intel-vaapi VP9 4k@60Hz stutters while media-driver iHD is smooth - why?

[arcivanov]

For years I thought that the reason I couldn't watch VP9 4K@60Hz on YouTube was first that my Skylake was underpowered. But then I upgraded to Coffeelake and Fedora 31 and kernel 5.3.8 and I still would lose 30% of all the frames and would experience constant stutter. So I thought it was chromium-vaapi/-freeworld that was the problem due to bugs and constant VAAPI module rewrites in the upstream, or slow rendering etc.

Today I tried iHD and all my issues went away - frames dropped are in single digits, not a single stutter, CPU consumption is much lower. So the issue is definitively an intel-vaapi driver. It's 100% reproducible and the only difference is whether chromium is launched with LIBVA_DRIVER_NAME=iHD.

The question is why? Are there any profiling tools in libva/vaapi toolkit that would allow to see the decoding/rendering pipeline to determine the difference?

Below is some info about the system and screenshots of the chrome://gpu video capabilities. As you can see iHD reports VP9 decoding to up to 8192x8192.

00:02.0 VGA compatible controller [0300]: Intel Corporation UHD Graphics 630 (Mobile) [8086:3e9b] (rev 02)

$ vainfo
libva info: VA-API version 1.6.0
libva info: va_getDriverName() returns 0
libva info: Trying to open /usr/lib64/dri/i965_drv_video.so
libva info: Found init function __vaDriverInit_1_6
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.6 (libva 2.6.0.pre1)
vainfo: Driver version: Intel i965 driver for Intel(R) Coffee Lake - 2.3.0
vainfo: Supported profile and entrypoints
      VAProfileMPEG2Simple            : VAEntrypointVLD
      VAProfileMPEG2Simple            : VAEntrypointEncSlice
      VAProfileMPEG2Main              : VAEntrypointVLD
      VAProfileMPEG2Main              : VAEntrypointEncSlice
      VAProfileH264ConstrainedBaseline: VAEntrypointVLD
      VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice
      VAProfileH264ConstrainedBaseline: VAEntrypointEncSliceLP
      VAProfileH264Main               : VAEntrypointVLD
      VAProfileH264Main               : VAEntrypointEncSlice
      VAProfileH264Main               : VAEntrypointEncSliceLP
      VAProfileH264High               : VAEntrypointVLD
      VAProfileH264High               : VAEntrypointEncSlice
      VAProfileH264High               : VAEntrypointEncSliceLP
      VAProfileH264MultiviewHigh      : VAEntrypointVLD
      VAProfileH264MultiviewHigh      : VAEntrypointEncSlice
      VAProfileH264StereoHigh         : VAEntrypointVLD
      VAProfileH264StereoHigh         : VAEntrypointEncSlice
      VAProfileVC1Simple              : VAEntrypointVLD
      VAProfileVC1Main                : VAEntrypointVLD
      VAProfileVC1Advanced            : VAEntrypointVLD
      VAProfileNone                   : VAEntrypointVideoProc
      VAProfileJPEGBaseline           : VAEntrypointVLD
      VAProfileJPEGBaseline           : VAEntrypointEncPicture
      VAProfileVP8Version0_3          : VAEntrypointVLD
      VAProfileVP8Version0_3          : VAEntrypointEncSlice
      VAProfileHEVCMain               : VAEntrypointVLD
      VAProfileHEVCMain               : VAEntrypointEncSlice
      VAProfileHEVCMain10             : VAEntrypointVLD
      VAProfileHEVCMain10             : VAEntrypointEncSlice
      VAProfileVP9Profile0            : VAEntrypointVLD
      VAProfileVP9Profile0            : VAEntrypointEncSlice
      VAProfileVP9Profile2            : VAEntrypointVLD

i965:

$ LIBVA_DRIVER_NAME=iHD vainfo
libva info: VA-API version 1.6.0
libva info: va_getDriverName() returns 0
libva info: User requested driver 'iHD'
libva info: Trying to open /usr/lib64/dri/iHD_drv_video.so
libva info: Found init function __vaDriverInit_1_6
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.6 (libva 2.6.0.pre1)
vainfo: Driver version: Intel iHD driver - 1.0.0
vainfo: Supported profile and entrypoints
      VAProfileNone                   : VAEntrypointVideoProc
      VAProfileNone                   : VAEntrypointStats
      VAProfileMPEG2Simple            : VAEntrypointVLD
      VAProfileMPEG2Simple            : VAEntrypointEncSlice
      VAProfileMPEG2Main              : VAEntrypointVLD
      VAProfileMPEG2Main              : VAEntrypointEncSlice
      VAProfileH264Main               : VAEntrypointVLD
      VAProfileH264Main               : VAEntrypointEncSlice
      VAProfileH264Main               : VAEntrypointFEI
      VAProfileH264Main               : VAEntrypointEncSliceLP
      VAProfileH264High               : VAEntrypointVLD
      VAProfileH264High               : VAEntrypointEncSlice
      VAProfileH264High               : VAEntrypointFEI
      VAProfileH264High               : VAEntrypointEncSliceLP
      VAProfileVC1Simple              : VAEntrypointVLD
      VAProfileVC1Main                : VAEntrypointVLD
      VAProfileVC1Advanced            : VAEntrypointVLD
      VAProfileJPEGBaseline           : VAEntrypointVLD
      VAProfileJPEGBaseline           : VAEntrypointEncPicture
      VAProfileH264ConstrainedBaseline: VAEntrypointVLD
      VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice
      VAProfileH264ConstrainedBaseline: VAEntrypointFEI
      VAProfileH264ConstrainedBaseline: VAEntrypointEncSliceLP
      VAProfileVP8Version0_3          : VAEntrypointVLD
      VAProfileVP8Version0_3          : VAEntrypointEncSlice
      VAProfileHEVCMain               : VAEntrypointVLD
      VAProfileHEVCMain               : VAEntrypointEncSlice
      VAProfileHEVCMain               : VAEntrypointFEI
      VAProfileHEVCMain10             : VAEntrypointVLD
      VAProfileHEVCMain10             : VAEntrypointEncSlice
      VAProfileVP9Profile0            : VAEntrypointVLD
      VAProfileVP9Profile2            : VAEntrypointVLD

iHD:

[arcivanov]

This is the example video that allows to reproduce the issue and the workaround 100% of the time.

https://www.youtube.com/watch?v=LXb3EKWsInQ

[xhaihao]

@arcivanov we fixed some vp9 issues in master branch. If possible, you may give a try with master branch. As for 8K, we won't add support for 8K in this driver.

[LittleSouken]

i like use the small monitor more easy this is old machine and old model of monitor television machine can slow because resolution

[dvershinin]

I can just add my support to everything of what @arcivanov said.

A build of chromium-freeworld (the one with VA-API patch) + latest release from here + go to any Youtube 4k video, right-click and choose "stats for nerds" = Dropped frames

The same, but with intel-media-driver instead = No/very few dropped frames

Something is not right with intel-vaapi-driver!