Added BestStream

Author: djthorpe

pkg/ffmpeg/reader.go

@@ -10,6 +10,7 @@ import (
 	"time"
 
 	// Packages
+	media "github.com/mutablelogic/go-media"
 	ff "github.com/mutablelogic/go-media/sys/ffmpeg61"
 
 	// Namespace imports
@@ -172,6 +173,30 @@ func (r *Reader) Duration() time.Duration {
 	return 0
 }
 
+// Return the "best stream" for a specific media type, or -1 if there is no
+// "best stream" for that type.
+func (r *Reader) BestStream(t media.Type) int {
+	switch {
+	case t.Is(media.VIDEO):
+		if stream, _, err := ff.AVFormat_find_best_stream(r.input, ff.AVMEDIA_TYPE_VIDEO, -1, -1); err == nil {
+			return r.input.Stream(stream).Id()
+		}
+	case t.Is(media.AUDIO):
+		if stream, _, err := ff.AVFormat_find_best_stream(r.input, ff.AVMEDIA_TYPE_AUDIO, -1, -1); err == nil {
+			return r.input.Stream(stream).Id()
+		}
+	case t.Is(media.SUBTITLE):
+		if stream, _, err := ff.AVFormat_find_best_stream(r.input, ff.AVMEDIA_TYPE_SUBTITLE, -1, -1); err == nil {
+			return r.input.Stream(stream).Id()
+		}
+	case t.Is(media.DATA):
+		if stream, _, err := ff.AVFormat_find_best_stream(r.input, ff.AVMEDIA_TYPE_DATA, -1, -1); err == nil {
+			return r.input.Stream(stream).Id()
+		}
+	}
+	return -1
+}
+
 // Return the metadata for the media stream, filtering by the specified keys
 // if there are any. Artwork is returned with the "artwork" key.
 func (r *Reader) Metadata(keys ...string) []*Metadata {

type.go

@@ -38,3 +38,11 @@ func (t Type) String() string {
 		return "UNKNOWN"
 	}
 }
+
+///////////////////////////////////////////////////////////////////////////////
+// METHODS
+
+func (t Type) Is(u Type) bool {
+	// TODO: Change later to flags
+	return t == u
+}