nixpkgs/nixos/modules/services/video/v4l2-relayd.nix
2023-04-09 00:41:45 +02:00

200 lines
5.3 KiB
Nix

{ config, lib, pkgs, utils, ... }:
let
inherit (lib) attrValues concatStringsSep filterAttrs length listToAttrs literalExpression
makeSearchPathOutput mkEnableOption mkIf mkOption nameValuePair optionals types;
inherit (utils) escapeSystemdPath;
cfg = config.services.v4l2-relayd;
kernelPackages = config.boot.kernelPackages;
gst = (with pkgs.gst_all_1; [
gst-plugins-bad
gst-plugins-base
gst-plugins-good
gstreamer.out
]);
instanceOpts = { name, ... }: {
options = {
enable = mkEnableOption (lib.mdDoc "this v4l2-relayd instance");
name = mkOption {
type = types.str;
default = name;
description = lib.mdDoc ''
The name of the instance.
'';
};
cardLabel = mkOption {
type = types.str;
description = lib.mdDoc ''
The name the camera will show up as.
'';
};
extraPackages = mkOption {
type = with types; listOf package;
default = [ ];
description = lib.mdDoc ''
Extra packages to add to {env}`GST_PLUGIN_PATH` for the instance.
'';
};
input = {
pipeline = mkOption {
type = types.str;
description = lib.mdDoc ''
The gstreamer-pipeline to use for the input-stream.
'';
};
format = mkOption {
type = types.str;
default = "YUY2";
description = lib.mdDoc ''
The video-format to read from input-stream.
'';
};
width = mkOption {
type = types.ints.positive;
default = 1280;
description = lib.mdDoc ''
The width to read from input-stream.
'';
};
height = mkOption {
type = types.ints.positive;
default = 720;
description = lib.mdDoc ''
The height to read from input-stream.
'';
};
framerate = mkOption {
type = types.ints.positive;
default = 30;
description = lib.mdDoc ''
The framerate to read from input-stream.
'';
};
};
output = {
format = mkOption {
type = types.str;
default = "YUY2";
description = lib.mdDoc ''
The video-format to write to output-stream.
'';
};
};
};
};
in
{
options.services.v4l2-relayd = {
instances = mkOption {
type = with types; attrsOf (submodule instanceOpts);
default = { };
example = literalExpression ''
{
example = {
cardLabel = "Example card";
input.pipeline = "videotestsrc";
};
}
'';
description = lib.mdDoc ''
v4l2-relayd instances to be created.
'';
};
};
config =
let
mkInstanceService = instance: {
description = "Streaming relay for v4l2loopback using GStreamer";
after = [ "modprobe@v4l2loopback.service" "systemd-logind.service" ];
wantedBy = [ "multi-user.target" ];
serviceConfig = {
Type = "simple";
Restart = "always";
PrivateNetwork = true;
PrivateTmp = true;
LimitNPROC = 1;
};
environment = {
GST_PLUGIN_PATH = makeSearchPathOutput "lib" "lib/gstreamer-1.0" (gst ++ instance.extraPackages);
V4L2_DEVICE_FILE = "/run/v4l2-relayd-${instance.name}/device";
};
script =
let
appsrcOptions = concatStringsSep "," [
"caps=video/x-raw"
"format=${instance.input.format}"
"width=${toString instance.input.width}"
"height=${toString instance.input.height}"
"framerate=${toString instance.input.framerate}/1"
];
outputPipeline = [
"appsrc name=appsrc ${appsrcOptions}"
"videoconvert"
] ++ optionals (instance.input.format != instance.output.format) [
"video/x-raw,format=${instance.output.format}"
"queue"
] ++ [ "v4l2sink name=v4l2sink device=$(cat $V4L2_DEVICE_FILE)" ];
in
''
exec ${pkgs.v4l2-relayd}/bin/v4l2-relayd -i "${instance.input.pipeline}" -o "${concatStringsSep " ! " outputPipeline}"
'';
preStart = ''
mkdir -p $(dirname $V4L2_DEVICE_FILE)
${kernelPackages.v4l2loopback.bin}/bin/v4l2loopback-ctl add -x 1 -n "${instance.cardLabel}" > $V4L2_DEVICE_FILE
'';
postStop = ''
${kernelPackages.v4l2loopback.bin}/bin/v4l2loopback-ctl delete $(cat $V4L2_DEVICE_FILE)
rm -rf $(dirname $V4L2_DEVICE_FILE)
'';
};
mkInstanceServices = instances: listToAttrs (map
(instance:
nameValuePair "v4l2-relayd-${escapeSystemdPath instance.name}" (mkInstanceService instance)
)
instances);
enabledInstances = attrValues (filterAttrs (n: v: v.enable) cfg.instances);
in
{
boot = mkIf ((length enabledInstances) > 0) {
extraModulePackages = [ kernelPackages.v4l2loopback ];
kernelModules = [ "v4l2loopback" ];
};
systemd.services = mkInstanceServices enabledInstances;
};
meta.maintainers = with lib.maintainers; [ betaboon ];
}