Microsoft has directly accused Google of sabotaging the YouTube app on the Windows Phone platform with "impossible roadblocks", accusing the web company - which owns the video streaming network - of demanding unnecessary development restrictions and blocking customer access to the app.
"You may be wondering what happened to the YouTube app for Windows Phone," wrote Microsoft corporate VP and deputy general counsel of litigation and antitrust, David Howard, on the company's TechNet blog.
"Last May, after we launched a much improved app on our platform, Google objected on a number of grounds. We took our app down and agreed to work with Google to solve their issues. This week, after we addressed each of Google's points, we re-launched the app, only to have Google technically block it.
Howard describes a "sticking point" in the original collaboration between the companies to build the YouTube app for Windows Phone, which was Google's insistence that Microsoft use HTML5 as the coding language.
"This was an odd request since neither YouTube's iPhone app nor its Android app are built on HTML5," wrote Howard.
"Nevertheless, we dedicated significant engineering resources to examine the possibility."
Howard suggests that the difficulty Microsoft engineers found in building YouTube in HTML5 is "why we assume YouTube has not yet made the conversaion of its iPhone and Android apps".
After taking the app down last May on Google's insistence, Microsoft relaunched the app as a non-HTML5 version this week only, said Howard, to have Google "technically block it" with immediacy.
While Google has told Microsoft that a significant reason for the block is that the new app "doesn't always serve ads based on conditions imposed by content creators", Microsoft maintains it is using "all the metadata available to us", and that Google has "refused" to provide the kind of data Android and iPhone versions of the apps get to properly display advertising.
Therefore, wrote Howard, it seems to Microsoft "that Google's reasons for blocking our app are manufactured so that we can't give our users the same experience Android and iPhone users are getting. The roadblocks Google has set up are impossible to overcome, and they know it."
Howard maintains that, "Nonetheless, we are committed to giving our users the experience they deserve, and are happy to work with Google to solve any legitimate concerns they may have."
In the meantime, he asks, "we once again request that Google stop blocking our YouTube app."