Thank you for this initiative to try to create a constructive dialogue between public organizations and private companies related to webcast services.
The technical specifications and requirements on what UNFCCC wants in terms of webcast are pretty clear.
In addition to the technical requirements, what could be interesting would be to understand your communication objectives (as previously mentioned by Iwan Lawerman) and your targeted audience in order to better help you reach your goals.
Beyond technical aspects (which are key to ensure quality -- well mentioned by previous contributors to this dialogue), webcasting (both live and on-demand) is a tool to be fully integrated in your communication strategy (pre-during-post each conferences and meetings) and to be fully linked with the other communication tools (for instance social platforms as well as more conventional media/press) and the other content (text, publications, video reports), in order to reach success.
Do you have enough information about your current audience, that is your current "community"? Part of it are the 7773 twitter followers of @UNFCCCwebcast , the 117000 persons who liked the UNFCCC organization facebook page. But who is your specific targeted audience(s) for the webcasts: country representatives, local politicians, NGO, IGO, industry representatives, journalists, experts in different fields, key opinion leaders, bloggers/influencers in specific domains, any citizen of any age?
What are the needs of your most active online members/followers today with regards to webcasting? Would they like to be more engaged? What do they really want when watching the webcasts live and on-demand? By knowing those answers, we would understand how we can efficiently serve you and your community via webcasting and its related functionalities: do they want to follow the full sessions live the whole day (or night) like someone is watching a movie or her favourite sport on TV passively as observers only? or would they prefer to get a summary with pointers to specific key parts of the conferences afterwards, including recommendations from other co-delegates so as to help them drawing their own conclusions? Would they like functionalities to better access the structured content in a more visual way, searching through the transcripts and through all possible metadata including text in the slides / working documents, filtering by topic, speaker, date? Or would the remote delegates mainly prefer to be more active during (or only before?) the live sessions, being heard, asking questions, networking, making comments with full interaction with the physical participants in the room, rating, sharing ideas and experiences related to each item of the agenda of the meetings?
State-of-the-art technical webcasting aspects are fundamental and essential. We are convinced that combining them with a user/community centered approach will help you reach an efficient communication & knowledge management strategy.