Android RTMP直播(续二)

软硬件环境

• ubuntu 16.04
• Android Studio 2.1.3
• OTT BOx with android 5.1.1
• nginx 1.11.3
• nginx-rtmp-module
• VLC

前言

Android RTMP直播(续)介绍了HLS协议相关的基础内容,本文将继续深入学习HLS的其它高级特性.

服务端多码率支持

nginx.conf

#user  nobody;worker_processes  auto;rtmp_auto_push on;error_log  logs/error.log;error_log  logs/error.log  notice;error_log  logs/error.log  info;#pid        logs/nginx.pid;events {    worker_connections  1024;}rtmp {    server {        listen 1935;        chunk_size 4000;        # TV mode: one publisher, many subscribers        #application mytv {            # enable live streaming            #live on;            # record first 1K of stream            #record all;            #record_path /tmp/av;            #record_max_size 1K;            # append current timestamp to each flv            #record_unique on;            # publish only from localhost            #allow publish 127.0.0.1;            #deny publish all;            #allow play all;        #}        # Transcoding (ffmpeg needed)        #application big {        #    live on;            # On every pusblished stream run this command (ffmpeg)            # with substitutions: $app/${app}, $name/${name} for application & stream name.            #            # This ffmpeg call receives stream from this application &            # reduces the resolution down to 32x32. The stream is the published to            # 'small' application (see below) under the same name.            #            # ffmpeg can do anything with the stream like video/audio            # transcoding, resizing, altering container/codec params etc            #            # Multiple exec lines can be specified.        #    exec ffmpeg -re -i rtmp://localhost:1935/$app/$name -vcodec flv -acodec copy -s 32x32                        #-f flv rtmp://localhost:1935/small/${name};        #}        #application small {        #    live on;        #    # Video with reduced resolution comes here from ffmpeg        #}        #application webcam {        #    live on;            # Stream from local webcam        #    exec_static ffmpeg -f video4linux2 -i /dev/video0 -c:v libx264 -an                               #-f flv rtmp://localhost:1935/webcam/mystream;        #}#        application mypush {#            live on;            # Every stream published here            # is automatically pushed to            # these two machines            #push rtmp1.example.com;            #push rtmp2.example.com:1934;#        }#        application mypull {#            live on;            # Pull all streams from remote machine            # and play locally            #pull rtmp://rtmp3.example.com pageUrl=www.example.com/index.html;#        }#        application mystaticpull {#            live on;            # Static pull is started at nginx start            #pull rtmp://rtmp4.example.com pageUrl=www.example.com/index.html name=mystream static;#        }        # video on demand#        application vod {#            play /opt/www/vod;#        }#        application vod2 {#            play /var/mp4s;#        }        # Many publishers, many subscribers        # no checks, no recording        #application videochat {         #   live on;            # The following notifications receive all            # the session variables as well as            # particular call arguments in HTTP POST            # request            # Make HTTP request & use HTTP retcode            # to decide whether to allow publishing            # from this connection or not         #   on_publish http://localhost:8080/publish;            # Same with playing         #   on_play http://localhost:8080/play;            # Publish/play end (repeats on disconnect)         #   on_done http://localhost:8080/done;            # All above mentioned notifications receive            # standard connect() arguments as well as            # play/publish ones. If any arguments are sent            # with GET-style syntax to play & publish            # these are also included.            # Example URL:            #   rtmp://localhost/myapp/mystream?a=b&c=d            # record 10 video keyframes (no audio) every 2 minutes          #  record keyframes;          #  record_path /tmp/vc;          #  record_max_frames 10;          #  record_interval 2m;            # Async notify about an flv recorded          #  on_record_done http://localhost:8080/record_done;        #}        # HLS        # For HLS to work please create a directory in tmpfs (/tmp/hls here)        # for the fragments. The directory contents is served via HTTP (see        # http{} section in config)        #        # Incoming stream must be in H264/AAC. For iPhones use baseline H264        # profile (see ffmpeg example).        # This example creates RTMP stream from movie ready for HLS:        #        # ffmpeg -loglevel verbose -re -i movie.avi  -vcodec libx264        #    -vprofile baseline -acodec libmp3lame -ar 44100 -ac 1        #    -f flv rtmp://localhost:1935/hls/movie        #        # If you need to transcode live stream use 'exec' feature.        #        application hls {            live on;            hls on;            hls_path /opt/www/live;            hls_nested on;            hls_variant _low BANDWIDTH=800000;            hls_variant _mid BANDWIDTH=1200000;            hls_variant _hi  BANDWIDTH=2000000;        }        # MPEG-DASH is similar to HLS        #application dash {        #    live on;        #    dash on;        #    dash_path /tmp/dash;        #}    }}# HTTP can be used for accessing RTMP statshttp {    server {        listen      8081;        location / {            root /opt/www/;        }        # This URL provides RTMP statistics in XML        location /stat {            rtmp_stat all;            # Use this stylesheet to view XML as web page            # in browser            rtmp_stat_stylesheet stat.xsl;        }        location /stat.xsl {            # XML stylesheet to view RTMP stats.            # Copy stat.xsl wherever you want            # and put the full directory path here            root /home/djstava/Workshop/Web/nginx-rtmp-module/;        }        location /hls {            # Serve HLS fragments            types {                application/vnd.apple.mpegurl m3u8;                video/mp2t ts;            }            root /opt/www/;            add_header Cache-Control no-cache;        }        #location /dash {            # Serve DASH fragments        #    root /tmp;        #    add_header Cache-Control no-cache;        #}    }}

主要看看application hls的内容

application hls {            live on;            hls on;            hls_path /opt/www/live;            hls_nested on;            hls_variant _low BANDWIDTH=800000;            hls_variant _mid BANDWIDTH=1200000;            hls_variant _hi  BANDWIDTH=2000000;        }

这里设定当带宽分别为800k 1200k 2000k的时候,终端都播放相对应的m3u8索引文件

ffmpeg推流

这里需要利用ffmpeg推送3路不同的流,对应上面提到的低 中 高

ffmpeg -re -i ~/Videos/xjcy.mp4 -vcodec copy -acodec copy -b:v 800k -b:a 32k -f flv rtmp://10.10.10.59/hls/livestream_low

ffmpeg -re -i ~/Videos/xjcy.mp4 -vcodec copy -acodec copy -b:v 1200k -b:a 64k -f flv rtmp://10.10.10.59/hls/livestream_mid

ffmpeg -re -i ~/Videos/xjcy.mp4 -vcodec copy -acodec copy -b:v 2000k -b:a 128k -f flv rtmp://10.10.10.59/hls/livestream_hi

推送开始后,hls的root目录下就会生成相应的文件内容,如下图所示

此时livestream.m3u8文件内容为

#EXTM3U#EXT-X-VERSION:3#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=800000livestream_low/index.m3u8#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=1200000livestream_mid/index.m3u8#EXT-X-STREAM-INF:PROGRAM-ID=1,BANDWIDTH=2000000livestream_hi/index.m3u8

相应的,播放链接为 http://10.10.10.59:8081/live/livestream.m3u8,播放器需要做的就是根据自身的网络状况,切换到其它的索引文件.

直播节目的录制

直播进行的同时一般都会有本地录制的需求,nginx-rtmp-module提供了这个功能,接下来实践一下.还是看nginx.conf配置文件

application hls {            live on;            hls on;            hls_path /opt/www/live;            hls_nested on;            hls_variant _low BANDWIDTH=800000;            hls_variant _mid BANDWIDTH=1200000;            hls_variant _hi  BANDWIDTH=2000000;            recorder all {                record all;                record_suffix -%Y-%m-%d-%H_%M_%S.flv;                record_max_size 200000K;                record_path /opt/www/record;            }        }

record all录制所有内容,也可以只录音频或者视频.

推流后/opt/www/record路径下就会自动生成带对应时间戳的flv文件,用vlc测试播放OK.

时移电视

要想实现时移电视(这里指的是服务器端)的话,首先需要在服务器上保留足够的切片文件,比如说你提供1小时的时移,就意味着要有1小时的切片文件,而且索引文件中包含前1小时的切片序列.

application hls {            live on;            hls on;            hls_path /opt/www/live;            hls_continuous on;            hls_sync 100ms;            hls_nested on;            hls_playlist_length 5m;            hls_fragment 10s;            hls_variant _low BANDWIDTH=800000;            hls_variant _mid BANDWIDTH=1200000;            hls_variant _hi  BANDWIDTH=2000000;            #exec /home/djstava/Workshop/Web/nginx-1.11.3/build/test.sh;            #exec_kill_signal term;            #recorder all {            #    record all;            #    record_suffix -%Y-%m-%d-%H_%M_%S.flv;            #    record_max_size 6200000K;            #    record_path /opt/www/record;            #}        }

hls_fragment指的是切片文件的长度,这里是10秒,hls_playlist_length指的是索引文件的长度,我这里设的是5分钟.推流开始后,你到切片生成的目录,会发现*.m3u8文件包含了30个ts序列.所以,在上面这种情况下,就只能进行5分钟的时移,当播放进度到达当前直播点时则继续回到直播状态.

执行外部shell脚本

比如有个脚本test.sh,内容如下

#!/bin/bashon_die (){    # kill all children    pkill -KILL -P $$}trap 'on_die' TERMffmpeg -re -i /home/djstava/Videos/ygdx.mp4  -vcodec copy -acodec copy -f flv rtmp://10.10.10.48/hls/ygdx &wait

我这里把它放在hls application中执行,则nginx.conf应如下

application hls {            live on;            hls on;            hls_path /opt/www/live;            hls_continuous on;            hls_sync 100ms;            hls_nested on;            hls_playlist_length 5m;            hls_fragment 10s;            hls_variant _low BANDWIDTH=800000;            hls_variant _mid BANDWIDTH=1200000;            hls_variant _hi  BANDWIDTH=2000000;            exec /home/djstava/Workshop/Web/nginx-1.11.3/build/test.sh;            exec_kill_signal term;            #recorder all {            #    record all;            #    record_suffix -%Y-%m-%d-%H_%M_%S.flv;            #    record_max_size 6200000K;            #    record_path /opt/www/record;            #}        }

当hls服务正常启动时(如上面写过的ffmpeg推流动作),外部脚本test.sh也被执行了.脚本中捕捉了退出的中断信号,也就说,如果ffmpeg推流动作中断了,那么test.sh脚本也就不再执行了.

制作RAMDISK

为了提高HLS的读写效率,可以把切片和索引文件操作放在内存中进行.

mount -t tmpfs -o size=512m tmpfs /opt/www/live

参考文献

1 https://github.com/arut/nginx-rtmp-module/wiki/Directives