question how to add own customized element between source element and decodebin2 element when using playbin2

Tue Nov 13 23:51:58 PST 2012

Hi,

Only the sound of the stream is getting corrupted. Video plays smooth
still. Can this still be explained by clock skew or stream data corruption?
I would suspect to see corruption or frame drops in the video too. So there
is never a queue (buffering) needed to play a live udp stream?

Do you have more information on the gio performance issue? Could I find out
somehow that my system is affected?

GStreamer version:
base: 0.10.36
good: 0.10.31
bad: 0.10.23
ugly: 0.10.19

Best regards,

Christophe

On Wed, Nov 14, 2012 at 8:24 AM, Edward Hervey <bilboed at gmail.com> wrote:

> Hi,
>
>   summary: this issue doesn't require a queue to fix the issue.
>
>   What version of GStreamer are you using ?
>
>   The "crackling" is most likely due to clock skew happening, or data
> stream getting corrupted.
>
>   Depending on the version of GStreamer you are using and the bitrate
> being used, you might want to increase the udpsrc socket buffer-size to
> a bigger value (buffer-size property).
>   Also note that there is a performance issue with the underlying system
> being used by udpsrc (gio) which is currently being fixed. On some
> systems it could cause packet drops (because we don't read out the data
> from the socket fast enough).
>
>    Edward
>
> On Tue, 2012-11-13 at 21:09 +0100, Christophe Oosterlynck wrote:
> > Tim-Philipp, thanks for your quick and helpful reply. I'm glad I asked
> > here first before starting to implement something. I will try your
> > suggestion.
> >
> >
> > I'm also not sure if inserting a queue element right after the udp
> > source is the right way to catch my problems with udp streaming. The
> > actual problem I'm having is corrupted sound on playing a raw udp
> > stream containing a transport stream consisting of H264 video and MPEG
> > 1 layer 2 audio. The image is fine but the sound starts crackling
> > after a while until it sometimes disappears completely until it plays
> > fine again and repeats this in a cycle of 60 seconds.
> >
> >
> > As there is no buffering for live sources in playbin2, I'm suspecting
> > this to be a problem. Why is there no facility in playbin2 to delay
> > playback of a udp stream a bit to buffer it and handle possible packet
> > delays?
> >
> >
> > Best regards,
> >
> >
> > Christophe
> >
> >
> > On Tue, Nov 13, 2012 at 3:09 PM, Tim-Philipp Müller <t.i.m at zen.co.uk>
> > wrote:
> >         On Tue, 2012-11-13 at 05:40 -0800, Christophe Oosterlynck
> >         wrote:
> >
> >         > I'm looking to do the same thing. Right after the source, I
> >         want to insert
> >         > another element and let playbin2 do the rest.
> >         >
> >         > From what I see I have 2 possibilities:
> >         > * react to "notify::source" signal, add the extra element to
> >         the bin, link
> >         > it to the source and let playbin2 continue
> >         > * wait until playbin2 has finished constructing the whole
> >         pipeline, unlink
> >         > source and next element and insert extra element in between.
> >         >
> >         > Can I do one of these safely or shouldn't I fiddle with the
> >         playbin2
> >         > pipeline behind its back?
> >         >
> >         > What I want to achieve with this: buffer a live udp source.
> >         > The buffering mechanism in playbin2 is not usable for live
> >         sources as you
> >         > cannot pause them. I want to insert a queue element right
> >         behind the udpsrc
> >         > element with min-threshold-bytes. This works when I create a
> >         custom pipeline
> >         > with gst-launch. If this is not the best way to handle this,
> >         let me know.
> >         > Nevertheless, I'm still interested in the answer to my
> >         question on fiddling
> >         > with the playbin2 pipeline.
> >
> >
> >         You should not fiddle with playbin's pipeline, and certainly
> >         not link
> >         elements behind its back. It won't work. Even if it does work,
> >         it might
> >         stop working tomorrow. And we won't even feel bad for a second
> >         if your
> >         app breaks doing things like that ;)
> >
> >         The only sane way to do things like this is to write your own
> >         element,
> >         which could be a GstBin subclass where you add some source and
> >         whatever
> >         additional elements you want and then create a ghost source
> >         pad. You can
> >         then register a new (or existing, if you must) URI protocol
> >         for it, so
> >         if you do playbin uri=fooudp://a.b.c.d:port it will plug your
> >         bin.
> >
> >         Or you could try to come up with API for playbin to add such a
> >         thing,
> >         but I think would need to be rather well-justified and deemed
> >         interesting enough to be added.
> >
> >         (What does your "routine" element do, "BCXA" ?)
> >
> >          Cheers
> >           -Tim
> >
> >         _______________________________________________
> >         gstreamer-devel mailing list
> >         gstreamer-devel at lists.freedesktop.org
> >         http://lists.freedesktop.org/mailman/listinfo/gstreamer-devel
> >
> >
> >
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>
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