SDI-DVR 4CH Real time SDI Video Input H.264 Video Compression HDMI,VGA Output,4CH Real-Time Playback 6 Levels Adustable H.264 4CH Real Time SDI-DVR,HDMI,VGA Output,two-way Audio,RS485,RS422 SDI-DVR 4CH Real time SDI Video InputH.264 Video CompressionHDMI,VGA Output,4CH Real-Time Playback6 Levels Adustable SDI-DVR