Quicktime Player Can't Open An .mp4 File


I paid for and downloaded https://www.youtube.com/watch?v=iYZ2Ks8Jx8o, an .mp4 file, but was told that my Quicktime Player couldn't open it. I've never had this problem before, .mp4 being my usual download format, though I usually download them using DownloadHelper. But I play them back on Quicktime Player which has .mp4 at the top of its list of playable formats.

I complained to Metrodome / YouTube who promptly refunded me, but with a variety of explanations:
  • I would need to take up any download problems with the "platform" but, subsequently:
  • "YouTube paid content is for online streaming and cannot be downloaded" and that . . .
  • "paid content uses slightly different technology unlike free videos", but that . . .
  • "paid movies and TV shows can be saved for offline viewing on your Android, iOS or Chromebook device" provided there is a "Play Movies & TV App on your device". Then, finally . . .
  • "Any issues with playback should be addressed to Google". - I take it that "Google" here is the "platform" referred to in the first item above . . .
But, despite them saying it can't be done, the Metrodome site allowed me to and I did download the video, in .mp4 format.

I don't understand. I don't use any of the Android, etc, options. And I would rather have the thing on my computer than have to go online for it every time I wanted to play it.

I would be grateful to anyone who an put me straight about all this.

Doctor X

Not having had your problem let me wildly speculate for paragraphs as an excuse to avoid real, actual work. . . . :)

Get VLC: Linkypoo. That may solve all of your viewing problems and you can ignore the rest of this. And, frankly, it tends to play better than QuickTime. Safe and reliable.

If it does not it may have to do with copyright protection, and I defer to others on that note.

That being blathered, I do not download paid videos from Youtube. The few free ones I do will either be that format or flv. This is why I suspect a copyright block. However, I find the newest--now rather old--QuickTime 10.2 does not play everything well. It is "bloatware" in my opinion and you cannot edit with it--"Oh but use iMovie and Final Cut Ultra-Pro" yeah . . . yeah . . . yeah . . .

I saved and regularly used the ancient QuickTime 7.6.6 with the installed MPEG 2 codec you had to buy back in the Stone Age! which pretty much plays anything. If you have that and THAT does not play the video, I would suggest trying VLC.



Please excuse this belated response. Trying to find a download of the desired documentary - The Gatekeepers - and free if possible, blinded me to the simple solution of buying the DVD . . .

I have downloaded your recommended VLC player though; gets good recommendations from other users.



Is your MP4 protected like iTunes purchased m4v movies? I know MOV would be the best accepted video for QT. My suggestion would be transcoding MP4 to MOV and then add to Quick Time.


I stumbled on this very old (and updated) thread while searching for a solution for QT Player 7 spitting out this error:

"The movie could not be opened.
An invalid sample description was found in the movie."

The video I attempted to open is H.264 (x264) encoded with AAC audio in an mp4 container.

Yes, there are players that will do this, but I don't want to play the videos, I like that the tools in QT7 (export, etc.) are all in one package.

I guess I'm just looking for confirmation that QT Player 7 can't do anything with this video even though it has scads of codecs and components in its Library folder and there's nothing I can do to get QT 7 to play nice.