ffplay lag with some resolutions when using i915 and SNA acceleration method

[Vittorio G (VittGam)]

Hello,

When using SNA acceleration on an Intel GMA915 video card (IBM ThinkPad X41, screen is 1024x768), I'm having some problems with these resolutions in ffplay:

• 1018x576 through 1037x576

The problems are: increased IO-Wait and general lag of the mouse and screen, and frame drop in ffplay.

Width values smaller than 1018 or bigger than 1037 work fine instead. Even 1280x576 works perfectly.

The same problem is reproduced with other height values, such as 480.

A simple test case for this is:

ffplay -f lavfi -i testsrc=s=1024x576:r=25

• ffmpeg is latest (7042a55) from Git
• Kernel is 4.4.1-2-ARCH
• Distro is Arch Linux
• Desktop compositor is KWin from Plasma 5.

When using the older UXA acceleration method instead of SNA in the X server, the problem goes completely away.

Is this an ffplay issue? If not, should I report this problem to the i915 developers, the KWin developers, or the SDL developers?

Thank you,
Vittorio G

[Carl Eugen Hoyos]

I don't understand how your issue could have anything to do with FFplay but please add command line and complete, uncut console output to make this a valid ticket.