To edit an instant video and convert from MP4 to Matroska file in Corel VideoStudio Pro X5, follow these steps:
1. Import the MP4 video into the software.
2. Drag and drop the video onto the timeline.
3. Click on the Export button.
4. Choose "Matroska" as the output file format.
5. Adjust the export settings as desired.
6. Click on the "Start Export" button to export the video as a Matroska file.
