SampleAdaptiveOffset

[mikk9]

There is a confusion about SampleAdaptiveOffset. According to feature check it's not supported, but in the log (from Tigerlake) it says "sao: all" which suggests it's enabled. We can't disable it though, same for tskip by the way.

Ext. Features WeightP WeightB QPOffset tskip ctu:64 sao:all

There is also a hevcehw_g12_sao.h on github: https://github.com/Intel-Media-SDK/MediaSDK/blob/510d19dcace1d8c57567fdd40b557155ab11ab8e/_studio/mfx_lib/encode_hw/hevc/agnostic/g12/hevcehw_g12_sao.h

pHEVC->SampleAdaptiveOffset , mfxU16(MFX_SAO_UNKNOWN) , mfxU16(MFX_SAO_DISABLE) , mfxU16(!bNoSAO MFX_SAO_ENABLE_LUMA) , mfxU16(!bNoSAO MFX_SAO_ENABLE_CHROMA) , mfxU16(!bNoSAO * (MFX_SAO_ENABLE_LUMA | MFX_SAO_ENABLE_CHROMA)));

For grainy video content it can be beneficial to disable SAO because it tends to smooth things out, sometimes it's not needed.

[rigaya]

The parameters in the log is acquired by calling MFXVideoENCODE_GetVideoParam and somehow it is always returning tskip:on, ctu:64, sao:all, even if I set "--sao none" or "--ctu 16"...

I'm not sure the cause of this (whether my implementation is wrong or the driver error), but as the other parameters are returned correctly, I think there are some problem specific to these parameters (ctu, tskip and sao).

As feature check shows it is not supported, I think that it is not enabled in actual encoding.

I will remove printing these parameters from the next version, as it shows confusing results as you have mentioned.

[mikk9]

On Kabylake Gen9 it didn't show tskip and sao in the encoding log. CTU seems correct also, ctu 32 for Gen9 hardware which is correct and ctu 64 for Gen12, so I would guess tskip+sao is enabled on Gen12 hardware but for whatever reason it can't be enabled/disabled and properly detected from the feature check.

[Mister-XY]

I can confirm that I cannot deactivate SAO on the 12th generation.

[rigaya]

Gen12 graphics seems to have problem with ctu, tskip and sao. These will be not shown from QSVEnc 6.00 as it is rather confusing.

[mikk9]

I've tried QSVEnc 7.05 with newest driver and it works now, I can disable/enable SAO. I can also enable/disable tskip. I can say SAO and tskip were enabled from the beginning, the parameter in the log were correct. I think you can re-enable the tskip, SAO, ctu log parameter.

https://abload.de/img/saocgka0.png