Adobe has publicly documented the Real-Time Messaging Protocol (RTMP) that is used by Flash for streaming video, but the company has fiercely guarded RTMP content protection measures, making it impossible to create a fully compatible open source RTMP client. SWF Verification is one such security measure.
An RTMP streaming video server that has SWF Verification enabled will terminate connections from clients that fail to supply an authorization key. The purpose of this restriction is to ensure that the content is only accessible to specific SWF files, thus preventing third-party software from downloading the video.
Although SWF Verification is principally intended to serve as a barrier to piracy, it also blocks regular users from legitimately viewing content with open source video players. Fans of the popular XBMC media center application have discovered that the application can no longer be used to watch iPlayer content. The Totem BBC plugin, which was developed by the BBC itself in collaboration with Canonical and Collabora, is also apparently blocked.
Although it's technically possible to circumvent the blocks, Adobe has previously used DMCA takedown notices to stifle open source software projects that attempt to do so. Because SWF Verification makes it impossible to view iPlayer with DMCA-compliant open source software, users will now have to rely exclusively on Adobe's proprietary Flash plugin in order to view iPlayer content.
Source: Arstechnica.com
