This is the page where we have tried to answer the most frequently asked CaptionTools questions.  If you don’t find what you’re looking for, please submit a question through our Contact Form, and we will get back to you as soon as possible with an answer.

Uploading Media and Transcripts

What type of media files can I upload?  

CaptionTools accepts mp4 video and mp3 audio files that are under 500MB in size.

What if my video is larger than 500MB? 

It is best to convert it to an mp3 audio file, which will be smaller.

How do I convert video to mp3 audio?

If you have an mp4 file that is over 500MB in size, or if you have a different type of video file, you can convert it to an mp3 audio file that will work with CaptionTools.

You can use a video editing program like Camtasia, or Final Cut if you have one.  If you don’t have video editing software, you can use a free or paid media conversion software like Handbrake, Wondershare or Replay Converter.

Replay Converter is easy to use, and we use it the most. Here is a link to their official site:  http://applian.com/replay-converter/

There are also free online conversion tools, but they do require that you either link to or upload your media file, and they take more time.  Here are some examples of free online conversion tools:



What if I still want to edit the video?  Can I submit an unedited video and make the captions work later with the edited video?  

No.  It’s best to wait until the video is fully edited, then submit it for transcription and/or alignment of captions.  Our system takes the audio track and time codes to make your file.  If you edit the video after alignment, the time codes will be off.  While it is possible to use our caption file editor to edit the caption file after an edit, it’s best to avoid that if possible.

Can I upload more than one media file at a time?  

You can upload another file once the first file has been uploaded.  We plan to enable batch uploads in the future.

If I submit an mp3 file for transcript alignment, is it possible to use the actual larger mp4 video file to open when I edit the caption file?  I’d like to see the video while I edit. 

Yes, you can open the mp4 video file by browsing to it instead of the mp3 you uploaded.  It’s often helpful to see the video when editing the caption file.

What type of transcripts can I upload?  

You should upload a plain text file.  ASCII encoding is best.  There should be no page numbers, and no line numbers.  Those will be read as text, and they will appear in your caption file.

What if my transcripts are in Word? 

To save as plain text, follow these steps.

Inside the Word document, Click FILE —> SAVE AS, then choose PLAIN TEXT (*.txt).  Then if it gives you a warning that you may lose formatting, choose Text Encoding format of OTHER Encoding: US-ASCII (or ASCII on a mac.) Also, check the box called “ALLOW CHARACTER SUBSTITUTION.”

Caption Editor


  • Delete line(s) – Used mostly by realtime captioners to delete “test” lines, it can also be used if a video is edited after alignment, to delete a line or a section that is removed from video.  Delete Lines Tutorial
  • Display Time – change minimum display time for each caption line.  Display Time Tutorial
  • Download Caption & Transcript Files – caption and transcript files are downloaded from the dashboard in Caption Tools or from your Streamtext dashboard.  Tutorial
  • Edit Text – easily add or edit text.  Edit Text Tutorial
  • Find/Replace – allows replace and “replace all.”
  • Foot Pedal Supportthe media player works with foot pedals.  See the “shortcuts” to see what keystrokes to program into the foot pedal.  ALT-J is a toggle to play and pause.  The left arrow on the keyboard rewinds 2 seconds, and the right arrow key fast forwards the media 2 seconds.
  • Force Uppercase – make entire file all caps, if desired, by clicking on the “Uppercase” button at the top of the edit page.  You can undo this process by using the “oops” key (control-Z on a PC or command-Z on a mac)
  • Line Length – change number of characters per line.  Line Length Tutorial
  • Media Player – open and play media file.  Media Tutorial
  • Media Synchronization – click on caption time codes to queue media to that location.  Media Sync Tutorial
  • Merge Lines – join two short lines (time codes with words stay with words)  Merging Lines Tutorial
  • Quick Fix button – set line length, display time and first time code in one keystroke  Quick Fix Tutorial
  • Rename File – easily rename the file within our system.  Rename File Tutorial
  • Shortcut Keys – click on “view shortcuts” to see shortcut keys that use keystrokes to perform edits on the file.
  • Spellcheck – integrated spellcheck shows suspect words in red.  Spellcheck Tutorial
  • Split Lines – move text from one line down to the next line.   (Time codes for those words stay with the words!)  Splitting Lines Tutorial
  • Synchronize media file to text file – If you submitted your job for auto alignment, the media file and the text file should already be synchronized.  If you are a realtime captioner and created the text file in Streamtext, for instance, the “realtime” time codes will need to be changed so that the first word spoken lines up with the time code where you hear those words in the archived media file.  Then you will need to “ripple” the time codes throughout the file in order to keep the rest of the file in sync.   Synching Media Tutorial
  • Time Code Adjustment – adjust start, end and display for each caption.  Time Code Adjustment Tutorial

Caption Files

What kind of caption files can I download from CaptionTools? 

When you submit a file for auto transcription, CaptionTools produces transcripts and SRT caption files.

When you submit a transcript and media file for alignment and caption file production, you have more options.  You can download a plain transcript (with no time codes), SRT, TimedText 1.0 XML, WebVTT caption files.

How do I know what type of caption file I need? 

The caption file type is determined by where the video will be hosted.  Each hosting platform accepts a specific type or types of caption files.  You can do an internet search to determine how to upload caption files to the video hosting platform, and that will usually tell you what type of file to upload.

Here are some common platforms and the file type they accept:

YouTube – VTT (preferred) or SRT

Vimeo –  VTT

What if I need a caption file type that CaptionTools does not support? 

Let us know what file type you need, and if it’s a common type or we have a large demand for it, we will add that file to our export list.

If you need to convert or SRT, VTT or Timed Text 1.0 XML to another format, there are some free tools on the internet that you can use to covert to any caption file type.  Our favorite is called Subtitle Edit.  It is a free download.


Searchable Video

Information coming soon…