Those workout videos use the built-in HTML5 player. On a very high speed connection, they seem to work fine (the two unlocked ones on that page).

Can you tell whether your Firefox using the HTML5 player? The easiest way to check is to right-click the video and if Firefox is using a plugin, there will be a special menu indicating the name of the plugin. If you don't get that, then Firefox is using the built-in HTML5 player.

Can you tell whether Firefox is retrieving MP4 video? This usually gives the most attractive results, but some users might have disabled it in order to facilitate downloading MP3/MP4 media, or it might be disabled because they have a version of Windows that does not include Media Foundation, which Firefox needs to decode MP4 video. (Regarding the media feature pack, see: Download Media Format Feature Pack for Windows 7 N with Service Pack 1 and Windows 7 KN with Service Pack 1 (KB968211) from Official Microsoft Download Center)

In checking out several workouts, I noticed in one case that Firefox had to keep grabbing the MP4 stream (screen shot). I didn't notice any buffering or drop-outs, so this might not explain the problem you're seeing.

I tried that website - it offers two links - i tried downloading but it says this update does not apply to my computer so I can't even download it. when i right click the videos i don't' get any option

Can anyone help provide any support for this issue?

Hi anunes004, I was traveling for a while, so apologies for the delayed response.

When you right-click the video, you don't get any kind of context menu at all? Is that true on the problem Tumblr videos, too, or can you get a menu there?

on the cody website no.. no options at all, on Tumblr where it also stalls i see Share this page, Save Page as.. etc basically like right clicking anywhere on the screen of any page - those list of options come up.

Hi anunes004, on Tumblr you're definitely getting the built-in HTML5 player based on that menu.

If you open up the web console (Ctrl+Shift+k) then click the Network tab and then reload the Tumblr page, can you see what kind of media is being served? The most common for HTML5 are .webm and .mp4, but others are also possible. (Previously I was guessing it's an MPEG problem, but it would be useful to confirm that.)

Hi - please see the image below

Does anything show if you click Media at the bottom of this window (currently All is selected)?

i checked that first.. no nothing shows up there... mind you i don't have videos set to play

This is what comes up when the video is playing

For MP4, Firefox is going to need to use Media Foundation to decode and play the video in the native player.

That said, it might not be a Media Foundation problem but something that is causing Firefox to get only small chunks of video at a time (only the last entry in your screen shot is big enough to comprise a significant amount of video).

so.. technical talk aside... what's the solution.. i mean i can't be the only one having this issue right? there must be a fix for this

You could check the response to see if you get an error message and not the binary content of the media file.