diff --git a/config.toml.example b/config.toml.example
index 9e3ac6e..98cea59 100644
--- a/config.toml.example
+++ b/config.toml.example
@@ -50,8 +50,8 @@ vimeo = [ # Multiple keys will be rotated.
   # How often query for updates, examples: "60m", "4h", "2h45m"
   update_period = "12h"
 
-  quality = "high" # or "low"
-  format = "video" # or: "audio", "custom"
+  quality = "high" # "high" or "low"
+  format = "video" # "audio", "video" or "custom"
   # When format = "custom"
   # YouTubeDL format parameter and result file extension
   custom_format = { youtube_dl_format = "bestaudio[ext=m4a]", extension = "m4a" }
diff --git a/pkg/feed/xml.go b/pkg/feed/xml.go
index 0d96e8a..3b11868 100644
--- a/pkg/feed/xml.go
+++ b/pkg/feed/xml.go
@@ -133,6 +133,10 @@ func Build(_ctx context.Context, feed *model.Feed, cfg *Config, hostname string)
 		if feed.Format == model.FormatAudio {
 			enclosureType = itunes.MP3
 		}
+		if feed.Format == model.FormatCustom {
+			enclosureType = EnclosureFromExtension(cfg)
+		}
+
 
 		var (
 			episodeName = EpisodeName(cfg, episode)
@@ -164,9 +168,32 @@ func EpisodeName(feedConfig *Config, episode *model.Episode) string {
 	ext := "mp4"
 	if feedConfig.Format == model.FormatAudio {
 		ext = "mp3"
-	} else if feedConfig.Format == model.FormatCustom {
+	}
+	if feedConfig.Format == model.FormatCustom {
 		ext = feedConfig.CustomFormat.Extension
 	}
 
 	return fmt.Sprintf("%s.%s", episode.ID, ext)
 }
+
+func EnclosureFromExtension(feedConfig *Config) itunes.EnclosureType {
+	ext := feedConfig.CustomFormat.Extension
+	// Use switch on the day variable.
+	switch {
+	case ext == "m4a":
+		return itunes.M4A
+	case ext == "m4v":
+		return itunes.M4V
+	case ext == "mp4":
+		return itunes.MP4
+	case ext == "mp3":
+		return itunes.MP3
+	case ext == "mov":
+		return itunes.MOV
+	case ext == "pdf":
+		return itunes.PDF
+	case ext == "epub":
+		return itunes.EPUB
+	}
+	return -1
+}
diff --git a/pkg/model/feed.go b/pkg/model/feed.go
index fb6cc40..ac68af3 100644
--- a/pkg/model/feed.go
+++ b/pkg/model/feed.go
@@ -21,6 +21,21 @@ const (
 	FormatCustom = Format("custom")
 )
 
+// Format to convert episode when downloading episodes
+type Enclosure struct {
+	// ID of episode
+	ID          string        `json:"id"`
+	Title       string        `json:"title"`
+	Description string        `json:"description"`
+	Thumbnail   string        `json:"thumbnail"`
+	Duration    int64         `json:"duration"`
+	VideoURL    string        `json:"video_url"`
+	PubDate     time.Time     `json:"pub_date"`
+	Size        int64         `json:"size"`
+	Order       string        `json:"order"`
+	Status      EpisodeStatus `json:"status"` // Disk status
+}
+
 // Playlist sorting style
 type Sorting string
 
diff --git a/pkg/ytdl/ytdl.go b/pkg/ytdl/ytdl.go
index 7dfc178..1d33a92 100644
--- a/pkg/ytdl/ytdl.go
+++ b/pkg/ytdl/ytdl.go
@@ -197,7 +197,8 @@ func (dl *YoutubeDl) Download(ctx context.Context, feedConfig *feed.Config, epis
 	ext := "mp4"
 	if feedConfig.Format == model.FormatAudio {
 		ext = "mp3"
-	} else if feedConfig.Format == model.FormatCustom {
+	}
+	if feedConfig.Format == model.FormatCustom {
 		ext = feedConfig.CustomFormat.Extension
 	}