_type: u8,
    ssrc: u32,
    payloader: Box<dyn Payloader + Send + Sync>,
    sequencer: Box<dyn Sequencer + Send + Sync>,
    clock_rate: u32,
) -> impl Packetizer {
    PacketizerImpl {
        mtu,
        payload_type,
        ssrc,
        payloader,
        sequencer,
        timestamp: rand::random::<u32>(),
        clock_rate,
        abs_send_time: 0,
        time_gen: None,
    }
}

impl Packetizer for PacketizerImpl {
    fn enable_abs_send_time(&mut self, value: u8) {
        self.abs_send_time = value
    }

    fn packetize(&mut self, payload: &Bytes, samples: u32) -> Result<Vec<Packet>> {
        let payloads = self.payloader.payload(self.mtu - 12, payload)?;
        let mut packets = vec![];
        let (mut i, l) = (0, payloads.len());
        for payload in payloads {
            packets.push(Packet {
                header: Header {
                    version: 2,
                    padding: false,
                    extension: false,
                    marker: i == l - 1,
                    payload_type: self.payload_type,
                    sequence_number: self.sequencer.next_sequence_number(),
                    timestamp: self.timestamp, //TODO: Figure out how to do timestamps
                    ssrc: self.ssrc,
                    ..Default::default()
                },
                payload,
            });
            i += 1;
        }

        self.timestamp += samples;

        if l != 0 && self.abs_send_time != 0 {
            let st = if let Some(fn_time_gen) = &self.time_gen {
                fn_time_gen()
            } else {
                SystemTime::now()
            };
            let send_time = AbsSendTimeExtension::new(st);
            //apply http://www.webrtc.org/experiments/rtp-hdrext/abs-send-time
            let mut raw = BytesMut::with_capacity(send_time.marshal_size());
            raw.resize(send_time.marshal_size(), 0);
            let _ = send_time.marshal_to(&mut raw)?;
            packets[l - 1]
                .header
                .set_extension(self.abs_send_time, raw.freeze())?;
        }

        Ok(packets)
    }

    /// skip_samples causes a gap in sample count between Packetize requests so the
    /// RTP payloads produced have a gap in timestamps
    fn skip_samples(&mut self, skipped_samples: u32) {
        self.timestamp += skipped_samples;
    }

    fn clone_to(&self) -> Box<dyn Packetizer + Send + Sync> {
        Box::new(self.clone())
    }
}