When sourcing a CCTV DVR card, you must prioritize compression standards, typically H.264 or H.265, to ensure efficient storage and bandwidth usage. The frame rate (FPS) is critical; for smooth video, look for cards supporting 25/30 FPS per channel at the desired resolution. Additionally, verify the bus interface type (e.g., PCIe x1 or x4) to ensure compatibility with your server or PC motherboard, and check the number of channels (typically 4, 8, 16, or 32) to match your camera deployment scale.