Bitmovin's MP4Inspector tool now open-sourced and publicly available

One of Bitmovin’s most useful internal debugging tools, our MP4Inspector Chrome browser extension has been published with the open source MIT license and is now free and available for everyone!

There’s some more background and detail in this blog, but essentially it’s a Chrome Browser extension that supercharges the video debugging capabilities of Chrome’s built-in Developer Tools. It allows you to inspect, compare, concatenate and download mp4 segments directly from the same browser tab where the video is playing.

The project and installation instructions are on github. Give it a try and let us know what you think or if you have any feature requests in the comments. Or better yet, expand on it yourself and send us a pull request!

1 Like

Which file extensions are supported please ?
I tried with .ts HLS but icon remains gray


Hello there,

since .ts segments don’t contain MP4 boxes, you will currently not be able to inspect the content.

There was a workaround to see transmuxed data, which injected a little script to overwrite SourceBuffer.prototype.append and send the parameter to the Mp4Inspector, for inspection, but this approach has been broken by the Chrome Extension manifest update, which does not allow this anymore.

I am in the process of migrating this functionality, but it will need a little bit more refactoring before i merge it. You can check out the current state in Migrate to chrome.scripting.executeScript by bitmovin-kenny · Pull Request #3 · bitmovin/MP4Inspector · GitHub (you can also check out this branch and use the current state).

Please note that this will only be executed on localhost unless you alter the manifest.json file and add your URL to

  "host_permissions": ["*://localhost/*"],
  "externally_connectable": {
    "matches": ["*://localhost/*"]

Hello again, I am happy to inform you, that the executeScript PR got merged and you can now use the main branch to inspect the MP4 Segments which got generated from the .ts segments by the player.

The same location restrictions as mentioned above still apply.