Added fingerprinting

Author: djthorpe

README.md

@@ -66,7 +66,10 @@ import (
 )
 
 func main() {
-  manager := media.NewManager()
+  manager, err := media.NewManager()
+  if err != nil {
+    log.Fatal(err)
+  }
 
   // Open a media file for reading. The format of the file is guessed.
   // Alteratively, you can pass a format as the second argument. Further optional
@@ -111,7 +114,11 @@ import (
 )
 
 func main() {
-  manager := NewManager()
+  manager, err := media.NewManager()
+  if err != nil {
+    log.Fatal(err)
+  }
+
   media, err := manager.Open("etc/test/sample.mp4", nil)
   if err != nil {
     log.Fatal(err)
@@ -159,7 +166,53 @@ TODO
 
 ### Retrieving Metadata and Artwork from a media file
 
-TODO
+Here is an example of opening a media file and retrieving metadata and artwork.
+
+```go
+package main
+
+import (
+  "log"
+  "os"
+
+  media "github.com/mutablelogic/go-media"
+  file "github.com/mutablelogic/go-media/pkg/file"
+)
+
+func main() {
+  manager, err := media.NewManager()
+  if err != nil {
+    log.Fatal(err)
+  }
+
+  // Open a media file for reading. The format of the file is guessed.
+  // Alteratively, you can pass a format as the second argument. Further optional
+  // arguments can be used to set the format options.
+  reader, err := manager.Open(os.Args[1], nil)
+  if err != nil {
+    log.Fatal(err)
+  }
+  defer reader.Close()
+
+  // Retrieve all the metadata from the file, and display it. If you pass
+  // keys to the Metadata function, then only entries with those keys will be
+  // returned.
+  for _, metadata := range reader.Metadata() {
+    log.Print(metadata.Key(), " => ", metadata.Value())
+  }
+
+  // Retrieve artwork by using the MetaArtwork key. The value is of type []byte.
+  // which needs to be converted to an image. There is a utility method to
+  // detect the image type.
+  for _, artwork := range reader.Metadata(media.MetaArtwork) {
+    mimetype, ext, err := file.MimeType(artwork.Value().([]byte))
+    if err != nil {
+      log.Fatal(err)
+    }
+    log.Print("got artwork", mimetype, ext)
+  }
+}
+```
 
 ### Audio Fingerprinting
 

cmd/cli/fingerprint.go

@@ -0,0 +1,82 @@
+package main
+
+import (
+	"context"
+	"fmt"
+	"io/fs"
+	"path/filepath"
+	"time"
+
+	// Packages
+	"github.com/mutablelogic/go-media"
+	"github.com/mutablelogic/go-media/pkg/chromaprint"
+	"github.com/mutablelogic/go-media/pkg/file"
+)
+
+type FimgerprintCmd struct {
+	Path string `arg:"" required:"" help:"Media file or path" type:"path"`
+}
+
+func (cmd *FimgerprintCmd) Run(globals *Globals) error {
+	// Create the walker with the processor callback
+	walker := file.NewWalker(func(ctx context.Context, root, relpath string, info fs.FileInfo) error {
+		if info.IsDir() || info.Size() == 0 {
+			return nil
+		}
+		if err := cmd.mediaWalker(ctx, globals.manager, filepath.Join(root, relpath)); err != nil {
+			if err == context.Canceled {
+				globals.manager.Infof("Cancelled\n")
+			} else {
+				globals.manager.Errorf("Error processing %q: %v\n", relpath, err)
+			}
+		}
+		return nil
+	})
+
+	// Walk the filesystem
+	return walker.Walk(globals.ctx, cmd.Path)
+}
+
+func (cmd *FimgerprintCmd) mediaWalker(ctx context.Context, manager media.Manager, path string) error {
+	reader, err := manager.Open(path, nil)
+	if err != nil {
+		return err
+	}
+	defer reader.Close()
+
+	// Create a decoder for audio - needs to be s16 pcm for chromaprint
+	decoder, err := reader.Decoder(func(stream media.Stream) (media.Parameters, error) {
+		if stream.Type().Is(media.AUDIO) {
+			return manager.AudioParameters("mono", "s16", 22050)
+		} else {
+			return nil, nil
+		}
+	})
+	if err != nil {
+		return err
+	}
+
+	// Create a fingerprinter
+	fingerprint := chromaprint.New(22050, 1, time.Minute)
+	defer fingerprint.Close()
+
+	// Decode the frames
+	if err := decoder.Decode(ctx, func(frame media.Frame) error {
+		_, err := fingerprint.Write(frame.Int16(0))
+		if err != nil {
+			return err
+		}
+		return nil
+	}); err != nil {
+		return err
+	}
+
+	if hash, err := fingerprint.Finish(); err != nil {
+		return err
+	} else {
+		fmt.Println(path, "=>", hash)
+	}
+
+	// Return success
+	return nil
+}

cmd/cli/main.go

@@ -33,6 +33,7 @@ type CLI struct {
 	PixelFormats   PixelFormatsCmd   `cmd:"pixelfmts" help:"List video pixel formats"`
 	Metadata       MetadataCmd       `cmd:"metadata" help:"Display media metadata information"`
 	Artwork        ArtworkCmd        `cmd:"artwork" help:"Save artwork from media file"`
+	Fingerprint    FimgerprintCmd    `cmd:"fingerprint" help:"Fingerprint an audio file"`
 	Probe          ProbeCmd          `cmd:"probe" help:"Probe media file or device"`
 	Decode         DecodeCmd         `cmd:"decode" help:"Decode media"`
 	Thumbnails     ThumbnailsCmd     `cmd:"thumbnails" help:"Generate thumbnails from media file"`

cmd/examples/decode/main.go

@@ -9,7 +9,10 @@ import (
 )
 
 func main() {
-	manager := media.NewManager()
+	manager, err := media.NewManager()
+	if err != nil {
+		log.Fatal(err)
+	}
 
 	// Open a media file for reading. The format of the file is guessed.
 	// Alteratively, you can pass a format as the second argument. Further optional

cmd/examples/demux/main.go

@@ -9,7 +9,10 @@ import (
 )
 
 func main() {
-	manager := media.NewManager()
+	manager, err := media.NewManager()
+	if err != nil {
+		log.Fatal(err)
+	}
 
 	// Open a media file for reading. The format of the file is guessed.
 	// Alteratively, you can pass a format as the second argument. Further optional

cmd/examples/metadata/main.go

@@ -0,0 +1,44 @@
+package main
+
+import (
+	"log"
+	"os"
+
+	media "github.com/mutablelogic/go-media"
+	file "github.com/mutablelogic/go-media/pkg/file"
+)
+
+func main() {
+	manager, err := media.NewManager()
+	if err != nil {
+		log.Fatal(err)
+	}
+
+	// Open a media file for reading. The format of the file is guessed.
+	// Alteratively, you can pass a format as the second argument. Further optional
+	// arguments can be used to set the format options.
+	reader, err := manager.Open(os.Args[1], nil)
+	if err != nil {
+		log.Fatal(err)
+	}
+	defer reader.Close()
+
+	// Retrieve all the metadata from the file, and display it. If you pass
+	// keys to the Metadata function, then only entries with those keys will be
+	// returned.
+	for _, metadata := range reader.Metadata() {
+		log.Print(metadata.Key(), " => ", metadata.Value())
+	}
+
+	// Retrieve artwork by using the MetaArtwork key. The value is of type []byte.
+	// which needs to be converted to an image. There is a utility method to
+	// detect the image type.
+	for _, artwork := range reader.Metadata(media.MetaArtwork) {
+		mimetype, ext, err := file.MimeType(artwork.Value().([]byte))
+		if err != nil {
+			log.Fatal(err)
+		}
+		log.Print("got artwork", mimetype, ext)
+	}
+
+}