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BBC Optimizing UHD Video Streaming Over IP (bbc.co.uk)

Posted by Soulskill on from the go-big-or-go-home dept.

johnslater writes: A friend at the BBC has written a short description of his project to deliver UHD video over IP networks. The application bypasses the OS network stack, and constructs network packets directly in a buffer shared with the network hardware, achieving a ten-fold throughput improvement. He writes: "Using this technique, we can send or receive uncompressed UHD 2160p50 video (more than 8 Gbps) using a single CPU core, leaving all the rest of the server's cores free for video processing." This is part of a broader BBC project to develop an end-to-end IP-based studio system.

4 of 72 comments (clear)

  1. Interesting by jd · · Score: 5, Interesting

    Kernel bypass plus zero copy are, of course, old-hat. Worked on such stuff at Lightfleet, back when it did this stuff called work. Infiniband and the RDMA Consortium had been working on it for longer yet.

    What sort of performance increase can you achieve?

    Well, Ethernet latencies tend to run into milliseconds for just the stack. Tens, if not hundreds, of milliseconds for anything real. Infiniband can achieve eight microsecond latencies. SPI can get down to two milliseconds.

    So you can certainly achieve the sorts of latency improvements quoted. It's hard work, especially when operating purely in software, but it can actually be done. It's about bloody time, too. This stuff should have been standard in 2005, not 2015! Bloody slowpokes. Back in my day, we had to shovel our own packets! In the snow! Uphill! Both ways!

    --
    It's a small world and it smells funny; I'd buy another if it wasn't for the money; Take back what I paid (SoM)
    1. Re: Interesting by tomalpha · · Score: 3, Informative

      Yeah, this kind of thing has been around for a while.

      These days the added latency of going through the kernel IP stack is generally measured in micro rather than milliseconds but the difference is still the same order of magnitude. Solarflare, Mellanox and others will happily sell you expensive Ethernet network cards that come bundled with drivers that let you bypass the kernel IP stack. The stack itself isn't especially slow but the system call and extra memcpys still do all add up. I've also seen an in-house user space stack built largely on top of lwIP.

      So I'd agree that none of this particularly new, but I reckon it's still interesting that the BBC is using it. Maybe that'll help spur more widespread adoption.

  2. Re:I can't wait by SuricouRaven · · Score: 4, Informative

    This isn't for you to watch UHD. It's for internal use in production, so they can shunt live UHD video around their studios. That way they keep full quality right up until the final stage before distribution, when it gets resized according to the end device. Your TV will get plain old 1080p as always - but they'll have UHD capability ready to go for transmitting to cinemas or sending to big public displays, and they can archive a UHD version for future use so they can zoom in tighter on the action in future highlights.

  3. Re:instead of investing in super ultra hq video.. by Anonymous Coward · · Score: 3, Funny

    why not do 720p for everybody first, with no region locking or lockouts? fuck this uber hq shit. dvd quality is, quite frankly, good enough for all but the most anal of viewers.

    Shush! If UHD doesn't take, we'll be forever stuck with 1080p computer monitors. Do not be the person who prevented 8 MPixels desktop monitors from becoming mainstream.

    Dear Sirs,

    I'm the head of the UHD Panel Manufacturers' Association. I'm sorry to say that, having read the grandparent post by an Anonymous Coward, our members have unanimously decided to cancel all further development and manufacturing of ludicrously high-definition panels, and to shut down the association. In fact, we've decided to stop bothering with 1080p panels as well and in future will just be selling 1280 x 720 displays.

    The parent was correct in identifying the influence of a single post by an Anonymous Coward on a niche website; we consider Slashdot the be-all-and-end-all of our market research and as a result of that post we're ending our involvement in a potential multi-billion dollar industry.

    In fact, we're even considering going back to CRT displays, you ungrateful wretches.

    Yours sincerely,

    Hwang Beom-seok,

    President of the UHD Panel Manufacturers Association