imscED

imscED is an editor for the subtitles and caption format IMSC. It shows how imscJS from Pierre Lemieux can be used to manipulate style attributes from an parsed IMSC document and how to export it back to XML.

Note that this project is a pre-alpha release for developer review. It is a prototype in development and can change at any time. The code does not represent a public API.

Therefore it is not ready for production and use it at your own risk.

Restrictions

See below for some of the important restrictions.

Adding and removing content elements

• It is possible to add and remove a <p> element (refered to as subtitle block).

• It is possible to add and remove subtitle lines by inserting a <br> element and a new <span> element.

• It is not possible to add an additional <span> element on a subtitle line.

Timing values

• Timing values are only displayed and can be edited for p elements.

Parameter

• TTML parameter (ttp:timeBase, ttp:frameRate etc.) cannot be changed.
• Not all TTML parameter are exported.

Interactive positioning and resizing

• Dynamic positioning ("dragging") and resizing of regions work only if tts:origin and tts:extent are specified for a <region>.
• If tts:position is used instead of tts:origin dynamic positioning and resizing will not work.

File export

• The exported document structure is different from the original document structure. It is normalized based on the parsing by imscJS.
• TTML metadata, foreign namespace elements and foreign namespace attributes are not exported.
• Not all TTML parameters are exported.

Style attribute support

See below for the current style attribute support:

Style Attribute
backgroundColor
color
direction
display
displayAlign
extent
forcedDisplay
fillLineGap
fontFamily
fontSize
fontStyle
fontWeight
lineHeight
multiRowAlign
opacity
origin
ruby
rubyAlign
rubyPosition
shear
showBackground
textAlign
textShadow
unicodeBidi
visibility
wrapOption
writingMode

Player Controls

• Native player controls for closed captions and fullscreen do not work with timed text rendering.
• To view the video in full-screen mode, use the "Fullscreen" icon below the video.

Integrated REST services

SCF Service

The Subtitling Conversion Framework (SCF) is used as a REST service to import SRT and EBU STL files. At the moment a public URL for this REST service is configured (NOTE: This service is not available anymore). See the Service README of the SCF project how to setup your own SCF service.

Burnin-Service

The Video Image Burner (VIB) is used as a REST service to "burn in" IMSC subtitles. This option is deactivated by default. You need to setup your own VIB service, before activating this option in the configuration menu of the editor. See the README of the VIB project for more information.

To be used by imscED, the service needs to available at http://localhost:9010.

Configuration

Integration of Custom Settings in Build Process

A custom settings file can be added to the build process. This file is separated from the imscED repository. It is stored in a "custom" folder. This folder is ignored by this git repository. This way custom settings and other files can be maintained by the user in a seperate, user-specific repository.

To enable this customization feature the file .env.local needs to be added to the root directory.

touch .env.local

The content of the file needs to be as follows:

VUE_APP_CUSTOMSETTINGS  = true

Note: It is possible to use the .env file in the root directory as blueprint and to rename it into .env.local

Then a custom folder needs to be added to the root directory with a file named customSettings.json.

mkdir custom
touch custom/customSettings.json

The custom settings file need to have the following structure:

{
  "charsPerLine": 37,
  "lang": "de",
  "maxLinesPerST": 2,
  "minStDuration": 1,
  "readingSpeed": 14,
  "showHints": "show",
  "showVisualization": "show"
}

Values can be adapted to the user requirements.

Currently, only the following settings can be changed:

• language of the user interface (German and English are supported)
• maximum numbers of characters per line
• maximum number of lines per subtitle block
• minimum duration of the subtitle block
• assumed average reading speed
• switch to control the display of error messages and hints
• switch to control the display of the duration guideline compliance visualization

To get the settings into effect the project need to be rebuild (i.e. the development server needs to be restarted).

Build Setup

# install dependencies
npm install

# serve with hot reload at localhost:8080
npm run serve

# build for production with minification
npm run build

# You need to copy the content of the dist directory
# to your production environment

Authors

Development: Michaela Finger, Yury Lungantsov, Andreas Tai

UI Concept: Laura Ehlis, Michaela Finger

Requirements: Laura Ehlis, Andreas Tai and Rico Zimmermann

Acknowledgement

Parts of imscED were developed in the project dwerft - linked metadata for media (www.dwerft.de).

dwerft - linked metadata for media is a research and development project for innovative media tech solutions by different media and IT companies located at the renowned area of Babelsberg.

The project is funded by Bundesministerium für Bildung und Forschung and Innovative regionale Wachstumskerne PLUS.