Auto switch to fallback stream

The Auto Switch function can be used to replace an audio source that is no longer available - for example, as a fallback for a simulcast.

Workflow

Create a new additional source for this channel with the right incoming bitrate and select the fallback master server.

../_images/new_audio_source.png

When creating listener mounts transcoding should be “forced”. Otherwise transcoding will be skipped if the source and listener mount have the same spec (e.g. same bitrate/format). The fallback mechanism is part of our transcodings so it needs to be enabled.

../_images/transcoding.png

A special setting for the channel has to be created in “Advanced Settings”. This is the place for all settings that don’t have an UI and is written in JSON.

../_images/advanced_settings_fallback.png

Description Structure of the JSON document

  • parameters silence, noise and threshold are freely configurable

  • configuration per channel

  • transcoding feature necessary

{
    "fallback": {
        "url": "http://api.streamabc.net/sources/mounts/redirect/qc_0dm7w3mdgo3b_koaz",
        "max_silence": "10",
        "min_noise": "10",
        "threshold": "-30"
    }
}

fallback is the Key for the settings

url is the StreamURL of the fallback stream. You can just copy the URL of the source here. However, we have a special service that redirects to the source if a channelkey (our unique ID for a channel) is given. It auto-selects fallback mounts. The syntax is http://api.streamabc.net/sources/mounts/redirect/<channelkey> Just use the channelkey of the current channel here. You can find it under “Setup”

max_silence is the number of seconds that the stream has to be silent before switching to fallback

min_noise is the number of seconds without silence before switching back

threshold is the audio level in dB that is considered silence