优化 #202

src/N_m3u8DL-RE/Util/MergeUtil.cs

@@ -196,7 +196,7 @@ namespace N_m3u8DL_RE.Util
             if (mp4)
                 command.Append($" -strict unofficial -c:a copy -c:v copy -c:s mov_text "); //mp4不支持vtt/srt字幕，必须转换格式
             else
-                command.Append($" -strict unofficial -c copy -c:s {(srt ? "srt" : "webvtt")} ");
+                command.Append($" -strict unofficial -c:a copy -c:v copy -c:s {(srt ? "srt" : "webvtt")} ");
 
             //CLEAN
             command.Append(" -map_metadata -1 ");