Transmit absolute time

[Sebastian Dröge]

On Mi, 2015-10-21 at 16:15 +0200, Pietro Bonfa' wrote:
> Dear You,
> 
> at the present stage I can send and receive timestamps with a
> slightly
> modified version of the onvif plugin that I found in gst-plugins-bad
> but
> I'm facing two issues:
> 
> 1) With both the following two pipelines
> 
> "videotestsrc is-live=true ! videoconvert ! x264enc
> tune=\"zerolatency\"
> ! rtph264pay pt=96 ! rtpatimetimestamp name=pay0 ntp-offset=0"
> 
> "appsrc name=mysrc ! videoconvert ! x264enc tune=\"zerolatency\" !
> rtph264pay pt=96 ! rtpatimetimestamp name=pay0 ntp-offset=0"
> 
> the PTS of the incoming buffers in rtpatimetimestamp (*) starts from
> 3600000000000000 (ns) independently on the PTS information present in
> the source element.
> I'm tend to think that this is due to x264enc but I cannot find
> anything about this in the docs.

See

gst-launch-1.0 videotestsrc is-live=true ! x264enc tune=zerolatency ! fakesink silent=false -v

It indeed starts at 1000 hours, which is not a problem though. However
the timestamps (PTS) are not the interesting things. The corresponding
clock-time is.

> 2) Rather than touching timestamps in the receiver part wouldn't it
> be better to attach metadata to the buffer with
> gst_buffer_add_meta()?

Depends on if you want to synchronize with those timestamps, or just
have them at metadata.

-- 
Sebastian Dröge, Centricular Ltd · http://www.centricular.com

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