bigredfish
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I notice a difference from say 2048 or 4096 to 8192 at night in color especially. From 6144 and up to say 10 I can’t say there is as big of a difference in image quality.
Max bit rate??
- Thread starter Rakin
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It depends on the FPS too. If you like the quality of 4096 bitrate for 15FPS, then decide to up the FPS to 30, you technically need to up the bitrate to 8192 to get the same image quality.
That is why in the camera settings, when you change the FPS, different bitrates become available (at least on my Dahua cams).
That is why in the camera settings, when you change the FPS, different bitrates become available (at least on my Dahua cams).
Well I’ve put 4 of the cameras on 15fps/15iframe and 8192 max bitrate and set quality at the highest setting. I also adjusted some conditions for day and night. Major difference! They are staying maxed quite frequently. I’m using a ton of storage, like 3 times what I was. I also bought a 10TB WD purple.
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area651
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I've always been surprised that the newer, higher mp cameras are sticking to 100mb and not going into gigabit needed bandwidth. If you look at the poe switches, most tend to be 10/100 with MAYBE some having a gb uplink. I look at it like this, if you have the room & the horsepower to handle the load, FILL THE PIPE UP!
biggen
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Gigabit ports on each camera just aren't needed. Using H.264 for 1080@30fps with audio is only about 12Mbps max. So writing to a NAS and delivering a stream to an end user would only use about 25% (~24Mbps) of a 10/100 Fast Ethernet port.
Even at 4k with audio @ 30fps, you are looking at ~28Mbps max using H.265. Still plenty of available bandwidth left for a 10/100 connection if wanting to run two streams.
area651
Getting comfortable
Gotcha. thanks for the numbers breakdown (I was just too lazy to research it). I just meant that it often seems like technology will use as much room as they have. I'm surprised the camera world hasn't looked at it and decided they have plenty of room so they'd fill up the pipe.
biggen
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Yeah, its just to keep the costs down. Probably adds another couple of $ for gigabit ports vs 10/100 ports. Over the course of several million cameras it's a lot of money. BTW, if you want an easy to read primer on resolution bandwidth this site is pretty good. Has some nice tables at the bottom that make it a good quick reference guide.
area651
Getting comfortable
that makes me think of a question. lets say you have a 10/100 poe switch and running 10 or so 4k cameras. We've already established that each camera really only consumes at most 25% of the bandwidth on the port. But you have the BI machine plugged into one of the 10/100 ports of the same switch and you have the gigabit uplink on that switch going to a gigabit switch so it can interface w/ a NAS that's storing all the data. Is there now a bottleneck on the 10/100 port to the BI machine? I'm just imagining the path from the BI computer to the cameras that have to store up to the NAS. Even if you took the NAS out of the equation & stored all the data on the BI machine, you'd still only have a 10/100 pipe to the computer trying to cram 6 cameras worth of data onto it.
or maybe I'm overthinking it?
The uplink on my poe switch is a 1000 t base. If I was doing like you are talking about I would have the poe switch plugged in to a small 5port gigabit switch along with the computer and nas.
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biggen
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In this specific case, yes. But really, if you're spending money on 4K cameras and you want to record at that quality, then you need to upgrade your network to handle the load. Gigabit PoE switches aren't all that more costly. You can pick up used Cisco/HPE PoE switches on eBay all day long.
Lots of 10/100 switches also have twin Gigabit uplinks. So you would use those for your non-PoE devices (e.g. BI server and NAS). Or, if you don't have twin gigabit uplinks, you need to move the BI server and NAS to the same Gigabit switch. Get that BI server off that PoE switch entirely.