[streaming] Re: Big data blocks to network from videoinput?

Marian Durkovic md at bts.sk
Sat Mar 1 11:15:59 CET 2003


On Fri, Feb 28, 2003 at 11:25:13AM +0100, Christophe Massiot wrote:
> On Fri, Feb 28, 2003, Marian Durkovic wrote:
> 
> > > >   doing some tests with live streaming from MPEG2 encoder board I've run
> > > > into following problem:
> > > > 
> > > >   Encoder board outputs data only once per frame (i.e. once every 40 ms).
> > > > When it outputs I-frame (every 15-th block of data), the data block could be
> > > > as large as 100 KB or even more.
> > > 
> > > Does your encoder output PS or TS ?
> > 
> > It's PS.
> 
> Then I know no solution to your problem, as VLS is forced to read each
> PES packet entirely before sending out TS packets. A solution would be to
> increase the buferring on VLS's side, but I have no idea how to do it
> (maybe a VLS developer can help you on this).

Well, not sure if this is a good idea due to MPEG2 nature, but perhaps the 
network output (or ts_streamer) could have some mechanism which prevents it 
from pushing e.g. 80 IP packets (with size of 1316 bytes each) to the net 
at the same moment.

For example, the 4 Mbit/s stream needs to deliver approx. 400 IP packets/s
which means that in optimal situation packet shoud be sent to network every
2.5 miliseconds. Seems the TS streams received from sattelite behave exactly 
this way - and thus I have no problem to watch any sat channel on a PC with 
10 Mbps connection. However, the stream received from MPEG2 encoder board 
(or from file?) ouputs those big blocks of data which is causing problems.

   Thanks for any help and/or comments.


	With kind regards,

		M.

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----                                                                  ----
----   Marian Durkovic                       network  manager         ----
----                                                                  ----
----   Slovak Technical University           Tel: +421 2 524 51 301   ----
----   Computer Centre, Nam. Slobody 17      Fax: +421 2 524 94 351   ----
----   812 43 Bratislava, Slovak Republic    E-mail: md at bts.sk        ----
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