Fix #794, refine the comments.
Fix #794, refine the comments.

winlinvip/srs,ossrs/srs,winlinvip/srs,ossrs/srs,ossrs/srs,winlinvip/simple-rtmp-server,winlinvip/srs,ossrs/srs,winlinvip/srs,ossrs/srs,ossrs/srs,winlinvip/srs,winlinvip/srs