[vlc-devel] Overhead and JXTA

Giovane Moreira giovane at gmail.com
Tue Apr 5 21:24:53 CEST 2005

Hello Folks,

I'm studying the vlc performance while I'm streaming multimedia content. 
I streamed a MP3 file (cbr 128kbps) to another machine, 1 hop
distance, and I used snmp to monitoring my ethernet card. I found out
that I need 186,31 kbps (average) to transmit this mp3 file (cbr
128kpbs). In my research I'm trying to measure how much overhead is
generated on many different scenarios.

So I started guessing: -Who's responsable for this overhead? 
In tcp/ip stack, we have:

Application layer: that's where VLC mount the package. JXTA protocol
is used here (that's what ethereal showed me on my linux box)

Transport Layer: VLC use UDP (and there's a little bit overhead here
too - 64 bits per udp package)

Network Layer: IP protocol - a lot of overhead here... IP has many field 

Link Layer: Ethernet  overhead.

So here I am: Is my approach correct? I'm justing summing all fiels of
non-data(I mean, metadata, the data except the mp3 file... such
checksum, port, source fields) of all protocols used in all layers in
transmittion. So if I sum all this then I got my overhead. Is this

Example: transmit 100 bytes of mp3 file. I should then add the JXLA
overhead (couse of JXLA protocol fields and other protocols). So I
should add UDP overhead (64bits per package) then IP overhead(192bits
per package) and then Ethernet Overhead(26bits per package).

I'm supposing that snmp count all this data.And I got who's generating
the overhead. Is this ok:?

And other question: Why VLC uses JXTA? Why not another api?

Thank you so much,


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