Selecting alsasrc slave-method: resample not implemented?

Arun Raghavan arun at
Wed Nov 2 16:29:27 UTC 2022

On Fri, 28 Oct 2022, at 4:36 AM, Michiel Konstapel via gstreamer-devel wrote:
> I am trying to select the most appropriate pipeline clock for multiple 
> long running capture/streaming pipelines, each capturing multiple audio 
> sources and one video source. By default, the pipeline selects the 
> clock from an alsasrc, but I have noticed that this drifts noticeably 
> over the course of several hours (I've seen about 40 ppm, so 150 ms per 
> hour). Instead, I figured GstNetClientClocks synced to the server would 
> be more appropriate for long-term stable timekeeping. However, that led 
> me to look into how to clock the alsasrc. Documentation on the effect 
> of the various slave-methods is quite limited, but "resample" sounds 
> the most accurate/stable/smooth? However, source diving appears to 
> indicate that resample isn't actually implemented, and uses "skew" 
> instead:

One way to manage this is to use `drift-tolerance` and `alignment-threshold` to effectively limit the size of discontinuity introduced (at the "cost" of making more frequent adjustments).

-- Arun

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