[gst-devel] add latency to audio in gstrtpbin

[Tristan Matthews]

Thanks for the feedback Eric. I had seen the RFC before but that book 
looks pretty useful as well.
My concern isn't that the AV will get out of sync in 
gstreamer/gstrtpbin, but rather that it will be out of sync immediately 
at the capture stage, i.e. if i have video input from a camera with more 
latency than a separate audio source. An example scenario is given here:
http://chris.pirillo.com/2007/07/11/audio-video-capture/
where you have video of someone clapping and you have to adjust the 
delay to make the sound and image of the clap line up.
I would need to be able to manually adjust the latency to ensure the 
video and audio are sync'd. Should I just put the audio through a 
Ladspa-delay or is their a better solution in gstreamer?

-T

Eric Zhang wrote:
> Hi, Tristan:
>
>     You should not adjust video/audio latency manually because RTP 
> provides a mechanism to accomplish this, called `lip-synchronization'. 
> Refer to RFC 3550 or book `RTP: Video and Audio for the Internet' for 
> more details. These will help you a lot.
>
> Eric Zhang
>
> 2008/9/3 Tristan Matthews <tristan at sat.qc.ca <mailto:tristan at sat.qc.ca>>
>
>     Hi,
>
>     If I have a pipeline using gstrtpbin (similar to the example in the
>     documentation) to send audio and video, what is the best/most reliable
>     way of adding latency to the audio? Would gst_event_new_latency work
>     (and if so, how), or am I missing its intent:
>     http://gstreamer.freedesktop.org/data/doc/gstreamer/stable/gstreamer/html/gstreamer-GstEvent.html#gst-event-new-latency
>
>     Basically my concern is that if video capture is too slow, can I
>     manually adjust the audio latency to match.
>
>     Best,
>
>     Tristan
>
>     --
>     Tristan Matthews
>     Société des arts technologiques [SAT]
>     email: tristan at sat.qc.ca <mailto:tristan at sat.qc.ca>
>     web: http://www.music.mcgill.ca/~tmatthews
>     <http://www.music.mcgill.ca/%7Etmatthews>
>
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-- 
Tristan Matthews
Société des arts technologiques [SAT]
email: tristan at sat.qc.ca
web: http://www.music.mcgill.ca/~tmatthews