Supply the seconds position where a thumbnail is generated (#22)

Reviewed-on: https://git.mills.io/prologic/tube/pulls/22
Co-authored-by: gabek <gabek@noreply@mills.io>
Co-committed-by: gabek <gabek@noreply@mills.io>

app/app.go

@@ -302,7 +302,7 @@ func (a *App) uploadHandler(w http.ResponseWriter, r *http.Request) {
 			"-i", uf.Name(),
 			"-y",
 			"-vf", "thumbnail",
-			"-t", "3",
+			"-t", fmt.Sprint(a.Config.Thumbnailer.PositionFromStart),
 			"-vframes", "1",
 			"-strict", "-2",
 			"-loglevel", "quiet",

app/config.go

@@ -32,7 +32,8 @@ type ServerConfig struct {
 
 // ThumbnailerConfig settings for Transcoder
 type ThumbnailerConfig struct {
-	Timeout int `json:"timeout"`
+	Timeout           int `json:"timeout"`
+	PositionFromStart int `json:"position_from_start"`
 }
 
 // Sizes a map of ffmpeg -s option to suffix. e.g: hd720 -> #720p

config.json

@@ -13,7 +13,8 @@
         "max_upload_size": 104857600
     },
     "thumbnailer": {
-        "timeout": 60
+        "timeout": 60,
+        "position_from_start": 3
     },
     "transcoder": {
         "timeout": 300,