... HD DVR -USB,PTZ,Audio,Network,VGA,HDMI -SATA HDD up to 2TB -Up to 720P resolution 4 channel HD ... DVR Features: 1. H.264 Real-time Recording, support USB, PTZ, network, two-way audio, VGA, ... 2pcsOperation SystemLinuxVideoVideo CompressionH.264Video Preview Resolution720P:1280*720Video Input4CH HD-SDIVideo Recording120fps@720PVideo Playback1ch Realtime or 4ch non-realtimeVideo ...