We're calling on all EU-based Mozillians with iOS or iPadOS devices to help us monitor Apple’s new browser choice screens. Join the effort to hold Big Tech to account!

Avatar for Username

Search Support

Avoid support scams. We will never ask you to call or text a phone number or share personal information. Please report suspicious activity using the “Report Abuse” option.

Learn More

This thread was archived. Please ask a new question if you need help.

Playing online mp4 in Firefox no longer possible?

CarlosMdq
CarlosMdq
more options

I have a number of mp4 videos stored in an online platform. After uploading a video, I used to be able to check that the video played correctly, by entering the URL on firefox, thus loading and playing the video inside the FF tab. Now, upon entering the URL, a pop up window opens up, offering to download the video to my hard drive. I can no longer play the online mp4 video. I messed a bit with the About:config commands but wasn't able to find a solution.

I have a number of mp4 videos stored in an online platform. After uploading a video, I used to be able to check that the video played correctly, by entering the URL on firefox, thus loading and playing the video inside the FF tab. Now, upon entering the URL, a pop up window opens up, offering to download the video to my hard drive. I can no longer play the online mp4 video. I messed a bit with the About:config commands but wasn't able to find a solution.

All Replies (3)

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 10 Contributor
more options

Could you check something: in the tab where you want to play the video, first open Firefox's Network Monitor, one of the Developer tools, in the lower part of the tab. You can do that using either:

  • menu > Developer > Network Monitor
  • Ctrl+Shift+k then click "Network" along the top edge of the web console

Now try loading the video in the upper part of the tab. Cancel the download.

The Network Monitor should show the request. If you click it, usually Firefox will show "Headers" and among these should be the Content-type. Does it show video/mp4 or some other content type? If it's not video/mp4, Firefox might not think it can play it.

The headers might also include Content-disposition. If that is there, does it say inline or attachment? (Attachment forces a download, inline should play in the tab.)

CarlosMdq
CarlosMdq Question owner
more options

Thanks jscher2000. I checked your suggestion. The Content-type shows 'application/octet-stream'. I should add that I'm using a private platform by Amazon to upload the videos.

I have solved half the problem by changing the value of media.play-stand-alone to true. However, I'm uploading two kinds of mp4 videos. Upon checking both on the freeware software 'MediaInfo', I can say that the ones identified as M4V (Codec ID) are now playing in FF, while the ones identified as isom still try to download.

Maybe is a matter of keep changing values in the About:config tab, but I don't know what else to change yet.

jscher2000 - Support Volunteer
jscher2000 - Support Volunteer
  • Top 10 Contributor
more options

CarlosMdq said

The Content-type shows 'application/octet-stream'.

Can you modify the server settings to send video/mp4 ?