VoiceThread Docs / Troubleshooting / File types accepted

VoiceThread allows you to have conversations around almost any type of file, including images, videos, documents, and presentations; however, it is a big, wild world of technological standards out there, and there will be times when you run into a file that just doesn’t work the way you expect. Here is an overview of our currently supported file types and advice about what to do when one of them doesn’t seem to work.

First, always make sure that you are using the latest version of Google Chrome or Mozilla Firefox as your web browser.

File-type basics

  • Size. No single file can be larger than 25MB with a Free account. If your presentation or video is larger than that, try breaking it up into smaller files and uploading them individually. To upgrade your account, please visit the VoiceThread Products page.
  • Originals. If you have an upgraded account, VoiceThread will save and store your original file so that you can allow others to download the original file. If the owner of the VoiceThread allows it, you can right-click on any slide within a VoiceThread to download the original document and save it on your computer.
  • Import from a link. If you enter the direct URL of a file, you can import it right into a VoiceThread, but the link must be absolutely correct. Note that most “links” to videos hosted by online services like Vimeo do not point directly to the video file, so they won’t work with this upload method. In this case, you’ll need to search for a third-party program to download the video on your computer and then upload it from your computer to VoiceThread. Please keep in mind all fair-use and copyright laws when using online content with VoiceThread. Note: VoiceThread does support import from YouTube.
  • Files you definitely can’t upload: .swf, .html, and .txt


JPEG, GIF, PNG, and BMP are all acceptable image types that you can upload into a VoiceThread. Because a VoiceThread can zoom in and out on images and documents, we recommend that your images be at least 1280×960 (which a 2mp or higher camera can produce) so that when you zoom in on an image, it appears crisp and detailed. We also accept a number of less common image formats, including vector graphics like SVG.


Audio files must be in MP3 or WAV format.


It seems like we should have a list of all the video file types we accept, but it gets a little complicated. There are a number of “container” formats like QuickTime, WMV, and AVI, that are like an envelope containing the video. A QuickTime movie can be encoded by close to 40 different codecs. We can convert the vast majority of them, but not all, so we can’t say we can accept “all” QuickTime, WMV, or AVI videos, but we do accept most. Unfortunately a little trial and error is the only way to know for sure. We’re constantly adding to the list of file types we support. Having said that, we can definitely recommend the best format, both for us to convert and to produce the highest quality possible. There are only two key parameters:

  • Use the H.264 codec to encode or compress your videos.
  • Upload videos that roughly match the native size of a VoiceThread, which is 600 x 450 pixels.

If you do those two things, then the quality of the video prior to your upload should match the quality after.

Of course, your videos don’t have to be sized perfectly, or even use the H.264 compression codec, but if you want the absolute best results, this is what you’ll need to do.

VoiceThread’s video doodling feature, which allows you to draw on a video, can only stop on “keyframes,” so if the subject of your video requires you to stop precisely in a fast moving video, e.g., a golf swing, then you’ll want more frequent keyframes. If you don’t know what we’re talking about, that’s absolutely fine. The default settings will work perfectly 99% of the time.


DOC, DOCX, PDF, ODT, XLS, XLSX, and ODS are all supported.

If you are adding the document to your VoiceThread in order to provide additional printable materials to your participants, make sure to tell them how to download and print them. See Playback Options for more information. If a user right-clicks on page 5 of 30 in a document, we’ll allow him to download the entire original document, not just that one page. You may want to mention to your participants that this is an option.

If you’re putting a document into your VoiceThread because you want to have a discussion about the text within it, then we suggest changing the format to “landscape” mode (wider and shorter) and making your text much bigger. You should also consider changing the default Playback Option to “Open in Full Screen”. This will make the text much more accessible and readable to the average participant. Take a look at this tutorial for details about formatting documents for VoiceThread.

If you’re dissatisfied with VoiceThread’s conversion of your document, the most reliable format to use is PDF. The PDF format was designed for document portability and precise reproduction, so it’s the best way to get exactly what you want.


PPT, PPTX, ODP, and PDF are all supported presentation file types. When you upload a presentation file, we will store the original and then break it up into individual slides within the VoiceThread. Please note that animations, links, and transitions are not preserved in VoiceThread. SWF files are not supported at this time. If you experience any formatting issues (strange fonts or layout) after you’ve uploaded the presentation, try converting the original presentation to a PDF and then upload it again.

While a VoiceThread allows you to have a conversation about almost any type of media, there are occasionally times when a file simply won’t work because of an uncommon or undocumented incompatibility with some element within the file. If you cannot convert the file to a format that VoiceThread will accept, send us a note, and we’ll see if we can help.