IP Camera streams what kind of data?

[sexydadee 0]

I am confused on who sets the recording rate? The IP Camera or the NVR? I thought the camera specifies what resolution and rate it streams to whoever wants the data and then the NVR just records whatever the camera streamed.

 

So, why do I see recording res and rate specified on NVR's? I see NVR's that specifies "400 ips @ 4CIF" (Samsung SRN-3250). I thought only DVR's do this because NVR's just record whatever the res/rate the camera streams.

 

I also see this on a QNAP NVR

 

"Recording Performance - Up to 30 fps at D1 or VGA for each channel"

 

Am I misinterpreting something? Does this mean that it sets a limit so as not to overtax the bandwidth/processor of the NVR?

[empiresecuritycamera 0]

The IPC will output at a certain resolution, but it is up to the Hybrid DVR or NVR to display and record this resolution. Most Hybrid DVR's and NVR's will have a limit on resolution, fps, bitrate, etc. While the IPC could be transmitting at 1080p, a D1 Resolution NVR will only record and/or display at D1 resolution.

 

I am confused on who sets the recording rate? The IP Camera or the NVR? I thought the camera specifies what resolution and rate it streams to whoever wants the data and then the NVR just records whatever the camera streamed.

 

So, why do I see recording res and rate specified on NVR's? I see NVR's that specifies "400 ips @ 4CIF" (Samsung SRN-3250). I thought only DVR's do this because NVR's just record whatever the res/rate the camera streams.

 

I also see this on a QNAP NVR

 

"Recording Performance - Up to 30 fps at D1 or VGA for each channel"

 

Am I misinterpreting something? Does this mean that it sets a limit so as not to overtax the bandwidth/processor of the NVR?

[sexydadee 0]

so the NVR has the ability to downsample (or upsample if IPC outputs low res) video data that it receives from the camera?

 

also, can the camera stream @ h.264 while the NVR records it @ mpeg-2?

[Soundy 1]

so the NVR has the ability to downsample (or upsample if IPC outputs low res) video data that it receives from the camera?

 

also, can the camera stream @ h.264 while the NVR records it @ mpeg-2?

I am confused on who sets the recording rate? The IP Camera or the NVR?

As with other recent questions, the answer is again, "IT DEPENDS". Different cameras and different NVRs interact in different ways. Sometimes it varies with different codecs as well.

 

Case in point: with a Vigil DVR, when you're using a camera that stream MJPEG, you just select your record rate in Vigil. With an H.264 camera, however, you can either set your record rate at 1fps, or select "Set By Camera", in which case you set the framerate in the camera, and Vigil simply receives and writes the stream.

 

Most WILL NOT downsample for recording, although many can re-encode the video to a smaller stream for remote viewing. I've never seen one that would upsample -that would just be pointless, taking up less space but offering no real improvement.

 

also, can the camera stream @ h.264 while the NVR records it @ mpeg-2?

And again, that depends on the camera. Some support multi-streaming, some don't. I'm looking at a Vivotek right now that actually has FOUR separate user-configurable streams, and allows you to set frame size (resolution), framerate, and quality (compression) level, for MPEG-4, JPEG, and H.264... all configured separately for each stream. Many cameras simply offer one high-quality stream for recording, and one sub-stream at CIF or D1 for remote viewing. And many others just give you one stream.

 

I also see this on a QNAP NVR

 

"Recording Performance - Up to 30 fps at D1 or VGA for each channel"

 

Am I misinterpreting something? Does this mean that it sets a limit so as not to overtax the bandwidth/processor of the NVR?

Exactly... because overloading the system would lead to image problems and thus to user complaints. So, most will put a "hard limit" in software and allow some headroom.

[buellwinkle 0]

On the NVR software and cameras I use, I have it display one stream but record another. For example, I have it display VGA resolution to save bandwidth for remote viewing but it records a stream with megapixel resolution. On my older single stream cameras it displays and records the same stream.

[MaxIcon 0]

Another useful example is Blue Iris. You set the frame rate for the camera with its software, and you also set the frame rate in BI. If the two don't match, you can get jerky recordings, depending on how the frame rates sync up. BI has an indicator that shows when a camera's output doesn't match the channel frame rate.

 

In theory, having the frame rates exact multiples of each other minimizes problems with smoothness. If the camera puts out 10 fps and BI records 5 fps, it should be smooth, as BI gets every other frame and stays in sync. If the camera puts out 7.5 fps, though, BI can't keep in sync, and you get jerky video.