intel-vaapi-driver conflicts with window manager compiz in plugin scale

[Heinz Assmus]

I'm using Ubuntu 20.04 MATE with window manager compiz and 4 screens with compiz plugins Expo and Desktop Wall with hot corners for Scale-plugin.
Hardware accellerated videos with mpv and vlc leads to stuttering previews in scale function in overview for all windows when the actice screen is not the screen where the active porgram (mpv or vlc) was started.
In Terminal both programs gives several failure messages (see adendon).
If i play the same video with gstreamer gst-play-1.0 the video runs fine in all screens when Scale gives an overview of all windows of all workspaces.
If i check vaapi with intel-gpu-tools with the command intel_gpu_top it seems that gstreamer is using the Engines Render/3D Blitter and Video for hardware decoding, whereas vlc and mpv only uses the Engines Render/3D and Video for hardware decoding.
The Engine Blitter is not used.

Terminal messages:

tux@tux-Aspire-V5-573G:~/Videos$ gst-play-1.0 hr__tierisch-schlau-waschbaeren3-banse_syn2_1920x1080-50p-8000kbit.mp4
Geben Sie »k« ein, um die Liste der Tastenkombinationen zu sehen.
Momentan wird /home/tux/Videos/hr__tierisch-schlau-waschbaeren3-banse_syn2_1920x1080-50p-8000kbit.mp4 wiedergegeben
Redistribute latency...
Redistribute latency...
0:01:02.6 / 0:04:52.1
tux@tux-Aspire-V5-573G:~/Videos$ mpv hr__tierisch-schlau-waschbaeren3-banse_syn2_1920x1080-50p-8000kbit.mp4
 (+) Video --vid=1 (*) (h264 1920x1080 50.000fps)
 (+) Audio --aid=1 (*) (aac 2ch 48000Hz)
[vaapi] libva: /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so init failed
Using hardware decoding (vaapi).
AO: [pulse] 48000Hz stereo 2ch float
VO: [gpu] 1920x1080 vaapi[nv12]
AV: 00:00:04 / 00:04:52 (2%) A-V: 0.000

Audio/Video desynchronisation detected! Possible reasons include too slow
hardware, temporary CPU spikes, broken drivers, and broken files. Audio
position will not match to the video (see A-V status field).

AV: 00:00:44 / 00:04:52 (15%) A-V: 0.000 Dropped: 1605

Exiting... (Quit)
tux@tux-Aspire-V5-573G:~/Videos$ vlc hr__tierisch-schlau-waschbaeren3-banse_syn2_1920x1080-50p-8000kbit.mp4
VLC media player 3.0.9.2 Vetinari (revision 3.0.9.2-0-gd4c1aefe4d)
[000055f2dd4e45b0] main libvlc: VLC wird mit dem Standard-Interface ausgeführt. Benutzen Sie 'cvlc', um VLC ohne Interface zu verwenden.
libva info: VA-API version 1.7.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so
libva info: Found init function __vaDriverInit_1_7
libva error: /usr/lib/x86_64-linux-gnu/dri/iHD_drv_video.so init failed
libva info: va_openDriver() returns 1
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/i965_drv_video.so
libva info: Found init function __vaDriverInit_1_6
libva info: va_openDriver() returns 0
[00007f0cc4d022f0] avcodec decoder: Using Intel i965 driver for Intel(R) Haswell Mobile - 2.4.0 for hardware decoding
[h264 @ 0x7f0cc4d28840] co located POCs unavailable
[h264 @ 0x7f0cc4d9d440] mmco: unref short failure
[h264 @ 0x7f0cc4d80c80] mmco: unref short failure
[h264 @ 0x7f0cc4d385c0] co located POCs unavailable
[h264 @ 0x7f0cc4db9bc0] mmco: unref short failure
[h264 @ 0x7f0cc4d9d440] mmco: unref short failure
[h264 @ 0x7f0cc4d80c80] co located POCs unavailable
[h264 @ 0x7f0cc4d28840] mmco: unref short failure
[h264 @ 0x7f0cc4db9bc0] mmco: unref short failure
[h264 @ 0x7f0cc4d9d440] co located POCs unavailable
[h264 @ 0x7f0cc4d385c0] mmco: unref short failure
[h264 @ 0x7f0cc4d28840] mmco: unref short failure
[h264 @ 0x7f0cc4db9bc0] co located POCs unavailable
[h264 @ 0x7f0cc4d80c80] mmco: unref short failure
[h264 @ 0x7f0cc4d385c0] mmco: unref short failure
[h264 @ 0x7f0cc4d28840] co located POCs unavailable
[h264 @ 0x7f0cc4d9d440] mmco: unref short failure
[h264 @ 0x7f0cc4d80c80] mmco: unref short failure
[h264 @ 0x7f0cc4d385c0] co located POCs unavailable
[h264 @ 0x7f0cc4d80c80] mmco: unref short failure
[h264 @ 0x7f0cc4d385c0] co located POCs unavailable
[h264 @ 0x7f0cc4db9bc0] mmco: unref short failure
[h264 @ 0x7f0cc4d9d440] mmco: unref short failure
[h264 @ 0x7f0cc4d80c80] co located POCs unavailable
[h264 @ 0x7f0cc4db9bc0] mmco: unref short failure
[h264 @ 0x7f0cc4d9d440] co located POCs unavailable
[h264 @ 0x7f0cc4d28840] mmco: unref short failure
[h264 @ 0x7f0cc4d28840] co located POCs unavailable
[h264 @ 0x7f0cc4db9bc0] co located POCs unavailable
[h264 @ 0x7f0cc4d385c0] mmco: unref short failure
[h264 @ 0x7f0cc4d385c0] co located POCs unavailable
[h264 @ 0x7f0cc4d28840] co located POCs unavailable
[h264 @ 0x7f0cc4d80c80] mmco: unref short failure
[h264 @ 0x7f0cc4d80c80] co located POCs unavailable
[h264 @ 0x7f0cc4d385c0] co located POCs unavailable
[h264 @ 0x7f0cc4d9d440] mmco: unref short failure
[h264 @ 0x7f0cc4d9d440] co located POCs unavailable
[h264 @ 0x7f0cc4d80c80] co located POCs unavailable
[h264 @ 0x7f0cc4db9bc0] mmco: unref short failure
[h264 @ 0x7f0cc4db9bc0] co located POCs unavailable
[h264 @ 0x7f0cc4d9d440] co located POCs unavailable
[h264 @ 0x7f0cc4d28840] mmco: unref short failure
[h264 @ 0x7f0cc4d28840] co located POCs unavailable
[h264 @ 0x7f0cc4db9bc0] co located POCs unavailable
[h264 @ 0x7f0cc4d385c0] mmco: unref short failure
[h264 @ 0x7f0cc4d385c0] co located POCs unavailable
[h264 @ 0x7f0cc4d28840] co located POCs unavailable
[h264 @ 0x7f0cc4d80c80] mmco: unref short failure
[h264 @ 0x7f0cc4d385c0] co located POCs unavailable
[h264 @ 0x7f0cc4d28840] co located POCs unavailable
[h264 @ 0x7f0cc4d80c80] mmco: unref short failure
[h264 @ 0x7f0cc4d385c0] get_buffer() failed
[h264 @ 0x7f0cc4d385c0] thread_get_buffer() failed
[h264 @ 0x7f0cc4d385c0] decode_slice_header error
[h264 @ 0x7f0cc4d385c0] no frame!
[h264 @ 0x7f0cc4d80c80] get_buffer() failed
[h264 @ 0x7f0cc4d80c80] thread_get_buffer() failed
[h264 @ 0x7f0cc4d80c80] decode_slice_header error
[h264 @ 0x7f0cc4d80c80] no frame!
QObject::~QObject: Timers cannot be stopped from another thread
tux@tux-Aspire-V5-573G:~/Videos$

nearly the same with snap program vlc

tux@tux-Aspire-V5-573G:~/Videos$ /snap/bin/vlc hr__tierisch-schlau-waschbaeren3-banse_syn2_1920x1080-50p-8000kbit.mp4
ERROR: ld.so: object 'libgtk3-nocsd.so.0' from LD_PRELOAD cannot be preloaded (failed to map segment from shared object): ignored.
VLC media player 3.0.14 Vetinari (revision 3.0.14-0-g41878ff4f2)
[000055d633936a00] main libvlc: VLC wird mit dem Standard-Interface ausgeführt. Benutzen Sie 'cvlc', um VLC ohne Interface zu verwenden.
Qt: Session management error: Could not open network socket
Failed to open VDPAU backend libvdpau_va_gl.so: cannot open shared object file: No such file or directory
[00007f3c88427c50] avahi renderer discovery error: failed to create avahi client: Daemon not running
[00007f3c88427c50] main renderer discovery error: no suitable renderer discovery module for 'avahi_renderer'
[h264 @ 0x7f3c58db9160] co located POCs unavailable
[h264 @ 0x7f3c58d80ee0] co located POCs unavailable
[h264 @ 0x7f3c58d80ee0] co located POCs unavailable
[h264 @ 0x7f3c58d9cf60] mmco: unref short failure
[h264 @ 0x7f3c58d29600] mmco: unref short failure
[h264 @ 0x7f3c58db9160] co located POCs unavailable
[h264 @ 0x7f3c58db9160] co located POCs unavailable
[h264 @ 0x7f3c58d80ee0] co located POCs unavailable
[h264 @ 0x7f3c58d80ee0] co located POCs unavailable
[h264 @ 0x7f3c58d9cf60] mmco: unref short failure
[h264 @ 0x7f3c58d29600] co located POCs unavailable
[h264 @ 0x7f3c58d80ee0] mmco: unref short failure
[h264 @ 0x7f3c58d29600] mmco: unref short failure
[h264 @ 0x7f3c58db9160] co located POCs unavailable
[h264 @ 0x7f3c58d29600] mmco: unref short failure
[h264 @ 0x7f3c58d29600] mmco: unref short failure
[h264 @ 0x7f3c58d38da0] co located POCs unavailable
[h264 @ 0x7f3c58d80ee0] mmco: unref short failure
[h264 @ 0x7f3c58d38da0] get_buffer() failed
[h264 @ 0x7f3c58d38da0] thread_get_buffer() failed
[h264 @ 0x7f3c58d38da0] decode_slice_header error
[h264 @ 0x7f3c58d38da0] no frame!
[h264 @ 0x7f3c58d80ee0] get_buffer() failed
[h264 @ 0x7f3c58d80ee0] thread_get_buffer() failed
[h264 @ 0x7f3c58d80ee0] decode_slice_header error
[h264 @ 0x7f3c58d80ee0] no frame!
QObject::~QObject: Timers cannot be stopped from another thread
tux@tux-Aspire-V5-573G:~/Videos$

Would be nice if the bug can be eliminated, because i like Ubuntu MATE with compiz for my older laptop. It works with cupertino tweak like MacOS.

[Daniel van Vugt (vanvugt)]

> If i check vaapi with intel-gpu-tools with the command intel_gpu_top
> it seems that gstreamer is using the Engines Render/3D Blitter and
> Video for hardware decoding, whereas vlc and mpv only uses the Engines
> Render/3D and Video for hardware decoding.
> The Engine Blitter is not used.

That part is probably not a bug. A well-written player ideally should not be using the Blitter. You just need 'Video' for decoding the video and 'Render/3D' for putting it on screen. Using 'Blitter' possibly means gstreamer is using too much software rendering, somewhere. That's a bug in gstreamer.