VLC and Intel Quick Sync Video (QSV) Decoding

[metaldave]

Hi, there.

I'm running VLC v3.0.8 on Windows 10 with an Intel Quick Sync Video (QSV) enabled processor (Intel Core i7-8550U). As there is no discrete setting for QSV decoding in VLC, I wanted to know if there was a way to verify that VLC is using QSV hardware acceleration to decode for playback of HEVC video files.

There isn't anything specific under the Input & Codecs tab of the settings. The "Hardware-accelerated decoding" pull-down menu offers "Automatic," "Direct3D11 Video Acceleration," "DirectX Video Acceleration (DVXA) 2.0," and "Disable" as the only options. I'd like to assume that DirectX is taking care of it on the OS level, but, again, I'd like to confirm. VLC takes a moment to buffer when starting playback of files (video frame freezes for a few seconds while audio continues), so I want to verify how the decoding is being performed.

Thanks in advance!

- Dave

[Lotesdelere]

AFAIK VLC can encode using QSV, but nothing about decoding, yet.

Decoding combinations that should work:
https://forum.videolan.org/viewtopic.php?p=487467#p487467

[metaldave]

Thanks for the reply. It looks like the post you referenced reiterated what I'd already assessed: DirectX (Direct3D, etc.) are the only selectable options for decoding in hardware. OpenGL doesn't appear in my list of options, but I am guessing this is either a) outmoded or obsolete, or b) just not showing up as I've not installed an OpenGL software solution.

Maybe this is more of a question of whether DirectX uses QSV? If that's the method of implementation selected by VideoLAN to get to QSV decoding (kind-of passing the buck to the OS), then we'd just need to confirm if DirectX is doing the job. Thoughts?

[unidan]

Hi,

Maybe this is more of a question of whether DirectX uses QSV? If that's the method of implementation selected by VideoLAN to get to QSV decoding (kind-of passing the buck to the OS), then we'd just need to confirm if DirectX is doing the job. Thoughts?

Intel should expose a direct3d decoder; but you can check the log to see which driver is used.

Thanks for the reply. It looks like the post you referenced reiterated what I'd already assessed: DirectX (Direct3D, etc.) are the only selectable options for decoding in hardware. OpenGL doesn't appear in my list of options, but I am guessing this is either a) outmoded or obsolete, or b) just not showing up as I've not installed an OpenGL software solution.

OpenGL isn't a decoder API at all, it's not even taking care of most resource allocation. It's only about rendering.

[metaldave]

Intel should expose a direct3d decoder; but you can check the log to see which driver is used.

Per the VLC 3.0 release page, "VLC 3.0 activates hardware decoding by default, to get 4K and 8K playback!" I'm guessing we've been cared for. Looking in the preferences on the macOS release, it looks like it's now, simply, a Check Box to enable or disable.

OpenGL isn't a decoder API at all, it's not even taking care of most resource allocation. It's only about rendering.

Thank makes sense; I'd always thought OpenGL was an alternative to DirectX for all access types to the GPU (not just rendering). Thanks for the correction.

[shaodan1997]

On Windows10, an intuitive way to verify if hardware acceleration is being used is using Task Manager.

Switch to GPU interface in "Performance" tab, then select "Video Decode"(the default is 3D). Graphics will appear if hardware acceleration is being used.