Which subtitles to use

This blog post was originally published by Sofia Enamorado on August 14, and has since been updated for accuracy, clarity, and freshness. Before fully understanding the difference between subtitles for the deaf and hard of hearing SDH Subtitles and closed captions, it is helpful…. What is closed captioning? Closed captions are chunks of time-synchronized text that reflect the audio track and can be read while watching the video. The process of closed captioning involves transcribing the audio to text, dividing the text into chunks known….

Sign up to receive our blog digest and other information on this topic. You can unsubscribe anytime. As you improve your proficiency in the target language, you will be able to handle more foreign-language input, but as with any other type of learning, this is a process that takes time. This means that different people learn in different ways, and can benefit more from using different materials. As such, when choosing which subtitles to use, experiment and try different things, until you find the solution that works best for you.

Finally, remember that the most important factor to consider with regard to choosing which subtitles to use is your motivation to engage in the learning process. At the same time, however, be aware that language learning can be difficult sometimes, and that eventually, you need to advance to the more complex material, even if it seems scary at first.

For example, regions at the top should be "before" edge aligned, and those at the bottom should be "after" edge aligned. Regions in the central vertical area may be "center" aligned. Whereas Teletext is a monospaced system, typically the resulting subtitles will be presented using a proportionally spaced font. When the text is rendered, it may occupy more width than the original Teletext. To allow for this, where all the text in a tt:region has the same value of tts:textAlign , the left and right edges of the region should be extended such that the text is in the same position, up to the limits specified above.

This reduces the chance of unexpected line breaks. Applying these rules should allow any text size customisation to retain appropriate relative positioning of each line, without introducing gaps between lines, for example. Illustrative diagram:. This is usually but not always Time expressions must be in UTC. For implementation details, see ttp:timeBase. It is structured around the key TTML elements and attributes: see the example document below and click on elements and attributes to go to their respective section.

This is intended to be a developer-friendly view of the specifications, but not to replace them. However where BBC-specific constraints exist they are described, in relation to the subtitle guidelines that they support.

The specifications remain authoritative and they should be consulted alongside this document:. Because closed subtitles are processed from file, it is possible for a presentation processor e. Generally, the processor should respect the author's intentions. However, where requirements exist that are specific for the authoring or processing of subtitle documents, they are listed separately under the relevant XML element.

Note that in the spirit of an iterative process, there may be further releases making improvements to the developer guidance. In particular, the focus here is on EBU-TT-D creation for online only subtitle delivery; where there is commonality with EBU-TT Part 1 delivery for archive and downstream conversion to a distribution format this is described; however we do not expect that all existing EBU-TT Part 1 delivery requirements are captured here.

Styling and layout are applicative, in other words styling and positional information are defined and identified, and content specifies the styles and positioning by referencing those identified style and regions. Content elements can be timed using begin and end attributes. This example can also be downloaded here. This illustration shows how the document above is interpreted only the subtitle text and the black background will be displayed.

In the following tables, prefixes are used as shortcuts for the following namespaces:. Note that although the examples in this document explicitly include the tt: prefix, there is no requirement that real world documents do so.

For example a common approach is to declare the default XML namespace prefix to be the main TTML namespace, and then omit the relevant prefixes. Attempt to display subtitles as close as possible to their respective begin and end times, regardless of the actual displayed frame rate. Expresses a virtual 2 dimensional grid of cells. The first value defines the number of columns and the second value defines the number of rows.

The cell height 'c' unit is used as the basis for calculating font size and therefore indirectly line height. For example, the default value "32 15" creates a cell with height 6. Font size percentages are relative to the parent element's font size, or if none is set, the cell height.

See Section Describes the area within the root container region that contains subtitles, i. This area typically fully contains all of the referenced regions within the Document Instance.

The active area may be used by a player to ensure that the subtitles remain in the visible area of the screen if the player area is not the same shape as the video image, for example. The visible area of the video must include the specified active area occupied by subtitles. In normal conditions the registration or positional alignment of the subtitle rendering area against the video image must not be modified to achieve this.

The exception would be if the subtitle rendering area is adjusted temporarily for example to accommodate controls. Sets a generic or a named font family. This attribute can contain a prioritised list of font names, which are typically processed in order until a match is found, thus allowing predictable fallbacks to be used.

This list may be evaluated on a per glyph basis to deal with the case where most glyphs are present in a font but later fonts include specific required glyphs omitted from earlier fonts, for example.

Set to Reith Sans, fall back to device-specific and then generic proportional sans-serif fonts so that the end device uses its default font e. Roboto in Android. Fall back to the system defined sans serif font if a downloadable font is not available. Prefer proportional fonts if there is a choice. Double values can be used to set height and width separately, known as anamorphic font sizing - this scales the font by different amounts horizontally and vertically. A single value only can be used.

Percentage values are relative to the parent element's font size, or the cell size when the parent element and every ancestor has no specified font size. Calculate percentage values relative to the parent element's font size, if specified, or the cell size otherwise. Apply a scaling factor based on the device's physical screen size see Presentation font size. For a 32" TV and an authored font size corresponding to the authored font size guideline , apply a scaling factor of 0.

A player supports Reith Sans and the subtitle document specifies that Reith Sans is to be used. The processor also needs to apply a scaling factor of 0. The actual scaling factor to be applied is 0. Note that there is no uniform implementation of the value "normal" by CSS-based rendering processors.

Additionally, different browsers render different line heights for the same font and size. This contributes to a known issue where a gap appears between lines of text. See also itts:fillLineGap. The example below illustrates this: different fonts of the same size were used, with a line height set to "normal". Processors should render as on the right example, without a gap between the lines:. Calculate the line height for a line area using the font's ascender, descender and lineGap attributes, including leading if available.

Alignment of inline areas in a containing block. The alignment values "start" and "end" depend on the value of the writing mode, which in turn depends on the Unicode bidi mode and the style attributes tts:unicodeBidi , tts:direction and tts:writingMode applied to the element.

See also ebutts:multiRowAlign , which provides extra alignment options. Should requirement if only supporting left to right scripts; Shall requirement if support for any non-Latin or non-left-to-right text is required:. Calculate text alignment correctly based on the value of tts:textAlign , the Unicode bidirectional algorithm, and all defined values of tts:unicodeBidi and tts:direction and tts:writingMode.

Calculate text alignment relative to the region after taking into account any start or end padding. If the value is "wrap" , automated line-breaking occurs if the line overflows the region. If the value is "noWrap" , no automated line-breaking occurs and overflow is treated in accordance with the value of tts:overflow attribute of the corresponding region. Note that if tts:wrapOption is set to "noWrap" , the region that corresponds to the affected content should have the attribute tts:overflow set to "visible" so that any overflowing text remains visible.

Subtitlers and authoring software are expected to manage the width of text on each line so that the text does not overflow. There is no constraint on adding manual breaks regardless of the value of tts:wrapOption.

Disable automatic line wrapping so that the editor creates line break manually. If tts:wrapOption is set to "noWrap" , set the attribute tts:overflow to "visible" on the region that corresponds to the affected content. When deriving break points, use the UAX14 line breaking algorithm.

Use the UAX14 line breaking algorithm. If the text overflows its region, attempt to display the overflow even if ugly so that viewers who depend on subtitles don't miss important information. See page 33 of the specification. This attribute effectively creates additional alignment points for multiple rows of text, thus it has no effect if only a single row of text is present. See the references for more detail on this. If the ebutts:multiRowAlign attribute as specified on a tt:p element has the same value as tts:textAlign or is set to "auto" , each generated line area in the tt:p shall be aligned according to the computed value of tts:textAlign.

Background color applies to the line area including the padding. Application of padding affects the layout of text, for example by reducing the maximum width available in which to render text on a single line see line length and region definition. Note this attribute is different from tts:padding , which applies space to a region and in TTML2, to other content elements.

Must be applied to tt:p only. This should be calculated from the aspect ratio, the grid and the font size. For the purposes of the calculation, 1em can be assumed to be equal to the font size. The following example calculation uses non-recommended values for illustration purposes only. If no line padding exists and there is sufficient space available, add 0.

Note that the recommended behaviour for tts:overflow is that it is "visible" and that tts:wrapOption is "noWrap". When laying out line areas inset the line areas by twice the value of ebutts:linePadding from the start and end edges of the region, after having applied any tts:padding values. If scaling the line padding, it may be reduced by up to the same percentage as the relative reduction in font size i.

The attribute can have one of these values only see Speaker Colours :. Set background colour to solid black do not allow opacity. White space that is not styled with a background colour will appear in browsers as gaps in the background. Draw the background area behind each generated line area in the specified colour. Make the height of the background equal to the font's computed line height so that no gap exists between lines.

See tt:span. Specifies whether any gap between the background areas of adjacent lines should be filled or left unfilled. The example below illustrates this: the same font and line height are specified, with itts:fillLineGap set to false on the left, and true on the right. Defines an area in which subtitle content is to be placed. Setting the width of a region to A region of such a size should be centred horizontally i. If no tt:layout element and therefore no tt:region elements is defined in a document, the default region applies, which is the entire size of the rendering area; Default values of the region style attributes also apply.

This is extremely unlikely to be a desirable effect. Note that legacy non-EBU-TT flavours of TTML may exist that omit the tt:layout element: at the time when those documents were created, the default region semantic may have been different. Processors may therefore apply more sensible defaults in this scenario, for example locating subtitles in a predefined position such as bottom and centre. Documents must not contain overlapping regions that are active at the same time where a region is active if any content that is flowed into it is active.

The region's origin x coordinate must be greater than or equal to The sum of the region's origin x coordinate and extent width must be less than or equal to The number of regions active at any one time must not exceed 4 IMSC 1 requirement. Support at least eight regions that are active at the same time. Support at least four regions that are active at the same time. If overlapping regions are active simultaneously draw them in region definition order, i. The x and y coordinates of the top left corner of a region with respect to the root container region, which is the active video for EBU-TT 1.

Presentation implementations are expected to map these to device pixels for optimum display of text. This attribute can be specified on either tt:region or tt:tt elements. It sets the width and height of the region area, being either the root container region, when specified on the tt:tt element or a defined region within that, when specified on a tt:region element.

Note that where pixel coordinates are used they are logical coordinates in the TTML space only and do not need to match actual encoded video or device pixels. Alignment in the block progression direction. When block progression direction is top-to-bottom, "before" would result in "top" alignment and "after" would result in "bottom" alignment. A tts:displayAlign attribute shall be present on every region element. The active lines within the region are aligned in the block progression direction to the before edge of the region for "before" , usually the top for top to bottom left to right , the middle for "center" or the after edge for "after" , usually the bottom for top to bottom left to right.

Defines the directions for stacking block and inline areas within a region area. Applies to region elements only. This attributes interacts with tts:direction and tts:unicodeBidi.

May requirement where support for Latin scripts or left-to-right-top-to-bottom scripts only is required :. Shall requirement where support for any non left-to-right-top-to-bottom script is required :.

Defines whether a region area is clipped if the content of the region overflows the specified extent of the region.

If the author intends to avoid truncated content the tts:overflow attribute should always be specified and be set to "visible".

Note that setting the value to "visible" does not guarantee that content that overflows the region will be presented, for example if it overflows the active video region "root container". See also tts:wrapOption. Set overflow to "visible" so that subtitles are visible even if they overflow.

A logical container of subtitle text. Intended to hold semantic information, for example sections within a programme. A tt:div must contain at least one tt:p element. Represents a logical paragraph. When reference is made to "a subtitle" it is most closely analogous to a tt:p element in general. Timing may be applied to a tt:p element using the begin and end attributes, or to each span inside the element, but in EBU-TT-D such timing must not be present in both.

Each tt:p element must have an xml:id attribute value that is unique in the document. Used to apply style information to the enclosed textual content. This style information is added to or overwrites style information from the currently active context. This is to help ensure no gap exists between lines. This is an example of a prepared subtitle file.

This is not a complete file: multiple instances of elements have been removed and long values shortened. Not all possible elements are included for example, elements required for live subtitles are not included. It includes elements for audio description and signs-language documents that can be omitted for subtitle files.

These instructions assume no prior knowledge and if followed closely will produce a valid but minimal file. You can then use this file as a basis for additional styling such elements such as colour.

Note that these instructions are for creating a bare-bones file that does not include many of the features required by the BBC. All subtitles will appear in white text on a black background and centred at the bottom of the screen. This minimal formatting excludes features like colour to identify speakers , positioning to avoid obscuring important information and cumulative subtitles. You should therefore check with the commissioning editor that this minimal file is suitable.

This is important: Do not follow these instructions if you need to deliver subtitles for broadcast or if the presentation requires more than simple white-on-black text centred at the bottom of the screen.

Consult the rest of this Guidelines document for these cases. Prepare the text. If available, begin with a transcript file so you don't have to type in the text. Add labels if required e. Add line breaks and timings. This is commonly done with an authoring tool. Ideally, the tool should allow you to configure all of the features that determine line length line padding, region definition, cell resolution, font family and font size.

This will allow you to preview the subtitles as reliably as possible the final appearance will be determined by the user's system. Use a wide font such as Verdana to minimise the risk of text overflowing the region when rendered in the final display font. It is not recommended to control line length using a character count limit only: this is a crude method that does not take into account the width of individual letters and fonts.

Although 37 characters would fit most of the time, in some cases they might not e. If you use this method you should test your subtitles in different browsers and operating systems before delivery. Timings must be relative to a programme begin time of Format timings. This means that if you want one subtitle to follow another without any gaps, you should set the end time of the first subtitle to be the same as the begin time of the following subtitle.

Format lines. Remove unnecessary line breaks and white space at the beginning or end of a subtitle. Escape characters. Replace special characters with their escaped version as detailed in Encoding characters. Update the copyright. Save the file with a. If you are new to subtitling, please start there. Who should read this? Anyone providing or handling subtitles for the BBC: authors of subtitle respeakers, stenographers, editors ; producers and distributors of content; developers of software tools for authoring, validating, converting and presenting subtitles; anyone involved in controlling subtitle quality and compliance.

What prior knowledge is expected? What should I read for Further assistance Assistance with these guidelines and specific technical questions can be emailed to subtitle-guidelines bbc.

Example sections are inset and styled with a side border. For example, if you subtitle a scene where a character is speaking rapidly, these are some of the decisions you may have to make: Can viewers read the subtitles at the rate of speech? Should you edit out some words to allow more time? Should you use cumulative subtitles to convey the rhythm of speech for example, if rapping? If there are shot changes within the sequence, should the subtitles be synchronised with those?

Should you use one, two or three lines of subtitles? Should you change the position of the subtitle to avoid obscuring important visual information or to indicate the speaker? In EBU-TT-based implementations, line length is determined by the following attributes: tt:region tts:extent attribute ttp:cellResolution tts:fontFamily tts:fontSize ebutts:linePadding. Because line breaks require considering all of the above, they are better inserted manually.

Implementers should avoid automatic line breaking. See the tts:wrapOption XML attribute. Colour is implemented using tts:color and tt:span. Authored font size, correct positioning: The processor displays the larger font size, as authored.

Reduced font size, wrong positioning: The region's tts:displayAlign is set to "before" so with a smaller font size the text moves up and the second line obscures the mouth. Reduced font size, correct positioning: To avoid this, set the region's tts:displayAlign property to "center" or "after". Authored font size, large region: Line breaks were used to position the subtitles lower within the region. Reduced font size, large region: The line breaks are resized with the rest of the text.

Reduced font size, defined region: Better to define the region so that it does not cover the face and avoid white space. Note, however, that the size of line padding is expressed in cell units, requiring additional calculation. For this purpose, 1em can be assumed to equal font size.

See example in ebutts:linePadding. If scaling the presentation font size, a processor should reduce the value of ebutts:linePadding by the same factor. Vertical positioning is controlled mainly by the tt:region element, which is defined using tts:extent and tts:origin. However, other attributes can also affect positioning within the region. See tts:displayAlign for more details. Horizontal positioning is controlled by the tt:region element, whose size and position are defined using tts:extent and tts:origin.

Within the region, horizontal alignment of lines is achieved using tts:textAlign and ebutts:multiRowAlign. If the frame rate is a whole number of frames per second then the value of frameRateMultiplier is "1 1" ttp:markerMode - value must be "discontinuous".

See specification for details. When the calculation of the framerate from the ttp:frameRate and ttp:frameRateMultiplier results in an integer then the value is "nonDrop". Example: For a 32" TV and an authored font size corresponding to the authored font size guideline , apply a scaling factor of 0. Example: A player supports Reith Sans and the subtitle document specifies that Reith Sans is to be used.

Teletext constraint. The number of characters that generate this width is determined by the font used, the given font size see fonts and the width of the characters in the particular piece of text for example, 'lilly' takes up less width than 'mummy' even though both contain the same number of characters. The set top box or television determines the font - this is most commonly used on the Sky platform. The client determines the font using information from within the subtitle data e.

One of the best benefits of watching foreign films is the growth that you can experience with the language. Usually, this can be hard to master and requires time spent conversing with others who speak that language. Watching foreign films with subtitles on can speed up this learning process. Pro-tip: Repeat movie lines and common phrases out loud to master new vocabulary.

Over time, this will help you sound more confident and natural when speaking. While you might know one way to say everyday words such as lunch or hotel, movies expose you to new phrases. Some of which might be more common than the traditional word you learned. How so? More often than not, foreign films use less formal, slang words that are common among native speakers. Reading subtitles is a great way for viewers to expand their vocabulary. Reading subtitles as they play on the screen also improves grammar.

Take advantage of the pause button, and stop to study the captions on the screen.