stairs artifact

[Michal Lazo]

I found really wired stairs artifact from top left and go right cross the video in encoded video

start in 53-56s

source video is fine and output from x264 is also fine

I did tests on x265 1.9 and git version

and outputs are same

source video

http://www.mdragon.org/test/test60.ts

encoded video

http://www.mdragon.org/test/encoded.mp4

ffmpeg -i test60.ts -f yuv4mpegpipe -pix_fmt yuv420p - | x265 --y4m -o encoded.265 -

ffmpeg -i encoded.265 -c copy encoded.mp4

I also did try preset veryslow with same result

[Deepthi Nandakumar]

What bitrate/CRF are you encoding this at? Did you try lowering the CRF?

The default CRF values are very different across x264 and x265 in terms of impact on bitrate.

[Michal Lazo]

ffmpeg -i test60.ts -f yuv4mpegpipe -pix_fmt yuv420p - | x265 --y4m -o encoded.265 -

So x265 default value

[Michal Lazo]

same result with --bitrate 2000 --slow

and same result with --crf 32 --slow

I also get same result if I use gstreamer with x265enc plugins

[Andreas Rheinhardt]

I cannot reproduce this: If I watch it in MPC-HC or in VLC, this very frame doesn't show these artefacts (yes, I am looking at encoded.mp4): Therefore my guess is that this is just an issue in the HEVC decoder used to play encoded.mp4 and no issue in x265.

[Michal Lazo]

decoder problem