The annual Telecom Applications Workshop, held at ESA-ESTEC on 22 and 23 November 2006, was broadcast live throughout Europe using IP multicast technologies. This page describes in detail how the distribution throughout Europe and the redistibution through SatNEx were established.
The video/audio and slides presentation were live encoded during the workshop using the Envivio streaming server. This and ESA leased capacity on the Hellassat II satellite made remote participation possible to various sites throughout Europe.
An Envivio encoded MPEG-4 streaming was uplinked from ESA-ESTEC (uplink station HOL-ESA-8) onto the Hellassat II satellite (39 deg E) at about 1.6 Mbps maximum data rate, using IP multicast. The DVB transmission was done in SCPC mode on the ESA-assigned carrier DVB2222#1 (SR=2222 kSps, frequ.=12730 MHz , pol.=horiz., FEC=½, max. data rate= 2048 kbps).
remote site | participants (est.) |
ESA-ESRIN, Italy | 5 |
University of Salzburg, Austria | 5 to 15 |
University of Graz, Austria | 3 to 8 |
University of Aberdeen, United Kingdom | 4 to 9 |
University Tor Vergata | 1 to 2 |
IST event, Helsinki Finland | many |
Some potential remote participation sites could not join because, in the scope of the SatNEx project (EC FP6 Satellite Network of Excellence programme) their TVRO dishes were pointed to Eutelsat W3A satellite. The workshop had also coincided with another SatNEx event held in Helsinki where a number of SatNEx members were attending.
Nevertheless, on the first day of the workshop the University of Salzburg confirmed that they were able to receive the IP multicast streaming from Hellassat II, and then re-route the streaming, which terminated in the Fraunhofer Institute in Hamburg Germany receiving the multicast traffic via unicast. Here it was converted into a multicast stream again and uplinked to the SatNEx capacity on Eutelsat W3A satellite (a carrier of about 1.8 kSps and a maximum user data rate of not more that 1 Mbps). Additionally, University of Salzburg prepared session description protocol (SDP) files for the audio and video, which permitted Rx only reception.
From the beginning, this SatNEx streaming was successfully received at the SatNEx booth at the IST event in Helsinki Finland. The University of Salzburg provided a reception PC to DLR, who then had took it to the IST event Helsinki Finland. The University of Salzburg further received both the original stream from Hellassat II and the rebroadcast stream from SatNEx for qualitative comparison. In summary, although the re-broadcast was squeezed into the SatNEx satellite pipe that was undersized by more than 25 per cent on average, the perceived video and audio quality was still more than sufficient to follow the workshop.
The SatNEx rebroadcast was also successfully received in Rome at the University Tor Vergata in Rome. Due to technical problems they were only able to receive the streaming in the last 1 hour of the workshop.
The University of Aberdeen followed the workshop both days, on the first, through the ESA-provided Hellassat II signal, and on the second through the SatNEx streaming on Eutelsat W3A.
All participating sites confirmed that in general the quality of the live streaming of video, audio and slides was perceived as good to very good. All involved sites expressed that such an event was highly appreciated and a re-distribution of following ESA events would be highly welcome.
In addition to the live transmission of the workshop, the Envivio streaming server was also used to record the presentations for off-line use. After some post-processing these MPEG-4 encoded multimedia files including synchronised video/audio and slides will be made available on the ESA Telecom website.
ESA Telecom warmly thanks all participants and those persons and organisations involved in making this possible. In particular, thanks are extended to Bernhard Collini-Nocker and Wolfgang Brauneis, both from the University of Salzburg, Peter Schrotter from the University of Graz, Gorry Fairhurst from the University of Aberdeen, Anton Donner from DLR and Francesco Zampognaro from the University Tor Vergata.
For more technical information please contact Heico Salfeld or Frode MÃ¥len by clicking at the right of this page.