If you have any video clips that you want to join together into a large video file, then you can either use command line tools like FFmpeg or you can get a GUI tool like Video Combiner. It is a useful tool for merging videos together. You can take video files from multiple video formats and join them together in the same order as you have selected them using this software. You can also choose the bitrate and the screen size of the resulting output video.
Video Combiner has a very nice and easy-to-use user interface. You can start by dragging and dropping video files on its window to add them to the source videos list. You have to be careful in adding the videos because the videos are joined in the same order in which you add them to the list. If you add them in the wrong order, then you can use the up and down button in the toolbar to rearrange the order of the source videos. You can add videos of file types MP4, AVI, MOV, MPG, FLV, MKV, WMV, MPEG, M4V, and 3GP.
From the options, you can choose the output file types for the resulting video file. You can choose the output video resolution manually or you can set it to choose the maximum resolution automatically for the selected videos. For joining the videos, it can use the maximum CPU acceleration but this option is available only on 64 bit machines. There seems to be no option to leverage the power the graphics card.
After you click on the Combine Videos Now! button, it goes to work right away. It joins all the files after analyzing them and setting a good resolution for the output file. The program is not faster than FFmpeg but is much easier to use.
You can download Video Combiner from https://www.mp3toolkit.com/videocombiner.html.