浅尝实时流媒体传输

低延迟实时流媒体传输要求

1. 数据可靠性

2. 流控算法

3. 网络传输协议

传输协议区别 RTP RTMP RTSP HLS FLV WebRTC

RTP：实时传输协议（Real-time Transport Protocol）

RTCP：实时传输控制协议（Real-time Transport Control Protocol）

SRTP & SRTCP

RTSP

RTMP/RTMPS

HLS

WebRTC

比较

• 重传慢：TCP 的 ACK 确认机制，丢包后发送侧超时重传，超时时间一般200ms，会造成接收侧帧抖动。

• 拥塞判断不准确：基于丢包的拥塞控制算法无法准确判断拥塞，丢包并不等于拥塞；也会造成发送链路 bufferbloat，链路 RTT 增大，延迟增加。

• 灵活性差：这是最主要原因，TCP 拥塞控制算法在操作系统内核层实现，优化成本较高，移动端只有利用系统已有的优化。

• 延迟： http-flv：低延迟，内容延迟可以做到2-5秒。 Rtmp：低延迟，内容延迟可以做到2-5秒。 Hls:：延迟较高。

• 三者的易用性： rtmp和http-flv：播放端安装率高。只要浏览器支持FlashPlayer就能非常简易的播放。 hls：最大的优点：HTML5可以直接打开播放；这个意味着可以把一个直播链接通过微信 等转发分享，不需要安装任何独立的APP，有浏览器即可。

• rtmp和http-flv比较：

#user  nobody;
worker_processes  auto;
worker_cpu_affinity auto;
worker_rlimit_nofile 1024;

#error_log  logs/error.log;
#error_log  logs/error.log  notice;
#error_log  logs/error.log  info;
#error_log  "pipe:rollback logs/error_log interval=1d baknum=7 maxsize=2G";

#pid        logs/nginx.pid;


events {
    use epoll;
    worker_connections 1024;
    multi_accept on;
}


http {
    include       mime.types;
    default_type  application/octet-stream;

    #log_format  main  '$remote_addr - $remote_user [$time_local] "$request" '
    #                  '$status $body_bytes_sent "$http_referer" '
    #                  '"$http_user_agent" "$http_x_forwarded_for"';

    #access_log  logs/access.log  main;
    #access_log  "pipe:rollback logs/access_log interval=1d baknum=7 maxsize=1G"  main;

    sendfile        on;
    tcp_nopush     on;

    keepalive_timeout  60;
    tcp_nodelay on;
    client_header_buffer_size 4k;
    open_file_cache max=102400 inactive=20s;
    open_file_cache_valid 30s;
    open_file_cache_min_uses 1;
    client_header_timeout 15;
    client_body_timeout 15;
    reset_timedout_connection on;
    send_timeout 15;
    server_tokens off;
    client_max_body_size 1g;

    gzip  on;
    gzip_min_length 1k;
    gzip_buffers 4 32k;
    #gzip_http_version 1.1;
    gzip_comp_level 6;
    gzip_types text/plain text/css text/javascript application/json application/javascript application/x-javascript application/xml;
    gzip_vary on;
    gzip_proxied any;

    # ssl
    ssl_certificate cert.crt;
    ssl_certificate_key cert.key;
    ssl_session_cache shared:SSL:10m;
    ssl_session_timeout 5m;
    ssl_session_tickets on;
    ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
    ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
    ssl_prefer_server_ciphers on;
    #ssl_stapling on;
    #ssl_stapling_verify on;

    #resolver 114.114.114.114;

    upstream pi {
       server 127.0.0.1:9090;
    }

    server {
       listen 80;
        listen [::]:80;
        server_name ijava.me pi.ijava.me static.ijava.me v6.ijava.me static-v6.ijava.me pi-v6.ijava.me;
        return 301 https://$host$request_uri;
    }

    server {
        listen 80 default;
        listen [::]:80 default;
        listen 443 ssl http2 default;
        listen [::]:443 ssl http2 default;
        rewrite ^(.*) <https://ijava.me>;
    }

    server {
       listen 443 ssl http2;
       isten [::]:443 ssl http2;
       server_name static.ijava.me static-v6.ijava.me;
       charset utf-8;
       location / {
           root /home/pi/data/static;
           autoindex on;
           autoindex_exact_size on;
            autoindex_format html;
            autoindex_localtime on;
            set $limit_rate 1M;
       }
    }

    server {
        listen 443 ssl http2;
        listen [::]:443 ssl http2;
        server_name ijava.me v6.ijava.me;

        #ssl_certificate      ijava_me.crt;
        #ssl_certificate_key  ijava_me.key;
        #ssl_session_cache    shared:SSL:10m;
        #ssl_session_timeout  5m;
       #ssl_session_tickets on;
       #ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
        #ssl_ciphers ECDHE-ECDSA-AES128-GCM-SHA256:ECDHE-RSA-AES128-GCM-SHA256:ECDHE-ECDSA-AES256-GCM-SHA384:ECDHE-RSA-AES256-GCM-SHA384:ECDHE-ECDSA-CHACHA20-POLY1305:ECDHE-RSA-CHACHA20-POLY1305:DHE-RSA-AES128-GCM-SHA256:DHE-RSA-AES256-GCM-SHA384;
        #ssl_prefer_server_ciphers  on;
       #ssl_stapling on;
        #ssl_stapling_verify on;

        location / {
            root   /home/pi/data/html;
            index  index.html index.htm;
           charset utf-8;
        }

        location /status {
          stub_status on;
       }
    }

    server {
        listen 443 ssl http2;
        listen [::]:443 ssl http2;
        server_name pi.ijava.me pi-v6.ijava.me;

        location / {
            proxy_pass <https://pi>;
            proxy_set_header X-Forwared-For $proxy_add_x_forwarded_for;
                  proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_redirect off;
        }

        location /cockpit/socket {
            proxy_pass <https://pi>;
            proxy_redirect off;
            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
            proxy_set_header Host $host;
            proxy_set_header X-Real-IP $remote_addr;
            proxy_http_version 1.1;
            proxy_set_header Upgrade $http_upgrade;
            proxy_set_header Connection 'upgrade';
        }

        location ~* \\.(ico|jpe?g|gif|png|bmp|swf|flv)$ {
            proxy_pass <https://pi>;
            expires 30d;
            #log_not_found access_log off;
            access_log off;
        }

        location ~* \\.(js|css)$ {
            proxy_pass <https://pi>;
            expires 7d;
            log_not_found off;
            access_log off;
        }
    }
}

net.core.default_qdisc=fq
net.ipv4.tcp_congestion_control=bbr

# optimiaze
fs.file-max = 999999
net.ipv4.ip_forward = 0
net.ipv4.conf.default.rp_filter = 1
net.ipv4.conf.default.accept_source_route = 0
kernel.sysrq = 0
kernel.core_uses_pid = 1
kernel.msgmnb = 65536
kernel.msgmax = 65536
kernel.shmmax = 68719476736
kernel.shmall = 4294967296
net.ipv4.tcp_max_tw_buckets = 6000
net.ipv4.tcp_sack = 1
net.ipv4.tcp_window_scaling = 1
net.ipv4.ip_local_port_range=1024 65000
net.ipv4.tcp_synack_retries = 1
net.ipv4.tcp_syn_retries = 1
net.ipv4.tcp_tw_recycle = 1
net.ipv4.tcp_tw_reuse = 1
net.ipv4.tcp_keepalive_time = 30
net.ipv4.tcp_syncookies = 1
net.core.somaxconn = 40960
net.ipv4.tcp_max_orphans = 3276800
net.ipv4.tcp_timestamps = 0
net.core.netdev_max_backlog = 262144
net.ipv4.tcp_max_syn_backlog = 262144
net.ipv4.tcp_rmem = 10240 87380 12582912
net.ipv4.tcp_wmem = 10240 87380 12582912
net.core.rmem_default = 8388608
net.core.wmem_default = 8388608
net.core.rmem_max = 16777216
net.core.wmem_max = 16777216
net.ipv4.tcp_mem = 94500000 915000000 927000000
net.ipv4.tcp_fin_timeout = 1

安装 tengine

1. 获取安装包

curl -O <https://tengine.taobao.org/download/tengine-2.3.3.tar.gz>

1. 解压编译安装

tar -xf tengine-2.3.3.tar.gz && cd tengine-2.3.3

./configure --add-module=nginx-rtmp-module --with-openssl=openssl

make && make install