[xiph-rtp] Re: new RTP development list

[illiminable]

----- Original Message ----- 
From: "Ralph Giles" <giles at xiph.org>
To: "Aaron Colwell" <acolwell at real.com>
Cc: <xiph-rtp at xiph.org>
Sent: Thursday, October 21, 2004 12:01 PM
Subject: [xiph-rtp] Re: new RTP development list
>> Part of this may be historical reasons. Various file formats are 
>> suboptimal for
>> HTTP delivery becuase vital information is at the end of the file. Ogg 
>> has
>> this problem as well because you can't know the length of the file 
>> without
>> seeking to the end. HTTP 1.1 with byte-range support has helped with this
>> problem a little, but for a long time 1.1 support was rare and/or 
>> incomplete.
>
> Yes. We felt like we fixed all of these. There's of course no reason for 
> id3
> tags to be at the end either, it's just a stupid format. Ogg of course 
> goes
> further the other way as a pure streaming format: there's no two modes 
> about
> it.
>
> I guess you want the total length so you can provide a playback 
> progress/seek
> bar? We could also resolve that with a metadata field, I imagine.

Yeah... having the duration at the end is as bad from the players 
perspective as having the metadata at the end, if you want it to be 
seekable, or to show progress information.

Though i guess in live streaming... it generally is neither seekable nor of 
known duration... but for stream-from-file cases it still means you have to 
seek to the end before you can start playing.

Isn't one problem with chaining and rtp going to be that with chains, time 
appears to go backwards at chain boundaries... not knowing a great deal 
about rtp... isn't the idea that time only increases with a stream ?

And it's not realiable transport is it ?

So given the following case...

song 1 packets....
...
short radio station promo (very few packets)
song 2 packets....
...

There's no gaurantee that those few promo packets will arrive before song 
2's start packets is there ? And since they are not time continuous, you 
have no way to know they are out of order. So potentially... you could see 
song 2's packet... start up a new chain... then recieve the promo packets, 
think it's a new chain... then get more song 2 packets and be totally 
confused about what order you should be playing things in.

Or do i not fully nuderstand how it works ?

Zen.