Timestamping buffers with live and non-live sources

[Bob Barker]

Hi All,

We’re new to GStreamer, writing our own elements and trying to understand
the implications of these excerpts from the GStreamer Plugin Writers Guide:

Sec 18.4.1 Non-live source elements

“They must choose the timestamps and the values of the SEGMENT event in
such a way that the

*running-time of the buffer starts from 0.” *





Sec 18.4.2 Live Source Elements

They must choose the timestamps and the values of the SEGMENT event in such
a way that the *running-time of the buffer* *matches exactly the
running-time of the pipeline clock when the first byte in the buffer was
captured.*









Questions:

-For live sources:  does this mean that if a buffer was captured live at
time 1934234.34, the timestamp is also 1934234.34?

-For live sources: When is the base time snapped? When the sensor captures
the first sample? When the first element retrieves the first sample?



We went through the tutorial at

http://docs.gstreamer.com/display/GstSDK/Tutorials

and couldn’t find anything explaining this. If there’s some documentation
clarifying all this, please point us at it.

TIA
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