QSV is Faster than Nvenc

  • hello there

    i have done some testing for encoding speeds and i found that Quick Sync is Faster than NVENC

    same project :

    QSV: 9min

    NVENC: 9:45


    vbr 60-65mbit


    use maximum rendering quality : ✔ use previews : ✔


    GTX 1070

    16GB DDR4

    I5 6600

  • First: You can't really compare different encoders to eachother. There are various settings of each encoder like filesize vs. speed, quality vs. speed. i.e. I could make VP9 faster than x264 with setting all the options to speed priority. Ok, the quality would be rubbish, the filesize huge but it would be fast.

    Second: Encoding FPS has it's limits. Lets break it down to one frame:

    Rendering with 60fps means one frame needs to be rendered in 16.6ms. And there are some steps in this chain:

    t = trender + tpreprocess + tencode + tfilewrite

    If you have a very complex video sequence with lots of overlays, effects, fades, etc. trender could be like 20ms. In that case you could have the fastest hardware encoder capable of 4000 fps but you will never get near 60fps. If the sum of it all would be like 40ms you'd get 25fps exactly.

    I don't know how many frames you have in your project, or what framesize... or even your exact nvenc settings. So i can not tell if this 9m45s is actually fast or slow. Same with QSV. Depends on the processor, settings, iGPU, etc. Maybe in some cases on newer CPUs with special settings QSV is actually faster. Who knows?

  • What they said. Oh and also don't forget to see if some silly background services churn away during encoder performance tests. Best practice is to switch off all the non-essential services and also to check in task-manager for any hiding apps too. Also depending on the antivirus you use, some tend to disable AV too during encoding performance tests or at the very least add exceptions, and some even go as far as taking the computer offline (networking) during the test.

    GPU is faster at some types of computations and the CPU is most definitely leagues faster at some other types of computation, so it is quite difficult to say which is better. In the ideal world it would be nice if QSV and NVENC worked together to bring even greater benefits to the table.

  • In my experience I had to disable all integrated GPU functionality to get a decent NVENC encoding. I disabled the iGPU completely. It was just slowing down.

    Because it's trying to decode video using iGPU for some reason. At least i've seen this with HEVC NVENC encoding.