This year marks my 40th anniversary in subtitling and I thought I’d take the time to reflect on how much things have changed since I began working in the industry.

In the early days, subtitles simply travelled with the picture as teletext, utilising the same infrastructure for distribution all the way to the transmitter.

As subtitle preparation became increasingly outsourced from the broadcasting operation itself, live subtitles often had to be delivered separately from the programme material, often using dedicated communications infrastructures, and only combined with the pictures and sound at the playout site. Ensuring that the correct subtitles meet up with the corresponding programme material in real time remains a constant challenge to this day, especially in complex broadcaster networks.

Early playout of pre-recorded subtitles often involved using a modified subtitle preparation system, synchronised to the playout VTR, and feeding directly into a local inserter. Subtitle files were often derived from those used by TV caption generators (Aston, for example, produced an early subtitle preparation terminal based on their ubiquitous TV character generator). File formats were specific to equipment suppliers, and used a variety of media — how many of us remember the 8” floppy disks from those days!

Subtitle files soon needed to be moved between preparation and playout operations, and subtitles were also sold with programme material, often between countries, making it difficult to guarantee compatibility between origination and playout. Clearly there was a need for a standard means of subtitle exchange.

The earliest attempt I recall to standardise a subtitle file format took place in the early 1980s, led by ex-IBA teletext and subtitling guru Peter Hutt. Working as a private consultant, his “International Caption Exchange Programme” was an ambitious collaboration between BBC, ITV and the US National Captioning Institute to promote a common subtitle exchange mechanism. The initiative was ahead of its time, and although not successful itself, paved the way for a more formalised approach by the European Broadcasting Union, eventually leading to the creation of the so-called “EBU format” for pre-recorded subtitle files in 1992.

The EBU file structure was very simple, encompassing both the “closed” teletext subtitles that were used throughout Europe at the time, but also “open” subtitles for on-screen use. The original specification presumed the use of 3.5” 1.44 MB floppy disks compatible with MS/DOS 3.3! Despite its apparent antiquity, the “closed” EBU format remains in use today, with many broadcasters and subtitle providers having amassed large archives of legacy subtitle material.

The move to high-definition (HD) TV with the need for improved subtitle presentation, as well as the introduction of file-based production workflows, and the unstoppable convergence with the web and online data, mean that the EBU format is no longer appropriate. A new format — EBU-TT — is now becoming the new interchange standard, This format is much “richer”, compatible with the latest web media, and will ensure that subtitles authored for linear broadcast can be used seamlessly in VOD, catch up and other web-delivered environments. It provides for higher-quality display and more accurate timing of subtitle text, allowing subtitles to be increasingly used in innovative ways, such as metadata for text-based indexing and searching of programme material.

Subtitling has seen a lot of change already; I wonder what the next 40 years will bring?

John Hedger, Consultant Project Manager, Access Services