[vlc-devel] Re: Overhead and JXTA
gcmmoura at gmail.com
Tue Apr 5 21:59:46 CEST 2005
Ok, Sigmund. Thank you.
I'm using --sout udp:IP_ADDRESS in my command line. What can you tell me
more about this?
About JXLA. I got it on my ethereal.. See the screeshot
Do you think ethereal is wrong?
Sigmund Augdal wrote:
>On Tue, Apr 05, 2005 at 04:24:53PM -0300, Giovane Moreira wrote:
>>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:?
>in general, for streaming media you have application layer protocol and
>container format. Both these add overhead to the bare codec data. These are
>specified using access and mux keywords when
>constructing a vlc stream output. Vlc have several, so you need to tell
>which ones you are using if we are to give useful feedback.
>>And other question: Why VLC uses JXTA? Why not another api?
>never heard of that. Quite sure there are some mixup there.
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