GStreamer
GStreamer is a popular multimedia framework to handle a variety of video and audio formats on different platforms in a uniform way through a powerful and convenient API in order to build multimedia apps, video/audio editors and streaming services. It consists of a huge amount low-level plugins like "videotestsrc", "videoconvert" and "autovideosink" as well as a few higher level test-and-combine framework tools like "gst-inspect", "gst-launch" etc.
Installing via nixpkgs
In Nix as in other Linux distributions those tools and plugins are split into separate packages, which you can bring together with a custom Nix shell environment:
# file: flake.nix
{
description = "A GStreamer development flake";
outputs = { self, nixpkgs }:
let
system = "x86_64-linux";
pkgs = nixpkgs.legacyPackages.${system};
in {
devShells.${system}.default = pkgs.mkShell {
buildInputs = with pkgs; [
# Video/Audio data composition framework tools like "gst-inspect", "gst-launch" ...
gst_all_1.gstreamer
# Common plugins like "filesrc" to combine within e.g. gst-launch
gst_all_1.gst-plugins-base
# Specialized plugins separated by quality
gst_all_1.gst-plugins-good
gst_all_1.gst-plugins-bad
gst_all_1.gst-plugins-ugly
# Plugins to reuse ffmpeg to play almost every video format
gst_all_1.gst-libav
# Support the Video Audio (Hardware) Acceleration API
gst_all_1.gst-vaapi
#...
];
};
};
}
To activate this environment in your terminal run
$ nix develop
You can find all available Nix package names through the Nix search page.
Test the installation
You can test that the gst_all_1.gstreamer
tools are available by running a dummy pipeline
$ gst-launch-1.0 videotestsrc ! videoconvert ! autovideosink
which should open a colored video window.
You can test that the plugins like from gst_all_1.gst-plugins-base
are available to the higher level tools by inspecting such a base plugin like filesrc
with
$ gst-inspect-1.0 filesrc
Factory Details:
...
Long-name File Source
Description Read from arbitrary point in a file
...
Plugin Details:
Name coreelements
Description GStreamer core elements
Filename /nix/store/p39g1.../libgstcoreelements.so
...
or by using it in a pipeline. Here, we could play a video from the local machine with
$ gst-launch-1.0 filesrc location=my_video.mp4 ! videoconvert ! autovideosink
If the plugins are not correctly made available to the higher level tools, you'll get an error
$ gst-inspect-1.0 filesrc
No such element or plugin 'filesrc'
Troubleshooting
erroneous pipeline: no element "filesrc"
In some cases while creating a shell using "mkShell" or "writeShellApplication" just setting the "runtimeInputs" is not enough. It's necessary to manually set the "GST_PLUGIN_SYSTEM_PATH_1_0" environment variable.[1]
Adding the following export to your script, sets "gstreamer" and "gst-plugins-base" and "gst-plugins-good" paths. Similarly you can add any other "gst-plugins" package as well.
export GST_PLUGIN_SYSTEM_PATH_1_0="${gst_all_1.gstreamer.out}/lib/gstreamer-1.0:${gst_all_1.gst-plugins-base}/lib/gstreamer-1.0:${gst_all_1.gst-plugins-good}/lib/gstreamer-1.0"
Note: "gstreamer.out" is the derivative that contains "/lib" directory for that package.