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    A file-based content exchange ecosystem

    October 24, 2014

    Heiko Sparenberg, Head of the Digital Cinema group at Fraunhofer IIS in Germany, presented a paper co-authored by Siegfried Foessel on "A Concept for a File Based Content Exchange Ecosystem using Scalable Media." With the availability of high-speed data networks, data exchange over the Internet because a cost-effective distribution method, he said. VoD has worked in this space for years. Exchange of sequences/projects during post-production is also common in cities where high-speed networks throughput is available. But there are differences between VoD distribution and content exchange between two post facilities. VoD uses inter-frame compression and no frame drops are accepted by the user; no more data is necessary once the user has watched the movie. To the contrary, in a post exchange, there is only moderate use of Intra--Frame Compression (maybe lossless) and the best available quality and resolution need to be transferred. "It usually takes hours to transfer minutes of content," he added.

    "Our solution is different," he said. "We want to read a small portion of the file and then simulate the remainder of it, which avoids fragmentation." He developed a "substitution method" with the main motivation being that image data is often not completely transferred from System A to System B when the latter system needs the data for further processing. When using non-scalable media, further processing isn't possible; when using scalable media, at least a reduced variant can be displayed. "Since we want to prevent file-fragmentation on the receiver side, we have to simulate the data that hasn't been transferred." The "Substitution Strategy" allows the software running at the destination to rebuild the file-structure of each file and to simulate the remaining data so that the images can be used for further processing before the overall transmission is completed. Sparenberg showed a clip  showing this method, using SteM material encoded in 4K using lossy JPEG 2000 at three resolution levels.

    The Concept Exchange Ecosystem uses a simple file server as host; the recipient uses the following algorithm to archive the desired behavior: it analyzes the file-structure of source files (PLT Markers determine length and offset of codestream-packets) and generates pseudo-JPEG 2000 files on the receiver side comprising identical file-structure, header-information and other metadata. The innovation of this concept is the possibility that the recipient may start to work with the transmitted content even before completion of the transfer due to the scalability feature.

    The prototype implementation can be optimized so the overhead can be reduced in the future, but a scalable transmission will never outperform a non-scalable transmission," he concluded. "The current implementation can be extended so the scalable transmission may work with container formats like MXF. Therefore an application in Digital Cinema, Digital Archiving as well as interoperable mastering is feasible."

    Tag(s): 4K , MXF

    Debra Kaufman

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