User Agent: Mozilla/5.0 (Windows NT 6.3; Win64; x64; rv:106.0) Gecko/20100101 Firefox/106.0

Steps to reproduce:

navigate to URL containing MP4 video, such as: http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ForBiggerFun.mp4

Actual results:

error message displayed: "Video can't be played because the file is corrupt."

console shows message: "Media resource http://commondatastorage.googleapis.com/gtv-videos-bucket/sample/ForBiggerFun.mp4 could not be decoded, error: Error Code: NS_ERROR_DOM_MEDIA_FATAL_ERR (0x806e0005)
Details: Error no decoder found for audio/mp4a-latm"

Expected results:

video should have played.

more information: https://support.mozilla.org/en-US/questions/1392159

The severity field is not set for this bug.
:jimm, could you have a look please?

For more information, please visit auto_nag documentation.

The severity field is not set for this bug.
:jimm, could you have a look please?

For more information, please visit auto_nag documentation.

Reporter, would you mind giving us the "raw data" from about:support? This includes codec support information, so we can check if something looks off there.

It plays fine (including sound) on my machine that has the following:

Edition Windows 11 Home
Version 22H2
Installed on ‎6/‎27/‎2022
OS build 22622.586
Experience Windows Feature Experience Pack 1000.22634.1000.0

Additionally, the reporter notes the following on support.m.o:

issue exists in 105.0
video plays in 104.0.2, but not audio

Reporter, can you use https://mozilla.github.io/mozregression/ to find what made the video stop playing? Maybe it will help finding what's going on, since we can't reproduce at all.

Plays for me as well on Windows 11.

comparing the problematic installation to a different computer's working installation, i notice codec "AAC SW" is missing from the problematic installation. perhaps the video playback error is caused only by that missing audio codec.

apparently windows 8.1 was given support for AAC by KB3000850. this update was already installed, but i re-installed it anyway. unfortunately that did not change the behavior.

Reporter, can you use https://mozilla.github.io/mozregression/ to find what made the video stop playing?

will do tomorrow.

We can't decode AAC without OS support, because it's a patented format, and we can't ship a fallback ourselves. Indeed, the about:support information shows that this machine is lacking an AAC decoder.

At the very least, we need to change the error message here to make it extra clear that this is fixable. With KB3000850 installed, and after rebooting, do you see AAC SW available? Without it, we can't do much, really.

Reporter, can you use https://mozilla.github.io/mozregression/ to find what made the video stop playing?

i tried to use this tool but was not able to due to the above error when it launches.

We can't decode AAC without OS support, because it's a patented format, and we can't ship a fallback ourselves. Indeed, the about:support information shows that this machine is lacking an AAC decoder.

windows media player is able to play this file with audio. i think that means windows has an AAC decoder.

attached is a file ("wmpsupport.htm") generated by windows media player (help > about windows media player > technical support information). in that file "MSAudDecMFT.dll" is listed. i think that DLL is listed here as microsoft's AAC decoder for windows 8.

With KB3000850 installed, and after rebooting, do you see AAC SW available?

no, re-installing that update did not change anything.

Does this bug only happen on Windows 8.1? Firefox versions >= 116 no longer support Windows versions < 10. Should we resolve this bug as WONTFIX? If do we fix this bug, the fix would need to be backported to Firefox ESR 115.

I don't anticipate that we can fix this, a required software that we can't ship (because of patents) is missing from the OS. Let's close a WONTFIX.