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ON24 Knowledge Center

Presenter Media Specifications

Describes presenter media, the differences between video clips and presenter media, and the audio and video file specifications.

*Available for Simu-live, Sim-2-live, and On Demand Presentations

As an alternative to recording audio over the phone, you can upload a pre-recorded media file of your presenters. Presenter Media can be a video (.mp4 at 1 Mbps) or an audio (.wav at 128 kbps) file.

Once the media file is uploaded, you will need to set your slide timings accordingly. To learn how to upload your Presenter Media file and set your slide timings, click here.


Video Clips

Presenter Media

  • Added to the storyboard of the webcast
  • Used in combination with other elements such as PowerPoints, polls, and URLs
  • Supported for all webcast present types
  • Generally shorter clips

Find Video Clip Specifications here

Find more information on adding video clips to your storyboard here

  • Recordings of ENTIRE presentations
  • Can be either audio or video files
  • Used for Simu-live or On Demand Recordings

Find Presenter Media specifications here


Presenter Media files must be encoded with a Constant Bit Rate (CBR).  If Variable Bit Rate encoding is used on the files, it may generate lip sync issues when the files are played back during the event.

Audio File Specifications

If you wish to use a pre-recorded audio file, upload a .wav file and use the interface in the Presentation View window to set the timings for the storyboard elements. The best practice is to upload a 16-bit mono .wav file.

The encoding specification ON24 uses for Simple Audio .wav files are:

Maximum File Size 2 GB

Audio Format

PCM Unsigned

Audio Sample Rate

8 kHz

Audio Sample Size

16 bit

Bit Rate

128 Kbps - A constant bitrate (CBR) is required. 


1 (mono)


Video File Specifications

Maximum File Size 2 GB
File Format MP4 (.mp4)
Video Format

H.264 / AVC or VPG 

These codecs are absolute necessities.

*MPEG4-Visual codec is not supported.

Audio Format

ACC or MP3 

AAC audio format is preferred if using H.264, with MP3 the mobile stream might encounter issues.

Audio Sample Rate 48 kHz

32 Kbps mono is sufficient and will allow the video to be encoded at a higher bit rate.

Anything over 96 Kbps for the mono audio stream is unnecessary unless the audio was recorded in a studio (16 Kbps is the approximate audible top-end of a traditional copper telephone connection).

Stereo is supported, with speeds up to 128 Kbps.

Frame Size

The video must be a 16:9 or 4:3 aspect ratio.

16:9 - We recommended 1280 x 720 pixels or 800x450 to minimize file size and bandwidth issues.

4:3 - 960x720 or 800x600 

The frame size of the video should match the size of the Media Player in the audience console.  Some customers may use a 20% larger frame size in the encode to allow the attendees to enlarge the video player on the console without losing resolution.

Bitrate - a number of "bits per second" (bps) at which data in a video is being delivered.   Normally quoted in kbps or Mbps (kilobits or megabits per second)

1 Mbps / 1024 Kbps (Add both the audio and the video channels to get the total bit rate.)  Generally speaking, the higher the bit rate, the higher the bandwidth requirement for the audience.

A constant bitrate (CBR) is required.

We recommend a max of 1024 Kbps, but those desiring higher quality media will see some improvement up to approximately 3 Mbps.  Bit rates up to 3 Mbps are supported.

The inbound audio and video are transcoded to support Adjustable Bit Rate (ABR); currently speeds of 750 Kbps video/1500 Kbps video + 64 Kbps audio is the rate distributed to the audience. 

If there is not an overriding need for high quality, we would appreciate you using 1 Mbps for uploaded video.  Higher rates are supported, but give rise to quite larger files, with the associated slow uploads to the platform.

Frame Rate - Frames per second (fps) 30 fps or less;  25 fps is common in countries using 50 Hz power




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