From: Wim T. <wim...@gm...> - 2008-09-04 16:51:29
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On Thu, 2008-09-04 at 11:34 -0400, Tristan Matthews wrote: > 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? > This situation can not occur in gstreamer when you have a well written source element that generates correct timestamps and reports its latency correctly. You could write an element that applies an offset to all timestamps on the buffers. Wim > -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 <tr...@sa... <mailto:tr...@sa...>> > > > > 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: tr...@sa... <mailto:tr...@sa...> > > web: http://www.music.mcgill.ca/~tmatthews > > <http://www.music.mcgill.ca/%7Etmatthews> > > > > > > ------------------------------------------------------------------------- > > This SF.Net email is sponsored by the Moblin Your Move Developer's > > challenge > > Build the coolest Linux based applications with Moblin SDK & win > > great prizes > > Grand prize is a trip for two to an Open Source event anywhere in > > the world > > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > > <http://moblin-contest.org/redirect.php?banner_id=100&url=/> > > _______________________________________________ > > gstreamer-devel mailing list > > gst...@li... > > <mailto:gst...@li...> > > https://lists.sourceforge.net/lists/listinfo/gstreamer-devel > > > > > > ------------------------------------------------------------------------ > > > > ------------------------------------------------------------------------- > > This SF.Net email is sponsored by the Moblin Your Move Developer's challenge > > Build the coolest Linux based applications with Moblin SDK & win great prizes > > Grand prize is a trip for two to an Open Source event anywhere in the world > > http://moblin-contest.org/redirect.php?banner_id=100&url=/ > > ------------------------------------------------------------------------ > > > > _______________________________________________ > > gstreamer-devel mailing list > > gst...@li... > > https://lists.sourceforge.net/lists/listinfo/gstreamer-devel > > > > |