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Spoken output for interfaces



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3.3 Spoken output for interfaces


As highlighted in the report ‘Developer's Guide to Creating Talking Menus for Set-top Boxes and DVDs [National Center on Accessible Media (NCAM, 2009)] the highly visual nature of interfaces used in new digital media formats has created serious and growing barriers for blind and low-vision consumers. The more visual the interface, the harder it is for a blind user to use it. The provision of an audio interface for people with visual impairments will resolve issues relating to use of the visual interface.

In August 2010, INTECO, the Spanish National Institute of Communication Technologies, released a DTV operating system that features similar spoken output and control of display settings such as the size and colour of text in the menus and EPG. This operating system consists of an open source software solution that can be integrated into any digital set top box or integrated television.


Smart Talk Freeview digital box, the first commercially available terrestrial set top box with spoken output of menus and EPG information went on sale in the UK in 2010. The set top box features a fully talking Electronic Programme Guide (EPG), spoken output of all menu settings and one-click access to audio description through a dedicated button on the remote control.
In addition, "Speech Solutions for Next-Generation Media Centers" (NCAM, 2009) developed open source software for talking set-top boxes built on the Linux-based MythTV platform.

Text to speech [TTS] provision opens many doors for people with sight loss as an alternate means of navigation in this graphic-rich environment and enables independent access to new programmes and services on the television. It also demonstrates that TTS technology for television is technologically possible.


Where spoken output is not provided, the thoughtful choice of tones or audible feedback can assist greatly in low vision or non-visual use.

3.3.1 Audible feedback- characteristics


Audible feedback is used to acknowledge a command given by the user, possibly for an operation, potentially a person with sight loss, uses a television receiver e.g. audible confirmation that a key has been pressed on the remote control.
It must be noted here that the feedback has the potential to indicate a number of operations:

  • feedback announcing the receipt of a command from the user or the start of an action

  • feedback prompting the end of an action

  • feedback confirming the receipt of a standard command or in another case the receipt of an unrecognised command

It is critical that this feedback is unique in its temporal pattern so that it can:

- be understood without giving further instruction to the user and

- not be confused easily with other audible feedback signals used in the same product or those in another product used simultaneously and in the same place.


Since audible feedback is less tangible than spoken commands, there is a definite need for the temporal pattern of different feedback signals to be distinct so that the user is able to differentiate one signal from the other i.e. {onomatopoeic description of different signals} Pip, Peep, Pip-pip [in quick succession], Pi,·pi,·pi,·peep (slowly), Pip, pip, pip, pip, …(specified times, slowly).

Often a user is operating a toggle, where a feature is switched on and off by use of the same remote control button. Here, the use of ascending and descending pairs of tones are commonly used to indicate on and off respectively.


Note: Difference between spoken out and audible feedback.

There are various ways in which blind and partially sighted people access information. For example, some use large or modified print materials, some use Braille and some use audio information.


Audio information can broadly be split into two types-

Spoken output, which comprises information that is read out by another person - either live, or on a recording or via synthetic speech.

Audible feedback in the form of auditory signals e.g. Pip, Peep, Pip-pip [in quick succession]. These are normally used to confirm the receipt of a signal or completion of a task.

3.4 On-screen displays


Adaptable fonts, changeable colours, simple uncluttered layout with zoom functions are all attributes that can transform a completely inaccessible on-screen display into a more usable product for blind and partially sighted viewers.
However, lack of demand in the mainstream market has so far prevented equipment manufacturers looking into or providing features that will support the needs of blind and partially sighted people. These functional attributes have been discussed in section 4 on user requirements.

3.5 Remote controls


The remote control is the principal piece of equipment that is used to interact with the television set, so due consideration needs to be given to its design and functionality. DTV, equipment and services are more or less unusable without a remote control.
Several studies conducted around the accessibility of remote controls for people with disabilities have published a set of recommendations that relate to its ergonomics and utility. For example, the guide for remote controls in Handbook of Adult Anthropometric and Strength Measurements [DTI, May 1998] includes suggestions for its nomenclature and button size/positioning. These recommendations have been discussed in the section 4.2.2. [DTI Publications, May 1998]

3.6 Internet television and IPTV


Internet television and IPTV are relatively new platforms for viewing television content that are fast gaining popularity and due to improvements in internet speeds, they are likely to become more and more popular.
Internet television (sometimes known as online television) is a television service distributed via the internet. It allows the viewers to choose programmes that they want to watch from an archive of programs or from a channel directory.
Internet Protocol television [IPTV] is a system through which television services are delivered using the internet and broadband internet access networks, instead of being delivered through traditional radio frequency broadcast or satellite or cable television.

Internet Protocol Television [IPTV]: IPTV services can be grouped into 3 main categories:



  • Live television, with or without interactivity linked to the television programme in progress;

  • Time-shifted programming and catch-up television;

  • Video on demand (VOD): browse a catalogue of videos

Watching content over Internet Protocol Television [IPTV] involves watching content on a system that has a browser and an internet connection. It is advisable to use User Interface Web Browser Guidelines where content is delivered through a web browser. These guidelines identify characteristics that would provide a more adaptable user interface to allow users, not only those with disabilities, to have a much greater selection in what suits them most. These guidelines can be found on http://www.w3.org/WAI/UA/wai-browser-gl#Introduction to WWW Browser. [Accessed on 9th March 2011 at 12:15 pm]


However it is the Web Content Accessibility Guidelines [WCAG] that will be applicable for content that is made available on the internet. Web "content" generally refers to the information on a web page or web application, including text, images, forms, sounds, and such. [http://www.w3.org/WAI/intro/wcag.php- accessed on 0th March 2011 at 12:20pm].
Since, both technologies deliver television, and because technology varies across the world, this document covers both.


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