Skip hardware probe when decode is disabled

Author: tces1

internal/config/config.go

@@ -40,6 +40,36 @@ type Transcode struct {
 	IdleTimeout         time.Duration `json:"-"`
 }
 
+func (t *Transcode) UnmarshalJSON(data []byte) error {
+	type transcodeAlias Transcode
+	aux := struct {
+		HardwareDecode json.RawMessage `json:"hardware_decode"`
+		*transcodeAlias
+	}{
+		transcodeAlias: (*transcodeAlias)(t),
+	}
+	if err := json.Unmarshal(data, &aux); err != nil {
+		return err
+	}
+	if len(aux.HardwareDecode) == 0 || string(aux.HardwareDecode) == "null" {
+		return nil
+	}
+	var text string
+	if err := json.Unmarshal(aux.HardwareDecode, &text); err == nil {
+		t.HardwareDecode = text
+		return nil
+	}
+	var enabled bool
+	if err := json.Unmarshal(aux.HardwareDecode, &enabled); err == nil {
+		if !enabled {
+			t.HardwareDecode = "false"
+			return nil
+		}
+		return errors.New(`transcode.hardware_decode boolean true is not supported; use "vaapi"`)
+	}
+	return errors.New(`transcode.hardware_decode must be a string or false`)
+}
+
 type ClientProfile struct {
 	Name      string   `json:"name"`
 	Match     []string `json:"match"`

internal/config/config_test.go

@@ -99,3 +99,23 @@ func TestLoadSupportsVAAPIHardwareDecode(t *testing.T) {
 		t.Fatalf("hardware device = %q", cfg.Transcode.HardwareDevice)
 	}
 }
+
+func TestLoadSupportsBooleanFalseHardwareDecode(t *testing.T) {
+	path := filepath.Join(t.TempDir(), "config.json")
+	err := os.WriteFile(path, []byte(`{
+		"upstream": {"url": "http://upstream.local"},
+		"transcode": {"hardware_decode": false}
+	}`), 0o600)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	cfg, err := config.Load(path)
+	if err != nil {
+		t.Fatal(err)
+	}
+
+	if cfg.Transcode.HardwareDecode != "false" {
+		t.Fatalf("hardware decode = %q", cfg.Transcode.HardwareDecode)
+	}
+}

internal/transcode/ffmpeg_args_test.go

@@ -247,6 +247,26 @@ func TestResolveHardwareDecodeFallsBackToSoftwareWhenProbeFails(t *testing.T) {
 	}
 }
 
+func TestResolveHardwareDecodeFalseSkipsHardwareProbe(t *testing.T) {
+	called := false
+	options, err := resolveHardwareDecodeOptionsStrict("/definitely/missing/ffmpeg", FFmpegOptions{
+		HardwareDecode: "false",
+		HardwareDevice: "/dev/dri/renderD128",
+	}, func(string, FFmpegOptions) error {
+		called = true
+		return errors.New("probe should not run")
+	})
+	if err != nil {
+		t.Fatal(err)
+	}
+	if called {
+		t.Fatal("hardware probe should not run when hardware decode is false")
+	}
+	if options.HardwareDecode != "" || options.HardwareDevice != "" {
+		t.Fatalf("expected software options, got %+v", options)
+	}
+}
+
 func TestDefaultHardwareProbeRejectsVAAPIWhenDeviceInitializationFails(t *testing.T) {
 	tempDir := t.TempDir()
 	ffmpegPath := filepath.Join(tempDir, "ffmpeg")