Adding Video to Blogger.com (Blogspot)
First of all, go to the setup tool and get the player ready. I found that the player fits best when resized to around 400x225, but you may like to try a few different sizes depending on your blog theme.
Copy the generated code and paste it into your "New Post" form — making sure you paste it into the HTML view, not the standard view.
Now here's the important part: If you post the code as is, blogger.com will automatically add unwanted tags to the code and stop it working (<br> tags to be exact). You need to remove all the line breaks so the code is effectively one long line. It should look something like this:
You may need to post the blog before you see the video appear — I found that the preview is unreliable. If the video hasn't worked, check to make sure there are no line breaks in the code. You could try copying the code into Wordpad first so it's easier to see.
An alternative method is to change your settings so the line breaks aren't converted to tags. This is what I do and it works well, but it does mean that all formatting must now be done manually with HTML. For example, you need to add <p> tags for paragraphs. If you like full control this is the best option but if you don't fancy having to constantly enter HTML tags you probably won't like it.
If you still can't get it going try asking for help in the support forum.