Video Decoding Explained — CCTV Decoders and H.265

Within the spec of every NVR on the market is a decoding capability. This spec was fairly minor before 4MP and 4K cameras became affordable and mainstream as usually the bitrate was the
biggest bottleneck in systems. Now with H.265 bitrates and more affordable 4MP and 8MP 4K cameras, decoding is a spec users will want to understand.

It’s important to understand what decoding capability means and does not mean. It’s important to note that decoding does not affect recording: Even though the NVR or DVR can display just one 4K Camera at a time, it can still record all 4K cameras. Decoding capability in simple terms is the ability for the NVR or DVR to display any given stream or recording reliability at the same time. This includes and apps and mobile streaming.

Lets look at this example from the Hikvision Datasheet for the Hikvision iDS-7716NXI-M4/16P/X NVR :

2-ch@32MP
4-ch@12 MP
8-ch@8MP
16-ch@4MP

This means this NVR can Display or Playback simultaneously :
2 x 32mp cameras at the same time on a multi screen.
4 x 12mp cameras at the same time on a multi screen 8 x 8mp cameras at the same time on a multi screen
16 x 4mp cameras at the same time on a multi screen

Single camera view, Recording & Playback will be at the higest resolution set on camera & the NVR

on most NVRs and DVR's a single (one) camera view will be the mainstream since this is going to be a large view, it makes sense to show the fullest quality. On smaller views, such as 2x2 (four cameras) or larger, it will switch to a substream. In most cases this is indistinguishable to a user. In a limited image size a substream will look nearly as good (and even better in some cases) than a full sized image that is attempting to be squished down. This is an effect called aliasing. So for most cases as long as you follow the software’s default settings you will not have to worry about decoding capability.

If the decoding capability is pushed beyond the limits you may notice video lag, unresponsive UI, or freezes.

December 7, 2024 | View: 2888 | Categories: Knowledgebase | Tags: Decoding | By: netviewcctv.co.uk

My Wish List

Last Added Items

You have no items in your wish list.

Video Decoding Explained — CCTV Decoders and H.265

Share this post

About the Author