BaroneOSD is a PAL video overlay impression WITHOUT additional hardware required (NO LM1881 Sync generator).
Use only 3 pin:
D1 (USART TX) used to pump pixel in the video connected with a 330 ohm resistor to D6
D6 (AIN0) Video in/out, connect here you camera or radio TX.
D7 (AIN1) 0.3V Voltage reference (you can use a partitor resistor)