Comment by orisho
1 day ago
A 15 frame min anf max GOP size would do the trick, then you'd get two 15 frame GOPs. Each GOP can be concatenated with another GOP with the same properties (resolution, format, etc) as if they were independent streams. So there is actually a way to do this. This is how video splitting and joining without re encoding works, at GOP boundary.
In my case, bandwidth really mattered, so I wanted all one GOP.
Ended up making a bunch of patches o libx264 to do it, but the compute cost of all the encoding on CPU is crazy high. On the decode side (which runs on consumer devices), we just make the user decode the prefix many times.