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Captioning Vodcasts - Accessibility Toolkit - Version 3 - 2009

There will be people who won't be able to access the audio content of the video because:

• They are deaf or hearing impaired;
• They are in a noisy environment; or
• They cannot play sound.

Vodcasts cannot be made fully accessible, but they can be made accessible to some people with disabilities; for example people who are hearing impaired or deaf. A vodcast is made accessible by:

• Providing a transcript of the video in text or HTML; and
• Providing captions of all the audio content in the video.

Relationship to WCAG1 checkpoints:

Checkpoint 1.4 requires that for any time-based multimedia presentation (e.g. a movie or animation), there must be synchronized, equivalent alternatives (e.g. captions or auditory descriptions of the visual track) with the presentation

Tools you will need

In order to create captions of your vodcast, your file must be in MP4 format. You will need the following hardware and applications to create a vodcast:

• Speakers
• Microphone
• Webcam
• MAGpie 2.0 (see MAGpie installation instructions
• Quicktime Pro
• iTunes account (if you want to add the vodcast to iTunes)
• RSS feed URL

Using MAGpie to create captions

MAGpie is very well-known accessible captioning software.

Create a project:

• Under the File menu, select "New project"
• In the dialog box, select the "Browse" button and select your video file
• For "Caption styles" select 18pt, centred and click OK
• When the "Create new project track" dialog box opens, click OK

Create a caption:

• Press F6 to begin the video. After a sentence or two, press F6 again and type what you have heard into the "Caption" column.
• Each caption should not exceed two lines
• Speech does not need to be in quotes. Speech should be preceded by the name of the speaker in the first instance bracketed and in italics, e.g.: [Vera] We teach maths, English and LOTE
• Subsequent captions of speech do not need to be labeled unless there has been a change in speaker
• Important audio information should be included, bracketed and in italics, e.g.: [Laughs] Well we get all sorts in here
• Unimportant audio information should not be included, for example "um", "ah" etc.
• When there is a significant period of silence or background music without important audio information, then this should be captioned. Captions containing this information should be bracketed and in italics, eg: [Music plays]
• When you have completed one caption, press Enter twice to create a new row for a new caption.

Setting the timestamp:

• Press F7 to rewind the video to the beginning
• Move to the first row and press F9 – this will set a timestamp of 0:00:00.00 and means that the first caption will appear as soon as the movie starts
• Press F6 to begin playing the video
• When the beginning of the next caption is spoken press F9 – this will set a timestamp for the new caption  The caption must appear on the screen at the same time as the speech, or sound, that is being captioned
• Continue until all captions have timestamps
• MAGpie will automatically insert a new row at the end. Delete this row (right-click on the row and select "Delete selected rows")

Checking your work:

• Under the "Export" menu select "Quicktime – SMIL 1.0 format"
• Open Quicktime and select the SMIL file that MAGpie created
• Play the video with the sound on. Check that:
• Captions appear at the same time as the sound they are captioning; and
• That all important audio information has been captioned.
• Play the video with the sound off. Check that:
• Captions appear on the screen for enough time to read (approximately 3 – 4 seconds for a two line caption);
• There are no periods without captions; and
• That speech has been attributed to a particular speaker.

Associate captions with the vodcast

Associate captions

• Open the original vodcast (without captions) in Quicktime
• Open the vodcast.qt.txt document in Quicktime
• In the vodcast.qt.txt file, under the Edit menu, select the option "Select All"
• Under the Edit menu, select Copy
• Go to the original vodcast
• Under the Edit menu, select Add to movie

Position captions on the screen

• Under the Window menu, select Show Movie Properties
• Select Video Track and then the Visual Settings tab
• Write down the number in the second Scaled Size field (in the example below, this number is 240)

• Select Text Track and then the Visual Settings tab
• In the second field of the Scaled Size fields, change the number to 80.
• In the second Offset Field, insert the value you captured in step 3, above

Export to MP4

• Under the File menu, select Export
• Under Export As select Movie to MPEG4

Upload and insert the vodcast to a site

• Copy the vodcast to your web server
• Add a link to the vodcast

If your RSS feed is not already uploaded to iTunes:

• Go to iTunes
• Select iTunes store
• Select "Submit a podcast"
• Select Podcasts on the left hand side
• Down the bottom right hand side of the page, select "Submit a podcast"
• Insert your RSS URL
• Select Continue

iTunes will review your vodcasts before putting them on the iTunes site.

Example 1: Test vodcast

A test vodcast, complete with captions has been created at Gian Wild's web site.

Example 2: Koorie education captioned vodcast

A complex vodcast, complete with captions has been created at Gian Wild's web site

Further Information

• Checkpoint 1.4: For any time-based multimedia presentation (e.g. a movie or animation), synchronize equivalent alternatives (e.g. captions or auditory descriptions of the visual track) with the presentation
• NCDAE: Introduction to captioning
• MAGpie: Caption authoring
• WebAIM: Captioning with MAGpie 2.0
• Streaming Media: Merging captions and video
• Best practices in online captioning
• How to create an accessible podcast
• WebAxe Podcasts: Jeffrey Frey on Accessible Podcasts
• Accessible podcasts
• Podcasting and accessibility
• Jeffrey Frey's Podcast Captioning

Source: Accessibility Toolkit Version 3, September 2009. Section 5 - Captioning Vodcasts.

Last updated: 30 June 2010 Tweet

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