Change:
<del> { lib , stdenv , atk , cairo , czkawka , darwin , fetchFromGitHub , gdk-pixbuf , glib , gobject-introspection , gtk4 , pango , overrideSDK , pkg-config , rustPlatform , testers , wrapGAppsHook4 , xvfb-run </del> <ins> { lib, atk, cairo, callPackage, darwin, fetchFromGitHub, gdk-pixbuf, glib, gobject-introspection, gtk4, overrideSDK, pango, pkg-config, rustPlatform, stdenv, testers, wrapGAppsHook4, xvfb-run, </ins> }: let <del> pname = "czkawka"; version = "7.0.0"; src = fetchFromGitHub { owner = "qarmin"; repo = "czkawka"; rev = version; hash = "sha256-SOWtLmehh1F8SoDQ+9d7Fyosgzya5ZztCv8IcJZ4J94="; }; cargoPatches = [ ./time.patch ]; cargoHash = "sha256-cQv8C0P3xizsvnJODkTMJQA98P4nYSCHFT75isJE6es="; </del> buildRustPackage' = rustPlatform.buildRustPackage.override { stdenv = if stdenv.isDarwin then overrideSDK stdenv "11.0" else stdenv; }; <del> in buildRustPackage' { inherit pname version src cargoPatches cargoHash; nativeBuildInputs = [ gobject-introspection pkg-config wrapGAppsHook4 ]; </del> <ins> self = buildRustPackage' { pname = "czkawka"; version = "7.0.0"; </ins> <del> buildInputs = [ atk cairo gdk-pixbuf glib gtk4 pango ] ++ lib.optionals stdenv.hostPlatform.isDarwin (with darwin.apple_sdk.frameworks; [ Foundation AppKit ]); </del> <ins> src = fetchFromGitHub { owner = "qarmin"; repo = "czkawka"; rev = self.version; hash = "sha256-SOWtLmehh1F8SoDQ+9d7Fyosgzya5ZztCv8IcJZ4J94="; }; </ins> <del> nativeCheckInputs = [ xvfb-run ]; </del> <ins> cargoPatches = [ # Updates time and time-macros from Cargo.lock ./0000-time.diff ]; </ins> <del> strictDeps = true; </del> <ins> cargoHash = "sha256-cQv8C0P3xizsvnJODkTMJQA98P4nYSCHFT75isJE6es="; </ins> <del> checkPhase = '' runHook preCheck xvfb-run cargo test runHook postCheck ''; </del> <ins> nativeBuildInputs = [ gobject-introspection pkg-config wrapGAppsHook4 ]; </ins> <del> doCheck = stdenv.hostPlatform.isLinux && (stdenv.hostPlatform == stdenv.buildPlatform); </del> <ins> buildInputs = [ atk cairo gdk-pixbuf glib gtk4 pango ] ++ lib.optionals stdenv.hostPlatform.isDarwin ( with darwin.apple_sdk.frameworks; [ AppKit Foundation ] ); </ins> <del> passthru.tests.version = testers.testVersion { package = czkawka; command = "czkawka_cli --version"; }; </del> <ins> nativeCheckInputs = [ xvfb-run ]; </ins> <del> # Desktop items, icons and metainfo are not installed automatically postInstall = '' install -Dm444 -t $out/share/applications data/com.github.qarmin.czkawka.desktop install -Dm444 -t $out/share/icons/hicolor/scalable/apps data/icons/com.github.qarmin.czkawka.svg install -Dm444 -t $out/share/icons/hicolor/scalable/apps data/icons/com.github.qarmin.czkawka-symbolic.svg install -Dm444 -t $out/share/metainfo data/com.github.qarmin.czkawka.metainfo.xml ''; </del> <ins> strictDeps = true; </ins> <del> meta = { changelog = "https://github.com/qarmin/czkawka/raw/${version}/Changelog.md"; description = "Simple, fast and easy to use app to remove unnecessary files from your computer"; homepage = "https://github.com/qarmin/czkawka"; license = with lib.licenses; [ mit ]; mainProgram = "czkawka_gui"; maintainers = with lib.maintainers; [ AndersonTorres yanganto _0x4A6F ]; </del> <ins> doCheck = stdenv.hostPlatform.isLinux && (stdenv.hostPlatform == stdenv.buildPlatform); checkPhase = '' runHook preCheck xvfb-run cargo test runHook postCheck ''; # Desktop items, icons and metainfo are not installed automatically postInstall = '' install -Dm444 -t $out/share/applications data/com.github.qarmin.czkawka.desktop install -Dm444 -t $out/share/icons/hicolor/scalable/apps data/icons/com.github.qarmin.czkawka.svg install -Dm444 -t $out/share/icons/hicolor/scalable/apps data/icons/com.github.qarmin.czkawka-symbolic.svg install -Dm444 -t $out/share/metainfo data/com.github.qarmin.czkawka.metainfo.xml ''; passthru = { tests.version = testers.testVersion { package = self; command = "czkawka_cli --version"; }; wrapper = callPackage ./wrapper.nix { czkawka = self; }; }; meta = { homepage = "https://github.com/qarmin/czkawka"; description = "Simple, fast and easy to use app to remove unnecessary files from your computer"; changelog = "https://github.com/qarmin/czkawka/raw/${self.version}/Changelog.md"; license = with lib.licenses; [ mit ]; mainProgram = "czkawka_gui"; maintainers = with lib.maintainers; [ AndersonTorres yanganto _0x4A6F ]; }; </ins> }; <del> } </del> <ins> in self </ins>

Discussion:
The czkawka package is missing ffmpeg as a dependency. If ffmpeg is not found you get this error when trying to compare video files: Ignore the snap part, it throws this error when it can't find ffmpeg, regardless if snap or not. 't have ffmpeg installed on you system. comparing videos in czkawka throws error ffmpeg error. Just works. No error. Just works. First issue I've reported here, hopefully I'm doing this right. <!-- Please @ people who are in the list of the offending package or module. If in doubt, check for whoever last touched something. --Please run and paste the result. Add a :+1: [reaction] to [issues you find important]. [reaction]: [issues you find important]:
Before I propose any changes, let me know a thing or two. When you install both ffmpeg and czkawka, then czkawka finds ffmpeg, correct?
Correct. It finds it no problem.