Convert TMP to MP4

In general, files with a .tmp extension are temporary files that are created by software when a permanent file has not yet been created or is in the process of being built. Often, these files are used by the operating system or applications as backups or caches and are not intended for manual access or manipulation.

A .mp4 file extension indicates a multimedia file containing video, audio, and subtitles. The MP4 format is one of the most widely used video file formats. It is compatible with a variety of media players and devices.

To convert TMP file to MP4 file, you may rename the file extension to .mp4 and see if it plays in a media player. The temporary .tmp file must, however, be a complete and functional video file that simply has the wrong file extension. Try to open the file with a media player like VLC Media Player and try to play it. Even if you are not sure whether the video is complete or not, you can try playing the .tmp file with the VLC Media Player that is capable of playing incomplete or partially damaged files.

Renaming the .tmp file to the .mp4 file will only work if the original content of the .tmp file was in fact MP4 video. It is possible that the .tmp file contains no video data at all or was created for a different purpose and, therefore, cannot be converted to a video file.

Simply put, it is impossible to convert TMP to MP4 directly.
Thus, there is no so-called tmp to mp4 converter or a free online tmp to mp4 converter to be found.