I created a video file with vokoscreenng installed from the osnap store, video codec used: h264, mp4 format.
When I open the video with VLC, I see all black, if I open it with Totem I see everything normally.
Checking in the logs:
gen 21 19:33:11 emanuc org.gnome.Nautilus[30423]: [00007f4668c03b50] avcodec decoder: Using NVIDIA VDPAU Driver Shared Library 440.44 Sun Dec 8 03:27:26 UTC 2019 for hardware decoding
gen 21 19:33:11 emanuc org.gnome.Nautilus[30423]: [h264 @ 0x7f4668c32aa0] hardware accelerator failed to decode picture
Ubuntu 20.04
$ snap info vlc
name: vlc
summary: The ultimate media player
publisher: VideoLAN✓
store-url: https://snapcraft.io/vlc
contact: https://www.videolan.org/support/
license: unset
description: |
VLC is the VideoLAN project’s media player.
Completely open source and privacy-friendly, it plays every multimedia file
and streams.
It notably plays MKV, MP4, MPEG, MPEG-2, MPEG-4, DivX, MOV, WMV, QuickTime,
WebM, FLAC, MP3, Ogg/Vorbis files, BluRays, DVDs, VCDs, podcasts, and
multimedia streams from various network sources. It supports subtitles,
closed captions and is translated in numerous languages.
commands:
- vlc
snap-id: RT9mcUhVsRYrDLG8qnvGiy26NKvv6Qkd
tracking: latest/stable
refresh-date: 33 days ago, at 13:55 CET
channels:
stable: 3.0.8 2019-12-19 (1397) 212MB -
candidate: 3.0.8 2019-12-16 (1397) 212MB -
beta: 3.0.8-140-gc6f0441 2020-01-21 (1469) 212MB -
edge: 4.0.0-dev-10677-g039735dff4 2020-01-21 (1468) 334MB -
installed: 3.0.8