  This report describes the submission of the DKU-DukeECE-Lenovo team to the
VoxCeleb Speaker Recognition Challenge (VoxSRC) 2021 track 4. Our system
including a voice activity detection (VAD) model, a speaker embedding model,
two clustering-based speaker diarization systems with different similarity
measurements, two different overlapped speech detection (OSD) models, and a
target-speaker voice activity detection (TS-VAD) model. Our final submission,
consisting of 5 independent systems, achieves a DER of 5.07% on the challenge
test set.
