v2_CN_ARMTranscode
ARM下，譬如raspberry pi，转码音频还是可行的。ffmpeg转码音频的CPU占用50%。
使用系统的ffmpeg转码时，需要禁止srs编译ffmpeg，同时打开transcode选项：--with-transcode --without-ffmpeg，这样就不会编译ffmpeg，但是编译了直播转码功能。参考：Build
使用下面的配置：
listen 1935;
http_stream {
enabled on;
listen 8080;
dir ./objs/nginx/html;
}
vhost __defaultVhost__ {
transcode {
enabled on;
ffmpeg ./objs/ffmpeg/bin/ffmpeg;
engine arm_aonly {
enabled on;
vcodec copy;
acodec aac;
abitrate 48;
asample_rate 44100;
achannels 2;
aparams {
strict experimental;
}
output rtmp://127.0.0.1:[port]/[app]?vhost=hls/[stream];
}
}
}
vhost hls {
hls {
enabled on;
hls_path ./objs/nginx/html;
hls_fragment 10;
hls_window 60;
}
}启动后CPU占用：
top - 07:07:07 up 38 min, 2 users, load average: 0.96, 0.58, 0.44
Tasks: 74 total, 3 running, 71 sleeping, 0 stopped, 0 zombie
%Cpu(s): 53.2 us, 14.9 sy, 0.0 ni, 28.2 id, 0.0 wa, 0.0 hi, 3.6 si, 0.0 st
KiB Mem: 383156 total, 168808 used, 214348 free, 11704 buffers
KiB Swap: 102396 total, 0 used, 102396 free, 117676 cached
PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND
3592 winlin 20 0 41620 13m 3880 R 52.1 3.5 1:32.72 ./objs/ffmpeg/bin/ffmpeg
-f flv -i rtmp://127.0.0.1:1935/l
3591 winlin 20 0 3400 1464 1056 R 17.4 0.4 0:29.06 ./objs/srs -c console.conf启动的转码进程：
winlin@raspberrypi:~/srs$ ps aux|grep ffmpeg
winlin 3592 51.2 3.4 41620 13408 pts/0 R+ 07:04 1:43 ./objs/ffmpeg/bin/ffmpeg
-f flv -i rtmp://127.0.0.1:1935/live?vhost=__defaultVhost__/livestream -vcodec copy
-acodec aac -b:a 48000 -ar 44100 -ac 2 -strict experimental -f flv
-y rtmp://127.0.0.1:1935/live?vhost=hls/livestream生成的文件：
winlin@raspberrypi:~/srs$ ll objs/nginx/html/live/
total 6.1M
-rw-r--r-- 1 winlin winlin 936K Apr 5 07:07 livestream-21.ts
-rw-r--r-- 1 winlin winlin 935K Apr 5 07:08 livestream-22.ts
-rw-r--r-- 1 winlin winlin 155K Apr 5 07:08 livestream-23.ts
-rw-r--r-- 1 winlin winlin 833K Apr 5 07:08 livestream-24.ts
-rw-r--r-- 1 winlin winlin 905K Apr 5 07:08 livestream-25.ts
-rw-r--r-- 1 winlin winlin 934K Apr 5 07:08 livestream-26.ts
-rw-r--r-- 1 winlin winlin 933K Apr 5 07:08 livestream-27.ts
-rw-r--r-- 1 winlin winlin 529K Apr 5 07:09 livestream-28.ts.tmp
-rw-r--r-- 1 winlin winlin 155 Apr 5 06:43 livestream.html
-rw-r--r-- 1 winlin winlin 339 Apr 5 07:08 livestream.m3u8Winlin 2014