I don't know why people stuck with x264, not x265/H.265/HEVC on either CPU or GPU for superior quality stream. I did endless hours, days, weeks of tests with all methods and settings found Nvidia NVENC H.265 has same image quality as CPU H.265 on slower setting at same bitrate. Encoded Star Wars: The Force Awaken Blu-ray on NVENC H.265 at 6000kps bitrate took about 16 mins but encode on CPU H.265 never get done because it estimated to complete in 10 hours then it increased to 15 hours, 24 hours etc so I dont bothered encode it on CPU as it take forever no matter how many cores. I tried encoded 117MB Star Wars: The Last Jedi MPEG4 trailer on NVENC H.265 took amazing 6 secs to compacted 22MB at 1500kbps bitrate, CPU H.265 encoded took about 16 mins both GPU and CPU encoded had same image quality of original trailer which used higher 7308kbps bitrate. I read lots of interesting things about next generation AOMedia AV1 codec and tried encoded x264 and H.265 at 300-500kbps for fun but image quality was horrible blurred with artifacts. Encoded it with AV1 at 300kbps would see very clean image quality at tiny 7MB file size that will put x264, x265 and HEVC codec to shame.
http://www.streamingmedia.com/Artic...ard-Joins-Alliance-for-Open-Media-117634.aspx
https://www.elecard.com/news/results-of-elecards-latest-benchmarks-of-av1-compared-to-hevc
https://www.elecard.com/videos
Twitch 6000kbps bitrate on x264 is tiny compare to Crowd 1080p AV1 stream at 93962kbps around the quality of 4K Ultra HD Blu-ray bitrate.
Been watched AV1 test samples on Elecard Player blew me away with amazing image quality at very low and high bitrates, it is the only player at the moment capable to decode AV1 playback.
Compare Sintel trailer encoded in AV1, H.265 and H.264 at 300kbps bitrate:
Cant wait to use AV1 when software and browsers will have it enabled around Jan 2018 when AOMedia freeze AV1 codec experiment and release final version by 31 Dec 2017.