A free tool that shows you exactly what codec and bitrate the file uses. If it shows "No video stream," the file is empty.

Software like Untrunc or Shoviv can sometimes rebuild headers if you have a working 4K file from the same camera to use as a reference. 3. Hardware Limitations (4K Playback)

4K video requires significant processing power and specific hardware decoding.

Ensure your graphics drivers are updated. 4K stuttering is often a sign that your CPU is struggling to do all the work. 4. Incomplete Downloads or Transfers If this file was downloaded or moved from an SD card:

Right-click the file and change the name to something simple (e.g., test.mp4 ).