The video format register for the SDI receiver uses 4 bits for frame rate, 1 bit for progressive and 3 bits for "format". The video status register on the Audio Embedder use 4 bits for frame rate, 1 bit for progressive and 3 bits for "structure". So at that level they look the same, but the detail is completely different! The frame rate bits mean different things in the two registers and the format bits are different. The SDI receiver just has "SD" and doesn't distinguish between PAL and NTSC whereas the Embedder does. Just seems very strange that they are using different code to do exactly the same task, and so end up doing it very differently. The embedder seems to do a better job, it would seem, though I've not managed to test things fully yet.