[vlc-devel] Re: vlc: svn commit r13006 (fkuehne)

Viktor Kompaneyets vato at wnet.ua
Tue Nov 1 10:35:24 CET 2005


Marian Durkovic wrote:

> Hi Viktor,
> 
> On Mon, Oct 31, 2005 at 12:39:32PM +0200, Viktor Kompaneyets wrote:
>> A lot of my devices (linux boxes) use raw UDP and non-RTP udp protocols.
> 
> Could you perhaps give some more information, e.g. what are those devices
> - PCs or special devices (set-top-boxes) running Linux OS?

Special devices _like_ STB, but not equal.

> What 
> application are you using for receiving the raw UDP streams? Do you have
> source code of this aplication?

Yes, I have. I had _removed_ RTP from them to achive better wandwith
consumtion (with RTP it is not enough!)

> 
>> Disabling raw UDP will switch me from VLC completely or making an
>> transforming  from RTP to raw UDP.
> 
> Noone has proposed to disable raw UDP. Raw UDP is, and will be available
> from Open->StreamOutput Window as well as from command line.

Yes, I understand. But - I need _both_ opions in wizard.

> 
> This discussion was only about StreamingWizard i.e. the part of VLC aimed
> to assist users to pick the best choices suitable for most of them. RTP is
> certainly better than raw UDP (see my previous emails). Even in case of
> simple LAN where no reordering happens, RTP is better for at least two
> reasons:
> 
> 1) it exactly identifies the payload. 

I know exactly a payload of stream - so no need to make SDP.

> With raw UDP, only intelligent 
> guesswork could be used to estimate the payload type and at least with
> some streams this is not 100% safe 

No need - streams are hard defined.

> (sometimes MPEG-TS from Vbricks is 
> misdetected as being MPEG-PS). Such exact identification could also assist
> to properly set quality-of-service parameters in the network.

No need in my setup.

> 
> 2) RTP continuously checks the packet sequence numbers, and if some
> packet(s) are dropped in the network, it's able to inform the user and
> tell him how many packets are missing. This helps to separate network
> problems from others.

I can detect that at hardware lewel with more flexible error concealing -
and for detecting network problems I've separate control. 

> 
>> > - and most VLC users are aware of the
>> > need for RTP, even if they incorrectly announce their session as being
>> > raw UDP - but I've fixed this in [12899] so this should disappear as
>> > soon as they upgrade to 0.8.4.
>> 
>> Don't do so!
> 
> You've probably misunderstood this paragraph. Before [12899], VLC
> announced raw UDP streams as "raw UDP", but also RTP streams as "raw UDP".
> This was only working for VLC due to RTP autodetection, but other
> standard's based
> applications  were confused and unable to play such RTP streams. In
> [12899] I've fixed this problem, so now raw UDP streams are announced as
> "raw UDP" and RTP streams are correctly announced as "RTP".

In case, when you don't use announcement - there is no sense in RTP/SDP.


-- 
Viktor Kompaneyets
Wnet project manager

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