feature content distribution
transport of equal quality, but with a typical bandwidth saving of at least 60%; and Visually lossless: which employs floating point filtering and quantisation techniques to provide greater compression with no perceived loss of video quality. Typically, visually lossless JPEG2000 uses from 120-150 Mb/s, while the backhaul of uncompressed SDI video needs a 1.5 Gb/s pipe.
The advantages of JPEG2000 in contribution include: • Low latency.
• Picture-by-picture encoding. • Less visual artefacts.
• Robustness in case of transmission errors.
• Sustains multiple code/decode steps.
• Offers a choice of quality options, through support for both mathematically lossless (equal to uncompressed video) and visually lossless encoding.
format to be tailored for the various device screens and resolutions. At the same time the broadcaster canarchive the content in the highest quality for future reuse.
JPEG2000: an advanced compression scheme for IP video transport
T-VIPS is well known as the pioneer of JPEG2000 in broadcasting, being the first vendor to announce, ship and deploy JPEG2000 solutions. The reason we pioneered JPEG2000 video compression is that we anticipated the growth of IP in broadcast, recognised it was a game changer and then analysed the specific needs of key parts of the broadcast chain and re-engineered solutions to bring them into the world of IP. In high quality video transport there are a number of clear advantages that JPEG2000 compression provides. JPEG2000 is a wavelet based compression technology which provides a number of benefits compared to Discrete Cosine Transform (DCT) compression methods such as MPEG-2 and H.264. The compression process is composed of the following three steps: wavelet transformation,
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JPEG2000 compression, redundancy mechanisms and FEC, transport stream monitoring and intelligent switching all combine to make IP- based video- centric networks more flexible, powerful and easier to manage.
quantisation and entropy encoding. The input picture is transformed by a set of wavelet filters and thus pixel information is transformed into wavelet coefficients which are grouped into several sub-bands. Each sub-band contains wavelet coefficients that describe a specific horizontal and vertical spatial frequency range. One major difference is that, compared to the DCT compression of the MPEG family of codecs, the wavelet transform of JPEG2000 is carried out over the complete picture in one transform, and not by blocks of pixels, avoiding the well-known macro-blocking effect from MPEG.
The actual compression is achieved by truncating and/or re-quantising the bit streams contained in each code block. After the data has been quantised into a finite set of values, it enters the entropy encoding process which gives additional compression. JPEG2000 enables operators to choose from two alternative types of lossless compression: Mathematically lossless: which uses reversible integer wavelet filtering to ensure that the compressed data has all the information of uncompressed SDI video and therefore provides video
A company that has selected IP and JPEG2000 from T-VIPS for contribution is Italian Elettronica Industriale, a Mediaset company. According to its CTO, Piercarlo Invernizzi, it had evaluated several compression technologies for its next generation contribution network supporting SD and HD transport. The company wanted to migrate to IP connections, but only if it could do it without loss of quality. The T-VIPS JPEG2000-based solutions emerged as the clear winner, enabling EI to migrate to IP with all the power, flexibility and functionality it needed.
Enhancing IP networks for robust video transport
We have looked at how JPEG2000 compression over IP can enhance viewing experience, so let’s now take a look at how robustness can be engineered in to the IP networks to increase QoS levels. A fundamental requirement for IP contribution networks is to flawlessly handle single point of failure, both in the network and in the video processing devices. IP networks are typically designed with automatic and fast rerouting in the case of a node failure. The rerouting delays are highly dependent on the network design, but can be as low as 50ms in a well- designed MPLS network.
There are several mechanisms that can be employed to increase robustness in the IP network as seen from the video edge-devices. One mechanism is to use external
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