add foramt chose for subtitlse

goutubedl.go

@@ -225,15 +225,16 @@ var TypeFromString = map[string]Type{
 
 // Options for New()
 type Options struct {
-	Type                  Type
-	PlaylistStart         uint   // --playlist-start
-	PlaylistEnd           uint   // --playlist-end
-	Downloader            string // --downloader
-	DownloadThumbnail     bool
-	DownloadSubtitles     bool
-	DownloadSubtitlesLang []string
-	DownloadSections      string // --download-sections
-	Impersonate           string // --impersonate
+	Type                    Type
+	PlaylistStart           uint   // --playlist-start
+	PlaylistEnd             uint   // --playlist-end
+	Downloader              string // --downloader
+	DownloadThumbnail       bool
+	DownloadSubtitles       bool
+	DownloadSubtitlesLang   []string
+	DownloadSubtitlesFormat string
+	DownloadSections        string // --download-sections
+	Impersonate             string // --impersonate
 
 	ProxyUrl           string // --proxy URL  http://host:port or socks5://host:port
 	UseIPV4            bool   // -4 Make all connections via IPv4
@@ -491,6 +492,9 @@ func infoFromURL(
 		}
 
 		for _, caption := range info.AutomaticCaptions[lang] {
+			if caption.Ext != options.DownloadSubtitlesFormat {
+				continue
+			}
 			resp, respErr := get(caption.URL)
 			if respErr == nil {
 				buf, err := io.ReadAll(resp.Body)