Why Am I Getting Choppy Video? Solved

I'm having trouble finding the source for this choppy video in my recent installation. It's hard to notice, but if you look at the bubbles in the video, there is a slight pause every second or so.

[Update: this has been solved. Solution inside.]

I've checked each camera's direct feed video through a web browser and no chop. No errors posted in VMS, switch functioning properly, I've turned off motion on VMS side, & fps is @ 12. I even emptied all video files from the storage drive to start with a clean slate, but no go. Viewing & recording is occurring on same station. I am recording at 'Best" resolution, but with only 15 cameras installed that shouldn't be an issue. Any ideas?

VMS: DW Spectrum

Switch: Cisco SG300-28MP

Custom Computer: ASUS Z87-WS Motherboard, Intel Core i7-4770K, 32GB RAM, GeForce GTX 660 2GB, Samsung 840 Pro 128GB SSD (OS drive), Seagate Constellation ES.3 4TB HDD (storage drive).

What camera is it? Are all the other 14 cameras doing this or just this one?

All cameras are doing the same thing and all are Hikvision, most being 3MP bullets (DS-2CD2032-I). Strange thing is that this issue did not manifest iteslf when I first installed the system.

Jerome, I asked DW support for feedback.

Since, as you observe, the video does not chop through the camera's web browser but do through the VMS, it is likely related to the VMS.


Per my knowledge DW has patch for this, they worked around the issue..
All you need to do contact their support.
If you want, I can introduce you to the people who can help you, if you are interested, just e-mail me to sbystrov at networkoptix.com


Thanks. Do you have any color about what caused this? Was it a camera issue or?

Yes I think this is what it is....

Cameras sent RTP stream to VMS. At some network environment(with good portion of packetlost) some cameras deliver video with relatively big jitter(really depends on the camera).

VMS on one hand try to play video smoothly by introducing some display buffer. On another hand VMS tends to make this buffer small to minimize delay in the real time display.

I believe in the patch DW Spectrum introduced adaptive buffer size. So now in a good network they automatically have no delay, in bad network - the video is still smooth.

Thanks Sergey. I was really scratching my head on this one. Will contact DW tomorrow (if they're not gone for the holidays already).


I'm sure they resolve this for you. If by some reason they do not, show them this thread:-)


I just talked to Adam from DW about your issue.
He is waiting for your call ( feel free to call today or tomorrow )

He is gong to fix it for you.


Interesting, because we were recently testing a Hikvision camera on Milestone and noticed similarly choppiness. I am curious if something similar was happening there.

Likely it was the case.
There is a simple way to check it. Especially if you know RTSP link for the camera.
Id you do not you can get easily get it for ONVIF cameras using ODM (http://sourceforge.net/projects/onvifdm/ )

Assuming you have RTSP link...
Now you can use VLC player to verify if this is the issue.

1) Switch VLC to use RTP over TCP ( by default it does RTP over UDP)
( tools -> preferences -> input/codecs -> RTP over RTSP(TCP) -> Save

2) Media -> Open Network Stream -> Show more option -> caching. This is where you change buffer size. By default pretty big 1000ms.

Play with it. reduce the buffer, increase the buffer. If video is choppy with small buffer and not choppy with big one... This is the case.


So by default VLC has a 1 full second buffer / delay in displaying video?

We'll test this out on a few cameras. Thanks.

correct. it does.

That was great info on VLC. I'd been assuming the cameras' H264 encoder was responsible for the latency, but you've shattered another misconception -- thanks!

A minimum buffer size appears to be necessary for effective operation. At 200 ms and below, our VLC display freezes, but 250 ms seems to work consistently on our network. Using the industry standard hand waving test, the latency has clearly moved below 1/2 second with the VLC buffer set to 250 ms, which is nice.

Horace, what's interesting to me about that is VMSes tend to not buffer much at all. The ones we tested certainly were not introducing a 1 second buffer / delay, e.g., Testing IP Camera Latency

(mildly off topic) I used an Arecont5155 and a Hik2332 while troubleshooting the VLC latency issue. On the Hik, I changed camera compression settings to an I-frame every frame, but I was still seeing latencies of over a second (not realizing it was a VLC problem).

Mr. Bystrov's recommendation improved latency, but I was unable to reduce VLC's buffer to zero without degrading or killing the VLC display. This was true of both Hik2332 and Arecont5155, although the Hik@1536p tolerated a smaller buffer than the Arecont@5MP.

I agree, John, that something puzzling is happening. I wonder if my experience is reproducable. There's something interesting happening here, but I haven't the time to wring it out. Can anyone else shed some light on VLC's apparent requirement for a non-zero buffer size?

Well, a good test would be an Axis camera, same conditions :)

If you have one try it, else we will queue that up.

This kind of buffer is good when you have a bad network quality, but should be removed when you are using the PTZ of the camera. We used it frequently.

Based on our experience this could be not about camera only. This is about camera + network environment.

Some cameras do not behave in some network environments( there is nothing special about those environments, it's just not perfect switches with good portion of traffic ).

To campare apples to apples do test side by side...

Wow! Sergey, you're the best! I'll call him tomorrow so I can be in front of the terminal when I talk to him. Thanks again!

Good Evening Jerome

DW tech support will be open till 8pm est tonight and it will be also open tomorrow

I would like to help you dig into this with you

1-866-446-3595 my ext is 204 I am on the east coast I can talk to you tomorrow if you want

I am sure that the guys at NetworkOptix understand the software ;)

I spoke to Paul over @ DW today and he was extremely helpful. Installed their latest version of DW Spectrum and voila! No chop.

Paul did point out that my switch was a little light in the buffer department, but after the update everything was smooth as can be. Will have to watch if that buffer issue comes into play when I add the rest of the cameras, but for now two thumbs up for DW.


Thanks for following up and glad DW solved it!