There was no external support for extending the SPI api of a AT7456 chip to include interlace, sending telemetry, etc. This limited what I could do.
Check out my other project 'SW7456' which just emulates a MAX7456 chip without the graphics nonsense.
ORIGINAL:
Open source hardware/firmware project to replace the MAX7456 OSD chip commonly used in flight controllers.
Hardware schematic and first flight video available at ModdQuad.com
First software release still under development, only a documentation preview available here at this time.