Revamp the transcoding decision tree

server/ctrlsubsonic/handlers_raw.go

@@ -168,6 +168,7 @@ func (c *Controller) ServeStream(w http.ResponseWriter, r *http.Request) *spec.R
 	}
 	encodeOptions := encode.Options{
 		TrackPath:        trackPath,
+		TrackBitrate:     track.Bitrate,
 		CachePath:        c.CachePath,
 		ProfileName:      pref.Profile,
 		PreferredBitrate: params.GetOrInt("maxBitRate", 0),

server/encode/encode.go

@@ -146,14 +146,6 @@ func cacheKey(sourcePath string, profileName string, profile Profile) string {
 	)
 }
 
-// getBitrate checks if the client forces bitrate lower than set in profile
-func getBitrate(preferred, defined int) int {
-	if preferred != 0 && preferred < defined {
-		return preferred
-	}
-	return defined
-}
-
 type (
 	OnInvalidProfileFunc func() error
 	OnCacheHitFunc       func(Profile, string) error
@@ -162,6 +154,7 @@ type (
 
 type Options struct {
 	TrackPath        string
+	TrackBitrate     int
 	CachePath        string
 	ProfileName      string
 	PreferredBitrate int
@@ -175,7 +168,20 @@ func Encode(opts Options) error {
 	if !ok {
 		return opts.OnInvalidProfile()
 	}
-	profile.Bitrate = getBitrate(opts.PreferredBitrate, profile.Bitrate)
+	log.Printf("client requests %dk, transcoding profile %dk, track bitrate %dk \n", opts.PreferredBitrate, profile.Bitrate, opts.TrackBitrate)
+        if opts.PreferredBitrate != 0 && opts.PreferredBitrate >= opts.TrackBitrate {
+                log.Printf("Not transcoding, requested bitrate larger or equal to track bitrate \n")
+                return opts.OnInvalidProfile()
+        } else if opts.PreferredBitrate != 0 && opts.PreferredBitrate < opts.TrackBitrate {
+                profile.Bitrate = opts.PreferredBitrate
+                log.Printf("Transcoding according to client request of %dk \n", profile.Bitrate)
+        } else if opts.PreferredBitrate == 0 && profile.Bitrate >= opts.TrackBitrate {
+                log.Printf("Not transcoding, transcoding profile bitrate larger or equal to track bitrate \n")
+                return opts.OnInvalidProfile()
+        } else {
+                log.Printf("Transcoding according to transcoding profile of %dk \n", profile.Bitrate)
+        }
+
 	cacheKey := cacheKey(opts.TrackPath, opts.ProfileName, profile)
 	cachePath := path.Join(opts.CachePath, cacheKey)
 	if fileExists(cachePath) {