The VideoLAN Forums

found something strange....

if i download a video like:
https://www.youtube.com/watch?v=h6Lbo-4OsZk

with 4k downloader, loader.to, or any other...
4k downloader allows to download .mkv and .mp4 of the same link,
sometimes .mp4 is smaller,
sometimes .mkv is smaller,
https://www.4kdownload.com/downloads-2#

this time downloaded both mkv & mp4
same 1080p60fps


VLC sharpness is different at 100%
mp4 is very weak, barely noticiable.
mkv is very strong,
but Not as strong as CPU X11 XCB Video Output moduile.

Thats strange...
different sharpness level at same setting.
both using HW acceleration = No CPU.
same OpenGL GLX Video Out module.
why .mkv sharpness is stronger than .mp4 ?
why .mp4 shapness is weaker?
using same HW, same drivers.

according to MKVToolNix GUI https://mkvtoolnix.download/downloads.html
.mkv is a VP9 video codec
.mp4 is a AVC/H-264/MPEG-4p10

Question is:
is this a VLC Video Output module issue/Bug,?
a Nvidia Propietary Driver issue,?
or Nvidia GT 740 HW issue.?

Kubuntu 21.10
VLC 3.0.16 installed from Snap
Nvidia 470 propietary drivers.
OpenGL GLX

If using hardware decoding, sharpness if entirely up to the drivers, so you'll have to ask the driver vendor.

.mkv is a VP9 video codec
.mp4 is a AVC/H-264/MPEG-4p10

Looks like the GT 740 doesn't support hardware decoding for VP9:
https://developer.nvidia.com/video-enco ... ort-matrix
https://en.wikipedia.org/wiki/Nvidia_Pu ... HD.29_GPUs

Well, actually VDPAU did not support VP9 at all until recently. Not sure if FFmpeg supports it even now. So even if the GPU could do it, the drivers can't.

But anyway, my point stands: in the H.264 case (which is supposed by VDPAU) sharpening is handled by the GPU drivers, not by VLC.

True. need a better video card.

Nvidia seems to have better drivers for Linux,
AMD for OSX,

AMD Require VCN 1.0 minimum for VP9 HW Decoding.
https://en.wikipedia.org/wiki/Unified_Video_Decoder
https://en.wikipedia.org/wiki/Video_Core_Next
https://en.wikipedia.org/wiki/List_of_A ... sing_units

Raven Ridge Zen-based CPU cores, Ryzen APU (2017)
VCN 2.0 RX 5000 GPU (2019)

Lowest $$ with VP9:
GeForce GT 1030
Radeon RX 5300 / 5500 XT

[SOLVED]