The software did not receive a valid video file path — i.e. the input box on row 1 is empty or the path was rejected during parsing, so the task cannot start.
Steps:
Click the Select Video/Audio button in the top-left corner again and pick the file; confirm the full file name then appears in the input box before clicking Start Execution.
Check the file itself: rename it to a short name with only English letters/digits (e.g. video1.mp4) and move it to a shallow directory (e.g. D:\). Long names, Chinese characters, spaces and emoji (🔥👍 etc.) frequently cause the path to fail to parse and produce this error.
Check the software location: the current root_dir is C:/Users/User/Downloads/.... Move the whole extracted folder to a shallow path such as D:\pyVideoTrans. Also make sure you have fully extracted the archive with extraction software and are not double-clicking sp.exe from inside the archive.
If the file name does show in the input box but the error persists, provide the last 30 lines of the error in the latest log file under the software's logs/ folder for analysis.
Open source and free maintenance is not easy. If this project is helpful to you, please consider making a small donation to help the project continue to maintain and update.