Posts tagged "WebTV"

The Wireless Multicast TV event has been a success, everything worked correctly (even exceeding our initial expectations in fact). We used the following setup during the presentation:

Our objective was to get real time Web TV contents from the Internet and stream them locally to a certain number of clients using multicast over a wireless network. The incoming media resources from the Internet were handled by our proxy server (the box I worked on prevalently), re-encoded and then streamed to multicast addresses. The inner network was a wireless link, composed by one antenna linked to 10 CPEs. Each CPE was then cabled to a client computer, playing back the video streams.

The main point of the experiment being that, since multicast can be very cheap if implemented on a wireless network, it can be successfully used to deliver real time media without incurring in the typical bandwidth saturation that would be caused by using unicast streaming.

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I've been working at the University of Urbino for a couple of months, trying to get a working example of a Web TV over a wireless multicast transmission channel. All of the team's efforts (me and a couple of other people) are focused on the public event of tomorrow:

We will try to demo a proxy server (which has been built primarily by myself using ASP.NET and GStreamer) that receives various Web TVs from the Internet (our partners for the event are StreamIt and the italian RAI) and 1080p high definition movies stored locally on the server, transcodes the A/V stream and forwards it via multicast.

The multicast stream will then cross a radio link (provided by our partners at Essentia) and get to 10 client PCs, representing 10 households that might wish to receive TV contents through their wireless connection.

Essentially the demo will try to prove that such transmission methods provide much lower impact on the available bandwidth (which can be very scarce on metropolitan wireless connections, especially if shared between many clients of the same household). Wireless multicast TV is usually limited to “traditional” media delivery similar to that of the standard TV broadcast (that is, no on-demand video), but could be integrated with some innovative commercial solutions (for instance, on-demand video that gets cheaper as more users decide to watch it).

If everything works as planned (and so far it didn't ), starting tomorrow I'll have more time to write about the things we worked on: lots of stuff, starting with the RTMP protocol, GStreamer, RTP multicast streaming...

During the last month I have been working again at the university of Urbino, on a project that involves other two graduates of the Computer Science faculty, Andrea and Saverio. The objective, for now, is to build an embedded InternetTV decoder which should work like a low power set-top-box able to reproduce digital HD video.

The project was presented yesterday at a conference here in Urbino about the future of television (i.e. InternetTV, of course, which is slowly taking hold here in the old continent). A representative from StreamIt attended, the main partner and most promising content provider in Italy.

Our set-top-box is being developed on a Beagleboard, a quite cheap board powered by a Texas Instruments OMAP 3530 processor which also includes a dedicated DSP chip particularly suited to decode multimedia streams. On the software side, the board is running on Ångström (a Linux flavor) and we have been implementing an RTMP client (the Adobe / Flash streaming protocol) and a player (based on GStreamer + QT + Mono). That's a lot of topics I'd like to blog about if I ever find some time.

Anyway, in the past days we had some euphoric moments when suddendly we were able to decode some largish videos (not HD, but still) using the DSP and with a CPU load of ~15%. After weeks of banging our collective heads against the board...

Watch on Vimeo.