When I joined the telephony industry, the company I was at (Dialogic) specialized in media processing. Media processing for telephony in those days meant functionality like voice mail, conferencing, fax, and DTMF tones. Even though video was possible at this time over traditional telephony networks, it never really caught on. One problem was the not-quite-real-time video and its jittery, jerky motion. Another huge go-to-market issue was that there werent many phones able to use this capability, even if it had worked to perfection. So video never really entered the telephony mainstream.
Fast forward a few years to the mid-to-late 1990s as the nascent IP telephony industry was just starting. The protocol of choice at that time was H.323, the protocol used for video conferencing. The IP telephony industry used an existing spec and took only the part of the protocol that was useful for voice. But I, like others, took note of the video part of the spec and wondered if and when video would be combined with traditional telephony media so that the definition of telephony media by default would include video, as it includes voice and fax today.
Fast forward to today. Im not sure the definition of telephony media will ever include video by default because we now use the term multimedia to denote video. The marriage of traditional telephony with data and the coming-of-age of convergence has thrust video to the forefront, probably justifying this new term. Multimedia is alive and well thanks to the use of 2.5G and 3G cellular networks.
The basic use case for video revolves around the cell phone and the presence of cameras on cell phones. I, for one, initially didnt see the point of viewing a picture on a tiny one-inch-by-one-inch screen. I mean, what could you actually see? I guess if you put it really, really close to your eye and squinted at it, it would look like a huge flatscreen. But I never really got it. At any rate, when I needed to upgrade my cell phone to GSM so I could use it overseas when I travel, I got a camera phone since it wasnt that much more expensive.
Guess what? Yep, I use it. And when people send me pictures, I can actually see them. But better yet, when I send pictures I take with the camera phone via email, they come out pretty good. So we have multimedia communications using the cell network and the data communications network.
This use case is similar to a voice mail application. But instead of voice mail, you have video mail via video play/ record. I can also envision the color ring back tones (CRBT) that are so popular today overseas, and are just beginning to enter the US market, morphing into your favorite video playing while the phone is ringing (instead of your favorite song as in CRBT). I can also envision a video portal where you call in to choose content by browsing a menu. So instead of simply reading or hearing the latest score for the New York Mets game, you can actually see the game-winning hit by Mike Piazza.
From a network architecture perspective, two new elements need to be added: the video messaging server and the multimedia gateway. If the video message is staying within the cellular network because you are just sending a video to your friends cell phone, the gateway wouldnt necessarily be required and you would only need the video messaging server. This would be similar to the network voice mail system that you currently use when you access your cells voice mail. If someone left you a video message while your phone was off, you could access the video message when it was convenient for you.
From a technology standpoint, if you could treat video as another type of communications data, you wouldnt need to add a unique video messaging server, but could instead add the video capability to the existing unified messaging server. In fact, as Intel develops building block ingredients at the board level and host media processing at the software level for these messaging platforms, that is the approach we are taking.
A multimedia gateway would be required to deal with different types of endpoints that would connect to the mobile network: laptops, PDAs, IP phones, or even standard PSTN phones. The gateway would take the video format of the cell network (3G-324M) and convert it to voice with video coders that the IP and PSTN network could then use. For instance, in the case where the video message is coming to a phone on the PSTN network that doesnt have video capability, the video part needs to be stripped out and the voice converted to the standard 64 kbps. In the case where the video message is coming to a client on an IP network (such as your laptop or IP phone), the voice would need to be converted to G.711 (or possibly a compressed voice format such as G.723.1) and the video may need to be converted to a client-based video format such as RealVideo or Microsoft Windows Media if it doesnt support the type used in the cellular network.
Some IP clients might require additional multimedia gateway functionality. For instance, some IP clients would be more capable technology-wise of handling a video message i.e., a fully equipped laptop can handle more than a PDA. As such, the multimedia gateway would also be required to translate and resize the information, depending on the client. Also, since there are different types of video storage standards in the data world (different MPEG versions, for instance, AVI, RealVideo), the multimedia gateway would also need to be capable of transcoding the formats.
IPTV is another use case for video and IP. This is a very hot topic these days, with analyst reports showing huge growth potential, and it is very different from the types of use cases I described above. IPTV is using the IP network to watch real-time video. In your home, either the PC or your TV (through a set top box) would be the viewing client, or when you are mobile, your mobile client (laptop, PDA, etc.) would be the viewing client.
You might be saying to yourself, I have cable and thats real-time video, why do I need to watch real-time video over IP? Thats a good question. Think about the parts of the world that dont have well-developed cable networks. Or you might be traveling and want to watch your favorite game. Or you might even think that 157 channels arent enough, and you want to access more. I dont doubt there is a market here.
While there are interesting business go-to-market issues with IPTV and who the winners will be, the technical challenges relate to Quality of Service (QoS). While there are QoS challenges with VoIP, they pale in comparison to real-time video over IP. The bandwidth requirements are orders of magnitude more than VoIP and the packet-loss requirements are orders of magnitude less. This is one tough application to get right. I am not smart enough to know how the QoS issues will be resolved, but I have confidence they will be (as they were resolved for VoIP). I do believe though that this application will likely force more standards-based QoS discussions, and will likely force some kind of packet inspection at the edge network.
I started this column by talking about video phones and how they didnt succeed in the mid 1990s, even though video was possible over traditional phone networks. Because of the 2.5G and 3G networks capability to handle video and the fact that cameras are now a normal part of a cell phone, video has entered the mainstream of telephony. The inexorable march towards convergence continues and we now are on the threshold of IPTV, something I only vaguely imagined 10 years ago. There is money to be made here as video use cases continue to develop. Keep reading Internet Telephony to keep up-to-date with the latest developments. IT
Jim Machi is senior director, Modular Communication Product Platform Division, Intel. For more information, please visit www.intel.com.