How to merge similar MPEG/MPEG2 files quickly and without quality loss ? I have a downloaded movie which is in 2 parts and appears as dat files (as a result of the movie being copied into a VCD format). I want to join the two files. I have been hunting for software to do this. You can do that with freeware DVTool program. Download it from here: DV-Tool v.053 DVTool takes special care of MPEG1, MPEG2, VCD (.dat), XVCD, SVCD. You have to make sure that the videos you are combining are encoded and multiplexed in the same way. You can use MPEG Properties to verify that. 1) Choose the File Processor 2.62 tab. 2) Check the Merge files radio button (in "Function" table). 3) Open the files to be merged. (Click the Add element button (I) or drag & drop files). So, choose the files you want to merge: you can change the order of the files using the two arrow buttons. 4) Choose the output file. (Click the Output file: (or mask) .. and choose the path to save the file.). 5) Just click Start and wait several minutes.  See Also:  How to repair, fix MPEG video file ?  How to play MPEG-2 video files in ANY video player ?