When sourcing a CCTV DVR Box, you must prioritize channel capacity (4, 8, 16, or 32 channels) to match the number of cameras. Ensure the device supports H.265+ video compression, which significantly reduces bandwidth and storage consumption by up to 75% compared to older standards. Verify the recording resolution capabilities, aiming for at least 5MP or 4K (Ultra HD) to ensure forensic-level detail. Additionally, check for hybrid compatibility (5-in-1 DVRs) that support AHD, TVI, CVI, CVBS, and IP cameras to ensure maximum flexibility with existing infrastructure.