Couldn't something like this be used?
http://www.hobbytron.net/vk4306.htmlNot sure how it would be powered though, here are the spec's maybe someone can demisitfy it for me.
2 X 15 LED's
BAR OR DOT MODE
Scale : -23dB to +5dB, 15 LED's per channel.
dB-linear division from -4 to +5dB (1dB per LED).
Systematically growing steps below -4dB.
Accuracy : 0.5dB (1 KHz).
Frequency range : 20 Hz to 30 KHz (-3dB).
Three different LED colors : green, orange and red.
Adjustable sensitivity: 150mV to 5Vrms Low input, 1.5V to 50Vrms High Input
Input impedance : 47K Low input / 470K High input
POWER SUPPLY: 10 to 15VDC / 300mA max.
PCB DIMENSIONS: 150 x 57 mm
You can also apparently make your own input, they suggest 1/8" plug but I'd imagine doing something like RCA could be done too?
Hook it up to a Video camera through a standard stereo headphone 1/8 mini jack: This has terminal pins to solder to. With an adapter cable you make from the headphone jack to the PCB, you can use it as described. Requires a 12-15vdc power supply at 300mA.