Dahua NVR3208 - Best Playback Quality ? >>

[platinum 0]

Have a couple questions on getting the best playback quality out of recorded video.

 

1. Should I use CBR or VBR? I played with these and CBR seems to be better. I am not worried about HDD space if it gives me better quality.

2. What does the LAN Download option do? Setting is under /System Config/Network. Manual says it processes the downloaded data first. Is that a pre record buffer of some sort?

3. At what bitrate should I record. Right now I have it set to 4096 and that seems OK.

4. What is the difference between H.264 and H.264B?

5. I have a couple 1.3MP cameras, in the specs for the 3208 it mentions playback for 720 and 1080. Does that mean I should not record at 960 or that I will just get less total cameras than I potentially could hook up if I record at 960 instead of 720 for the 1.3MP's.

 

Any other tips for good playback?

[mroek 0]

I don't know the answers to all your questions, but I can answer a couple, I think:

 

1) CBR means constant bit rate, while VBR means variable bit rate. VBR may conserve some bandwidth and disk space, but I believe that the best quality would be achieved with a high CBR. I don't think it makes much sense to go over 4096 on a 1.3 MP camera of this quality.

3) See 1.

4) I am not certain, but I believe that H264B uses the baseline profile, while H264 uses the main profile. The latter should be better, theoretically.

[platinum 0]

thanks for the feedback.

 

Is there a general rule on bitrate per mexapixal or something I should follow?

[MaxIcon 0]

Higher bitrate is better quality.

 

Whether it's enough better to justify the lower max record time is an individual decision, and there's always a point of diminishing returns.

 

I'd test it in varying conditions with a lot of fast movement. If you set the bit rate really low, just for comparison, you should see a lot more pixelization around fast movement, and it'll give you an idea of what to look for between, say, 4096 and 8192.

[platinum 0]

I changed my main feed to CBR 6144 and my sub stream to VBR/6 1024. That seems to look good and I don't see any network bottlenecks so I should be fine. Using 24Mb/s on a 100Mb switch.

 

Let me know what else I should change.