[vlc-devel] Streaming wizard issues

Marian Ďurkovič md at bts.sk
Mon Nov 30 09:02:41 CET 2009


On Sun, Nov 29, 2009 at 05:20:16PM +0200, Rémi Denis-Courmont wrote:
> * Should the "Stream" button at the bottom not be greyed until at least one 
> destination has been added?

> * Disabling transcode does not seem to work in 1.0-bugfix. Did we forget to 
> backport something?
It does work, but the procedure is counter-intuitive. You need
to uncheck transcoding first, and only then add e.g. RTP output.

> * It does not make sense to have Audio and video port for RTP, since we're 
> only offering RTP/TS, does it?
Yes, those are confusing. However, we have another problem here as well:
this tab was purposedly kept in sync with Open Network tab and (here) we
were always telling our users that those two should be used the same
way. Now, the Open Network doesn't have the 'Port' field, and port needs
to be specified as ':1234', so we should use the same here. 

> * Should we split RTP into RTP/AVP and RTP/TS?
TS-muxed output is prevalent in any production environment, and for proper
IP-muxed RTP we still need to implement RTCP & A/V sync. Even if that's in,
(live555) the spec has shortcomings preventing proper sync until RTCP
packets for all streams were received. That said, I don't think we need
IP-muxed RTP in the GUI.  

> * Is "UDP" not a bit confusing (RTP is UDP too)? 
> How about "MPEG-TS over UDP" ?
Everyone uses udp in the URLs, so the main title should say UDP, maybe
a smaller explanation somewhere in the tab saying we're packing it
into MPEG-TS will be useful. Same for RTP. 

> * Could we prefill the RTP address to some pseudo-random ASM group?
No. We don't know whether the user wants to use global ASM group, GLOP
or some of the local group addresses.

> * Could we enable SAP by default and prefill it to "<user>'s stream" or 
> whatever?
No. Universities typically have global multicast connectivity, and not
everyone wants his stream to be publicly visible from the whole world.

> * If SAP is disabled, could we grey out SAP and SAP group fields?

> * Shouldn't SAP and group be greyed out or absent if there are no RTP nor UDP 
> targets?

> * Is "group name" really useful? Isn't it confusing? (Honestly, I first 
> thought it meant multicast group IP address)
We're using that a lot, maybe it could be renamed to something less
confusing like "Playlist category" or so.

One additional item:
* TTL is by default set to 1, which was supposed to limit multicast to the
LAN scope. But it's highly confusing for users and multicast scoping shouldn't
be done via TTL hacks as it might put too much burden on routers where TTL
expires. TTL should be set to 255 by default. 

    With kind regards,


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