Right so in the case of I-P-P mode I should get back the first encoded frame after submitting the first raw frame, the second encoded frame after submitting the second raw frame, etc, with the only delay being the execution time of the hardware to encode a frame?
If this is correct, and assuming it works fine when using the NVENC SDK directly then maybe it’s an issue with FFmpeg either incorrectly setting some configuration options or doing its own buffering or something.