To use Format Factory to preview video clips, you need to start Format Factory, select "Video" in the task category on the left, and then select a target format, such as MP4, which can be modified in "Output Configuration" Various parameters of the target format, such as screen size (resolution), video bit rate, etc., because the main purpose is video editing, so the parameters set here should be as close as possible to the original video.

Select "Add File", browse to the original video file, and add it. Double-click the file name to enter the preview window, where you can drag the progress bar, select the start time and end time, or manually enter the time period. If the original video contains multiple audio tracks and subtitles, you can select the audio track here for the audio stream and select the subtitles for the subtitle language here.

After the time period is selected and the preview is normal, click the "OK" button to return to the main window and click "Start" to convert the video. After the conversion is completed, you can find the clip in the output folder the final video file.