[gst-devel] streaming over mobile IP and multicast IP

Wim Taymans wim.taymans at chello.be
Wed Jan 15 08:46:11 CET 2003

On Wed, 2003-01-15 at 11:22, Erik Walthinsen wrote:
> On 15 Jan 2003, Luis Rodero wrote:
> >  sender   -> gst-launch filesrc location=file.mp3 ! udpsink port=7778
> >  receiver -> gst-launch udpsrc port=7778 ! mad ! osssink
> > the receiver can not even start to play the song, it seems like the data
> > travels 'too fast'. No data is lost, as we have introduced some delays
> > in the udpsink plugin to slow the sending rate,
> The raw file data coming from filesrc doesn't have any timestamps.  I


> don't know if udpsink/udpsrc are set up to pace data based on the
> timestamps, but they should be, and then you would put mp3parse between

UDPsink is able to pace data based on timestamps, provided there is a
plugin in front of it that generates those timestamps (currently no
plugin exists that can timestamp but not decode mp3 data AFAIK). You
also have to be aware that UDP drops packets when the network is

Adding timestamps to mp3parse wouldn't be hard.

> filesrc and udpsink.  Then the issue becomes one of global clock
> management, which wtay will have to answer.

There is currently no gstreamer support for syncing clocks accros
machines, it is however possible to create a new clock that does this
or one could sync the clocks at a lower layer with ntp or so.

about the multi-receiver case: I don't think it is supported yet

about capsnego over udp: udp does (minimal) capsnego, it serializes the
caps over a TCP socket to the receiver. This also explains why the
multi-receiver case doesn't work too well...


Wim Taymans <wim.taymans at chello.be>

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