Of course, if you encounter the "No valid source or titles found" prompt when importing the VIDEO_TS folder, this means that the VIDEO_TS file may contain copy protection encryption. Handbrake is unable to load and convert any encrypted files.
In this case, HandBrake alternative is the best solution. WonderFox DVD Ripper Pro is such a handy and powerful VIDEO_TS player and converter which enables you to convert DVD folder to a wide range of video audio formats such as VIDEO_TS to MKV, VIDEO_TS to AVI and portable devices for convenient playback. Free downloadFree download WonderFox DVD Ripper Pro to start to convert copy-protected VIDEO_TS files.