ffmpeg -i videoplayback.mp4 -i videoplayback.m4a -c:v copy -c:a copy output.mp4 .
Based on the search results, is not a single specific file, but rather a generic, default filename used frequently by web browsers and downloaders when saving video streams, particularly from YouTube, via tools like Pytube or browser extensions. 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: ffmpeg -i videoplayback
If you have a videoplayback.mp4 file that won't play or lacks audio, it is likely because it is a "fragmented" or partial download. If you are having trouble with a specific videoplayback
If you are having trouble with a specific videoplayback.mp4 file, let me know: What size is the file? Are you trying to open it or edit it? I can provide the specific commands or steps to fix it.
The easiest solution is to try downloading the video again, ensuring the downloader (e.g., YouTube video downloader extension) completes the process, which often automatically merges the audio and video.
To avoid having multiple videoplayback.mp4 files, it is highly recommended to rename them immediately upon downloading.