Phil Pilgrim (PhiPi) said...
Here's a one-pin NTSC solution:
White is logic high; sync, logic low; blank level, CTRB programmed for DUTY mode with FRQB set to $4924_0000. The advantage of this over tri-stating for the blanking level is that the Propeller's video generator can be used to generate the visible stuff while CTRB is active. When the video output is high, it's ORed with the DUTY output to yield a high; when low, the DUTY-mode value takes over. CTRB is simply turned off during the syncs, which has to be handled in software.
The resistor values have an output impedance of 75 ohms and will drive a 75-ohm load at 1V P-P. The cap is there to filter the DUTY doody.