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Posted: **29 Mar 2021 15:29**

I seem to be having an issue where the quality in vlc 3.0.9.2 on Ubuntu 20.04 is lower than that of the same version of VLC on Windows 10. In this scenario, I have a 720p stream that gets upscaled to 1080p. On Ubuntu, the image isn't as sharp, and there's a black bar at the bottom of the video. On windows, there is no black bar and the image is crisper. I'm using all the default settings as I have no idea what to change. I took comparison screenshots of the video here: https://imgur.com/a/0LpjvYT. The images are 1440p, but I usually watch the stream on my projector at 1080p. The problem persists regardless of resolution.

My cpu is a Ryzen 3600 and my gpu is a Radeon 5700XT, not sure if that matters or not. Thanks in advance

Posted: **29 Mar 2021 16:52**

Upscaling is done by the GPU, at least with the default settings, and black bar is inserted only if aspect ratii of the video and display don't match. So from VLC standpoint there should be no differences between Windows and Linux.

With no particular info, both issues seem to stem from GPU driver, which may well be a lot worse on Linux than on Windows.

Posted: **29 Mar 2021 19:20**

Thank you for the response. On windows I'm using the latest AMD drivers. On Ubuntu, I'm using mesa 20.2.6. Are there some settings I can play with, or something else I can do to narrow down the issue?

EDIT: Here's some output from the console when I try to play a video that's 720p. Seems to be doing the same as the stream.

Code: Select all

libva info: VA-API version 1.7.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so
libva info: Found init function __vaDriverInit_1_7
libva info: va_openDriver() returns 0
mesa: for the --simplifycfg-sink-common option: may only occur zero or one times!
mesa: for the --global-isel-abort option: may only occur zero or one times!
mesa: for the --amdgpu-atomic-optimizations option: may only occur zero or one times!
mesa: for the --structurizecfg-skip-uniform-regions option: may only occur zero or one times!
[00007fe780006d30] glconv_vaapi_x11 gl error: vaDeriveImage: operation failed
[00007fe7900122b0] main video output error: video output creation failed
[00007fe7b4016190] main decoder error: failed to create video output
[00007fe7b4016190] avcodec decoder: Using G3DVL VDPAU Driver Shared Library version 1.0 for hardware decoding
[00007fe7b40edf20] main decoder error: buffer deadlock prevented
[00007fe7b4016190] avcodec decoder error: hardware acceleration picture allocation failed
[h264 @ 0x7fe7b00c4280] get_buffer() failed
[h264 @ 0x7fe7b00c4280] thread_get_buffer() failed
[h264 @ 0x7fe7b00c4280] decode_slice_header error
[h264 @ 0x7fe7b00c4280] no frame!
[00007fe7b40ee7b0] mpeg4audio packetizer: AAC channels: 2 samplerate: 48000
[00007fe7b4016190] avcodec decoder error: hardware acceleration picture allocation failed
[h264 @ 0x7fe7b00e08c0] get_buffer() failed
[h264 @ 0x7fe7b00e08c0] thread_get_buffer() failed
[h264 @ 0x7fe7b00e08c0] decode_slice_header error
[h264 @ 0x7fe7b00e08c0] no frame!
[h264 @ 0x7fe7b0009480] reference picture missing during reorder
[h264 @ 0x7fe7b0009480] Missing reference picture, default is 65578

EDIT 2: output from vainfo

Code: Select all

libva info: VA-API version 1.7.0
libva info: Trying to open /usr/lib/x86_64-linux-gnu/dri/radeonsi_drv_video.so
libva info: Found init function __vaDriverInit_1_7
libva info: va_openDriver() returns 0
vainfo: VA-API version: 1.7 (libva 2.6.0)
vainfo: Driver version: Mesa Gallium driver 20.2.6 for AMD Radeon RX 5700 XT (NAVI10, DRM 3.38.0, 5.8.0-48-generic, LLVM 11.0.0)
vainfo: Supported profile and entrypoints
      VAProfileMPEG2Simple            : VAEntrypointVLD
      VAProfileMPEG2Main              : VAEntrypointVLD
      VAProfileVC1Simple              : VAEntrypointVLD
      VAProfileVC1Main                : VAEntrypointVLD
      VAProfileVC1Advanced            : VAEntrypointVLD
      VAProfileH264ConstrainedBaseline: VAEntrypointVLD
      VAProfileH264ConstrainedBaseline: VAEntrypointEncSlice
      VAProfileH264Main               : VAEntrypointVLD
      VAProfileH264Main               : VAEntrypointEncSlice
      VAProfileH264High               : VAEntrypointVLD
      VAProfileH264High               : VAEntrypointEncSlice
      VAProfileHEVCMain               : VAEntrypointVLD
      VAProfileHEVCMain               : VAEntrypointEncSlice
      VAProfileHEVCMain10             : VAEntrypointVLD
      VAProfileHEVCMain10             : VAEntrypointEncSlice
      VAProfileJPEGBaseline           : VAEntrypointVLD
      VAProfileVP9Profile0            : VAEntrypointVLD
      VAProfileVP9Profile2            : VAEntrypointVLD
      VAProfileNone                   : VAEntrypointVideoProc

EDIT 3:

So either disabling HWE completely, or setting it to "VA-API video decoder via DRM" seems to resolve the issue for me.

Posted: **30 Mar 2021 11:39**

The first log shows that your VA driver is completely broken, and VDPAU ends up being used. So the quality problems are probably caused by the VDPAU driver. No surprises there, the G3DVL VDPAU driver has always been complete crap.

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