CPU Usage and Frame Rate
  • On my Mac, I see the cpu usage of the VTDecoderXPCService running at around 800-900%. I understand this isn't too terrible for my 8 core Mac Pro machine but I currently have the frame rate for motion recording in SS set at 18FPS. This is probably unnecessarily high. I reduced all of my 12 cameras down to 10 FPS but didn't help. Do I have to reduce the frame rate in the camera's UI as well?
  • That is indeed rather high CPU usage, and should probably be reduced a bit.

    What is the exact model of this Mac Pro (what year etc.) and what is the encoding format of the video being delivered by the cameras (JPEG, H.264, H.265)?

    What is the "Idle" number shown in the lower left section of the Activity Monitor CPU window? This is the best measure of how loaded your machine is, as an overall figure. If this is less than about 15% then steps should be taken to lighten the load.

    The thing to do is log on to each camera via their web UIs and reduce their streaming frame rates. 10fps is probably a good level - this will still provide good quality streams, while avoiding excessive resource usage.

    Please report back and let us know how you get on with this.
  • I have noticed the same problem on my 2020 iMac 10th gen intel chip. 64gig ram. 1 camera only.

    VTDecoderXPCService utilization is very low until the program has been running for 30 hours, then it goes through the roof 600%. Reboot, its fine for another 30 hours, then same thing.
  • Ben, the idle number on the Mac is 30-32% so that isn't too bad. The encoding is H.264. These are Hikvision cameras and some of them have something called H.264+. Don't know if that would help. I'll reduce the frame rate to 10 from 15 on all of them and see if that helps. In addition to the fps setting, the cameras also have a max bitrate. Currently those are set to 8Mbit. Let me know if I should change those. I should mention that they are all 4k cameras too. ~Don
  • Hi Don, this kind of CPU usage isn't too surprising on your Mac Pro considering you are using 4K cameras. As long as you're seeing 30% idle, and unless you're seeing any specific problems such as error messages related to lack of resources, then I think this is fine and doesn't require any further action.

    H.264+ is not advisable: this is a proprietary variant implemented by Hikvision that takes extra steps to eke out slightly lower data rates (such as variable key frame intervals). It won't help with resource usage on your Mac, and may cause problems for SecuritySpy.

    In terms of other encoding settings, I would recommend using VBR with a high quality setting. VBR (Variable Bit Rate) is generally preferable to CBR (Constant Bit Rate), as with VBR the camera is able to dynamically adjust its bit rate to give good quality and efficient streams depending on the current conditions.

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