Ofcom publishes first results on quality of TV subtitles
30 Apr 2014 03:23 PM
Ofcom today published its first report on the
quality of live TV subtitles provided by broadcasters in the
Subtitles are used by over a million people with hearing
impairments to watch TV. Addressing concerns from viewers, Ofcom last year
required broadcasters to start reporting on the quality of live subtitles to
identify areas for improvement.
Today’s report samples the accuracy, speed and latency
– the delay between speech and the corresponding subtitle appearing
– of live TV subtitles. It is the first of four reports on live
subtitling Ofcom is producing over a two-year period.
Viewers have told Ofcom that poor latency is one of the
most frustrating aspects of live subtitling, often resulting in a disjointed
Samples of BBC, ITV, Channel 4, Channel 5 and Sky
programmes showed that the median latency was 5.6 seconds, which exceeds the
recommended guideline of a maximum 3 seconds delay.
Ofcom will ask broadcasters to consider how latency can
be reduced and whether, for example, they can take advantage of any small
delays in the transmission of live programmes to improve
speed of subtitling (words per minute displayed on screen) can also impact the
subtitles sampled met the current guidelines for a maximum speed of 160-180
words per minute. Ofcom will review these guidelines in light of the data
gathered over the four reports to see if they are appropriate for
Accuracy, another key measure, was rated as generally
good by researchers that audited the data on behalf of Ofcom. They consider
that 98% of subtitled words being accurate on live programmes is an acceptable
standard. However, accuracy did fall below 98%
on some occasions.
These measurements will be used with future samples to
build a better understanding of the quality of live subtitling provided by the
requiring broadcasters to measure quality of subtitles regularly, Ofcom expects
them to identify and act upon opportunities to improve live subtitling to
Further improvements to
Today’s report also examines new approaches that
broadcasters could take to tackle poor subtitling.
Ofcom is encouraged that broadcasters are making greater
efforts to increase the amount of block subtitles used in live programmes.
Block subtitles, where several words appear at once as a single block, are
easier and quicker for viewers to read than scrolling
However, Ofcom remains concerned that a significant
number of pre-recorded programmes are provided to broadcasters too close to
transmission to allow subtitles to be prepared in advance. This results in
lower quality subtitles for viewers.
this reason, Ofcom is asking broadcasters for a further report on how they
produce subtitles for pre-recorded programmes during the second half of 2014,
and will publish the findings next year.
Subtitled programmes double in a
Ofcom has also today published a report on
the development of TV ‘access services’. These are the
subtitling, signing and audio description of programmes, which benefit viewers
with hearing and sight impairments.
number of channels required to provide TV access services increased from 22 in
2004 to 73 in 2005, after Ofcom published strengthened requirements for
broadcasters. Today, these services are provided by 76 channels, which account
for over 90% of total TV viewing.
Since 2005, the new rules mean the access services
targets that each broadcaster is required to meet rise each year from the
launch of the service. For subtitling, this rises from 10% of programmes in the
first year to at least 80% in the tenth year a channel is on air; for signing
from 1% to 5%; and for audio description from 2% to 10%.
a result, the availability of access services has increased substantially as a
proportion of total broadcast hours for those channels required to provide
Between 2005 and 2013, subtitled hours doubled from
40.5% to 81.9% of hours of programming broadcast, audio description increased
four-fold (from 5.9 % to 23.3%), and signing rose from 1.8% to 5.6% for
channels required to provide access services.
NOTES FOR EDITORS:
- Under the Communications Act, Ofcom is required to have
regard to the needs of persons with disabilities when carrying out its
principal duty towards citizens and consumers under section 3. Ofcom also has a
specific duty under section 303 of the Act to provide guidance to broadcasters
on how they should promote the understanding and enjoyment of their services by
people with sensory impairments, including people with hearing
- Last year, Ofcom published a statement on the quality of subtitles. This required broadcasters to
measure the accuracy, latency and speed of subtitles at six monthly intervals
for a period of two years, with the results to be included in a series of
reports published by Ofcom.
measurements were carried out by broadcasters or their contractors, and were
checked for accuracy and consistency by the University of Roehampton for Ofcom.
The exercise measured a total of 60 ten-minute clips from 60 programmes, which
were analysed. These were from three genres (news, entertainment and chat
shows) and broadcast on five channels (BBC, ITV, Channel 4, Channel 5 and Sky).
In total, the analysis comprises ten hours of live TV material including
approximately 103,000 words and almost 15,000 subtitles.
- The Code on Television Access Services sets targets
for the amount of TV subtitling, signing and audio description that
broadcasters are required to provide. It also contains guidance about how
access services should be presented.
- Audio description is a commentary woven around the
soundtrack, exploiting pauses to explain on-screen action, describe characters,
locations, costumes, body language and facial expressions to enhance meaning
and enjoyment for blind or visually-impaired viewers.
- Sign language comprises the use of manual gestures,
facial expression and body language to convey meaning. British Sign Language
(BSL) is the most popular sign language in the UK.
- Viewers indicated in responses to our May 2013
consultation that they found latency one of the most frustrating aspects of
live subtitling. Historical guidelines for latency recommended that subtitles
should aim to have a latency of three seconds or lower.
- Today Ofcom also published its annual
report on access services for 2013.