Quicktime won't play files bigger than 4GB.

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Level 1

4 points

Quicktime won't play files bigger than 4GB.

I have transferred GoPro JPG and MP4 files onto a SSD. I am viewing the MP4 files on Quicktime on a Macbook Air with software up to date software Sonoma 14.7.6 All are viewable except the files over 4GB. The ones that are over that size all say they are 4.79GB which I believe to understate the size of those files. The codec must be right because all of the other MP4 files from the same GoPro play on Quicktime. Is there a video player preferably free that will play MP4 files over that size? If not, how do I reduce the file size so that I can play them without losing quality. Eg can I shorten the files into shorter segments under 4GB either on the GoPro or some other way on my Macbook Air?

MacBook Air (2018 – 2020)

Posted on Jun 15, 2025 7:32 PM

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Answer 1

Urquhart1244

Level 10

145,890 points

Jun 17, 2025 8:05 AM in response to Wedgetail161

Not sure if your issue matches this, but MP4/M4V/MOV files over 4GB need to be written a bit differently (64 bits chunk offset). This might be an issue for recording devices that do not know the final size when starting recording.

You may be able to re-save the problematic files in a more compatible way. I would use Subler for that. Just Open the file, then Save As, with the wanted options checked. (The options have tooltips when the mouse pointer hovers over them.) The other functions of the app are optional, and not needed for testing suitability.

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Answer 2

Jun 15, 2025 10:43 PM in response to Wedgetail161

Wedgetail161 wrote:

All are viewable except the files over 4GB. The ones that are over that size all say they are 4.79GB which I believe to understate the size of those files.

Maybe those files were somehow truncated and corrupted when transferring? Try if re-copying them from the GoPro to the Mac's internal APFS formatted disk helps. In my setup QuickTime Player plays 8 GB movies OK.

QuickTime Player can trim and edit large movies, and there are also other apps like Avidemux for that.

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Answer 3

Jun 15, 2025 11:51 PM in response to Wedgetail161

Wedgetail161 wrote:

I had already tried one file which I downloaded to my Macbook's hard drive desktop. The same thing happens. It doesn't show the thumbnail of the picture on the file, it just shows the Quicktime logo and shows the file to be 4.79GB and it will not open. [...] I could try Avidemux for Mac OS X 2.8.1v2 Monterey Qt6 (dmg), FossHub,. Is that the right one for me?

You could try to play the movie with IINA or VLC which, unlike QuickTime Player, can play almost any old obsolete and new codec.

https://iina.io/

https://www.videolan.org/vlc/

MediaInfo or Invisor can display movie codecs and other details.

https://mediaarea.net/en/MediaInfo

https://www.invisorapp.com/

That Avidemux version is OK and it works also at least in Intel Sequoia.

http://avidemux.sourceforge.net

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Answer 4

Jun 15, 2025 9:30 PM in response to Wedgetail161

Is the SSD formatted as FAT32 which has 4 GB file size limit so maybe files larger than that are corrupted?

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Answer 5

Wedgetail161 Author

Level 1

4 points

Jun 15, 2025 11:08 PM in response to Matti Haveri

Hi Matti, thanks again for your further advice. Yes I had already tried one file which I downloaded to my Macbook's hard drive desktop. The same thing happens. It doesn't show the thumbnail of the picture on the file, it just shows the Quicktime logo and shows the file to be 4.79GB and it will not open. I did not know that I can edit anything in Quicktime. However, I presume that I need to open it first to do that. I could try Avidemux for Mac OS X 2.8.1v2 Monterey Qt6 (dmg), FossHub,. Is that the right one for me?

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Answer 6

Wedgetail161 Author

Level 1

4 points

Jun 16, 2025 6:05 PM in response to Matti Haveri

Hi Matti, thank you sincerely for your help and advice. I have transferred the file to an iPhone and then shortened the clip so that it was under 4GB. Then I transferred it to my Macbook and it worked. I could play it on Quicktime. Interestingly, it was changed to a MOV file. I'm not sure where that happened. Have a great day/night.

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