diff --git a/internal/library/mediainfo/ffprobe_download_test.go b/internal/library/mediainfo/ffprobe_download_test.go
new file mode 100644
index 0000000..4179519
--- /dev/null
+++ b/internal/library/mediainfo/ffprobe_download_test.go
@@ -0,0 +1,130 @@
+package mediainfo
+
+import (
+	"archive/zip"
+	"bytes"
+	"runtime"
+	"testing"
+)
+
+func TestFFprobePlatformKey(t *testing.T) {
+	key, err := ffprobePlatformKey()
+	if err != nil {
+		// Only error on unsupported platforms
+		if runtime.GOOS != "linux" && runtime.GOOS != "darwin" && runtime.GOOS != "windows" {
+			return // expected to fail on unsupported platforms
+		}
+		t.Fatalf("ffprobePlatformKey: %v", err)
+	}
+	if key == "" {
+		t.Error("platform key should not be empty")
+	}
+
+	// Verify format based on current platform
+	switch runtime.GOOS {
+	case "linux":
+		switch runtime.GOARCH {
+		case "amd64":
+			if key != "linux-64" {
+				t.Errorf("key = %q, want linux-64", key)
+			}
+		case "arm64":
+			if key != "linux-arm64" {
+				t.Errorf("key = %q, want linux-arm64", key)
+			}
+		}
+	case "darwin":
+		if key != "osx-64" {
+			t.Errorf("key = %q, want osx-64", key)
+		}
+	case "windows":
+		if runtime.GOARCH == "amd64" && key != "windows-64" {
+			t.Errorf("key = %q, want windows-64", key)
+		}
+	}
+}
+
+func TestFFprobeCacheDir(t *testing.T) {
+	dir, err := FFprobeCacheDir()
+	if err != nil {
+		t.Fatalf("FFprobeCacheDir: %v", err)
+	}
+	if dir == "" {
+		t.Error("cache dir should not be empty")
+	}
+}
+
+func TestFFprobeCachePath(t *testing.T) {
+	path, err := FFprobeCachePath()
+	if err != nil {
+		t.Fatalf("FFprobeCachePath: %v", err)
+	}
+	if path == "" {
+		t.Error("cache path should not be empty")
+	}
+}
+
+func TestExtractFromZip(t *testing.T) {
+	// Create a zip in memory containing a "ffprobe" file
+	var buf bytes.Buffer
+	w := zip.NewWriter(&buf)
+
+	content := []byte("fake ffprobe binary content")
+	f, err := w.Create("ffprobe")
+	if err != nil {
+		t.Fatal(err)
+	}
+	f.Write(content)
+
+	// Add another file to make it realistic
+	readme, _ := w.Create("README.md")
+	readme.Write([]byte("some readme"))
+
+	w.Close()
+
+	data, err := extractFromZip(buf.Bytes(), "ffprobe")
+	if err != nil {
+		t.Fatalf("extractFromZip: %v", err)
+	}
+	if string(data) != string(content) {
+		t.Errorf("content = %q, want %q", string(data), string(content))
+	}
+}
+
+func TestExtractFromZipNotFound(t *testing.T) {
+	var buf bytes.Buffer
+	w := zip.NewWriter(&buf)
+	f, _ := w.Create("other-file.txt")
+	f.Write([]byte("data"))
+	w.Close()
+
+	_, err := extractFromZip(buf.Bytes(), "ffprobe")
+	if err == nil {
+		t.Error("expected error when target not in zip")
+	}
+}
+
+func TestExtractFromZipInvalidData(t *testing.T) {
+	_, err := extractFromZip([]byte("not a zip"), "ffprobe")
+	if err == nil {
+		t.Error("expected error for invalid zip data")
+	}
+}
+
+func TestExtractFromZipWindowsExe(t *testing.T) {
+	var buf bytes.Buffer
+	w := zip.NewWriter(&buf)
+
+	content := []byte("fake exe")
+	f, _ := w.Create("bin/ffprobe.exe")
+	f.Write(content)
+	w.Close()
+
+	data, err := extractFromZip(buf.Bytes(), "ffprobe.exe")
+	if err != nil {
+		t.Fatalf("extractFromZip: %v", err)
+	}
+	if string(data) != string(content) {
+		t.Errorf("content mismatch")
+	}
+}