I have a USB camera, and the qtcamera demo is very laggy. The amcap developed using DirectShow SDK is very smooth. I don't know why

[houyawei]

I have a USB camera, and the qtcamera demo is very laggy. The amcap developed using Microsoft DirectShow SDK is very smooth. I don't know why

[JoeCFD]

not sure which Qt version you are using. I guess Qt5 may use simple gstreamer bin type pipeline to render video streams. If it is the case, it has at least 2s delay. Try to write your own pipeline and it is not very hard.

[houyawei]

I found the problem, it's a resolution issue. Just set it from 4K to 1080

[JoeCFD]

@houyawei Reducing resolution does help solve the issue. There are two ways to do it. One way is to reduce resolution of your camera output. Another way is to reduce it in the pipeline. However, if your computer has a good GPU, hardware acceleration may be able to handle 4K.

[houyawei]

It is an all-in-one machine with poor performance. Currently using 1080 resolution