The output resolution should be determined by the application. NDI Monitor will receive that and display according to the resolution of the display or window size. If NDI Monitor is resized to a very small window size, it will use the low-resolution NDI stream, the quality difference is typically not noticeable in these cases, but the bandwidth and CPU requirements are much lower when working with the low-resolution stream.

As for resource use, there are multiple factors at play so 'it depends'.

In the case you are probably speaking to, CPU, a hardware capture card will probably have less overhead and this is because a capture card is going to bring in uncompressed video which requires the least amount of CPU power to process since there is no CODEC processing.

NDI is compressed and while the CODEC is extremely CPU efficient, it is still another step that has to be performed. I wouldn't say the difference is 'drastic' but they will not be the same.

Now there is a reverse aspect to this. NDI is compressed which uses far less bandwidth across the PCI bus than uncompressed video does. So if the issue is computer bus bandwidth, then NDI can be better than a video I/O card in this respect. This isn't a factor to overlook, as increasing your CPU will make a system process faster, but it will not increase the amount of bandwidth.

Also, NDI can support things like alpha channel, in which for a video I/O card you need to use two connectors, so in this case NDI is probably better since it is single signal containing both versus having to work with two separate video sources and put them together.

Kane Peterson
NewTek