Discrepancy in size of one hour clips

[MicahJames]

Hello all and thanks for any help.
I have almost all of my cameras recording one hour clips. Most of them are set to different resolutions and FPS but they all seem to record one hour clips at around 900mb.
Example: one camera records 20 FPS at 4MP resolution no audio and the clips are always around 800 mb

the other camera records at 15 FPS at 3MP (also no audio) and the clips are always around 900mb. So why would the lower FPS and lower resolution file contain more size? Both are in full color

they are the same camera just different settings. in blue iris the recording profile isset the same as far as I can tell. It this observation occurs throughout my 12 cameras. The exception being a 30 FPS 1080p which is alwaysblack and white and has a clip size of about 300mb.
Thanks for any insight

 

[fenderman]

Hello all and thanks for any help.
I have almost all of my cameras recording one hour clips. Most of them are set to different resolutions and FPS but they all seem to record one hour clips at around 900mb.
Example: one camera records 20 FPS at 4MP resolution no audio and the clips are always around 800 mb

the other camera records at 15 FPS at 3MP (also no audio) and the clips are always around 900mb. So why would the lower FPS and lower resolution file contain more size? Both are in full color

they are the same camera just different settings. in blue iris the recording profile isset the same as far as I can tell. It this observation occurs throughout my 12 cameras. The exception being a 30 FPS 1080p which is alwaysblack and white and has a clip size of about 300mb.
Thanks for any insight

This is normal. File size depends on one thing and one thing only. Bitrate. Not fps, not resolution. If you have your cameras set to Variable bit rate, the bitrate will fluctuate with the complexity of the scene, your selected fps and resolution.

 

[MicahJames]

This is normal. File size depends on one thing and one thing only. Bitrate. Not fps, not resolution. If you have your cameras set to Variable bit rate, the bitrate will fluctuate with the complexity of the scene, your selected fps and resolution.

I suspected there was a simple answer I was overloooking. Thank you for this.
I have all of them set to VBR but a cap of “4096”. Should I increase that ? I suspect if it’s lower than that I will lose some clarity

 

[bp2008]

I have all of them set to VBR but a cap of “4096”. Should I increase that ? I suspect if it’s lower than that I will lose some clarity

That is entirely up to you. Your average bit rates are currently only around half of the limit you have set. Increasing the limit won't likely have much effect unless you also increase the quality setting.

(800 megabytes per hour) to kilobits per second = 1778 Kbps

(900 megabytes per hour) to kilobits per second = 2000 Kbps

 

[MicahJames]

That is entirely up to you. Your average bit rates are currently only around half of the limit you have set. Increasing the limit won't likely have much effect unless you also increase the quality setting.

(800 megabytes per hour) to kilobits per second = 1778 Kbps

(900 megabytes per hour) to kilobits per second = 2000 Kbps

thank you that makes sense. What do you believe quality setting should be? I believe mine are set at “3” or somewhere in the middle.

 

[MicahJames]

Nevermind I answers my own question. Thanks for helping me make that revelation I appreciate it

 

[bp2008]

You want the highest quality possible while still meeting your goals for video retention (how long you want to keep the video for). If you record only on motion detection, then there is little reason not to just max out the bit rate and quality settings. If you record continuously, as is often recommended because motion detection is imperfect, that is where you should find a balance.

The simplest advice is, if you find you have more hard drive space than you need, then increase the quality and bit rate settings. Otherwise if you can't store video for as long as you want, then you either upgrade your storage or you reduce your video bit rate. The Quality setting is just one of the ways you can reduce the bit rate when encoding with VBR. You can also reduce the frame rate and that should yield a reduction in bit rate without a loss of image quality.

You'll notice the Quality setting is absent if you use CBR, or Constant Bit Rate encoding. CBR encoding gives you more direct control over the bit rate, which is ideal if you need the absolute best quality possible or if you just need your bit rates to be extremely predictable.

This page tries to explain how you can calculate disk space requirements: Calculating Required Hard Drive Size

 

[MicahJames]

Thank you BP I appreciate the link too. I never realized how much quality I was missing. I do record continuous and decided to increase my bit rate to about 4x what I had it at. Incredible increase in quality and detail and I have plenty of hard drive space and CPU to spare. Thank you