diff --git a/algo/common/dispatch.go b/algo/common/dispatch.go
index 263ad64..f37d35a 100644
--- a/algo/common/dispatch.go
+++ b/algo/common/dispatch.go
@@ -4,6 +4,8 @@ import (
 	"io"
 	"path/filepath"
 	"strings"
+
+	"go.uber.org/zap"
 )
 
 type DecoderParams struct {
@@ -11,6 +13,8 @@ type DecoderParams struct {
 	Extension string        // required, source extension, eg. ".mp3"
 
 	FilePath string // optional, source file path
+
+	Logger *zap.Logger // required
 }
 type NewDecoderFunc func(p *DecoderParams) Decoder
 
diff --git a/algo/qmc/key_mmkv.go b/algo/qmc/key_mmkv.go
index 062ba52..72b3815 100644
--- a/algo/qmc/key_mmkv.go
+++ b/algo/qmc/key_mmkv.go
@@ -8,12 +8,14 @@ import (
 	"runtime"
 	"strings"
 
+	"go.uber.org/zap"
 	"unlock-music.dev/mmkv"
 )
 
 var streamKeyVault mmkv.Vault
 
-func readKeyFromMMKV(file string) ([]byte, error) {
+// TODO: move to factory
+func readKeyFromMMKV(file string, logger *zap.Logger) ([]byte, error) {
 	if file == "" {
 		return nil, errors.New("file path is required while reading key from mmkv")
 	}
@@ -31,6 +33,7 @@ func readKeyFromMMKV(file string) ([]byte, error) {
 				return nil, fmt.Errorf("mmkv key valut not found: %w", err)
 			}
 		}
+
 		mgr, err := mmkv.NewManager(mmkvDir)
 		if err != nil {
 			return nil, fmt.Errorf("init mmkv manager: %w", err)
@@ -40,6 +43,8 @@ func readKeyFromMMKV(file string) ([]byte, error) {
 		if err != nil {
 			return nil, fmt.Errorf("open mmkv vault: %w", err)
 		}
+
+		logger.Debug("mmkv vault opened", zap.Strings("keys", streamKeyVault.Keys()))
 	}
 
 	buf, err := streamKeyVault.GetBytes(file)
@@ -52,9 +57,12 @@ func readKeyFromMMKV(file string) ([]byte, error) {
 			}
 			buf, err = streamKeyVault.GetBytes(key)
 			if err != nil {
-				// TODO: logger
+				logger.Warn("read key from mmkv", zap.String("key", key), zap.Error(err))
 			}
 		}
+		// TODO: use editorial judgement to select the best match
+		//       since MacOS may change some characters in the file name.
+		//       eg. "ぜ" -> "ぜ"
 	}
 
 	if len(buf) == 0 {
diff --git a/algo/qmc/qmc.go b/algo/qmc/qmc.go
index 987d01a..a775069 100644
--- a/algo/qmc/qmc.go
+++ b/algo/qmc/qmc.go
@@ -6,9 +6,12 @@ import (
 	"errors"
 	"fmt"
 	"io"
+	"runtime"
 	"strconv"
 	"strings"
 
+	"go.uber.org/zap"
+
 	"unlock-music.dev/cli/algo/common"
 	"unlock-music.dev/cli/internal/sniff"
 )
@@ -26,6 +29,8 @@ type Decoder struct {
 
 	rawMetaExtra1 int
 	rawMetaExtra2 int
+
+	logger *zap.Logger
 }
 
 // Read implements io.Reader, offer the decrypted audio data.
@@ -40,7 +45,7 @@ func (d *Decoder) Read(p []byte) (int, error) {
 }
 
 func NewDecoder(p *common.DecoderParams) common.Decoder {
-	return &Decoder{raw: p.Reader, params: p}
+	return &Decoder{raw: p.Reader, params: p, logger: p.Logger}
 }
 
 func (d *Decoder) Validate() error {
@@ -99,15 +104,21 @@ func (d *Decoder) validateDecode() error {
 }
 
 func (d *Decoder) searchKey() (err error) {
-	if d.params.Extension == ".mflach" {
-		d.decodedKey, err = readKeyFromMMKV(d.params.FilePath)
-		return err
-	}
-
 	fileSizeM4, err := d.raw.Seek(-4, io.SeekEnd)
 	if err != nil {
 		return err
 	}
+	fileSize := int(fileSizeM4) + 4
+
+	//goland:noinspection GoBoolExpressions
+	if runtime.GOOS == "darwin" {
+		d.decodedKey, err = readKeyFromMMKV(d.params.FilePath, d.logger)
+		if err == nil {
+			d.audioLen = fileSize
+			return
+		}
+		d.logger.Warn("read key from mmkv failed", zap.Error(err))
+	}
 
 	suffixBuf := make([]byte, 4)
 	if _, err := io.ReadFull(d.raw, suffixBuf); err != nil {
@@ -127,7 +138,7 @@ func (d *Decoder) searchKey() (err error) {
 		}
 
 		// try to use default static cipher
-		d.audioLen = int(fileSizeM4 + 4)
+		d.audioLen = fileSize
 		return nil
 	}
 
diff --git a/cmd/um/main.go b/cmd/um/main.go
index 01cf963..4eae5e8 100644
--- a/cmd/um/main.go
+++ b/cmd/um/main.go
@@ -148,9 +148,10 @@ func dealDirectory(inputDir string, outputDir string, skipNoop bool, removeSourc
 			continue
 		}
 
-		err := tryDecFile(filepath.Join(inputDir, item.Name()), outputDir, allDec, removeSource)
+		filePath := filepath.Join(inputDir, item.Name())
+		err := tryDecFile(filePath, outputDir, allDec, removeSource)
 		if err != nil {
-			logger.Error("conversion failed", zap.String("source", item.Name()), zap.Error(err))
+			logger.Error("conversion failed", zap.String("source", filePath), zap.Error(err))
 		}
 	}
 	return nil
@@ -167,6 +168,7 @@ func tryDecFile(inputFile string, outputDir string, allDec []common.NewDecoderFu
 		Reader:    file,
 		Extension: filepath.Ext(inputFile),
 		FilePath:  inputFile,
+		Logger:    logger.With(zap.String("source", inputFile)),
 	}
 
 	var dec common.Decoder