... . DVR7504 4ch stand alone DVR Features: 4 channels cost-effective standard DVR 4 Channel D1 real-time preview H.264 ... dual-stream video compression VGA /BNC synchronous video output 4 channel simultaneous real-time playback, GRID interface & smart search ... to second)Playback FunctionsPlay, Pause, Stop, Rewind, Fast play, Slow play, Next file, Previous file, Next camera, Previous camera, Full ...