OK, I know this will be a big can of worms, but doing it anyway. :-) Please reference this screen shot, and understand this is a representation of an issue we've spent several weeks testing. Let's put aside any judgements of my setup or networking skills and assume for a sec that I know what I'm doing.



Here's the issue. NDI Screen Capture drops a lot of frames and I would like know why, or at least have NewTek say something about this as I believe it's a problem with their product. As you can see, I have several NDI sources for comparison. This shot shows about 5 minutes of elapsed time, and the number of frames each source dropped.

Birddog P100 camera - 0
BirdDog FlexIn - 2
Pana AW-HE40 (HX) - 8
NUC7i5BNK - Intel HD GPU running NDI Screen Capture 4.6 - 4109
vMix5 i9-11990K/Quadro GPU running NDI Screen Capture 5.0.10 (latest i think) - 4313

The switch is a Cisco SG350X-24PD, with an optimized vLAN for NDI traffic. My vMix computers live on 10G legs, the NUC on a 2.5G leg, and the rest of the contribution devices all have a gigabit leg to themselves. Before you ask, I've also tried the same switch with a factory reset config with nearly same results. I've tried several other multi-gigabit switches (Cisco, Netgear AV, TP-Link) with same results, incl. a generic gigabit dumb switch. BTW the NIC load coming into vMix4 never goes over 550Mb. We've tried different NIC drivers on the computers, different versions of vMix as the host, changed out cables and even tried different NICs in all 3 computers. We keep coming back to NDI Tools Screen Capture as the only thing we see these amounts of dropped frames on, no matter which computer we run it on.

Now all of that said, most techs here don't see a problem in the Screen Capture video feed (i see the occasional frame freeze-just 1 frame), although the drop rate is running several hundred frames per minute. Not horrendous I guess, but it reminds me of a joke where the punchline is "how many drops of urine can i put in your coffee before you notice?". We can load vMix Desktop capture utility on the same contribution computers and see a very small number (less than 10) of dropped frames in the same 5min window.


So here's the request to the forum, and anyone at vMix or NewTek that cares to follow up with this. What are your dropped frame stats in vMix using NDI Screen Capture?? Are you seeing the same thing that we are? Is there another tool besides vMix I can use to check for dropped frames?

in this case, the screen capture computers were running a full screen video playback with constant motion. we have also seen this behavior when using screen capture with zoom/teams/skype video call content. if it was just powerpoint slides i wouldn't care.

I had a little time so I staged a simple test to compare three modes of capture from the same laptop.

- NDI Tools 5 NDI Screen Capture
- NDI Tools 5 NDI-HX Screen Capture
- HDMI output mirrored to a BirdDog Mini NDI encoder

Source is Lenovo X1 Carbon Gen 7
- Intel® Core™ i7-8565U
- Windows 10 Pro 64
- 16GB LPDDR3 2133MHz
- 512GB Solid State Drive M.2 PCIe-NVMe
- 14.0" FHD (1920 x 1080)
- Integrated Intel® UHD Graphics 620
- USB 3.0 Gigabit Ethernet interface

All captures are 1080p60, which is the native size and frame rate of the display.

A forensic 1080p60 clip (https://www.youtube.com/watch?v=ZrQsl5AGAMo) locally played in VLC.

Captured into vMix at 1080p60. Recorded at 1080p60 @ 20 Mb/s using hardware encoding. Examined in Premier Pro 2022.

The NDI Tools captured both show significant amount of "source frame dropped" over the 90 second duration of the clip. Like 2000+ frames.

The clip captured using the BirdDog encoder had <10 source frames dropped over 90 seconds.

Hardware capture is the definitive solution.

So what program is better than ndi screen capture?