Here is the step by step procedure to install a Eachine proDVR to your Goggles Two FPV Goggles (source RCgroups).
1)Diagram 1: solder the black wire to ÿGNDÿ, and the red wire to ÿVCCÿ. This is to supply power to the DVR.
2)Diagram 2: Splice the first wire from the right, and connect this to the ÿAudio Inÿ cable on the DVR.
3)Diagram 3: The second wire from the right is the ÿvideo outÿ wire. Split this cable, and connect it to the ÿvideo inÿ and ÿvideo outÿ wires on the DVR as shown below.
4)After completing Steps 1 ÿ 3, properly insulate the wires. Pass the connector through the ventilation holes on top of the goggles. Connect the connector to the DVR and secure the DVR
5)DVR On Screen Display (OSD) Menu
6)This concludes the installation of the DVR to the goggles two FPV Goggles.
Be aware with such wiring, the signal pass through the DVR and will introduce extra latency. One possibility is to use an extra 2-position switch to enable/disable DVR AVout feedback.