Broadcast Focus

Russell Trafford-Jones

Learning about the people and technology behind the broadcast and media industries.

  1. Ep 31: 'Secret' Uses for Teletext plus how Subtitles & the EPG Works by a Retired BBC Engineer #TechTalk

    01/07/2025

    Ep 31: 'Secret' Uses for Teletext plus how Subtitles & the EPG Works by a Retired BBC Engineer #TechTalk

    Behind the Scenes of Teletext: Subtitles, Data Broadcasting, and More Former BBC engineer Peter Wietzel joins Russell Trafford-Jones in this episode of Broadcast Focus as they delve into the intricacies of Teletext covering how subtitles work, why the BBC tansmission actually used two simultaneous subtitle transitions, and the many uses of carrying arbitrary data over Teletex were were the hidden heros! Peter finishes by talking about how the implementation was one of the first cross industry examples of collaboration in creating standards and talks about MHEG which replaced Teletext. Whether you're a technical enthusiast or just curious about broadcasting history, this should be good! 00:00 Welcome & Intro 02:30 Understanding Subtitles in Teletext 04:11 Technical Details of Subtitles Transmission 10:42 Subtitle Demo 11:10 Inserting Live and Recorded Subtitles 15:57 Dealing with Lack of Subtitles & Policing 18:35 Using 'Subtitles' to Help Deal with AFD/VI/Aspect Ratio 19:34 A Second Simultaneous Subtitle System for Internal Use 21:27 Inserting Subtitles in the BBC Regions 22:50 Teletext in SDI - SDI Bridge 25:25 Second Generation SDI Bridge 27:40 Quick look at Presfax 29:06 Databroadcasting – Sending Generic Data 31:40 Uses of Databroadcaster 34:00 Dairy Farming 36:00 Carrying audio over Teletext 40:40 Presfax Details 44:36 Controling Overlay Insertion at Transmitters 46:11 Ceefax In Vision 49:25 Teletext Standards 50:58 Collaboration and Standardisation in the 90s 54:58 Technical Enhancements and Memory Management 01:02:56 The Rise of Electronic Programme Guides 01:08:19 PDC - Recording Programmes 01:20:09 The Transition to Digital Broadcasting 01:23:00 The End of Teletext and Its Legacy 01:28:00 Reflections and Closing Remarks With thanks to https://www.nathanmediaservices.co.uk/ceefax/ for the demos and by extension ZXGuesser

    1h 31m
  2. Ep 30: Ex BBC Engineer Returns to Tell More About Teletext #TechTalk #Deepdive – Part II

    12/18/2024

    Ep 30: Ex BBC Engineer Returns to Tell More About Teletext #TechTalk #Deepdive – Part II

    Peter Weizel spent many years in the BBC working on Teletext and even wrote part of the standards so who better to continue guiding us on our journey into the first digital broadcasting on TV. Teletext is a pioneering pre-internet information distribution system. In part one, we heard about the inception of Ceefax at the BBC and the some of the inner workings of Teletext, its page and data structures, and its significant role in modern broadcasting technology. Part One: https://youtu.be/tbDB8FCOaV4 In part 2, we go into detail about data broadcasting, government interference, dynamic allocation of packets, using teletext for BBC internal staff information, regionalising CEEFAX 00:00 Welcome and Introduction 01:42 Ceefax Demo 02:11 Teletext Services and Features 03:03 Finding ways to apportion the VBI 05:11 Government Wants To Sell Teletext Space 07:15 Dynamic Allocation and Optimisation 11:18 Better Data Multiplexing 26:55 Test Equipment 31:05 Early Ceefax Architecture 33:23 Ceefax in the regions 39:49 BBC FAX service in Europe (WSTV) 45:28 Telfax – Ceefax for BBC Staff 49:04 Conclusion and Next Episode Teaser Many thanks to Nathan Dane for bringing Teletext to the internet: https://www.nathanmediaservices.co.uk Shout out to @ZXGuesser for the online interactive teletext viewer. Wikipedia's summary of Ceefax: https://en.wikipedia.org/wiki/Ceefax Wikipedia's summary of Teleteix: https://en.wikipedia.org/wiki/Teletext

    50 min

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Learning about the people and technology behind the broadcast and media industries.