Same compression ratio can result in different data rates, depending on movements in the scene. If can't guarantee that exact delay, deal with this at receive end by buffering up some data in reserve, always providing a store of packets.
Incoming packets go into the buffer for playback.
The only problem is if the delay is great enough to drain the buffer before new packets get added. Can tolerate, to some extent, lost packets. Can you sense the network and adapt compression ratio accordingly.