YouTube video downloading (using Pytube, youtube-dl) often separates video and audio streams, producing a .mp4 (video) and a .m4a or .webm (audio) file, which both might be named videoplayback .
If you have separate video ( .mp4 ) and audio ( .m4a ) files, you can merge them using FFmpeg in the command line: videoplaybackjn.mp4
If you are working on a project (like the OpenCV face recognition mentioned in the results), you would load it in Python like this: YouTube video downloading (using Pytube
To avoid having multiple videoplayback.mp4 files, it is highly recommended to rename them immediately upon downloading. videoplaybackjn.mp4