nginx gzip没有压缩mp4

Question

为什么我的gzip conf没有压缩mp4和jpg的任何想法？

nginx.conf包含我的gzip文件

#gzip  on;
include /etc/nginx/gzip;

-

gzip on;
gzip_http_version 1.0;
gzip_disable     "MSIE [1-6]\.";
gzip_buffers 16 8k;
gzip_min_length  1100;
gzip_comp_level 2;
gzip_proxied any;
gzip_types video/mp4 text/plain text/css application/x-javascript text/xml application/xml application/xml+rss text/javascript image/jpeg;