Maybe this is a known issue, but I searched around and didn't find a solution. The only solution I found involves VLC Player, but my issue is with Windows Explorer thumbnails, not VLC.
I'm trying to update the cover art of a MP4 video with Mp3Tag, but it doesn't work. It keeps the video original cover art, which I do not want. I'm using Media Preview for thumbnail generation with "Cover Art" option enabled. My cover arts are showing correctly for MP4 videos I converted from other formats, but I'm not being able to change arts for videos I already downloaded as MP4. I could reconvert them, but that is too much trouble.
Anyone knows what may be happening?
Oh, I'm in Windows 7 and usually use Media Player Classic for reproducing the videos.
Thank you all!
EDIT: I should have written "some MP4 files" in title, because I can change cover art for some original MP4 files as well, but for some others I can't.