input-selector sync-streams: on or off?

Michiel Konstapel michiel at
Wed Jun 23 14:00:02 UTC 2021

I am using input-selector to switch between live video from a webrtcbin 
and an imagefreeze (is-live=TRUE) "placeholder" source. I was wondering 
what the proper setting is for the input-selector's sync-streams 
property. The documentation is rather brief:

"If set to TRUE all inactive streams will be synced to the running time 
of the active stream or to the current clock.

To make sure no buffers are dropped by input-selector that might be 
needed when switching the active pad, sync-mode should be set to "clock" 
and cache-buffers to TRUE."

By default this is set to TRUE, but sync-mode defaults to 
"active-segment" and "cache-buffers" defaults to FALSE, which both do 
not match their recommended settings.

- What does the sync-streams setting actually do?
- Should I turn it on or off?
- If ON, what should the sync-mode and cache-buffers settings be?

Kind regards,

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