How to set a constant bitrate on Wowza Transcoder

You can enable a constant bitrate (CBR) for streams out of the Wowza Transcoder for default, NVENC, and Quicksync.  To do this, add a logging property to the encode block of your choice to discover what the bitrate mode should be for your transcoder configuration. To do so, add the following to the Encode/Properties section of the transcoder template:


Restart Wowza and publish your stream to see the transcoder fire up. Upon doing so, you will see a couple of comments in the logs (this is for “default” implementation):

INFO server comment – # long: bit_rate_mode: bit rate stuff: 0=H264_CBR, 1=H264_CQT, 2=H264_VBR or 3=H264_TQM
INFO server comment – mainconcept.bit_rate_mode: 2

This suggests that the current mode is VBR. To change this to use CBR, you would set the following property in your Video/Parameters section:


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