Trimming and Combining Videos with MPEG Streamclip

MPEG StreamClip is a free application for both Mac and Windows computers that makes it easy to create clips or stills from longer video files for use in your editing projects, as well as converting between formats. In this tutorial, we show you how to make smaller clips out of two different videos downloaded from YouTube (see how to do this) and then how to combine them in the application into a single video.


  • Use the i and o keys to mark the in and outpoints of your clip
  • Got to ”’Trim”’ under the ”’Edit”’ menu to reduce the file to just the portions selected, you can continue to trim more from
  •  Save the file as the original (usually MP4) format
  • Use the ”’Open Files” command to combine these trimmed clips into one final video
  • Use your command key (Mac OS) or ctrl key (Windows) to select multiple files to combine into a single video, the order of your selection should be the order in which you want them played


  1. Grace King

    November 1, 2012

    The save as problem actually happens anyways. I didn’t change the sizes of my clips and it still came up.

  2. Crystal Moyer

    November 2, 2012

    So what if the two clips are different sizes and changing the aspect ratio of both to 16:9 doesn’t fix it? :( Help please?

  3. Emma Stotz

    November 4, 2012

    I am having the same problem as Crystal. My aspect ration doesn’t change when I open the two files together to combine them. They are still different.

    • Joe

      April 15, 2014

      Hey did you ever find the answer to your question about the size difference and aspect ratio when combing clips? If you did that would be betty nice.

      • cogdog

        April 15, 2014

        Not really, but I did not look to far. Since its not really an editor, I don’t see how MPEG StreamClip could manage this. Even in an editor, you would have to resize, and if the aspect ratios were not the same, you would deal with cropping or having to letterbox.

        Use MPEG StreamClip what its good for, trimming clips. I stopped asking students to do this as an assignment

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