Do i really need two grounds
FPV = First-person video? CCD = Charge Coupled Device. BEC = Battery Eliminator Controller? PDB = Power Distribution Block? VTX = Video Transmit? Not everyone knows what these acronyms stand for. 

The top ground is probably "signal ground" for the video and audio, while the bottom ground is likely power ground. No datasheet was linked and googling "TS5840" finds only Chinese sellers. 

Since a craft such as this contains several powerful electric motors, "power ground" is likely very noisy. Connecting all grounds together will probably work, but the result may be less appealing than expected. "Signal grounds" (if that's what it even is, cannot tell) are provided for a separate ground which carries less of this transient noise, which could affect signal quality.

If it were my aircraft, I'd wire signal ground right to the same ground the camera is using. Hopefully the camera is powered from something providing it's own ground, like a 5v regulator. Typically, low-ESR capacitance is provided on both the input and output of regulators, so I'd expect the ground there to be less noisy than say, connecting directly to the battery negative.

If you find the image quality to be lacking and suspect noise, try adding some capacitance across the +V and ground as close to the transmitter and camera as possible. A 10nF ceramic and 1uF tantalum cap (in parallel) on each should do a decent job of filtering power to them.