The quick points below that describe the difference between subtitles, captions and transcripts are directly from the following presentation. Please see the full presentation for all the details.
Captioning & Web Video by Mark Gamble SC AT EXPO 3/26/2014
http://scvrd.net/downloads/pdfs/Captioning2014.pdf
Subtitles (See Slide 32) Quick Points:
Translations of audio content for non-native speakers
Assume you can hear sound effects or music cues
Captions (See Slides 34-35) Quick Points:
Assume that the viewer is completely deaf
Include all spoken content, sound effects, music cues and other significant audio
Typically displayed in two lines at the bottom of the screen, which is called a caption frame
Can be done in real time, referred to as CART (Communication Access Real-Time Translation), or in post-production, sometimes referred to as offline captioning
Transcripts (See Slide 36) Quick Points:
Displays everything that captions display
Identifies all speakers
For web video, both captions and a text transcript should be provided.
For content that is audio only, a transcript is sufficient.
Guidelines for Captions (See Slides 50-53) Quick Points:
Captions appear on-screen long enough to be read.
Synchronize captions with spoken words, or start slightly before speaker
Identify speakers when more than one person is on-screen or when the speaker is not visible
Write sound effects when they add to understanding.
Preserve use of slang and identify accent
Translating speech to text sometimes requires creative use of punctuation, but always remember the rules of good grammar.
Video/Transcript/Caption Examples (See Slides 37-39)
Ready Houston: Regional Disaster Preparedness RUN.HIDE.FIGHT.
Transcript: http://www.readyhoustontx.gov/trans-runhidefight.html
SCVRD Evaluation Center Promo http://spareroommedia.com/video.php?type=eval_center&title=SCVRD%20Evaluation%20Center%C2%A0Promo&autostart=false
Subtitle Workshop http://www.urusoft.net/products.php?cat=sw&lang=1
TextWranger (Mac)
http://www.barebones.com/products/textwrangler/
Notepad ++ http://notepad-plus-plus.org
HTML5 Video Caption Maker http://ie.microsoft.com/testdrive/Graphics/CaptionMaker/
It says it's a demo to "create simple video caption files. Start by loading a video in a format your browser can play. Then alternately play and pause the video, entering a caption for each segment." If you have a draft of your caption (in WebVTT or TTML format) you can upload it and edit it here, too.