2MP Bitrate quality question

[techcanuck]

Hey guys, I have 3 cameras. 1 is a Dahua IPC-HDW4231EM-ASE which I use for my backyard. The other two are cheap $50 cameras. They are all 2MP cameras, but the Dahua is streaming at about 500 kBps while the others two are at 100 kBps. The Dahua is using H265 and the other two are using H264. I set the max throughput on the Dahua to be at 4096 kbps (which = 500 kBps).

1. Is 4096 a typical setting for a 2MP camera using H265? I want "excellent" video quality for the Backyard/Dahua camera. I have the FPS set to 10 with iFrame set to 10 as well. I could set it higher, but it's already at 5x the throughput of the other cameras.

2. The cheap $50 cameras don't have a "max" limit, so I'm curious why they are so much lower. Maybe this is impossible to tell without looking at the settings... I could grab a screenshot. Given they're at 15 fps and using H264, I would have thought that they should be taking up more bandwidth.

 

[bug99]

Are you using variable bit rate (StreamCtr BRC_VBR)? I find the moment to moment (motion dependent) bit rate varies a lot (4:1), but the majority of the time mine are around 600 to 1200 kbps with a 10fps setting of "Best" quality under H265. I suspect that the lower quality cameras do something (compression?) like what the Dahua does when you select a lower "Quality" setting.

 

[SouthernYankee]

Are the camera bit rate type CBR or VBR ? if it is CBR you get the requested bit rate. if VBR is will change based upon the picture information. For VBR, the more movement, the more color, the more object, the closer to the max set rate you will get.

Also you are assuming that the quality of the encoding on the cheap cameras is a good as the quality camera.

I had a cheap 1080p camera that had a data rate twice as much as a dahua, shooting the exact same scene, but the picture quality was not as good

My cameras are set at 15 fps, 15 iframe, VBR, bit rate of 4096 Kb/sec, h264, smart codex off, some record at 90 kB/sec amd other at 480 KB/sec. i have a complete mixture of different cameras.
I have taken different cameras set with the same setting , and recorded a white wall board and gotten completely different KB/sec values from different manufactures .

Study up on how the video compression works and it will be next to impossible to have the same values for different manufactures with different implementations of the compression.

 

[techcanuck]

Thanks. I am using VBR and I do see that it varies between 400-500kBps. I guess due to the colour, brightness and amount of data to display it just takes that much bandwidth. Which, I'm ok with, just wanted to check if this was typical. Sounds like it's in the right ballpark.