[vorbis] streaming ogg audio

[Kenneth Arnold]

On Thu, Jun 27, 2002 at 06:06:01PM +0200, figyu wrote:
> 
> From: "Stephen Commiskey" <scommiskey at pharmacology.umsmed.edu>
> 
> > Is this what you were looking for, Figyu?
> 
> no, unfortunately not. all i would like to see is that winamp shows a seek
> bar when listening to a streaming ogg file, and also allows me to seek back
> and forth to my taste. unfortunately again, it does neither :-(
> 
> that's what i'd like to have a solution for, or pls recommend me a good
> player that can do this.

Peter's plugin for Winamp, which has now been included as the Vorbis
plugin for Winamp >=2.80, has the option. Check the box labelled
"Enable HTTP/1.1 seeking (slow)" (or at least that was the wording of
it a few versions ago -- I'm not even completely sure it's in the
current version).

Its method is a simple abuse of HTTP/1.1 resumed downloads, from my
knowledge and also snooping around in my server logs. It gets a file
length from the HTTP/1.1 response header, then whenever vorbisfile
asks for a seek, it just breaks the stream and asks to resume from
that point. Obviously it takes a sizable number of such resumes for
both opening the file and seeking to an arbitrary point. The actual
logic of where to seek to is apparently left to vorbisfile, which then
uses the same method that it uses for seeking in local files.

Obviously this will only work in getting an Ogg that's stored as a
regular file on a resume-capable webserver (relatively recent Apache
and IIS for sure, probably most other major webservers by
now). Seeking of any sort within a live stream is much more complex,
and practically only useful for seeking within what the client has
already downloaded (think VCR / PVR e.g. TiVo) while simultaneously
keeping up the incoming stream. This is very possible, but potentially
much more complex, especially in dealing with the player environment
(e.g. telling WinAmp that your file is growing, handling relative or
absolute seek requests, storing the file, etc.).

I'm pretty sure by the time I finally get to sending this out, someone
else will probably have given a similar reply... but it's worth a shot
:) Hope it's helpful.


-- 
Kenneth Arnold <ken at arnoldnet.net>
- "Know thyself."


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