Mara provides two methods of placing video into your pages, either by drag and drop, or by using a CKEditor plugin.
Files in .webm format can be added to pages in much the same way as static image files, by dragging and dropping from Explorer. Added this way, they will become streaming content which the visitor can click to start. Currently this is the only format supported by this approach; however it is the generally most useful, and should work in nearly all modern browsers without the need for any special plugins. In due course we may add .mp4 to the supported file types. When we get a round tuit, that is.
.webm and .mp4 are generally the most useful formats for modern video streaming. The older flv, avi or quicktime formats are not supported by Mara, and you would be better to convert any of these you have to a newer format anyway. You can embed m4a or mp3 sound only files, and these will appear in the page as a player.
It's important to note that using a local, high definition video file will commit you to a large and time consuming upload. Possibly anything up to a gigabyte or two. Therefore don't try this on a slow or expensive Internet connection! The upload will be queued in the same way as with dropped image files. Likewise you can remove it from the queue by deleting the placeholder. Sound files are much smaller and should upload quite quickly.
You can in fact drag and drop other types of video file into your page; in that case they will become links in the page which the visitor can download. They won't stream, though. For that, use the .webm format.
It is also possible to drag and drop links to YouTube videos this way. Open YouTube in a second browser window (You need to be able to see this at the same time as your webpage) then search for the content you want. Drag the text link beside or under a thumbnail into your page. (Note that dragging the thumbnail image will not work)
Since YouTube embeds are only links to the YouTube page bearing the video, they do not involve any uploading. (You will notice that they never have a hatched green border) and hence they are generally the easier option to take than embedding a local file. Of course, your video has to be on YouTube before you can do this.
This allows streaming video to be embedded from a number of sources. Simply get the URL from the browser's status bar whilst on the page in question. Press Control C to copy it, Control-V to paste it into the dialog.
It's probably best to use Center alignment. Avoid the None option.
The plugin only works with content which is already on the Web, you cannot upload local files with it. For that, use drag and drop.
As a final note, please be aware of the copyright implications of offering downloads from your site. If the material is pirated, you may be acting in breach of your hosting provider's terms and conditions. YouTube embeds are generally less of a problem in that respect, since in that case the file is not physically on your webspace.