Lets talk CBR vs VBR

handinpalm

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There is a lot of talk about optimizing your camera setting to get the most efficient storage capability. Not a lot of talk about setting your cameras on Constant Bit Rate (CBR) or Variable Bit Rate (VBR). I have 8 Dauha 1080 cams and a couple of old Cisco 640 cams, all set with 15 fps, continuous recording. Storage is 6TB WD purple HD operating with Blue Iris software. The Dahua cams came with CBR set as default. I was not satisfied with getting about 13 days of recordings stored on the 6TB HD, even though I thought the setting were optimized. I changed all cams to VBR with data rate cap set to 4096. I now get 22 days of stored video on the 6TB HD w/o sacrificing the video quality. What a difference in storage capacity! The more "quiet" scenes you have on your cam, the less data you will be storing. When using a constant bit rate setting, you are wasting a lot of storage. Evidently the only advantage of using CBR is the audio. I will never go back to CBR setting. Audio is good with VBR also. Here is a short writeup from IPVM on the differences. Anyone else have some experience to share?

CBR vs VBR vs MBR - Surveillance Streaming
 
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fenderman

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What he said. D2D at h265+, 5 cameras, 15fps, CBR, 17 days ~3.4TB
Note that blue iris or for that mater any other vms does not support h.265+ it is proprietary to the camera manufacturer and you will have issues with the video.
 

john-ipvm

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@fenderman we have tested Hikvision H.265+, Axis Zipstream, Hanwha's SmartStream, etc. and they have worked fairly widely with commercial VMSes (e.g., Exacq, Milestone, Avigilon) with no special settings or software needed. We have not tested them with Blue Iris so I don't know about that.
 

fenderman

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@fenderman we have tested Hikvision H.265+, Axis Zipstream, Hanwha's SmartStream, etc. and they have worked fairly widely with commercial VMSes (e.g., Exacq, Milestone, Avigilon) with no special settings or software needed. We have not tested them with Blue Iris so I don't know about that.
There have been numerous threads where the video is corrupted when using BI and the h.264+/265+. If it doesn't play nicely 100 percent of the time, its useless. How much video did you record and review? Have you tested Dahua?
 

john-ipvm

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Yes, we have tested Dahua Smart H.265. We record various cameras for numerous weeks as we are testing a number of these manufacturers every week. Also, we track reports of issues from thousands of integrators and there are very few reported issues with smart codecs on the major commercial VMSes over the last ~2 years they have been available.
 

marku2

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For me, HD space is cheap. I like CBR and max bitrate.
so true hd space is cheap but the hikvision h265+, made there 4k 2385s run a lot easier on the 7600 series nvr
i had a bitch of a time getting past or adding more that 5 cameras to one nvr everything started to freeze up
now with everything ticked to h265+ the bandwidth seems to flow a lot better
its a bonus the hd space lasts for ages
i have run back on the recordings and they seem fine on my test unit
i couldn't at the time see the point of 4k cameras running at 1080 to make things work but seems this new 4k tech is here to stay and hikvision have to make it work into a bandwidth that is usable
but my 2mp lowlight still blows away a 2385.
 

framednlv

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Set all the cameras to run proper on CBR without tearing or ghosting then switch them to VBR.

My opinion only.
 

austwhite

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I know this is a pretty ancient thread, but if someone finds it now wanting more current information they may look like I have.
Well. I havent found a definitive answer regarding the benefits of CBR vs VBR. IF you get everything working good with CBR, then switch to CBR and see if there is a difference.
If you are recording 24/7 you may save storage wiith VBR, but there is a small quality hit.

Regarding smart codecs some mentioned, including H265+ Do not use them if you use Direct to Disc recording in Blue Iris as it causes issues, at least with a lot of Dahua camera's I have tested. They save bandwidth be completely trashing the iFrame/Key frame rate and this will cause you issues. For me, using the "Smart Codec" caused the Keyframe rate to drop sometimes as low as 0.03. The issue with this is that Blue Iris uses the Keyframes to trigger recording and to switch from the substream to the main stream. So the seconds waiting for Blue Iris to switch to the main stream, or to start recording, are seconds of footage being missed and this could be critical.
H265 is fine, but the "Smart Codec" (H265+) option in, at least in current Dahua firmware, seems to cause issues by making the iFrame rate dynamic.

VBR and Standard H265 where you still can control the iFrame rate is fine and will work fine, with a slight quality hit over CBR. :)

Just my 5 cents worth on that.
 

handinpalm

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Since the Dahua 4MP cameras (5442) came out, I found better quality running CBR and max bit rate. So I take back my original statement about VBR. Things change over time.
 
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