We are interested only in appropriate formats for video streaming, and only they will be considered. First of all this is, of course, RTMP protocol, which specification is available here: http://www.adobe.com/devnet/rtmp.html. Further come Microsoft Smooth Streaming and Adobe HTTP Dynamic Streaming. Let’s consider them in order. It should be noted that previously I have never dealt with flash, there was no experience in this field at all, and all my knowledge was confined to the fact that there is such a thing - Flash player, in particular, used on youtube. So, any technology, which I will choose, I will have to examine from scratch.

RTMP. In the first place I started with this protocol. Indeed, it exists many years, and has open source realizations. But it turned out that documentation, which is provided by Adobe, leaves much to be desired: maximum - you can get general information about the protocol from it, but for his own realization this is not enough. In the worldwide web one can find articles on reverse engineering of this protocol, even I tried to examine them, but there was no dice anyway. Of course, I could try one more time to examine source codes of protocol realizations, which exist, but it would require considerable time and effort. Also it was clear - there are trends that this protocol will lose its dominance sooner or later, making way for protocols, based on HTTP streaming. I.e. if I had to spend a lot of time to understand and develop my own RTMP server, most probably, I couldn’t use my knowledge on this field anywhere else. In future it turned out, I was a bit wrong - read the note Adobe HTTP Dynamic Streaming.

Microsoft Smooth Streaming. This format is based on so-called fragmented mp4 files. Initially, the technology was meant to use in Silverlight players, but in descriptions of a number of Flash players I have noted information that this format is supported as well. But, as in the case with RTMP, there was no accurate standard, on which basis I could make realization of this protocol. Plus I have not found official Adobe confirmation that they support Microsoft Smooth Streaming. The result - this format is not appropriate as well. The last is remained - Adobe HTTP Dynamic Streaming.

Adobe HTTP Dynamic Streaming. Relatively new format, it is also based on fragmented mp4 files. An additional plus is the fact, that this format is very close to recently adopted standard of Mpeg Dash streaming, which support is also expected in flash. There is a specification from Adobe, although it was written in such way that it is possible to get only general information about the protocol, which is absolutely not enough for its own realization. But, as with the rest of the protocols situation was the same, we choose Adobe HTTP Dynamic Streaming. You can read more about technology nuances in the note Adobe HTTP Dynamic Streaming.

Igor, October 2012.