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Using IT Equipment in Live Broadcast


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SMPTE UK Presentation

Published in: Technology

Using IT Equipment in Live Broadcast

  1. 1. Using IT Equipment In Live Broadcast @openbroadcastsy - #ITinBroadcast Kieran Kunhya –
  2. 2. What I’ll talk about today • IT in Live Broadcast Television (orders of magnitude differences for latency/bitrate compared to OTT). • History of IT in Live Broadcast • Being a “broadcast manufacturer” around modern software development. • Using IT equipment in live broadcast • Can’t explain everything (Wikipedia your friend! - WestminsterGuest Wi-Fi) • Dense topics – so some attempt of lightheartedness
  3. 3. Who are we? What do we do? • Founded in 2012 • Globally Distributed Team of 4, average age 27 • No traditional broadcast background (3x Physics, 1 CompSci) • Main business, encoders and decoders for news/sport. Entirely around IT equipment. • Open Source vast majority of code (Redhat-like) • Developers of FFmpeg, VLC etc. • Goal: All code written in house (99.99% there)
  4. 4. What we do (2) • Operate a satellite downlink centre, with nine racks and fibre connectivity. • Lets us develop software in a real-world environment (DevOps?).
  5. 5. What we do (3) • Drastically lower the barrier to entry to broadcast television. • Make the broadcast apps room look exactly like an IT server room. • Vertically integrated broadcast manufacturer?
  6. 6. Traditional hardware architecture • Single or limited function cards with onboard FPGAs or DSPs doing majority of work. • Smaller CPU to perform control aspects.
  7. 7. A true software architecture Standard CPU performs all non- physical data processing ASI SDI MADI AES/EBU IP etc. ASI SDI MADI AES/EBU IP etc.
  8. 8. A true software architecture Standard CPU performs all non- physical data processing ASI SDI MADI AES/EBU IP etc. ASI SDI MADI AES/EBU IP etc.
  9. 9. Technological changes • Intel Nehalem (2008/09) • Realtime 1080i encoding • Only possible with overclocking before • Low cost SDI/ASI boards • Full 10-bit, VANC • Commodity hardware Everything available next-day!
  10. 10. Early trailblazers • BBC News Raven • Software-based EVS for bureaus/sat-trucks • Played-out News bulletins at 2012 Olympics • Free (French ISP) • National IPTV service entirely software driven • Encoding/Transcoding/Remux • 5m+ subscribers • A lot of ISP tech built in-house • Not just TV, STB, DSLAM etc
  11. 11. Myth 1: IT hardware is too large and too power hungry Units reside in street furniture outside Downing Street, Buckingham Palace etc. Low depth (200mm) chassis, low power CPU. Encode/decode, ASI processing, Intercom.
  12. 12. Myth 2: IT hardware isn’t powerful enough And another 17 more cropped out! • Huge processing power available • 432 CPUs (small supercomputer) • Costs falling dramatically • Powerful enough for example to do high- bitrate VC-2 encoding/decoding, very high density H.264 decoding, ASI processing. • ~2-3x less rackspace for equivalent functionality compared to hardware • Processing power for new functions
  13. 13. Building broadcast tech the IT-way • Can’t have expensive Tektronix/Phabrix etc. in 3 countries • Built in-house SDI analyser (based of Dektec Dtu-351) • Unified with IP-codebase • Testing, testing, testing • Fuzz testing, intelligent mutation of data to cause crashes • Continuous process, happens 24/7 (billions of iterations) • Process used to find Heartbleed • Heavy unit testing
  14. 14. Building broadcast tech the IT-way Unit test physical hardware Large number of combinations of • OS Version (kernel etc) • Network card driver • SDI card model • SDI card driver
  15. 15. IT and IP in the Studio
  16. 16. Standards in software context SMPTE 2022-6 – SDI over IP • Pixels spanning packets • Costly CRC TR-03 – separate RTP streams for video/audio • Pixels no longer span packets (RFC4175) • Soon SMPTE 2110
  17. 17. Pixel formats Only YUV 4:2:2 domain (as example)! • Planar 10b – main working format • Planar 8b - preview quality • UYVY 10b (16-bit aligned) – SDI datastream • Apple v210 – hardware • Contiguous 10-bit – 2022-6/TR-03 packing Tricky to work with in software.
  18. 18. Handwritten (no intrinsics!) SIMD for every mapping (and others). • 5-15x speed improvements compared to C • Do it once, make it fast once and for all (until new CPU…) • Generic conversion library a difficult problem • Intermediate pixel format(s) always a compromise • Add special cases until you’ve done them all! Pixel formats
  19. 19. One does not simply… Bypass the operating system DPDK, Netmap, Registered I/O A presentation in itself. See BBC R&D at UKNOF: L8wl8YUwA
  20. 20. Kernel Bypass No network stack – You are the network stack • Craft Ethernet, IP, UDP headers yourself • No ARP, hardcoded MAC • Handle most of this in userspace • Lets you do pixel processing directly to/from Network Card memory.
  21. 21. SMPTE 2022-6 in the real-world MISSING THE POINT • 2x SDI ports per 10Gbps port (Wastes 8.5Gbps duplex – 17Gbps) • Definitely not COTS, long lead-times, single supplier
  22. 22. SMPTE 2022-6 in the real-world Issues with 2022-6 receivers not accepting software streams • Unrealistic tolerances to jitter • Network induced and source induced • Interoperability tests in closed, controlled environment • Limited number of hardware manufacturers • Tradeshow demos don’t represent reality More detailed work needed on real-world kit and (loaded) networks. No metrics exist.
  23. 23. IT-based live production today • Dual-capable, SDI/ASI/AES and IP • Make it look the same to end-users, buttons, SNMP etc. • Incremental improvements like a web browser • Allow users to understand multifunctionality • Integrate seamlessly (e.g MPEG-TS)
  24. 24. IT-based live production tomorrow • A BIG COMPUTE RESOURCE • Live and offline on the same CPU • Remote kit can be processing low-priority batch jobs • Flash override on live broadcasts • Possible today but no orchestrator (microservices?) • FIMS too old (SOAP lol) • Control network and CPU resources
  25. 25. Decode MPEG-TS multicast Orchestrator goes and finds CPU resources somewhere, onsite or otherwise. Spin me up a multiviewer Transcode this file Not possible with SDI because SDI associated with a connector on a machine.
  26. 26. The V-word, Virtualisation • OS provides priorities to run multiple applications already • Many vendors on Windows (often without good reason) • Getting > 1Gbps of data out of VM nontrivial. • Live migration of complex, stateful broadcast applications not easy. (Not a web server…) • Complexity may outweigh benefits.
  27. 27. Using IT networks for contribution • Trend towards using generic, unmanaged, IP networks for broadcast contribution. • Regular in News (including cellular) • Growing use for Sport and Channel contribution • Packet loss and Jitter (relative to traditional metrics) • Do it properly, using UDP. TCP not suited. • Variations on three main techniques.
  28. 28. Using IT networks for contribution (1) • SMPTE 2022-1/2 FEC • XOR based matrix (adds 2 * matrix latency) • Basic but wide support (albeit many broken implementations) Row FEC Column FEC
  29. 29. Using IT networks for contribution (2) • Retransmits (aka ARQ) • Receiver requests sender to transmit a copy of lost packet. • Affected by round-trip latency • Negative acknowledgment Sender Receiver
  30. 30. Using IT networks for contribution (3) • Dual-pathing (SMPTE 2022-7) • Hitless Switching Path1 Path2 Out
  31. 31. Example of IT and Unmanaged IP • Three nights of the One Show on BBC1 delivered using public internet • Reverse vision video on same unit. • Next step (in UK), long-form programming delivered over cellular?
  32. 32. Summary • IT equipment is on-air in the live broadcast chain today • The advent of IP-based production provides an opportunity to use multifunction IT equipment and gain massive flexibility. • Standards need to reflect this • The use of generic connectivity is increasing, and not just for financial reasons. • Going to be some very high-profile announcements in coming months