Merge pull request '小更改 - mmkv 相关' (#93) from qmc-mmkv-cipher into master

Reviewed-on: https://git.unlock-music.dev/um/cli/pulls/93

.drone.jsonnet

@@ -20,10 +20,11 @@ local StepGoBuild(GOOS, GOARCH) = {
   local filepath = 'dist/um-%s-%s.tar.gz' % [GOOS, GOARCH],
 
   name: 'go build %s/%s' % [GOOS, GOARCH],
-  image: 'golang:1.19',
+  image: 'golang:1.22',
   environment: {
     GOOS: GOOS,
     GOARCH: GOARCH,
+    GOPROXY: "https://goproxy.io,direct",
   },
   commands: [
     'DIST_DIR=$(mktemp -d)',
@@ -39,7 +40,7 @@ local StepUploadArtifact(GOOS, GOARCH) = {
   local pkgname = '${DRONE_REPO_NAME}-build',
 
   name: 'upload artifact',
-  image: 'golang:1.19',  // reuse golang:1.19 for curl
+  image: 'golang:1.22',  // reuse golang:1.19 for curl
   environment: {
     DRONE_GITEA_SERVER: 'https://git.unlock-music.dev',
     GITEA_API_KEY: { from_secret: 'GITEA_API_KEY' },
@@ -68,7 +69,10 @@ local PipelineBuild(GOOS, GOARCH, RUN_TEST) = {
          (
            if RUN_TEST then [{
              name: 'go test',
-             image: 'golang:1.19',
+             image: 'golang:1.22',
+             environment: {
+               GOPROXY: "https://goproxy.io,direct",
+             },
              commands: ['go test -v ./...'],
            }] else []
          )
@@ -94,7 +98,10 @@ local PipelineRelease() = {
     },
     {
       name: 'go test',
-      image: 'golang:1.19',
+      image: 'golang:1.22',
+      environment: {
+        GOPROXY: "https://goproxy.io,direct",
+      },
       commands: ['go test -v ./...'],
     },
     StepGoBuild('linux', 'amd64'),

.drone.yml

@@ -8,7 +8,9 @@ steps:
   name: fetch tags
 - commands:
   - go test -v ./...
-  image: golang:1.19
+  environment:
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go test
 - commands:
   - DIST_DIR=$(mktemp -d)
@@ -19,7 +21,8 @@ steps:
   environment:
     GOARCH: amd64
     GOOS: linux
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build linux/amd64
 - commands:
   - curl --fail --include --user "um-release-bot:$GITEA_API_KEY" --upload-file "dist/um-linux-amd64.tar.gz"
@@ -30,7 +33,7 @@ steps:
     DRONE_GITEA_SERVER: https://git.unlock-music.dev
     GITEA_API_KEY:
       from_secret: GITEA_API_KEY
-  image: golang:1.19
+  image: golang:1.22
   name: upload artifact
 trigger:
   event:
@@ -54,7 +57,8 @@ steps:
   environment:
     GOARCH: amd64
     GOOS: windows
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build windows/amd64
 - commands:
   - curl --fail --include --user "um-release-bot:$GITEA_API_KEY" --upload-file "dist/um-windows-amd64.tar.gz"
@@ -65,7 +69,7 @@ steps:
     DRONE_GITEA_SERVER: https://git.unlock-music.dev
     GITEA_API_KEY:
       from_secret: GITEA_API_KEY
-  image: golang:1.19
+  image: golang:1.22
   name: upload artifact
 trigger:
   event:
@@ -89,7 +93,8 @@ steps:
   environment:
     GOARCH: amd64
     GOOS: darwin
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build darwin/amd64
 - commands:
   - curl --fail --include --user "um-release-bot:$GITEA_API_KEY" --upload-file "dist/um-darwin-amd64.tar.gz"
@@ -100,7 +105,7 @@ steps:
     DRONE_GITEA_SERVER: https://git.unlock-music.dev
     GITEA_API_KEY:
       from_secret: GITEA_API_KEY
-  image: golang:1.19
+  image: golang:1.22
   name: upload artifact
 trigger:
   event:
@@ -117,7 +122,9 @@ steps:
   name: fetch tags
 - commands:
   - go test -v ./...
-  image: golang:1.19
+  environment:
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go test
 - commands:
   - DIST_DIR=$(mktemp -d)
@@ -128,7 +135,8 @@ steps:
   environment:
     GOARCH: amd64
     GOOS: linux
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build linux/amd64
 - commands:
   - DIST_DIR=$(mktemp -d)
@@ -139,7 +147,8 @@ steps:
   environment:
     GOARCH: arm64
     GOOS: linux
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build linux/arm64
 - commands:
   - DIST_DIR=$(mktemp -d)
@@ -150,7 +159,8 @@ steps:
   environment:
     GOARCH: "386"
     GOOS: linux
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build linux/386
 - commands:
   - DIST_DIR=$(mktemp -d)
@@ -161,7 +171,8 @@ steps:
   environment:
     GOARCH: amd64
     GOOS: windows
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build windows/amd64
 - commands:
   - DIST_DIR=$(mktemp -d)
@@ -172,7 +183,8 @@ steps:
   environment:
     GOARCH: "386"
     GOOS: windows
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build windows/386
 - commands:
   - DIST_DIR=$(mktemp -d)
@@ -183,7 +195,8 @@ steps:
   environment:
     GOARCH: amd64
     GOOS: darwin
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build darwin/amd64
 - commands:
   - DIST_DIR=$(mktemp -d)
@@ -194,7 +207,8 @@ steps:
   environment:
     GOARCH: arm64
     GOOS: darwin
-  image: golang:1.19
+    GOPROXY: https://goproxy.io,direct
+  image: golang:1.22
   name: go build darwin/arm64
 - image: plugins/gitea-release
   name: create release

README.md

@@ -1,22 +1,21 @@
 # Unlock Music Project - CLI Edition
 
-Original: Web Edition https://github.com/ix64/unlock-music
+Original: Web Edition https://git.unlock-music.dev/um/web
 
-- [Release Download](https://github.com/unlock-music/cli/releases/latest)
+- [![Build Status](https://ci.unlock-music.dev/api/badges/um/cli/status.svg)](https://ci.unlock-music.dev/um/cli)
+- [Release Download](https://git.unlock-music.dev/um/cli/releases/latest)
+- [Latest Build](https://git.unlock-music.dev/um/-/packages/generic/cli-build/)
 
 ## Features
 
-- [x] All Algorithm Supported By `ix64/unlock-music`
-- [ ] Complete Cover Image
-- [ ] Parse Meta Data
-- [ ] Complete Meta Data
+- [x] All Algorithm Supported By `unlock-music/web`
+- [x] Complete Metadata & Cover Image
 
 ## Hou to Build
 
-- Requirements: **Golang 1.17**
+- Requirements: **Golang 1.19**
 
-1. Clone this repo `git clone https://github.com/unlock-music/cli && cd cli`
-2. Build the executable `go build ./cmd/um`
+1. run `go install unlock-music.dev/cli/cmd/um@master`
 
 ## How to use
 

algo/common/dispatch.go

@@ -4,9 +4,19 @@ import (
 	"io"
 	"path/filepath"
 	"strings"
+
+	"go.uber.org/zap"
 )
 
-type NewDecoderFunc func(rd io.ReadSeeker) Decoder
+type DecoderParams struct {
+	Reader    io.ReadSeeker // required
+	Extension string        // required, source extension, eg. ".mp3"
+
+	FilePath string // optional, source file path
+
+	Logger *zap.Logger // required
+}
+type NewDecoderFunc func(p *DecoderParams) Decoder
 
 type decoderItem struct {
 	noop    bool
@@ -19,6 +29,7 @@ func RegisterDecoder(ext string, noop bool, dispatchFunc NewDecoderFunc) {
 	DecoderRegistry[ext] = append(DecoderRegistry[ext],
 		decoderItem{noop: noop, decoder: dispatchFunc})
 }
+
 func GetDecoder(filename string, skipNoop bool) (rs []NewDecoderFunc) {
 	ext := strings.ToLower(strings.TrimLeft(filepath.Ext(filename), "."))
 	for _, dec := range DecoderRegistry[ext] {

algo/common/interface.go

@@ -5,6 +5,10 @@ import (
 	"io"
 )
 
+type StreamDecoder interface {
+	Decrypt(buf []byte, offset int)
+}
+
 type Decoder interface {
 	Validate() error
 	io.Reader
@@ -14,12 +18,12 @@ type CoverImageGetter interface {
 	GetCoverImage(ctx context.Context) ([]byte, error)
 }
 
-type Meta interface {
+type AudioMeta interface {
 	GetArtists() []string
 	GetTitle() string
 	GetAlbum() string
 }
 
-type StreamDecoder interface {
-	Decrypt(buf []byte, offset int)
+type AudioMetaGetter interface {
+	GetAudioMeta(ctx context.Context) (AudioMeta, error)
 }

algo/common/meta.go

@@ -0,0 +1,50 @@
+package common
+
+import (
+	"path"
+	"strings"
+)
+
+type filenameMeta struct {
+	artists []string
+	title   string
+	album   string
+}
+
+func (f *filenameMeta) GetArtists() []string {
+	return f.artists
+}
+
+func (f *filenameMeta) GetTitle() string {
+	return f.title
+}
+
+func (f *filenameMeta) GetAlbum() string {
+	return f.album
+}
+
+func ParseFilenameMeta(filename string) (meta AudioMeta) {
+	partName := strings.TrimSuffix(filename, path.Ext(filename))
+	items := strings.Split(partName, "-")
+	ret := &filenameMeta{}
+
+	switch len(items) {
+	case 0:
+		// no-op
+	case 1:
+		ret.title = strings.TrimSpace(items[0])
+	default:
+		ret.title = strings.TrimSpace(items[len(items)-1])
+
+		for _, v := range items[:len(items)-1] {
+			artists := strings.FieldsFunc(v, func(r rune) bool {
+				return r == ',' || r == '_'
+			})
+			for _, artist := range artists {
+				ret.artists = append(ret.artists, strings.TrimSpace(artist))
+			}
+		}
+	}
+
+	return ret
+}

algo/common/meta_test.go

@@ -0,0 +1,38 @@
+package common
+
+import (
+	"reflect"
+	"testing"
+)
+
+func TestParseFilenameMeta(t *testing.T) {
+
+	tests := []struct {
+		name     string
+		wantMeta AudioMeta
+	}{
+		{
+			name:     "test1",
+			wantMeta: &filenameMeta{title: "test1"},
+		},
+		{
+			name:     "周杰伦 - 晴天.flac",
+			wantMeta: &filenameMeta{artists: []string{"周杰伦"}, title: "晴天"},
+		},
+		{
+			name:     "Alan Walker _ Iselin Solheim - Sing Me to Sleep.flac",
+			wantMeta: &filenameMeta{artists: []string{"Alan Walker", "Iselin Solheim"}, title: "Sing Me to Sleep"},
+		},
+		{
+			name:     "Christopher,Madcon - Limousine.flac",
+			wantMeta: &filenameMeta{artists: []string{"Christopher", "Madcon"}, title: "Limousine"},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if gotMeta := ParseFilenameMeta(tt.name); !reflect.DeepEqual(gotMeta, tt.wantMeta) {
+				t.Errorf("ParseFilenameMeta() = %v, want %v", gotMeta, tt.wantMeta)
+			}
+		})
+	}
+}

algo/common/raw.go

@@ -14,8 +14,8 @@ type RawDecoder struct {
 	audioExt string
 }
 
-func NewRawDecoder(rd io.ReadSeeker) Decoder {
-	return &RawDecoder{rd: rd}
+func NewRawDecoder(p *DecoderParams) Decoder {
+	return &RawDecoder{rd: p.Reader}
 }
 
 func (d *RawDecoder) Validate() error {

algo/kgm/kgm.go

@@ -16,8 +16,8 @@ type Decoder struct {
 	header header
 }
 
-func NewDecoder(rd io.ReadSeeker) common.Decoder {
-	return &Decoder{rd: rd}
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader}
 }
 
 // Validate checks if the file is a valid Kugou (.kgm, .vpr, .kgma) file.

algo/kwm/kwm.go

@@ -30,8 +30,8 @@ func (d *Decoder) GetAudioExt() string {
 	return "." + d.outputExt
 }
 
-func NewDecoder(rd io.ReadSeeker) common.Decoder {
-	return &Decoder{rd: rd}
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader}
 }
 
 // Validate checks if the file is a valid Kuwo .kw file.

algo/ncm/meta.go

@@ -6,21 +6,23 @@ import (
 	"unlock-music.dev/cli/algo/common"
 )
 
-type RawMeta interface {
-	common.Meta
+type ncmMeta interface {
+	common.AudioMeta
+
+	// GetFormat return the audio format, e.g. mp3, flac
 	GetFormat() string
+
+	// GetAlbumImageURL return the album image url
 	GetAlbumImageURL() string
 }
-type RawMetaMusic struct {
+
+type ncmMetaMusic struct {
 	Format        string          `json:"format"`
-	MusicID       int             `json:"musicId"`
 	MusicName     string          `json:"musicName"`
 	Artist        [][]interface{} `json:"artist"`
 	Album         string          `json:"album"`
-	AlbumID       int             `json:"albumId"`
 	AlbumPicDocID interface{}     `json:"albumPicDocId"`
 	AlbumPic      string          `json:"albumPic"`
-	MvID          int             `json:"mvId"`
 	Flag          int             `json:"flag"`
 	Bitrate       int             `json:"bitrate"`
 	Duration      int             `json:"duration"`
@@ -28,10 +30,11 @@ type RawMetaMusic struct {
 	TransNames    []interface{}   `json:"transNames"`
 }
 
-func (m RawMetaMusic) GetAlbumImageURL() string {
+func (m *ncmMetaMusic) GetAlbumImageURL() string {
 	return m.AlbumPic
 }
-func (m RawMetaMusic) GetArtists() (artists []string) {
+
+func (m *ncmMetaMusic) GetArtists() (artists []string) {
 	for _, artist := range m.Artist {
 		for _, item := range artist {
 			name, ok := item.(string)
@@ -43,22 +46,23 @@ func (m RawMetaMusic) GetArtists() (artists []string) {
 	return
 }
 
-func (m RawMetaMusic) GetTitle() string {
+func (m *ncmMetaMusic) GetTitle() string {
 	return m.MusicName
 }
 
-func (m RawMetaMusic) GetAlbum() string {
+func (m *ncmMetaMusic) GetAlbum() string {
 	return m.Album
 }
-func (m RawMetaMusic) GetFormat() string {
+
+func (m *ncmMetaMusic) GetFormat() string {
 	return m.Format
 }
 
 //goland:noinspection SpellCheckingInspection
-type RawMetaDJ struct {
+type ncmMetaDJ struct {
 	ProgramID          int          `json:"programId"`
 	ProgramName        string       `json:"programName"`
-	MainMusic          RawMetaMusic `json:"mainMusic"`
+	MainMusic          ncmMetaMusic `json:"mainMusic"`
 	DjID               int          `json:"djId"`
 	DjName             string       `json:"djName"`
 	DjAvatarURL        string       `json:"djAvatarUrl"`
@@ -80,32 +84,32 @@ type RawMetaDJ struct {
 	RadioPurchaseCount int          `json:"radioPurchaseCount"`
 }
 
-func (m RawMetaDJ) GetArtists() []string {
+func (m *ncmMetaDJ) GetArtists() []string {
 	if m.DjName != "" {
 		return []string{m.DjName}
 	}
 	return m.MainMusic.GetArtists()
 }
 
-func (m RawMetaDJ) GetTitle() string {
+func (m *ncmMetaDJ) GetTitle() string {
 	if m.ProgramName != "" {
 		return m.ProgramName
 	}
 	return m.MainMusic.GetTitle()
 }
 
-func (m RawMetaDJ) GetAlbum() string {
+func (m *ncmMetaDJ) GetAlbum() string {
 	if m.Brand != "" {
 		return m.Brand
 	}
 	return m.MainMusic.GetAlbum()
 }
 
-func (m RawMetaDJ) GetFormat() string {
+func (m *ncmMetaDJ) GetFormat() string {
 	return m.MainMusic.GetFormat()
 }
 
-func (m RawMetaDJ) GetAlbumImageURL() string {
+func (m *ncmMetaDJ) GetAlbumImageURL() string {
 	if strings.HasPrefix(m.MainMusic.GetAlbumImageURL(), "http") {
 		return m.MainMusic.GetAlbumImageURL()
 	}

algo/ncm/ncm.go

@@ -29,10 +29,8 @@ var (
 	}
 )
 
-func NewDecoder(rd io.ReadSeeker) common.Decoder {
-	return &Decoder{
-		rd: rd,
-	}
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader}
 }
 
 type Decoder struct {
@@ -43,7 +41,7 @@ type Decoder struct {
 
 	metaRaw  []byte
 	metaType string
-	meta     RawMeta
+	meta     ncmMeta
 	cover    []byte
 }
 
@@ -174,10 +172,10 @@ func (d *Decoder) readCoverData() error {
 func (d *Decoder) parseMeta() error {
 	switch d.metaType {
 	case "music":
-		d.meta = new(RawMetaMusic)
+		d.meta = new(ncmMetaMusic)
 		return json.Unmarshal(d.metaRaw, d.meta)
 	case "dj":
-		d.meta = new(RawMetaDJ)
+		d.meta = new(ncmMetaDJ)
 		return json.Unmarshal(d.metaRaw, d.meta)
 	default:
 		return errors.New("unknown ncm meta type: " + d.metaType)
@@ -234,8 +232,8 @@ func (d *Decoder) GetCoverImage(ctx context.Context) ([]byte, error) {
 	return d.cover, nil
 }
 
-func (d *Decoder) GetMeta() common.Meta {
-	return d.meta
+func (d *Decoder) GetAudioMeta(_ context.Context) (common.AudioMeta, error) {
+	return d.meta, nil
 }
 
 func init() {

algo/qmc/client/base.go

@@ -0,0 +1,146 @@
+package client
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+	"time"
+)
+
+type QQMusic struct {
+	http *http.Client
+}
+
+func (c *QQMusic) rpcDoRequest(ctx context.Context, reqBody any) ([]byte, error) {
+	reqBodyBuf, err := json.Marshal(reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcDoRequest] marshal request: %w", err)
+	}
+
+	const endpointURL = "https://u.y.qq.com/cgi-bin/musicu.fcg"
+	req, err := http.NewRequestWithContext(ctx, http.MethodPost,
+		endpointURL+fmt.Sprintf("?pcachetime=%d", time.Now().Unix()),
+		bytes.NewReader(reqBodyBuf),
+	)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcDoRequest] create request: %w", err)
+	}
+
+	req.Header.Set("Accept", "*/*")
+	req.Header.Set("Accept-Language", "zh-CN")
+	req.Header.Set("User-Agent", "Mozilla/5.0 (compatible; MSIE 9.0; Windows NT 6.1; WOW64; Trident/5.0)")
+	req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
+	// req.Header.Set("Accept-Encoding", "gzip, deflate")
+
+	reqp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcDoRequest] send request: %w", err)
+	}
+	defer reqp.Body.Close()
+
+	respBodyBuf, err := io.ReadAll(reqp.Body)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcDoRequest] read response: %w", err)
+	}
+
+	return respBodyBuf, nil
+}
+
+type rpcRequest struct {
+	Method string `json:"method"`
+	Module string `json:"module"`
+	Param  any    `json:"param"`
+}
+
+type rpcResponse struct {
+	Code    int    `json:"code"`
+	Ts      int64  `json:"ts"`
+	StartTs int64  `json:"start_ts"`
+	TraceID string `json:"traceid"`
+}
+
+type rpcSubResponse struct {
+	Code int             `json:"code"`
+	Data json.RawMessage `json:"data"`
+}
+
+func (c *QQMusic) rpcCall(ctx context.Context,
+	protocol string, method string, module string,
+	param any,
+) (json.RawMessage, error) {
+	reqBody := map[string]any{protocol: rpcRequest{
+		Method: method,
+		Module: module,
+		Param:  param,
+	}}
+
+	respBodyBuf, err := c.rpcDoRequest(ctx, reqBody)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] do request: %w", err)
+	}
+
+	// check rpc response status
+	respStatus := rpcResponse{}
+	if err := json.Unmarshal(respBodyBuf, &respStatus); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] unmarshal response: %w", err)
+	}
+	if respStatus.Code != 0 {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] rpc error: %d", respStatus.Code)
+	}
+
+	// parse response data
+	var respBody map[string]json.RawMessage
+	if err := json.Unmarshal(respBodyBuf, &respBody); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] unmarshal response: %w", err)
+	}
+
+	subRespBuf, ok := respBody[protocol]
+	if !ok {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] sub-response not found")
+	}
+
+	subResp := rpcSubResponse{}
+	if err := json.Unmarshal(subRespBuf, &subResp); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] unmarshal sub-response: %w", err)
+	}
+
+	if subResp.Code != 0 {
+		return nil, fmt.Errorf("qqMusicClient[rpcCall] sub-response error: %d", subResp.Code)
+	}
+
+	return subResp.Data, nil
+}
+
+func (c *QQMusic) downloadFile(ctx context.Context, url string) ([]byte, error) {
+	req, err := http.NewRequestWithContext(ctx, http.MethodGet, url, nil)
+	if err != nil {
+		return nil, fmt.Errorf("qmc[downloadFile] init request: %w", err)
+	}
+
+	//req.Header.Set("Accept", "image/webp,image/*,*/*;q=0.8") // jpeg is preferred to embed in audio
+	req.Header.Set("Accept-Language", "zh-CN,zh;q=0.8,en-US;q=0.6,en;q=0.5;q=0.4")
+	req.Header.Set("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.47.134 Safari/537.36 QBCore/3.53.47.400 QQBrowser/9.0.2524.400")
+
+	resp, err := c.http.Do(req)
+	if err != nil {
+		return nil, fmt.Errorf("qmc[downloadFile] send request: %w", err)
+	}
+	defer resp.Body.Close()
+
+	if resp.StatusCode != http.StatusOK {
+		return nil, fmt.Errorf("qmc[downloadFile] unexpected http status %s", resp.Status)
+	}
+
+	return io.ReadAll(resp.Body)
+}
+
+func NewQQMusicClient() *QQMusic {
+	return &QQMusic{
+		http: &http.Client{
+			Timeout: 10 * time.Second,
+		},
+	}
+}

algo/qmc/client/cover.go

@@ -0,0 +1,21 @@
+package client
+
+import (
+	"context"
+	"fmt"
+	"strconv"
+)
+
+func (c *QQMusic) AlbumCoverByID(ctx context.Context, albumID int) ([]byte, error) {
+	u := fmt.Sprintf("https://imgcache.qq.com/music/photo/album/%s/albumpic_%s_0.jpg",
+		strconv.Itoa(albumID%100),
+		strconv.Itoa(albumID),
+	)
+	return c.downloadFile(ctx, u)
+}
+
+func (c *QQMusic) AlbumCoverByMediaID(ctx context.Context, mediaID string) ([]byte, error) {
+	// original: https://y.gtimg.cn/music/photo_new/T002M000%s.jpg
+	u := fmt.Sprintf("https://y.gtimg.cn/music/photo_new/T002R500x500M000%s.jpg", mediaID)
+	return c.downloadFile(ctx, u)
+}

algo/qmc/client/search.go

@@ -0,0 +1,52 @@
+package client
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+)
+
+type searchParams struct {
+	Grp         int    `json:"grp"`
+	NumPerPage  int    `json:"num_per_page"`
+	PageNum     int    `json:"page_num"`
+	Query       string `json:"query"`
+	RemotePlace string `json:"remoteplace"`
+	SearchType  int    `json:"search_type"`
+	//SearchID    string `json:"searchid"` // todo: it seems generated randomly
+}
+
+type searchResponse struct {
+	Body struct {
+		Song struct {
+			List []*TrackInfo `json:"list"`
+		} `json:"song"`
+	} `json:"body"`
+	Code int `json:"code"`
+}
+
+func (c *QQMusic) Search(ctx context.Context, keyword string) ([]*TrackInfo, error) {
+
+	resp, err := c.rpcCall(ctx,
+		"music.search.SearchCgiService",
+		"DoSearchForQQMusicDesktop",
+		"music.search.SearchCgiService",
+		&searchParams{
+			SearchType: 0, Query: keyword,
+			PageNum: 1, NumPerPage: 40,
+
+			// static values
+			Grp: 1, RemotePlace: "sizer.newclient.song",
+		})
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[Search] rpc call: %w", err)
+	}
+
+	respData := searchResponse{}
+	if err := json.Unmarshal(resp, &respData); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[Search] unmarshal response: %w", err)
+	}
+
+	return respData.Body.Song.List, nil
+
+}

algo/qmc/client/track.go

@@ -0,0 +1,178 @@
+package client
+
+import (
+	"context"
+	"encoding/json"
+	"fmt"
+
+	"github.com/samber/lo"
+)
+
+type getTrackInfoParams struct {
+	Ctx   int   `json:"ctx"`
+	Ids   []int `json:"ids"`
+	Types []int `json:"types"`
+}
+
+type getTrackInfoResponse struct {
+	Tracks []*TrackInfo `json:"tracks"`
+}
+
+func (c *QQMusic) GetTracksInfo(ctx context.Context, songIDs []int) ([]*TrackInfo, error) {
+	resp, err := c.rpcCall(ctx,
+		"Protocol_UpdateSongInfo",
+		"CgiGetTrackInfo",
+		"music.trackInfo.UniformRuleCtrl",
+		&getTrackInfoParams{Ctx: 0, Ids: songIDs, Types: []int{0}},
+	)
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[GetTrackInfo] rpc call: %w", err)
+	}
+	respData := getTrackInfoResponse{}
+	if err := json.Unmarshal(resp, &respData); err != nil {
+		return nil, fmt.Errorf("qqMusicClient[GetTrackInfo] unmarshal response: %w", err)
+	}
+
+	return respData.Tracks, nil
+}
+
+func (c *QQMusic) GetTrackInfo(ctx context.Context, songID int) (*TrackInfo, error) {
+	tracks, err := c.GetTracksInfo(ctx, []int{songID})
+	if err != nil {
+		return nil, fmt.Errorf("qqMusicClient[GetTrackInfo] get tracks info: %w", err)
+	}
+
+	if len(tracks) == 0 {
+		return nil, fmt.Errorf("qqMusicClient[GetTrackInfo] track not found")
+	}
+
+	return tracks[0], nil
+}
+
+type TrackSinger struct {
+	Id    int    `json:"id"`
+	Mid   string `json:"mid"`
+	Name  string `json:"name"`
+	Title string `json:"title"`
+	Type  int    `json:"type"`
+	Uin   int    `json:"uin"`
+	Pmid  string `json:"pmid"`
+}
+type TrackAlbum struct {
+	Id       int    `json:"id"`
+	Mid      string `json:"mid"`
+	Name     string `json:"name"`
+	Title    string `json:"title"`
+	Subtitle string `json:"subtitle"`
+	Pmid     string `json:"pmid"`
+}
+type TrackInfo struct {
+	Id       int           `json:"id"`
+	Type     int           `json:"type"`
+	Mid      string        `json:"mid"`
+	Name     string        `json:"name"`
+	Title    string        `json:"title"`
+	Subtitle string        `json:"subtitle"`
+	Singer   []TrackSinger `json:"singer"`
+	Album    TrackAlbum    `json:"album"`
+	Mv       struct {
+		Id    int    `json:"id"`
+		Vid   string `json:"vid"`
+		Name  string `json:"name"`
+		Title string `json:"title"`
+		Vt    int    `json:"vt"`
+	} `json:"mv"`
+	Interval   int    `json:"interval"`
+	Isonly     int    `json:"isonly"`
+	Language   int    `json:"language"`
+	Genre      int    `json:"genre"`
+	IndexCd    int    `json:"index_cd"`
+	IndexAlbum int    `json:"index_album"`
+	TimePublic string `json:"time_public"`
+	Status     int    `json:"status"`
+	Fnote      int    `json:"fnote"`
+	File       struct {
+		MediaMid      string        `json:"media_mid"`
+		Size24Aac     int           `json:"size_24aac"`
+		Size48Aac     int           `json:"size_48aac"`
+		Size96Aac     int           `json:"size_96aac"`
+		Size192Ogg    int           `json:"size_192ogg"`
+		Size192Aac    int           `json:"size_192aac"`
+		Size128Mp3    int           `json:"size_128mp3"`
+		Size320Mp3    int           `json:"size_320mp3"`
+		SizeApe       int           `json:"size_ape"`
+		SizeFlac      int           `json:"size_flac"`
+		SizeDts       int           `json:"size_dts"`
+		SizeTry       int           `json:"size_try"`
+		TryBegin      int           `json:"try_begin"`
+		TryEnd        int           `json:"try_end"`
+		Url           string        `json:"url"`
+		SizeHires     int           `json:"size_hires"`
+		HiresSample   int           `json:"hires_sample"`
+		HiresBitdepth int           `json:"hires_bitdepth"`
+		B30S          int           `json:"b_30s"`
+		E30S          int           `json:"e_30s"`
+		Size96Ogg     int           `json:"size_96ogg"`
+		Size360Ra     []interface{} `json:"size_360ra"`
+		SizeDolby     int           `json:"size_dolby"`
+		SizeNew       []interface{} `json:"size_new"`
+	} `json:"file"`
+	Pay struct {
+		PayMonth   int `json:"pay_month"`
+		PriceTrack int `json:"price_track"`
+		PriceAlbum int `json:"price_album"`
+		PayPlay    int `json:"pay_play"`
+		PayDown    int `json:"pay_down"`
+		PayStatus  int `json:"pay_status"`
+		TimeFree   int `json:"time_free"`
+	} `json:"pay"`
+	Action struct {
+		Switch   int `json:"switch"`
+		Msgid    int `json:"msgid"`
+		Alert    int `json:"alert"`
+		Icons    int `json:"icons"`
+		Msgshare int `json:"msgshare"`
+		Msgfav   int `json:"msgfav"`
+		Msgdown  int `json:"msgdown"`
+		Msgpay   int `json:"msgpay"`
+		Switch2  int `json:"switch2"`
+		Icon2    int `json:"icon2"`
+	} `json:"action"`
+	Ksong struct {
+		Id  int    `json:"id"`
+		Mid string `json:"mid"`
+	} `json:"ksong"`
+	Volume struct {
+		Gain float64 `json:"gain"`
+		Peak float64 `json:"peak"`
+		Lra  float64 `json:"lra"`
+	} `json:"volume"`
+	Label       string   `json:"label"`
+	Url         string   `json:"url"`
+	Ppurl       string   `json:"ppurl"`
+	Bpm         int      `json:"bpm"`
+	Version     int      `json:"version"`
+	Trace       string   `json:"trace"`
+	DataType    int      `json:"data_type"`
+	ModifyStamp int      `json:"modify_stamp"`
+	Aid         int      `json:"aid"`
+	Tid         int      `json:"tid"`
+	Ov          int      `json:"ov"`
+	Sa          int      `json:"sa"`
+	Es          string   `json:"es"`
+	Vs          []string `json:"vs"`
+}
+
+func (t *TrackInfo) GetArtists() []string {
+	return lo.Map(t.Singer, func(v TrackSinger, i int) string {
+		return v.Name
+	})
+}
+
+func (t *TrackInfo) GetTitle() string {
+	return t.Title
+}
+
+func (t *TrackInfo) GetAlbum() string {
+	return t.Album.Name
+}

algo/qmc/key_mmkv.go

@@ -0,0 +1,158 @@
+package qmc
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"runtime"
+
+	"github.com/samber/lo"
+	"go.uber.org/zap"
+	"golang.org/x/exp/slices"
+	"golang.org/x/text/unicode/norm"
+	"unlock-music.dev/mmkv"
+)
+
+var streamKeyVault mmkv.Vault
+
+// 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")
+	}
+
+	//goland:noinspection GoBoolExpressions
+	if runtime.GOOS != "darwin" {
+		return nil, errors.New("mmkv vault not supported on this platform")
+	}
+
+	if streamKeyVault == nil {
+		mmkvDir, err := getRelativeMMKVDir(file)
+		if err != nil {
+			mmkvDir, err = getDefaultMMKVDir()
+			if err != nil {
+				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)
+		}
+
+		streamKeyVault, err = mgr.OpenVault("MMKVStreamEncryptId")
+		if err != nil {
+			return nil, fmt.Errorf("open mmkv vault: %w", err)
+		}
+
+		logger.Debug("mmkv vault opened", zap.Strings("keys", streamKeyVault.Keys()))
+	}
+
+	_, partName := filepath.Split(file)
+	partName = normalizeUnicode(partName)
+
+	buf, err := streamKeyVault.GetBytes(file)
+	if buf == nil {
+		filePaths := streamKeyVault.Keys()
+		fileNames := lo.Map(filePaths, func(filePath string, _ int) string {
+			_, name := filepath.Split(filePath)
+			return normalizeUnicode(name)
+		})
+
+		for _, key := range fileNames { // fallback: match filename only
+			if key != partName {
+				continue
+			}
+			idx := slices.Index(fileNames, key)
+			buf, err = streamKeyVault.GetBytes(filePaths[idx])
+			if err != nil {
+				logger.Warn("read key from mmkv", zap.String("key", filePaths[idx]), zap.Error(err))
+			}
+		}
+
+	}
+
+	if len(buf) == 0 {
+		return nil, errors.New("key not found in mmkv vault")
+	}
+
+	return deriveKey(buf)
+}
+
+func OpenMMKV(mmkvPath string, key string, logger *zap.Logger) error {
+	filePath, fileName := filepath.Split(mmkvPath)
+	mgr, err := mmkv.NewManager(filepath.Dir(filePath))
+	if err != nil {
+		return fmt.Errorf("init mmkv manager: %w", err)
+	}
+
+	// If `vaultKey` is empty, the key is ignored.
+	streamKeyVault, err = mgr.OpenVaultCrypto(fileName, key)
+
+	if err != nil {
+		return fmt.Errorf("open mmkv vault: %w", err)
+	}
+
+	logger.Debug("mmkv vault opened", zap.Strings("keys", streamKeyVault.Keys()))
+	return nil
+}
+
+// /
+func readKeyFromMMKVCustom(mid string) ([]byte, error) {
+	if streamKeyVault == nil {
+		return nil, fmt.Errorf("mmkv vault not loaded")
+	}
+
+	// get ekey from mmkv vault
+	eKey, err := streamKeyVault.GetBytes(mid)
+	if err != nil {
+		return nil, fmt.Errorf("get eKey error: %w", err)
+	}
+	return deriveKey(eKey)
+}
+
+// / getRelativeMMKVDir get mmkv dir relative to file (legacy QQMusic for macOS behaviour)
+func getRelativeMMKVDir(file string) (string, error) {
+	mmkvDir := filepath.Join(filepath.Dir(file), "../mmkv")
+	if _, err := os.Stat(mmkvDir); err != nil {
+		return "", fmt.Errorf("stat default mmkv dir: %w", err)
+	}
+
+	keyFile := filepath.Join(mmkvDir, "MMKVStreamEncryptId")
+	if _, err := os.Stat(keyFile); err != nil {
+		return "", fmt.Errorf("stat default mmkv file: %w", err)
+	}
+
+	return mmkvDir, nil
+}
+
+func getDefaultMMKVDir() (string, error) {
+	homeDir, err := os.UserHomeDir()
+	if err != nil {
+		return "", fmt.Errorf("get user home dir: %w", err)
+	}
+
+	mmkvDir := filepath.Join(
+		homeDir,
+		"Library/Containers/com.tencent.QQMusicMac/Data",
+		"Library/Application Support/QQMusicMac/mmkv",
+	)
+	if _, err := os.Stat(mmkvDir); err != nil {
+		return "", fmt.Errorf("stat default mmkv dir: %w", err)
+	}
+
+	keyFile := filepath.Join(mmkvDir, "MMKVStreamEncryptId")
+	if _, err := os.Stat(keyFile); err != nil {
+		return "", fmt.Errorf("stat default mmkv file: %w", err)
+	}
+
+	return mmkvDir, nil
+}
+
+// normalizeUnicode normalizes unicode string to NFC.
+// since macOS may change some characters in the file name.
+// e.g. "ぜ"(e3 81 9c) -> "ぜ"(e3 81 9b e3 82 99)
+func normalizeUnicode(str string) string {
+	return norm.NFC.String(str)
+}

algo/qmc/qmc.go

@@ -5,7 +5,9 @@ import (
 	"encoding/binary"
 	"errors"
 	"fmt"
+	"go.uber.org/zap"
 	"io"
+	"runtime"
 	"strconv"
 	"strings"
 
@@ -14,7 +16,8 @@ import (
 )
 
 type Decoder struct {
-	raw io.ReadSeeker // raw is the original file reader
+	raw    io.ReadSeeker // raw is the original file reader
+	params *common.DecoderParams
 
 	audio    io.Reader // audio is the encrypted audio data
 	audioLen int       // audioLen is the audio data length
@@ -23,8 +26,20 @@ type Decoder struct {
 	decodedKey []byte // decodedKey is the decoded key for cipher
 	cipher     common.StreamDecoder
 
-	rawMetaExtra1 int
+	songID        int
 	rawMetaExtra2 int
+
+	albumID      int
+	albumMediaID string
+
+	// cache
+	meta          common.AudioMeta
+	cover         []byte
+	embeddedCover bool          // embeddedCover is true if the cover is embedded in the file
+	probeBuf      *bytes.Buffer // probeBuf is the buffer for sniffing metadata, TODO: consider pipe?
+
+	// provider
+	logger *zap.Logger
 }
 
 // Read implements io.Reader, offer the decrypted audio data.
@@ -34,12 +49,14 @@ func (d *Decoder) Read(p []byte) (int, error) {
 	if n > 0 {
 		d.cipher.Decrypt(p[:n], d.offset)
 		d.offset += n
+
+		_, _ = d.probeBuf.Write(p[:n]) // bytes.Buffer.Write never return error
 	}
 	return n, err
 }
 
-func NewDecoder(r io.ReadSeeker) common.Decoder {
-	return &Decoder{raw: r}
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{raw: p.Reader, params: p, logger: p.Logger}
 }
 
 func (d *Decoder) Validate() error {
@@ -75,6 +92,9 @@ func (d *Decoder) Validate() error {
 	}
 	d.audio = io.LimitReader(d.raw, int64(d.audioLen))
 
+	// prepare for sniffing metadata
+	d.probeBuf = bytes.NewBuffer(make([]byte, 0, d.audioLen))
+
 	return nil
 }
 
@@ -84,7 +104,7 @@ func (d *Decoder) validateDecode() error {
 		return fmt.Errorf("qmc seek to start: %w", err)
 	}
 
-	buf := make([]byte, 16)
+	buf := make([]byte, 64)
 	if _, err := io.ReadFull(d.raw, buf); err != nil {
 		return fmt.Errorf("qmc read header: %w", err)
 	}
@@ -97,11 +117,22 @@ func (d *Decoder) validateDecode() error {
 	return nil
 }
 
-func (d *Decoder) searchKey() error {
+func (d *Decoder) searchKey() (err error) {
 	fileSizeM4, err := d.raw.Seek(-4, io.SeekEnd)
 	if err != nil {
 		return err
 	}
+	fileSize := int(fileSizeM4) + 4
+
+	//goland:noinspection GoBoolExpressions
+	if runtime.GOOS == "darwin" && !strings.HasPrefix(d.params.Extension, ".qmc") {
+		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 {
@@ -113,6 +144,17 @@ func (d *Decoder) searchKey() error {
 		return d.readRawMetaQTag()
 	case "STag":
 		return errors.New("qmc: file with 'STag' suffix doesn't contains media key")
+	case "cex\x00":
+		footer, err := NewMusicExTag(d.raw)
+		if err != nil {
+			return err
+		}
+		d.audioLen = fileSize - int(footer.TagSize)
+		d.decodedKey, err = readKeyFromMMKVCustom(footer.MediaFileName)
+		if err != nil {
+			return err
+		}
+		return nil
 	default:
 		size := binary.LittleEndian.Uint32(suffixBuf)
 
@@ -121,7 +163,7 @@ func (d *Decoder) searchKey() error {
 		}
 
 		// try to use default static cipher
-		d.audioLen = int(fileSizeM4 + 4)
+		d.audioLen = fileSize
 		return nil
 	}
 
@@ -182,7 +224,7 @@ func (d *Decoder) readRawMetaQTag() error {
 		return err
 	}
 
-	d.rawMetaExtra1, err = strconv.Atoi(items[1])
+	d.songID, err = strconv.Atoi(items[1])
 	if err != nil {
 		return err
 	}
@@ -213,7 +255,9 @@ func init() {
 		"776176",   //QQ Music Weiyun Wav
 
 		"mgg", "mgg1", "mggl", //QQ Music New Ogg
-		"mflac", "mflac0", //QQ Music New Flac
+		"mflac", "mflac0", "mflach", //QQ Music New Flac
+
+		"mmp4", // QQ Music MP4 Container, tipically used for Dolby EAC3 stream
 	}
 	for _, ext := range supportedExts {
 		common.RegisterDecoder(ext, false, NewDecoder)

algo/qmc/qmc_footer_musicex.go

@@ -0,0 +1,93 @@
+package qmc
+
+import (
+	bytes "bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"strings"
+)
+
+type MusicExTagV1 struct {
+	SongID        uint32 // Song ID
+	Unknown1      uint32 // unused & unknown
+	Unknown2      uint32 // unused & unknown
+	MediaID       string // Media ID
+	MediaFileName string // real file name
+	Unknown3      uint32 // unused; uninitialized memory?
+
+	// 16 byte at the end of tag.
+	// TagSize should be respected when parsing.
+	TagSize    uint32 // 19.57: fixed value: 0xC0
+	TagVersion uint32 // 19.57: fixed value: 0x01
+	TagMagic   []byte // fixed value "musicex\0" (8 bytes)
+}
+
+func NewMusicExTag(f io.ReadSeeker) (*MusicExTagV1, error) {
+	_, err := f.Seek(-16, io.SeekEnd)
+	if err != nil {
+		return nil, fmt.Errorf("musicex seek error: %w", err)
+	}
+
+	buffer := make([]byte, 16)
+	bytesRead, err := f.Read(buffer)
+	if err != nil {
+		return nil, fmt.Errorf("get musicex error: %w", err)
+	}
+	if bytesRead != 16 {
+		return nil, fmt.Errorf("MusicExV1: read %d bytes (expected %d)", bytesRead, 16)
+	}
+
+	tag := &MusicExTagV1{
+		TagSize:    binary.LittleEndian.Uint32(buffer[0x00:0x04]),
+		TagVersion: binary.LittleEndian.Uint32(buffer[0x04:0x08]),
+		TagMagic:   buffer[0x04:0x0C],
+	}
+
+	if !bytes.Equal(tag.TagMagic, []byte("musicex\x00")) {
+		return nil, errors.New("MusicEx magic mismatch")
+	}
+	if tag.TagVersion != 1 {
+		return nil, errors.New(fmt.Sprintf("unsupported musicex tag version. expecting 1, got %d", tag.TagVersion))
+	}
+
+	if tag.TagSize < 0xC0 {
+		return nil, errors.New(fmt.Sprintf("unsupported musicex tag size. expecting at least 0xC0, got 0x%02x", tag.TagSize))
+	}
+
+	buffer = make([]byte, tag.TagSize)
+	bytesRead, err = f.Read(buffer)
+	if err != nil {
+		return nil, err
+	}
+	if uint32(bytesRead) != tag.TagSize {
+		return nil, fmt.Errorf("MusicExV1: read %d bytes (expected %d)", bytesRead, tag.TagSize)
+	}
+
+	tag.SongID = binary.LittleEndian.Uint32(buffer[0x00:0x04])
+	tag.Unknown1 = binary.LittleEndian.Uint32(buffer[0x04:0x08])
+	tag.Unknown2 = binary.LittleEndian.Uint32(buffer[0x08:0x0C])
+	tag.MediaID = readUnicodeTagName(buffer[0x0C:], 30*2)
+	tag.MediaFileName = readUnicodeTagName(buffer[0x48:], 50*2)
+	tag.Unknown3 = binary.LittleEndian.Uint32(buffer[0xAC:0xB0])
+	return tag, nil
+}
+
+// readUnicodeTagName reads a buffer to maxLen.
+// reconstruct text by skipping alternate char (ascii chars encoded in UTF-16-LE),
+// until finding a zero or reaching maxLen.
+func readUnicodeTagName(buffer []byte, maxLen int) string {
+	builder := strings.Builder{}
+
+	for i := 0; i < maxLen; i += 2 {
+		chr := buffer[i]
+		if chr != 0 {
+			builder.WriteByte(chr)
+		} else {
+			break
+		}
+	}
+
+	return builder.String()
+}

algo/qmc/qmc_meta.go

@@ -0,0 +1,128 @@
+package qmc
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"strings"
+
+	"github.com/samber/lo"
+
+	"unlock-music.dev/cli/algo/common"
+	"unlock-music.dev/cli/algo/qmc/client"
+	"unlock-music.dev/cli/internal/ffmpeg"
+)
+
+func (d *Decoder) GetAudioMeta(ctx context.Context) (common.AudioMeta, error) {
+	if d.meta != nil {
+		return d.meta, nil
+	}
+
+	if d.songID != 0 {
+		if err := d.getMetaBySongID(ctx); err != nil {
+			return nil, err
+		}
+		return d.meta, nil
+	}
+
+	embedMeta, err := ffmpeg.ProbeReader(ctx, d.probeBuf)
+	if err != nil {
+		return nil, fmt.Errorf("qmc[GetAudioMeta] probe reader: %w", err)
+	}
+	d.meta = embedMeta
+	d.embeddedCover = embedMeta.HasAttachedPic()
+
+	if !d.embeddedCover && embedMeta.HasMetadata() {
+		if err := d.searchMetaOnline(ctx, embedMeta); err != nil {
+			return nil, err
+		}
+		return d.meta, nil
+	}
+
+	return d.meta, nil
+}
+
+func (d *Decoder) getMetaBySongID(ctx context.Context) error {
+	c := client.NewQQMusicClient() // todo: use global client
+	trackInfo, err := c.GetTrackInfo(ctx, d.songID)
+	if err != nil {
+		return fmt.Errorf("qmc[GetAudioMeta] get track info: %w", err)
+	}
+
+	d.meta = trackInfo
+	d.albumID = trackInfo.Album.Id
+	if trackInfo.Album.Pmid == "" {
+		d.albumMediaID = trackInfo.Album.Pmid
+	} else {
+		d.albumMediaID = trackInfo.Album.Mid
+	}
+	return nil
+}
+
+func (d *Decoder) searchMetaOnline(ctx context.Context, original common.AudioMeta) error {
+	c := client.NewQQMusicClient() // todo: use global client
+	keyword := lo.WithoutEmpty(append(
+		[]string{original.GetTitle(), original.GetAlbum()},
+		original.GetArtists()...),
+	)
+	if len(keyword) == 0 {
+		return errors.New("qmc[searchMetaOnline] no keyword")
+	}
+
+	trackList, err := c.Search(ctx, strings.Join(keyword, " "))
+	if err != nil {
+		return fmt.Errorf("qmc[searchMetaOnline] search: %w", err)
+	}
+
+	if len(trackList) == 0 {
+		return errors.New("qmc[searchMetaOnline] no result")
+	}
+
+	meta := trackList[0]
+	d.meta = meta
+	d.albumID = meta.Album.Id
+	if meta.Album.Pmid == "" {
+		d.albumMediaID = meta.Album.Pmid
+	} else {
+		d.albumMediaID = meta.Album.Mid
+	}
+
+	return nil
+}
+
+func (d *Decoder) GetCoverImage(ctx context.Context) ([]byte, error) {
+	if d.cover != nil {
+		return d.cover, nil
+	}
+
+	if d.embeddedCover {
+		img, err := ffmpeg.ExtractAlbumArt(ctx, d.probeBuf)
+		if err != nil {
+			return nil, fmt.Errorf("qmc[GetCoverImage] extract album art: %w", err)
+		}
+
+		d.cover = img.Bytes()
+
+		return d.cover, nil
+	}
+
+	c := client.NewQQMusicClient() // todo: use global client
+	var err error
+
+	if d.albumMediaID != "" {
+		d.cover, err = c.AlbumCoverByMediaID(ctx, d.albumMediaID)
+		if err != nil {
+			return nil, fmt.Errorf("qmc[GetCoverImage] get cover by media id: %w", err)
+		}
+	} else if d.albumID != 0 {
+		d.cover, err = c.AlbumCoverByID(ctx, d.albumID)
+		if err != nil {
+			return nil, fmt.Errorf("qmc[GetCoverImage] get cover by id: %w", err)
+		}
+	} else {
+		return nil, errors.New("qmc[GetAudioMeta] album (or media) id is empty")
+	}
+
+	return d.cover, nil
+
+}

algo/qmc/qmc_test.go

@@ -7,6 +7,8 @@ import (
 	"os"
 	"reflect"
 	"testing"
+
+	"unlock-music.dev/cli/algo/common"
 )
 
 func loadTestDataQmcDecoder(filename string) ([]byte, []byte, error) {
@@ -29,13 +31,14 @@ func loadTestDataQmcDecoder(filename string) ([]byte, []byte, error) {
 func TestMflac0Decoder_Read(t *testing.T) {
 	tests := []struct {
 		name    string
+		fileExt string
 		wantErr bool
 	}{
-		{"mflac0_rc4", false},
-		{"mflac_rc4", false},
-		{"mflac_map", false},
-		{"mgg_map", false},
-		{"qmc0_static", false},
+		{"mflac0_rc4", ".mflac0", false},
+		{"mflac_rc4", ".mflac", false},
+		{"mflac_map", ".mflac", false},
+		{"mgg_map", ".mgg", false},
+		{"qmc0_static", ".qmc0", false},
 	}
 
 	for _, tt := range tests {
@@ -45,7 +48,10 @@ func TestMflac0Decoder_Read(t *testing.T) {
 				t.Fatal(err)
 			}
 
-			d := NewDecoder(bytes.NewReader(raw))
+			d := NewDecoder(&common.DecoderParams{
+				Reader:    bytes.NewReader(raw),
+				Extension: tt.fileExt,
+			})
 			if err := d.Validate(); err != nil {
 				t.Errorf("validate file error = %v", err)
 			}
@@ -81,7 +87,10 @@ func TestMflac0Decoder_Validate(t *testing.T) {
 			if err != nil {
 				t.Fatal(err)
 			}
-			d := NewDecoder(bytes.NewReader(raw))
+			d := NewDecoder(&common.DecoderParams{
+				Reader:    bytes.NewReader(raw),
+				Extension: tt.fileExt,
+			})
 
 			if err := d.Validate(); err != nil {
 				t.Errorf("read bytes from decoder error = %v", err)

algo/tm/tm.go

@@ -43,8 +43,8 @@ func (d *Decoder) Read(buf []byte) (int, error) {
 	return d.audio.Read(buf)
 }
 
-func NewTmDecoder(rd io.ReadSeeker) common.Decoder {
-	return &Decoder{raw: rd}
+func NewTmDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{raw: p.Reader}
 }
 
 func init() {

algo/xiami/xm.go

@@ -37,8 +37,8 @@ func (d *Decoder) GetAudioExt() string {
 	return ""
 }
 
-func NewDecoder(rd io.ReadSeeker) common.Decoder {
-	return &Decoder{rd: rd}
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader}
 }
 
 // Validate checks if the file is a valid xiami .xm file.

algo/ximalaya/ximalaya.go

@@ -16,8 +16,8 @@ type Decoder struct {
 	audio io.Reader
 }
 
-func NewDecoder(rd io.ReadSeeker) common.Decoder {
-	return &Decoder{rd: rd}
+func NewDecoder(p *common.DecoderParams) common.Decoder {
+	return &Decoder{rd: p.Reader}
 }
 
 func (d *Decoder) Validate() error {

cmd/um/main.go

@@ -2,10 +2,12 @@ package main
 
 import (
 	"bytes"
+	"context"
 	"errors"
 	"fmt"
 	"io"
 	"os"
+	"os/signal"
 	"path/filepath"
 	"runtime"
 	"runtime/debug"
@@ -13,6 +15,7 @@ import (
 	"strings"
 	"time"
 
+	"github.com/fsnotify/fsnotify"
 	"github.com/urfave/cli/v2"
 	"go.uber.org/zap"
 
@@ -20,12 +23,14 @@ import (
 	_ "unlock-music.dev/cli/algo/kgm"
 	_ "unlock-music.dev/cli/algo/kwm"
 	_ "unlock-music.dev/cli/algo/ncm"
-	_ "unlock-music.dev/cli/algo/qmc"
+	"unlock-music.dev/cli/algo/qmc"
 	_ "unlock-music.dev/cli/algo/tm"
 	_ "unlock-music.dev/cli/algo/xiami"
 	_ "unlock-music.dev/cli/algo/ximalaya"
+	"unlock-music.dev/cli/internal/ffmpeg"
 	"unlock-music.dev/cli/internal/logging"
 	"unlock-music.dev/cli/internal/sniff"
+	"unlock-music.dev/cli/internal/utils"
 )
 
 var AppVersion = "v0.0.6"
@@ -45,9 +50,15 @@ func main() {
 		Flags: []cli.Flag{
 			&cli.StringFlag{Name: "input", Aliases: []string{"i"}, Usage: "path to input file or dir", Required: false},
 			&cli.StringFlag{Name: "output", Aliases: []string{"o"}, Usage: "path to output dir", Required: false},
+			&cli.StringFlag{Name: "qmc-mmkv", Aliases: []string{"db"}, Usage: "path to qmc mmkv (`.crc` file also required)", Required: false},
+			&cli.StringFlag{Name: "qmc-mmkv-key", Aliases: []string{"key"}, Usage: "mmkv password (16 ascii chars)", Required: false},
 			&cli.BoolFlag{Name: "remove-source", Aliases: []string{"rs"}, Usage: "remove source file", Required: false, Value: false},
 			&cli.BoolFlag{Name: "skip-noop", Aliases: []string{"n"}, Usage: "skip noop decoder", Required: false, Value: true},
-			&cli.BoolFlag{Name: "supported-ext", Usage: "Show supported file extensions and exit", Required: false, Value: false},
+			&cli.BoolFlag{Name: "update-metadata", Usage: "update metadata & album art from network", Required: false, Value: false},
+			&cli.BoolFlag{Name: "overwrite", Usage: "overwrite output file without asking", Required: false, Value: false},
+			&cli.BoolFlag{Name: "watch", Usage: "watch the input dir and process new files", Required: false, Value: false},
+
+			&cli.BoolFlag{Name: "supported-ext", Usage: "show supported file extensions and exit", Required: false, Value: false},
 		},
 
 		Action:          appMain,
@@ -60,6 +71,7 @@ func main() {
 		logger.Fatal("run app failed", zap.Error(err))
 	}
 }
+
 func printSupportedExtensions() {
 	var exts []string
 	for ext := range common.DecoderRegistry {
@@ -70,6 +82,7 @@ func printSupportedExtensions() {
 		fmt.Printf("%s: %d\n", ext, len(common.DecoderRegistry[ext]))
 	}
 }
+
 func appMain(c *cli.Context) (err error) {
 	if c.Bool("supported-ext") {
 		printSupportedExtensions()
@@ -102,9 +115,6 @@ func appMain(c *cli.Context) (err error) {
 		}
 	}
 
-	skipNoop := c.Bool("skip-noop")
-	removeSource := c.Bool("remove-source")
-
 	inputStat, err := os.Stat(input)
 	if err != nil {
 		return err
@@ -122,18 +132,100 @@ func appMain(c *cli.Context) (err error) {
 		return errors.New("output should be a writable directory")
 	}
 
-	if inputStat.IsDir() {
-		return dealDirectory(input, output, skipNoop, removeSource)
-	} else {
-		allDec := common.GetDecoder(inputStat.Name(), skipNoop)
-		if len(allDec) == 0 {
-			logger.Fatal("skipping while no suitable decoder")
+	if mmkv := c.String("qmc-mmkv"); mmkv != "" {
+		// If key is not set, the mmkv vault will be treated as unencrypted.
+		key := c.String("qmc-mmkv-key")
+		err := qmc.OpenMMKV(mmkv, key, logger)
+		if err != nil {
+			return err
 		}
-		return tryDecFile(input, output, allDec, removeSource)
+	}
+
+	proc := &processor{
+		outputDir:       output,
+		skipNoopDecoder: c.Bool("skip-noop"),
+		removeSource:    c.Bool("remove-source"),
+		updateMetadata:  c.Bool("update-metadata"),
+		overwriteOutput: c.Bool("overwrite"),
+	}
+
+	if inputStat.IsDir() {
+		wacthDir := c.Bool("watch")
+		if !wacthDir {
+			return proc.processDir(input)
+		} else {
+			return proc.watchDir(input)
+		}
+	} else {
+		return proc.processFile(input)
 	}
 
 }
-func dealDirectory(inputDir string, outputDir string, skipNoop bool, removeSource bool) error {
+
+type processor struct {
+	outputDir string
+
+	skipNoopDecoder bool
+	removeSource    bool
+	updateMetadata  bool
+	overwriteOutput bool
+}
+
+func (p *processor) watchDir(inputDir string) error {
+	if err := p.processDir(inputDir); err != nil {
+		return err
+	}
+
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		return fmt.Errorf("failed to create watcher: %w", err)
+	}
+	defer watcher.Close()
+
+	go func() {
+		for {
+			select {
+			case event, ok := <-watcher.Events:
+				if !ok {
+					return
+				}
+
+				if event.Has(fsnotify.Create) || event.Has(fsnotify.Write) {
+					// try open with exclusive mode, to avoid file is still writing
+					f, err := os.OpenFile(event.Name, os.O_RDONLY, os.ModeExclusive)
+					if err != nil {
+						logger.Debug("failed to open file exclusively", zap.String("path", event.Name), zap.Error(err))
+						time.Sleep(1 * time.Second) // wait for file writing complete
+						continue
+					}
+					_ = f.Close()
+
+					if err := p.processFile(event.Name); err != nil {
+						logger.Warn("failed to process file", zap.String("path", event.Name), zap.Error(err))
+					}
+				}
+			case err, ok := <-watcher.Errors:
+				if !ok {
+					return
+				}
+				logger.Error("file watcher got error", zap.Error(err))
+			}
+		}
+	}()
+
+	err = watcher.Add(inputDir)
+	if err != nil {
+		return fmt.Errorf("failed to watch dir %s: %w", inputDir, err)
+	}
+
+	signalCtx, stop := signal.NotifyContext(context.Background(), os.Interrupt)
+	defer stop()
+
+	<-signalCtx.Done()
+	return nil
+}
+
+func (p *processor) processDir(inputDir string) error {
 	items, err := os.ReadDir(inputDir)
 	if err != nil {
 		return err
@@ -142,30 +234,47 @@ func dealDirectory(inputDir string, outputDir string, skipNoop bool, removeSourc
 		if item.IsDir() {
 			continue
 		}
-		allDec := common.GetDecoder(item.Name(), skipNoop)
+
+		filePath := filepath.Join(inputDir, item.Name())
+		allDec := common.GetDecoder(filePath, p.skipNoopDecoder)
 		if len(allDec) == 0 {
-			logger.Info("skipping while no suitable decoder", zap.String("file", item.Name()))
+			logger.Info("skipping while no suitable decoder", zap.String("source", item.Name()))
 			continue
 		}
 
-		err := tryDecFile(filepath.Join(inputDir, item.Name()), outputDir, allDec, removeSource)
-		if err != nil {
+		if err := p.process(filePath, allDec); err != nil {
 			logger.Error("conversion failed", zap.String("source", item.Name()), zap.Error(err))
 		}
 	}
 	return nil
 }
 
-func tryDecFile(inputFile string, outputDir string, allDec []common.NewDecoderFunc, removeSource bool) error {
+func (p *processor) processFile(filePath string) error {
+	allDec := common.GetDecoder(filePath, p.skipNoopDecoder)
+	if len(allDec) == 0 {
+		logger.Fatal("skipping while no suitable decoder")
+	}
+	return p.process(filePath, allDec)
+}
+
+func (p *processor) process(inputFile string, allDec []common.NewDecoderFunc) error {
 	file, err := os.Open(inputFile)
 	if err != nil {
 		return err
 	}
 	defer file.Close()
+	logger := logger.With(zap.String("source", inputFile))
+
+	decParams := &common.DecoderParams{
+		Reader:    file,
+		Extension: filepath.Ext(inputFile),
+		FilePath:  inputFile,
+		Logger:    logger,
+	}
 
 	var dec common.Decoder
 	for _, decFunc := range allDec {
-		dec = decFunc(file)
+		dec = decFunc(decParams)
 		if err := dec.Validate(); err == nil {
 			break
 		} else {
@@ -177,31 +286,96 @@ func tryDecFile(inputFile string, outputDir string, allDec []common.NewDecoderFu
 		return errors.New("no any decoder can resolve the file")
 	}
 
+	params := &ffmpeg.UpdateMetadataParams{}
+
 	header := bytes.NewBuffer(nil)
-	_, err = io.CopyN(header, dec, 16)
+	_, err = io.CopyN(header, dec, 64)
 	if err != nil {
 		return fmt.Errorf("read header failed: %w", err)
 	}
+	audio := io.MultiReader(header, dec)
+	params.AudioExt = sniff.AudioExtensionWithFallback(header.Bytes(), ".mp3")
+
+	if p.updateMetadata {
+		if audioMetaGetter, ok := dec.(common.AudioMetaGetter); ok {
+			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+			defer cancel()
+
+			// since ffmpeg doesn't support multiple input streams,
+			// we need to write the audio to a temp file.
+			// since qmc decoder doesn't support seeking & relying on ffmpeg probe, we need to read the whole file.
+			// TODO: support seeking or using pipe for qmc decoder.
+			params.Audio, err = utils.WriteTempFile(audio, params.AudioExt)
+			if err != nil {
+				return fmt.Errorf("updateAudioMeta write temp file: %w", err)
+			}
+			defer os.Remove(params.Audio)
+
+			params.Meta, err = audioMetaGetter.GetAudioMeta(ctx)
+			if err != nil {
+				logger.Warn("get audio meta failed", zap.Error(err))
+			}
+
+			if params.Meta == nil { // reset audio meta if failed
+				audio, err = os.Open(params.Audio)
+				if err != nil {
+					return fmt.Errorf("updateAudioMeta open temp file: %w", err)
+				}
+			}
+		}
+	}
+
+	if p.updateMetadata && params.Meta != nil {
+		if coverGetter, ok := dec.(common.CoverImageGetter); ok {
+			ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+			defer cancel()
+
+			if cover, err := coverGetter.GetCoverImage(ctx); err != nil {
+				logger.Warn("get cover image failed", zap.Error(err))
+			} else if imgExt, ok := sniff.ImageExtension(cover); !ok {
+				logger.Warn("sniff cover image type failed", zap.Error(err))
+			} else {
+				params.AlbumArtExt = imgExt
+				params.AlbumArt = cover
+			}
+		}
+	}
 
-	outExt := sniff.AudioExtensionWithFallback(header.Bytes(), ".mp3")
 	inFilename := strings.TrimSuffix(filepath.Base(inputFile), filepath.Ext(inputFile))
+	outPath := filepath.Join(p.outputDir, inFilename+params.AudioExt)
 
-	outPath := filepath.Join(outputDir, inFilename+outExt)
-	outFile, err := os.OpenFile(outPath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
-	if err != nil {
-		return err
+	if !p.overwriteOutput {
+		_, err := os.Stat(outPath)
+		if err == nil {
+			return fmt.Errorf("output file %s is already exist", outPath)
+		} else if !errors.Is(err, os.ErrNotExist) {
+			return fmt.Errorf("stat output file failed: %w", err)
+		}
 	}
-	defer outFile.Close()
 
-	if _, err := io.Copy(outFile, header); err != nil {
-		return err
-	}
-	if _, err := io.Copy(outFile, dec); err != nil {
-		return err
+	if params.Meta == nil {
+		outFile, err := os.OpenFile(outPath, os.O_CREATE|os.O_WRONLY|os.O_TRUNC, 0644)
+		if err != nil {
+			return err
+		}
+		defer outFile.Close()
+
+		if _, err := io.Copy(outFile, audio); err != nil {
+			return err
+		}
+		outFile.Close()
+
+	} else {
+		ctx, cancel := context.WithTimeout(context.Background(), time.Minute)
+		defer cancel()
+
+		if err := ffmpeg.UpdateMeta(ctx, outPath, params); err != nil {
+			return err
+		}
 	}
 
 	// if source file need to be removed
-	if removeSource {
+	if p.removeSource {
 		err := os.RemoveAll(inputFile)
 		if err != nil {
 			return err

go.mod

@@ -1,17 +1,26 @@
 module unlock-music.dev/cli
 
-go 1.17
+go 1.19
 
 require (
-	github.com/urfave/cli/v2 v2.23.5
-	go.uber.org/zap v1.23.0
-	golang.org/x/crypto v0.3.0
+	github.com/fsnotify/fsnotify v1.7.0
+	github.com/go-flac/flacpicture v0.3.0
+	github.com/go-flac/flacvorbis v0.2.0
+	github.com/go-flac/go-flac v1.0.0
+	github.com/samber/lo v1.39.0
+	github.com/urfave/cli/v2 v2.27.1
+	go.uber.org/zap v1.27.0
+	golang.org/x/crypto v0.22.0
+	golang.org/x/exp v0.0.0-20240416160154-fe59bbe5cc7f
+	golang.org/x/text v0.14.0
+	unlock-music.dev/mmkv v0.0.0-20240424090133-0953e6901f3a
 )
 
 require (
-	github.com/cpuguy83/go-md2man/v2 v2.0.2 // indirect
+	github.com/cpuguy83/go-md2man/v2 v2.0.4 // indirect
 	github.com/russross/blackfriday/v2 v2.1.0 // indirect
-	github.com/xrash/smetrics v0.0.0-20201216005158-039620a65673 // indirect
-	go.uber.org/atomic v1.10.0 // indirect
-	go.uber.org/multierr v1.8.0 // indirect
+	github.com/xrash/smetrics v0.0.0-20240312152122-5f08fbb34913 // indirect
+	go.uber.org/multierr v1.11.0 // indirect
+	golang.org/x/sys v0.19.0 // indirect
+	google.golang.org/protobuf v1.33.0 // indirect
 )

go.sum

@@ -1,88 +1,39 @@
-github.com/BurntSushi/toml v1.2.1/go.mod h1:CxXYINrC8qIiEnFrOxCa7Jy5BFHlXnUU2pbicEuybxQ=
-github.com/benbjohnson/clock v1.1.0 h1:Q92kusRqC1XV2MjkWETPvjJVqKetz1OzxZB7mHJLju8=
-github.com/benbjohnson/clock v1.1.0/go.mod h1:J11/hYXuz8f4ySSvYwY0FKfm+ezbsZBKZxNJlLklBHA=
-github.com/cpuguy83/go-md2man/v2 v2.0.2 h1:p1EgwI/C7NhT0JmVkwCD2ZBK8j4aeHQX2pMHHBfMQ6w=
-github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
-github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
+github.com/cpuguy83/go-md2man/v2 v2.0.4 h1:wfIWP927BUkWJb2NmU/kNDYIBTh/ziUX91+lVfRxZq4=
+github.com/cpuguy83/go-md2man/v2 v2.0.4/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
-github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/kr/pretty v0.1.0/go.mod h1:dAy3ld7l9f0ibDNOQOHHMYYIIbhfbHSm3C4ZsoJORNo=
-github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
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internal/ffmpeg/ffmpeg.go

@@ -0,0 +1,125 @@
+package ffmpeg
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"os/exec"
+	"strings"
+
+	"unlock-music.dev/cli/algo/common"
+	"unlock-music.dev/cli/internal/utils"
+)
+
+func ExtractAlbumArt(ctx context.Context, rd io.Reader) (*bytes.Buffer, error) {
+	cmd := exec.CommandContext(ctx, "ffmpeg",
+		"-i", "pipe:0", // input from stdin
+		"-an",              // disable audio
+		"-codec:v", "copy", // copy video(image) codec
+		"-f", "image2", // use image2 muxer
+		"pipe:1", // output to stdout
+	)
+
+	cmd.Stdin = rd
+	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
+	cmd.Stdout, cmd.Stderr = stdout, stderr
+
+	if err := cmd.Run(); err != nil {
+		return nil, fmt.Errorf("ffmpeg run: %w", err)
+	}
+
+	return stdout, nil
+}
+
+type UpdateMetadataParams struct {
+	Audio    string // required
+	AudioExt string // required
+
+	Meta common.AudioMeta // required
+
+	AlbumArt    []byte // optional
+	AlbumArtExt string // required if AlbumArt is not nil
+}
+
+func UpdateMeta(ctx context.Context, outPath string, params *UpdateMetadataParams) error {
+	if params.AudioExt == ".flac" {
+		return updateMetaFlac(ctx, outPath, params)
+	} else {
+		return updateMetaFFmpeg(ctx, outPath, params)
+	}
+}
+func updateMetaFFmpeg(ctx context.Context, outPath string, params *UpdateMetadataParams) error {
+	builder := newFFmpegBuilder()
+
+	out := newOutputBuilder(outPath) // output to file
+	builder.SetFlag("y")             // overwrite output file
+	builder.AddOutput(out)
+
+	// input audio -> output audio
+	builder.AddInput(newInputBuilder(params.Audio)) // input 0: audio
+	out.AddOption("map", "0:a")
+	out.AddOption("codec:a", "copy")
+
+	// input cover -> output cover
+	if params.AlbumArt != nil &&
+		params.AudioExt != ".wav" /* wav doesn't support attached image */ {
+
+		// write cover to temp file
+		artPath, err := utils.WriteTempFile(bytes.NewReader(params.AlbumArt), params.AlbumArtExt)
+		if err != nil {
+			return fmt.Errorf("updateAudioMeta write temp file: %w", err)
+		}
+		defer os.Remove(artPath)
+
+		builder.AddInput(newInputBuilder(artPath)) // input 1: cover
+		out.AddOption("map", "1:v")
+
+		switch params.AudioExt {
+		case ".ogg": // ogg only supports theora codec
+			out.AddOption("codec:v", "libtheora")
+		case ".m4a": // .m4a(mp4) requires set codec, disposition, stream metadata
+			out.AddOption("codec:v", "mjpeg")
+			out.AddOption("disposition:v", "attached_pic")
+			out.AddMetadata("s:v", "title", "Album cover")
+			out.AddMetadata("s:v", "comment", "Cover (front)")
+		case ".mp3":
+			out.AddOption("codec:v", "mjpeg")
+			out.AddMetadata("s:v", "title", "Album cover")
+			out.AddMetadata("s:v", "comment", "Cover (front)")
+		default: // other formats use default behavior
+		}
+	}
+
+	// set file metadata
+	album := params.Meta.GetAlbum()
+	if album != "" {
+		out.AddMetadata("", "album", album)
+	}
+
+	title := params.Meta.GetTitle()
+	if album != "" {
+		out.AddMetadata("", "title", title)
+	}
+
+	artists := params.Meta.GetArtists()
+	if len(artists) != 0 {
+		// TODO: it seems that ffmpeg doesn't support multiple artists
+		out.AddMetadata("", "artist", strings.Join(artists, " / "))
+	}
+
+	if params.AudioExt == ".mp3" {
+		out.AddOption("write_id3v1", "true")
+		out.AddOption("id3v2_version", "3")
+	}
+
+	// execute ffmpeg
+	cmd := builder.Command(ctx)
+
+	if stdout, err := cmd.CombinedOutput(); err != nil {
+		return fmt.Errorf("ffmpeg run: %w, %s", err, string(stdout))
+	}
+
+	return nil
+}

internal/ffmpeg/ffprobe.go

@@ -0,0 +1,141 @@
+package ffmpeg
+
+import (
+	"bytes"
+	"context"
+	"encoding/json"
+	"io"
+	"os/exec"
+	"strings"
+
+	"github.com/samber/lo"
+)
+
+type Result struct {
+	Format  *Format   `json:"format"`
+	Streams []*Stream `json:"streams"`
+}
+
+func (r *Result) HasAttachedPic() bool {
+	return lo.ContainsBy(r.Streams, func(s *Stream) bool {
+		return s.CodecType == "video"
+	})
+}
+
+func (r *Result) getTagByKey(key string) string {
+	for k, v := range r.Format.Tags {
+		if key == strings.ToLower(k) {
+			return v
+		}
+	}
+
+	for _, stream := range r.Streams { // try to find in streams
+		if stream.CodecType != "audio" {
+			continue
+		}
+		for k, v := range stream.Tags {
+			if key == strings.ToLower(k) {
+				return v
+			}
+		}
+	}
+	return ""
+}
+func (r *Result) GetTitle() string {
+	return r.getTagByKey("title")
+}
+
+func (r *Result) GetAlbum() string {
+	return r.getTagByKey("album")
+}
+
+func (r *Result) GetArtists() []string {
+	artists := strings.Split(r.getTagByKey("artist"), "/")
+	for i := range artists {
+		artists[i] = strings.TrimSpace(artists[i])
+	}
+	return artists
+}
+
+func (r *Result) HasMetadata() bool {
+	return r.GetTitle() != "" || r.GetAlbum() != "" || len(r.GetArtists()) > 0
+}
+
+type Format struct {
+	Filename       string            `json:"filename"`
+	NbStreams      int               `json:"nb_streams"`
+	NbPrograms     int               `json:"nb_programs"`
+	FormatName     string            `json:"format_name"`
+	FormatLongName string            `json:"format_long_name"`
+	StartTime      string            `json:"start_time"`
+	Duration       string            `json:"duration"`
+	BitRate        string            `json:"bit_rate"`
+	ProbeScore     int               `json:"probe_score"`
+	Tags           map[string]string `json:"tags"`
+}
+
+type Stream struct {
+	Index          int               `json:"index"`
+	CodecName      string            `json:"codec_name"`
+	CodecLongName  string            `json:"codec_long_name"`
+	CodecType      string            `json:"codec_type"`
+	CodecTagString string            `json:"codec_tag_string"`
+	CodecTag       string            `json:"codec_tag"`
+	SampleFmt      string            `json:"sample_fmt"`
+	SampleRate     string            `json:"sample_rate"`
+	Channels       int               `json:"channels"`
+	ChannelLayout  string            `json:"channel_layout"`
+	BitsPerSample  int               `json:"bits_per_sample"`
+	RFrameRate     string            `json:"r_frame_rate"`
+	AvgFrameRate   string            `json:"avg_frame_rate"`
+	TimeBase       string            `json:"time_base"`
+	StartPts       int               `json:"start_pts"`
+	StartTime      string            `json:"start_time"`
+	BitRate        string            `json:"bit_rate"`
+	Disposition    *ProbeDisposition `json:"disposition"`
+	Tags           map[string]string `json:"tags"`
+}
+
+type ProbeDisposition struct {
+	Default         int `json:"default"`
+	Dub             int `json:"dub"`
+	Original        int `json:"original"`
+	Comment         int `json:"comment"`
+	Lyrics          int `json:"lyrics"`
+	Karaoke         int `json:"karaoke"`
+	Forced          int `json:"forced"`
+	HearingImpaired int `json:"hearing_impaired"`
+	VisualImpaired  int `json:"visual_impaired"`
+	CleanEffects    int `json:"clean_effects"`
+	AttachedPic     int `json:"attached_pic"`
+	TimedThumbnails int `json:"timed_thumbnails"`
+	Captions        int `json:"captions"`
+	Descriptions    int `json:"descriptions"`
+	Metadata        int `json:"metadata"`
+	Dependent       int `json:"dependent"`
+	StillImage      int `json:"still_image"`
+}
+
+func ProbeReader(ctx context.Context, rd io.Reader) (*Result, error) {
+	cmd := exec.CommandContext(ctx, "ffprobe",
+		"-v", "quiet", // disable logging
+		"-print_format", "json", // use json format
+		"-show_format", "-show_streams", "-show_error", // retrieve format and streams
+		"pipe:0", // input from stdin
+	)
+
+	cmd.Stdin = rd
+	stdout, stderr := &bytes.Buffer{}, &bytes.Buffer{}
+	cmd.Stdout, cmd.Stderr = stdout, stderr
+
+	if err := cmd.Run(); err != nil {
+		return nil, err
+	}
+
+	ret := new(Result)
+	if err := json.Unmarshal(stdout.Bytes(), ret); err != nil {
+		return nil, err
+	}
+
+	return ret, nil
+}

internal/ffmpeg/meta_flac.go

@@ -0,0 +1,90 @@
+package ffmpeg
+
+import (
+	"context"
+	"mime"
+	"strings"
+
+	"github.com/go-flac/flacpicture"
+	"github.com/go-flac/flacvorbis"
+	"github.com/go-flac/go-flac"
+	"golang.org/x/exp/slices"
+)
+
+func updateMetaFlac(_ context.Context, outPath string, m *UpdateMetadataParams) error {
+	f, err := flac.ParseFile(m.Audio)
+	if err != nil {
+		return err
+	}
+
+	// generate comment block
+	comment := flacvorbis.MetaDataBlockVorbisComment{Vendor: "unlock-music.dev"}
+
+	// add metadata
+	title := m.Meta.GetTitle()
+	if title != "" {
+		_ = comment.Add(flacvorbis.FIELD_TITLE, title)
+	}
+
+	album := m.Meta.GetAlbum()
+	if album != "" {
+		_ = comment.Add(flacvorbis.FIELD_ALBUM, album)
+	}
+
+	artists := m.Meta.GetArtists()
+	for _, artist := range artists {
+		_ = comment.Add(flacvorbis.FIELD_ARTIST, artist)
+	}
+
+	existCommentIdx := slices.IndexFunc(f.Meta, func(b *flac.MetaDataBlock) bool {
+		return b.Type == flac.VorbisComment
+	})
+	if existCommentIdx >= 0 { // copy existing comment fields
+		exist, err := flacvorbis.ParseFromMetaDataBlock(*f.Meta[existCommentIdx])
+		if err != nil {
+			for _, s := range exist.Comments {
+				if strings.HasPrefix(s, flacvorbis.FIELD_TITLE+"=") && title != "" ||
+					strings.HasPrefix(s, flacvorbis.FIELD_ALBUM+"=") && album != "" ||
+					strings.HasPrefix(s, flacvorbis.FIELD_ARTIST+"=") && len(artists) != 0 {
+					continue
+				}
+				comment.Comments = append(comment.Comments, s)
+			}
+		}
+	}
+
+	// add / replace flac comment
+	cmtBlock := comment.Marshal()
+	if existCommentIdx < 0 {
+		f.Meta = append(f.Meta, &cmtBlock)
+	} else {
+		f.Meta[existCommentIdx] = &cmtBlock
+	}
+
+	if m.AlbumArt != nil {
+
+		cover, err := flacpicture.NewFromImageData(
+			flacpicture.PictureTypeFrontCover,
+			"Front cover",
+			m.AlbumArt,
+			mime.TypeByExtension(m.AlbumArtExt),
+		)
+		if err != nil {
+			return err
+		}
+		coverBlock := cover.Marshal()
+		f.Meta = append(f.Meta, &coverBlock)
+
+		// add / replace flac cover
+		coverIdx := slices.IndexFunc(f.Meta, func(b *flac.MetaDataBlock) bool {
+			return b.Type == flac.Picture
+		})
+		if coverIdx < 0 {
+			f.Meta = append(f.Meta, &coverBlock)
+		} else {
+			f.Meta[coverIdx] = &coverBlock
+		}
+	}
+
+	return f.Save(outPath)
+}

internal/ffmpeg/options.go

@@ -0,0 +1,131 @@
+package ffmpeg
+
+import (
+	"context"
+	"os/exec"
+	"strings"
+)
+
+type ffmpegBuilder struct {
+	binary  string            // ffmpeg binary path
+	options map[string]string // global options
+	inputs  []*inputBuilder   // input options
+	outputs []*outputBuilder  // output options
+}
+
+func newFFmpegBuilder() *ffmpegBuilder {
+	return &ffmpegBuilder{
+		binary:  "ffmpeg",
+		options: make(map[string]string),
+	}
+}
+
+func (b *ffmpegBuilder) AddInput(src *inputBuilder) {
+	b.inputs = append(b.inputs, src)
+}
+
+func (b *ffmpegBuilder) AddOutput(dst *outputBuilder) {
+	b.outputs = append(b.outputs, dst)
+}
+
+func (b *ffmpegBuilder) SetBinary(bin string) {
+	b.binary = bin
+}
+
+func (b *ffmpegBuilder) SetFlag(flag string) {
+	b.options[flag] = ""
+}
+
+func (b *ffmpegBuilder) SetOption(name, value string) {
+	b.options[name] = value
+}
+
+func (b *ffmpegBuilder) Args() (args []string) {
+	for name, val := range b.options {
+		args = append(args, "-"+name)
+		if val != "" {
+			args = append(args, val)
+		}
+	}
+
+	for _, input := range b.inputs {
+		args = append(args, input.Args()...)
+	}
+	for _, output := range b.outputs {
+		args = append(args, output.Args()...)
+	}
+
+	return
+}
+
+func (b *ffmpegBuilder) Command(ctx context.Context) *exec.Cmd {
+	bin := "ffmpeg"
+	if b.binary != "" {
+		bin = b.binary
+	}
+
+	return exec.CommandContext(ctx, bin, b.Args()...)
+}
+
+// inputBuilder is the builder for ffmpeg input options
+type inputBuilder struct {
+	path    string
+	options map[string][]string
+}
+
+func newInputBuilder(path string) *inputBuilder {
+	return &inputBuilder{
+		path:    path,
+		options: make(map[string][]string),
+	}
+}
+
+func (b *inputBuilder) AddOption(name, value string) {
+	b.options[name] = append(b.options[name], value)
+}
+
+func (b *inputBuilder) Args() (args []string) {
+	for name, values := range b.options {
+		for _, val := range values {
+			args = append(args, "-"+name, val)
+		}
+	}
+	return append(args, "-i", b.path)
+}
+
+// outputBuilder is the builder for ffmpeg output options
+type outputBuilder struct {
+	path    string
+	options map[string][]string
+}
+
+func newOutputBuilder(path string) *outputBuilder {
+	return &outputBuilder{
+		path:    path,
+		options: make(map[string][]string),
+	}
+}
+
+func (b *outputBuilder) AddOption(name, value string) {
+	b.options[name] = append(b.options[name], value)
+}
+
+func (b *outputBuilder) Args() (args []string) {
+	for name, values := range b.options {
+		for _, val := range values {
+			args = append(args, "-"+name, val)
+		}
+	}
+	return append(args, b.path)
+}
+
+// AddMetadata is the shortcut for adding "metadata" option
+func (b *outputBuilder) AddMetadata(stream, key, value string) {
+	optVal := strings.TrimSpace(key) + "=" + strings.TrimSpace(value)
+
+	if stream != "" {
+		b.AddOption("metadata:"+stream, optVal)
+	} else {
+		b.AddOption("metadata", optVal)
+	}
+}

internal/sniff/audio.go

@@ -1,6 +1,11 @@
 package sniff
 
-import "bytes"
+import (
+	"bytes"
+	"encoding/binary"
+
+	"golang.org/x/exp/slices"
+)
 
 type Sniffer interface {
 	Sniff(header []byte) bool
@@ -8,7 +13,7 @@ type Sniffer interface {
 
 var audioExtensions = map[string]Sniffer{
 	// ref: https://mimesniff.spec.whatwg.org
-	".mp3": prefixSniffer("ID3"),
+	".mp3": prefixSniffer("ID3"), // todo: check mp3 without ID3v2 tag
 	".ogg": prefixSniffer("OggS"),
 	".wav": prefixSniffer("RIFF"),
 
@@ -19,8 +24,8 @@ var audioExtensions = map[string]Sniffer{
 	},
 
 	// ref: https://www.garykessler.net/library/file_sigs.html
-	".m4a": mpeg4Sniffer{},            // MPEG-4 container, m4a treat as audio
-	".aac": prefixSniffer{0xFF, 0xF1}, // MPEG-4 AAC-LC
+	".m4a": m4aSniffer{},    // MPEG-4 container, Apple Lossless Audio Codec
+	".mp4": &mpeg4Sniffer{}, // MPEG-4 container, other fallback
 
 	".flac": prefixSniffer("fLaC"), // ref: https://xiph.org/flac/format.html
 	".dff":  prefixSniffer("FRM8"), // DSDIFF, ref: https://www.sonicstudio.com/pdf/dsd/DSDIFF_1.5_Spec.pdf
@@ -54,8 +59,48 @@ func (s prefixSniffer) Sniff(header []byte) bool {
 	return bytes.HasPrefix(header, s)
 }
 
+type m4aSniffer struct{}
+
+func (m4aSniffer) Sniff(header []byte) bool {
+	box := readMpeg4FtypBox(header)
+	if box == nil {
+		return false
+	}
+
+	return box.majorBrand == "M4A " || slices.Contains(box.compatibleBrands, "M4A ")
+}
+
 type mpeg4Sniffer struct{}
 
-func (mpeg4Sniffer) Sniff(header []byte) bool {
-	return len(header) >= 8 && bytes.Equal([]byte("ftyp"), header[4:8])
+func (s *mpeg4Sniffer) Sniff(header []byte) bool {
+	return readMpeg4FtypBox(header) != nil
+}
+
+type mpeg4FtpyBox struct {
+	majorBrand       string
+	minorVersion     uint32
+	compatibleBrands []string
+}
+
+func readMpeg4FtypBox(header []byte) *mpeg4FtpyBox {
+	if (len(header) < 8) || !bytes.Equal([]byte("ftyp"), header[4:8]) {
+		return nil // not a valid ftyp box
+	}
+
+	size := binary.BigEndian.Uint32(header[0:4]) // size
+	if size < 16 || size%4 != 0 {
+		return nil // invalid ftyp box
+	}
+
+	box := mpeg4FtpyBox{
+		majorBrand:   string(header[8:12]),
+		minorVersion: binary.BigEndian.Uint32(header[12:16]),
+	}
+
+	// compatible brands
+	for i := 16; i < int(size) && i+4 < len(header); i += 4 {
+		box.compatibleBrands = append(box.compatibleBrands, string(header[i:i+4]))
+	}
+
+	return &box
 }

internal/sniff/image.go

@@ -0,0 +1,30 @@
+package sniff
+
+// ref: https://mimesniff.spec.whatwg.org
+var imageMIMEs = map[string]Sniffer{
+	"image/jpeg": prefixSniffer{0xFF, 0xD8, 0xFF},
+	"image/png":  prefixSniffer{0x89, 'P', 'N', 'G', '\r', '\n', 0x1A, '\n'},
+	"image/bmp":  prefixSniffer("BM"),
+	"image/webp": prefixSniffer("RIFF"),
+	"image/gif":  prefixSniffer("GIF8"),
+}
+
+// ImageMIME sniffs the well-known image types, and returns its MIME.
+func ImageMIME(header []byte) (string, bool) {
+	for ext, sniffer := range imageMIMEs {
+		if sniffer.Sniff(header) {
+			return ext, true
+		}
+	}
+	return "", false
+}
+
+// ImageExtension is equivalent to ImageMIME, but returns file extension
+func ImageExtension(header []byte) (string, bool) {
+	ext, ok := ImageMIME(header)
+	if !ok {
+		return "", false
+	}
+	// todo: use mime.ExtensionsByType
+	return "." + ext[6:], true // "image/" is 6 bytes
+}

internal/utils/temp.go

@@ -0,0 +1,24 @@
+package utils
+
+import (
+	"fmt"
+	"io"
+	"os"
+)
+
+func WriteTempFile(rd io.Reader, ext string) (string, error) {
+	audioFile, err := os.CreateTemp("", "*"+ext)
+	if err != nil {
+		return "", fmt.Errorf("ffmpeg create temp file: %w", err)
+	}
+
+	if _, err := io.Copy(audioFile, rd); err != nil {
+		return "", fmt.Errorf("ffmpeg write temp file: %w", err)
+	}
+
+	if err := audioFile.Close(); err != nil {
+		return "", fmt.Errorf("ffmpeg close temp file: %w", err)
+	}
+
+	return audioFile.Name(), nil
+}