Multiple Bitrate Streaming with vMix

Note: adaptive (multiple) bitrate settings are available only when streaming with Flash Media Encoder or streaming with vMix.

When live streaming with vMix, the broadcaster has the option to add multiple bitrates for output video so that the viewers will be able to watch the stream at its best quality according to flash players on their devices.

In the example below, we introduced three values for bit rates and output video, in order to make the streaming available for all viewers, from low video players (e.g old generation mobiles) to HD video players (cinema mode).


Important: We recommend that the bit rates and the output sizes should be ascending from low, to standard, and then HD video quality

Items to consider when setting the vMix broadcaster:

1. The profile must be Baseline and level 4.1.

2. FMLE broadcasting tools must be previously installed on user PC.

3. AAC audio option will work only if related AAC encoder plugin is installed on user PC;
on our testing lab we were able to successfully stream using both MP3 and AAC audio options.

4. Stream name should always contain “_%i” similar with FMLE setup, otherwise the live stream will not work

5. If a specific setup is incorrect – there is no warning or hint displayed on Vmix like on FMLE interface


The user must also properly set the RTMP stream URL and stream name on the vMix broadcaster, based on the details taken from the Broadcast Options page:



When a viewer watches the live streaming channel, the channel Player will adopt the appropriate resolution for the best video quality.

Note: The video quality depends on the device used, on the internet connection, the bandwidth, and video/audio source used by the broadcaster

The channel player will usually start playing at the best resolution and it will switch to the lower one if the bandwidth or the internet connections are not high enough:


The viewer can manually select the resolution they desire from the available ones and the video the flash player will save that resolution, without making further changes.

Note: When the video changes from a resolution to another, the stream quality can sometimes be insignificant to the human eye.


Important: Multiple bitrate feature for videos is not available and can not be used if CDN module is activated. This feature was developed to work only through Adobe FMIS services and not CDN. Technically if CDN is activated, videos will play as expected, based on technical specifications and devices used, but mobile qualities will not be displayed and available on flash/non flash players.

E.g.: If I have a video having the following qualities: 480p, 360p, 240p, 144p and CDN module is activated on the site, video in question will be available for playback only at 480p.