I have been comparing quality between hw and sw encoding, and find that the quality is better when I use Software Encoder within vMix. The tradeoff is of course, extra CPU usage. 

The comparison is with all settings the same, and just tick and then untick Hardware Encoder. It is more obvious at medium bitrates, eg 2mbps. 1280 x 720. Profile: High, Level 3.1, Preset veryfast or medium.

So my choice is to use the Software encoder for streaming, and Hardware encoder for recording. It would be nice to use the second hardware encoder for streaming as well, but the quality makes it less desirable. 

Anyone out there notice this ? and find a solution for the Hardware Encoding performance.

Of interest is that it seems the Software encoder maintains a steady mildly fluctuating bitrate, that softens the background movement and makes for pleasurable viewing, whereas the Hardware encoder has greater fluctuation of the bitrate up and down, and background filling in is patchy, and slow to update, particularly noticeable when movement comes to a stop and the background then fills in. The following image shows two stream periods. The first part on the left is the hardware encoder streaming, then I stop stream, untick hardware and start stream (no other changes). The Software encoding definitely shows more bitrate, closer to the 2000.



Interested in other peoples observations.

Not necessarily. This was very much true in the past but ever since the RTX line or Turing NVENC so RTX 2080, 2070, 2060 and the GTX 1660 and up all have a newer NVENC chip that out performs x264 or at least measures up to x264 at a medium preset. So basically if you have a RTX card or higher or the GTX 1660 card you should use hardware encoding. If you have the older GTX cards or pascal NVENC then use x264.

@grantcoll what GPU do you have? Also note that the RTX\GTX line will only allow 3 hardware encoding as the Quadro RTX and up cards will allow for unlimited (resource limited only) natively. So it all depends on your hardware. Content can play a role as well. but if you have a RTX or better card then NVENC all the way.

-King

what cpu/setup you have? i think software is better also.