Recording IP cameras via NVR and compression. question

[gencom 0]

back in the day of analog cameras I can understand the recording system have to use the CPU (or some dedicated hardware board) to crunch compression algorithm to encode/capture the video to a file.

 

anyway now with the newer/current IP cameras that transmit MJPEG and H.264 out.

 

Can I assume that with the NVR software when it "records" it is just saving/copying the MJPEG/H.264 stream to the harddrive? meaning the camera itself compresses video to MJPEG/H.264 and send it out over the network. so basically the NVR is saving the stream and not using high cpu utilization to encode to MJEP/H.264

 

I'm asking because I plan on a 6 ip cam system and don't know if I a i5-3470t will be too bogged down if it have to do some kind of encoding.

[Peter_ 2]

True, which is why some cameras have the ability to record right to a networked hard drive without any trouble. The problem becomes more with the amount of bandwidth available on the network then.

[PluffMud 0]

"some" meaning Axis and Mobotix (can record to a network hard drive)...am I missing any?

 

Very good question and something I've been curious about. I actually run 6 or 7 IP cameras using BlueIris on an older quad core Q6700 Intel chip (still my main computer ). I don't have them all displayed on there right now but with 4 cameras BlueIris is using 22% CPU. Currently 2 are using H264 (720P) and the other two are MJPEG (standard definition).

[dexterash 0]

Please make a difference between NVR and STORAGE.

 

A NVR will initiate connections to camera, store, decode/display stream and manage the recordings.

 

In the STORAGE mode, the camera will connect to a storage device, uploading it's recordings. If this is done via FTP, the camera is unable to read the remaining space and manage the recordings; in this case No decoding/displaying is needed here (usually can't be done in real time).

[MaxIcon 0]

This totally depends on the software. Some NVRs dump the h.264 straight into a video wrapper with minimal CPU usage, but others (like Blue Iris) decode the video and save it in their own format, requiring more powerful PCs.

 

The other things to consider, along with what dexterash mentioned, are any kind of analytics, motion detect, etc. If these aren't done on the camera, they need CPU at the NVR.

 

If you're considering using Blue Iris, you should go to their community forum at cam-it.org, where there are many discussions about CPU power and how many MP and fps you can support. If you're looking at other systems, you'll need to ask about that specific software.

[bass1176 0]

Just wondering when does this play a role and which types of these cameras are mass produced currently in the market.

 

 

There are two kinds of IP cameras:

 

Centralized IP cameras, which require a central Network Video Recorder (NVR) to handle the recording, video and alarm management.

 

Decentralized IP cameras, which do not require a central Network Video Recorder (NVR), as the cameras have recording functionality built-in and can thus record directly to digital storage media, such as flash drives, hard disk drives or network attached storage.

 

http://en.wikipedia.org/wiki/IP_camera

[dexterash 0]

Recording MP cameras is space consuming, so SD cards/Flash Media will keep your recordings for 1-2 days (usually); the expected role of "local" storage should be backup, when network storage fails.

 

Recording to NAS depends on the protocol. As I stated before, FTP is not good for this, since it can't return free disk space(thus the IP Camera will just write to the NAS untill it's full). Of course, using NFS or CIFS should be ok and it's a good option, but you need cameras that support this. Also, some of the cameras need to write up logs (for motion detection, for example). You would require a software/station to read the records&logs and manage them.

 

Although this Wikipedia article is good, it's outdated and very general.