html5 video player lags while playing hd .mp4 video

I have created html5 video player with fallback option to flash player on Adobe Media Server 5.0. one can watch live as well as recorded videos. it works fine with the video mp4 file. Recently uploaded a pre-recorded HD file(Sorensen Squeeze 9.    Codec: MP4 YouTube 1080) and facing latency. Do I need to change the configuration to incorporate adaptive bitrate? this video player finds out mobile/non-mobile browser and then goes from there. Also for live stream it uses different

hds-live/livepkgr/_definst_/liveevent/livestream.f4m (for non-mobile browser , flash player)

hls-live/livepkgr/_definst_/liveevent/livestream.f4m(for mobile/ios browser)

what's the role of hds-vod in this scenario?