Of course. FFMpeg was used consistently on our backend; we cycled through various codecs to find the best one for our purpose and changed the frontend library accordingly.

And I think you're right on the encoding latency. I believe that H.264 buffers a little bit before it makes a decision on how to compress the frames, where as MPEG1 doesn't? I could be completely wrong but my gut is telling me that MPEG1 is basically independent, slightly-modified JPEG frames.