Sony claims to have played a major role in bringing the industry the global broadcast signal transport SDI, standardised by SMPTE in 1989, and wants the industry to listen once more as it promotes its vision for video over IP.
Senior executives are using Sony's part in the development of SDI to underscore its commitment to open standards, provided those standards adhere to Sony proposals.
According to Hugo Gaggioni, chief technology officer for broadcast and production systems division, Sony: “There are competing technologies out there with other vendors and different standards. Remember when Sony created SDI in the eighties, at the time there were competing proposals and we ended up creating chips that worked and we gave it to other manufacturers and slowly we created an infrastructure which was based on de facto things that work. And eventually the standards comply with a de facto solution.”
He argues: “Right now we have standards with limitations. Some are point to point only, some cannot be switched... others can't go through switchers of various plants. If we are going to adopt a signal that is IP, it has to goes through layer 2 and layer 3 switchers, otherwise the signal will never leave the building. The only proposal in the market capable of doing that is the Sony proposal. We can go through the layer 2 and layer 3 switchers perfectly. Other solutions are not doing this.”
Sony is building a live IP production infrastructure that marries commodity IT products with its own control layers. Much of the development has taken place at Sony's Japanese chipset developer LSI and it is talking with third party FPGA developers like Altera Corporation and Macnica Americas about licencing its technology.
Explaining the wider context is Claus Pfeifer (pictured), strategic marketing manager, live production, Sony Europe: “We've already seen a lot of productions over IP where the technology is mostly used for distribution of content between a stadium venue and broadcaster or for remote contribution over an IP network between facilities across the Atlantic.
“However, IP in these scenarios is only used for distribution where it doesn't matter if there is a delay of one or two seconds in transport. For production in and around a studio or between venues for live production you need very low latency. We need to send realtime video over IP with the same speed and latency as we do today with SDI, otherwise the technology will not be adopted. For Sony this is key.”
Sony admits that the first trials of 4K production – including the forthcoming one at the World Cup in Brazil – use a temporary solution. Based on 4x3G HD-SDI cabling, this is an expensive option in terms of weight of cabling when a single 10Gbps Ethernet cable can already transmit six uncompressed full HD signals.
“To promote low-cost remote HD and 4K production across multiple venues we have to reduce the cost of implementing 4K in OB trucks and the most difficult challenge is the cost of cabling,” said Pfeifer. “For 4K to be practical, the industry has to move to 4K over IP.”
One problem is that while 4K 25p fits into an existing standard 10Gbps cable, 4K at 120p - required for live action sports - requires at least 12Gbps or the use of low (mezzanine) compression.
“We don't believe that codecs like JPEG 2000 or AVC deliver on the extreme low latency required of live production, which is why Sony has developed a proprietary low latency video codec,” he said. “This is derived from the same codec used in our HDC studios cameras and digital triax connections. It is very good and is resilient over multiple generations.”
Much of Sony's video over IP technology for live production adheres to standards such as SMPTE 2022-6 [for transporting uncompressed HD-SDI] and precision time protocol IEEE1558, and it is working with the EBU/SMPTE/VSF Joint Task Force on Networked Media (JT-NM) to create a unified standard. However, compression does not fall under the Task Force's remit.
“We are being very open to the industry about offering this technology and believe a similar process will happen to that of the development of SDI, which was also an initiative of Sony, which Sony opened up, and which became universally adopted. The same must happen with IP live,” said Pfeifer.