Vorbis - Jun 2008 - can I inject metadata on every frame ?

Hello,

 	First of all, sorry for my fractured English ;-)

 	I am developing a project to control & stream audio from an 
amateur radio receiver and I need a way to send audio & extra data (small 
messages from receiver application).

 	Them I think about using metadata of streams, something as using 
Title/Artist tag, to include this "extra data", example:

 	On title, send always actual Frequency of receiver, so if this 
change, clients can view the changes. This updates on metadata must be 
refreshed too much, on every second of stream will be acceptable. On 
artist maybe the actual mode of receiver (AM/FM...) or incoming signal 
station (decibels).

 	I know that maybe metadata was not created for this purpose, but 
for my project, this solution is perfect, because only one channel of data 
is used.

 	FAQ tells that there is some way of multiplexing data in the OGG 
container, but I don't know if this multiplexing is done for every frame. 
So I am wondering if this is possible, to continue with project, or 
develop another solution (with stream and data separated).

 	thanks!

On 1-Jun-08, at 11:31 AM, alex wrote:
> On title, send always actual Frequency of receiver, so if this
> change, clients can view the changes. This updates on metadata must  
> be refreshed too much, on every second of stream will be acceptable.
If you're streaming to normal "internet radio" clients, what
you're
supposed to do is end the current stream and start a new encoding  
every time the metadata changes. It's done this way so the metadata  
can be found after a seek if the stream is stored. However, because  
the codec setup headers have to resent at the same time, there's a  
bitrate penalty, so this doesn't work well if your metadata is  
changing more than every 30 seconds or so.
> FAQ tells that there is some way of multiplexing data in the OGG  
> container, but I don't know if this multiplexing is done for every  
> frame.
So I was speaking above about the built-in vorbis metadata, which is  
"per stream segment" not per frame, etc. You can multiplex another,  
custom data stream with the vorbis data, with whatever time  
resolution you like. This is the best thing to do if it's a custom  
application, where you control both the server and the client. The  
problem is there's no standard for a separate 'metadata' stream, so
most regular Ogg stream clients will just ignore the updates, and  
some hardware players won't play it at all.

FWIW,
  -r