Media Captioning

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Thanks to browser standards made public by the folks at W3C™ it's pretty easy to caption video on CDs and the Internet.  All you need is a file with each caption and when the caption will appear and most browsers will take care of the rest.

Here's an example:

00:00:02:00  00:00:04:10  Here is a simple example.
00:00:04:11  00:00:07:08  It has two captions.

That's the theory at least.

In reality there are a lot of permutations.  The permutations are typically distinguished by the file extent -- like xyz.TT or xyz.SUB.  None of these permutations or formats are really difficult to make, just incredibly tedious if you have to do it without AutoCaption.

Click here to see an example of a media file captioned with a SMIL file.  In addition to generating SMIL format caption files, AutoCaption also generates Timed Text (.TT), FLV, and SUB format caption files.

Here's a list of some things a captioner must consider when making a file to caption media:

  • How is the appearance time described?
    • By how long the caption will be presented (duration)
    • By how long after the video starts will the caption appear
    • By how long after the video starts will the caption appear and how long it will be presented
    • By how long after the video starts will the caption appear and when will it be removed

  • How is time expressed?
    • HH:MM:SS:FF — hours, minutes, seconds and frames like SMPTE time code.
    • HH:MM:SS — hours, minutes, and whole seconds
    • HH:MM:SS.SS — hours, minutes, and decimal seconds
    • SSSS.SS — decimal seconds
    • TTTTTT — tenths, hundredths, or even thousandths of a second(rare)

  • What ends a line or separates time or text entries?
    • A carriage return (hexadecimal 0D) ends a line
    • A carriage return followed by a line feed (hexadecimal 0A) ends a line
    • A HTML tag ends a line
    • A line feed ends a line
    • Blank spaces separate times or text
    • Tabs (hexadecimal 09) separate times or text

  • How is the caption described?
    • As conventional HTML
    • As XML
    • As simple text
    • As a subset of HTML or XML.  For example, font color changes or italics might not be allowed.
    • In a proprietary markup language.  This happens when the viewer will use a proprietary video player rather than a conventional Internet browser.

  • Where will caption be displayed?
    • In a fixed position in a fixed space.
    • Positioned within the image area
    • Positioned within a fixed space

  • How is the caption positioned?
    • Once at the start of the performance.
    • By commands inserted between captions.
    • By commands that are part of the caption
    • By inserting blank characters

AutoCaption is designed to let us quickly cope with these permutations -- and more.  If a client approaches you for a media captioning file, simply ask if the client has the file specifications (often called a "protocol") or if the client has an example of the kind of file they want.

You can use an ordinary word processor (like Microsoft's NotePad™) to check out a media caption file.  Odds are that AutoCaption already makes one with the same format, and if it doesn't we can usually have a suitable update in your hands within three days.

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