[mort96]

Well, you don't add 4s of latency for 4x encoding speed though. You add 4s of latency for very marginal quality/efficiency improvement and significant encoder simplification, because the baseline is current frame-parallel encoders, not sequential encoders.

Plus, computers aren't quad cores any more, people with powerful streaming rigs probably have 8 or 16 cores; and key frames aren't every second. Suddenly you're in this hellish world where you have to balance latency, CPU utilization and encoding efficiency. 16 cores at a not-so-great 8 seconds of extra latency means terrible efficiency with a key frame every 0.5 second. 16 cores at good efficiency (say, 4 seconds between key frames) means terrible 64 second of extra latency.