Hi Toty,
Can you please clarify what you mean? Are you having issues uploading video files into AtoM? Or are you having issues playing video files that have been uploaded? Additionally, it would help us provide better suggestions if you can tell us more about your installation. See for example the questions listed here:
If your issue is with uploading video:
AtoM's digital object upload via the user interface is currently done on demand via the web browser. Most web browsers have a built-in time out limit of about 1 minute, to prevent long running tasks from consuming all available resources. For this reason, it can be difficult to upload large files such as videos via the user interface. You may want to consider using the CSV import's digital object columns, or the command-line digital object load task instead. See:
If your issue is with playing uploaded or linked video:
In the current version of AtoM, we are still using a Flash-based video player. In most web browsers, Flash is now disabled by default for security purposes. You may need to enable Flash first in your browser to be able to play uploaded videos. A simple web search should return basic instructions on how to enable Flash in the browser you prefer to use. Remember that you will likely need to reload the page after enabling Flash to see AtoM's video player display.
In the next (2.6) major release, we will be upgrading AtoM's media player to something HTML5 based, so this will no longer be an issue.
Cheers,