For video transmissions using MPEG compression there is a clear trade-off between picture quality, encoding latency and jitter. Interactive applications that are dependent on high quality as well as low latency cannot fall back on compressed video, but must rely on fully uncompressed video transmissions. Since the high bit rates of such transmissions consume bandwidths between 300 Megabit/s and 1.5 Gigabit/s for each video signal, their transmissions are true challenges for current IP-based networks. The paper investigates uncompressed Serial Digital Interface (SDI) transmissions over a Multi-Partner European Test Beds for Research Networking (MUPBED) infrastructure using Label Switched Path (LSP) connections. IP Performance Measurements (IPPM) are presented for the MUPBED layer 2 link and are compared to IPPM measurements obtained from both the current German Research Network G-WiN as well as the European Research Network GEANT. The measurements show the huge strain of such intensive bit rate transmissions on network Quality of Service (QoS) parameters and demonstrate the need for Forward Error Correction (FEC) mechanisms to smooth out the impact of late loss on video quality. The study illustrates this link with subjective picture quality evaluations in connection with various FEC mechanisms for uncompressed SDI signals.
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