TwentyThree is built to make it easy to upload and use any kind of video files on the web. When you upload a file, the system will test whether the upload file is a valid video file — and if it is supported by TwentyThree.

Generally, we support any kind of video file (for example .mp4, .avi, .wmv, and .mov) and the vast majority of video and audio codecs (for example H.264, AAC, VP8, ProRes, WMV, WMA, Ogg and so on). In the event a video file or codec is not supported, please let us know.

You cannot upload non-video files, even if they happen to contain video clips within them. For example, uploading Word documents (.doc), Flash files (.swf) or Zip archives (.zip) will not work.

When you upload a video file we will generate video thumbnails and start converting the file into web-friendly formats in everything from mobile quality to Full HD. Formats include:

• MPEG-4 containers with H.264 video codec and ACC audio codec in bitrates from 300 kbps to 3,000 kbps.
• WebM containers with VP8 video codec and Ogg audio codec in bitrates from 900 kbps to 1,500 kbps.
• Various mobile formats in 3GP containers for smartphones.
• An audio-only version of the upload video, prepared in MP3 format.