Common questions and problems

• Linux
  • Snap unsupported
  • qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.
  • Fontconfig error: Cannot load config file from /etc/fonts/fonts.conf
• FastFlix
  • High memory usage
  • Too many packets buffered for output stream 0:1.
  • HDR colors washed out
  • Unrecognized option ...

Linux

Snap unsupported

Please refrain from using the snap version of FFmpeg as it has serval issues. If you do plan on using it, it will at minimum need installed with devmode enabled to work at all with 2-pass encodings.

qt.qpa.plugin: Could not load the Qt platform plugin "xcb" in "" even though it was found.

If you're on linux and experience this, you need to install some more packages for xcb. On Ubuntu those are:

sudo apt install libxcb-randr0-dev libxcb-xtest0-dev libxcb-xinerama0-dev libxcb-shape0-dev libxcb-xkb-dev

Debian 10 users there is a bug with QT5 currently, and you will have to link libxcb-util.so.0 to libxcb-util.so.1

# Make sure it's at the same place on your system
# find / -name libxcb-util.so.0

ln -s /usr/lib/x86_64-linux-gnu/libxcb-util.so.0 /usr/lib/x86_64-linux-gnu/libxcb-util.so.1

If you're still having issues please set the env variable QT_DEBUG_PLUGINS=1 and put the output into an issue for me to look at

QT_DEBUG_PLUGINS=1 ./FastFlix

Fontconfig error: Cannot load config file from /etc/fonts/fonts.conf

Move the fonts folder to a new location, and reinstall fontconfig to force a reconfiguration.

On Ubuntu / Debian:

mv /etc/fonts /etc/fonts.bak
sudo apt install fontconfig --reinstall

FastFlix

High memory usage

If you have "Burn In" subtitles enabled, this is probably the cause. The "overlay" filter can use huge amounts of memory as reported by Zeid164.

Too many packets buffered for output stream 0:1.

You need to increase the Max Musing Queue Size, command line equivalent: -max_muxing_queue_size 1024

HDR colors washed out

This is generally due to the color space not being transferred correctly. Possibly a bt2020 video was turned into a bt709. If it is happening with FastFlix please raise an issue with the MediaInfo text of the input and output video and the command FastFlix generated, would really help in fixing it fast or figuring out why it is behaving that way.

Unrecognized option ...

You probably need to update FFmpeg.

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