While a h264 stream created by the omxh264enc can be decoded with low latency, the stream produced by the nvv4l2h264enc cannot be decoded with low latency.
By analyzing the SPS NALUs for both encoders I found out that the issue is the pic_order_cnt_type.
With default settings the omxh264enc uses pic_order_cnt_type=2 which disables re-ordering of images and allows the decoder to work in low latency.
In contrast, the nvv4l2h264enc uses pic_order_cnt_type=0 which forces the decoder to hold onto decoded frames unneccesarily.
Is there an option to use pic_order_cnt_type=2 with the nvv4l2h264enc ?