Bitrate for 8mp camera with h265

[ipslascam]

Hi all - How can I find the right bitrate for my IPC-HFW1831E camera running at 3840x2160 resolution with h265? The Dahua software defaulted to 3072 Kb/s CBR (VBR is a mess with this camera). How do I figure out what a good CBR setting is on h265?

Thanks

 

[wittaj]

Every field of view is different.

Most here will use CBR.

Many here run H264 due to macroblocking issues with H265.

Most will start an 8MP bit rate around 12,000 and then go up and down until we don't notice an improvement or degradation.

 

[ipslascam]

Every field of view is different.

Most here will use CBR.

Many here run H264 due to macroblocking issues with H265.

Most will start an 8MP bit rate around 12,000 and then go up and down until we don't notice an improvement or degradation.

Thanks. Yea I was getting horrible macroblocking with VBR. Aside from macroblocking, what kind of things are you looking for in the video when trying different CBR settings?

 

[wittaj]

It is more of what your eye perceives. Some people can see differences that others don't or maybe a monitor limitation.

Personally when I am trying to figure out the bit rate I will start at a number, so in this case I would do 10,000, 12,000 and 14,000 and take pics at each one and then flip thru the pics and see if I notice a difference.

If not then I no bitrate is too high and then try the next set of numbers.

The higher the bit rate the more storage that is needed, so you want to run as low as you can before you see degradation.

Once I am down to a few bitrates then I will do a digital zoom and see if I notice a difference. A higher bitrate can usually allow for some digital zoom.

But again it comes down to your field of view and eyes.

 

[ipslascam]

It is more of what your eye perceives. Some people can see differences that others don't or maybe a monitor limitation.

Personally when I am trying to figure out the bit rate I will start at a number, so in this case I would do 10,000, 12,000 and 14,000 and take pics at each one and then flip thru the pics and see if I notice a difference.

If not then I no bitrate is too high and then try the next set of numbers.

The higher the bit rate the more storage that is needed, so you want to run as low as you can before you see degradation.

Once I am down to a few bitrates then I will do a digital zoom and see if I notice a difference. A higher bitrate can usually allow for some digital zoom.

But again it comes down to your field of view and eyes.

Thanks. For some reason this camera's firmware will only allow a CBR bitrate up to 9984, but I'll take some screenshots at different values. Presumably I'd want to have some movement in the screenshots to see if there's ghosting, or would that be more a shutter speed issue than a bitrate issue? This is where I'm not really sure what kind of problems might popup with different bitrates.

 

[wittaj]

Yeah ghosting is more a shutter, gain and gamma issue.