Why Codec Selection Matters

The video codec determines how much storage and network bandwidth your surveillance system requires. For a 32-camera system recording 24/7 at 4MP resolution, choosing H.265 over H.264 can reduce storage requirements by 40–50% — potentially saving thousands of dollars in NVR storage costs while maintaining the same image quality. For large enterprise systems, codec selection is one of the most impactful design decisions.

H.264 (AVC): The Current Standard

H.264 (Advanced Video Coding, also called MPEG-4 AVC) has been the dominant IP camera codec since roughly 2005. It works by encoding each video frame relative to reference frames using inter-frame prediction — only the differences between frames (rather than full frame data) are stored, dramatically reducing file size compared to MJPEG.

A typical H.264 stream at 1080p resolution and 15 fps uses approximately 2–4 Mbps. At 4MP (2688×1520) and 20 fps, expect 4–8 Mbps depending on scene complexity.

H.265 (HEVC): The Next Generation

H.265 (High Efficiency Video Coding) improves on H.264's compression algorithms by using larger coding tree units (CTUs), more sophisticated motion prediction, and better entropy coding. The result: H.265 achieves the same visual quality as H.264 at approximately 50% of the bitrate.

A 4MP camera streaming at 4 Mbps in H.264 would stream at approximately 2 Mbps in H.265 with equivalent quality. Over 30 days of recording for a 32-camera system:

  • H.264 at 4 Mbps: 32 × 4 Mbps × 86,400 sec/day × 30 days ÷ 8 = ~41 TB
  • H.265 at 2 Mbps: 32 × 2 Mbps × 86,400 sec/day × 30 days ÷ 8 = ~21 TB

H.265+ and Smart Codecs

Most major manufacturers (Hikvision, Dahua, Axis) offer proprietary variants — H.265+, Smart H.265, H.265 Pro — that add background modeling to further reduce bitrates for static surveillance scenes. A parking lot camera with H.265+ might stream at 512 Kbps rather than 2 Mbps during quiet periods, dropping to full bitrate only when motion occurs. These codecs can reduce storage by an additional 30–60% beyond standard H.265 for typical surveillance scenes.

Compatibility Considerations

H.265 decoding requires hardware support. Key compatibility issues:

  • NVR hardware — ensure the NVR has H.265 decoding chips. Many older NVRs only support H.264
  • Live view workstations — H.265 decode requires a GPU or CPU with HEVC support (Intel 6th gen+, NVIDIA Maxwell+)
  • VMS software — verify your Video Management System has H.265 playback support in its decoder library
  • Mixed systems — when integrating cameras from multiple manufacturers, H.264 is the lowest-common-denominator codec for NVR compatibility

When to Use Each Codec

Use H.265 for new greenfield installations where all cameras, NVR, and client workstations are selected together — you control the entire stack and can ensure compatibility. The storage and bandwidth savings justify the slight cost premium of H.265-capable hardware.

Use H.264 when integrating new cameras into an existing NVR or VMS that does not support H.265, when the client workstations are older and lack hardware decode capability, or when using a third-party VMS that has limited codec support.