[vorbis] Virgin Radio launches an Ogg stream

[James Cridland]

In this mail, Lawrence, you're talking about our audio processing. I would
quote the relevant paragraph, but when they built Blackberrys, they didn't
allow us to edit the quote that appears underneath, unwittingly meaning that
all Blackberry users look like top-posting newbies.

It may interest the group to know that we -do- process our online audio
streams, but they are processed with a dedicated sound processor that gets
the most out of audio online. There is a fair bit of dynamic compression
going on there, but emphasising different frequency ranges than FM or AM.

>From the online processor (it's a standard processor, with settings produced
primarily for our lower bandwidth feeds), it then gets mono'd for some of
boxes (in particular, the Real encoder we use has trouble creating a proper
mono signal).

The Ogg encoder is using a soundcard that we plan to roll out to all our
other services - a proper professional soundcard with decent balanced audio
inputs. Many of our other services are using domestic soundcards.

I too agree that our 96k Ogg stream sounds really good. I put it down, in
part, to the processing we're giving it, and in part to the new soundcards.
It ought to be noted that it could sound even better: the audio level going
into this card is a little lower than it could be, because some of the
domestic soundcards demanded a lower input level. We will be able to turn up
the wick a little, and thus get the encoder working even more efficiently,
once those cards are out of the system: for Virgin Radio's main service,
this is scheduled to be within the next few weeks.

Finally, from my experience, most other stations actually encode their
signal from their off-air feed, with a tuner - in most stations, IT and
Engineering don't have the happy co-existence that we have here. A signal
processed for FM, then transmitted (complete with the stereo enhancement
most FM stations run), then re-encoded off a cheap tuner, is not going to
make your audio sound any good online.

I believe our broadband stream is a great example of streaming Ogg Vorbis,
and any help any mailing-list readers could give us in shouting about it
would be very well received: whether on /., or in some of the more
mainstream media. I am available for interview (and funnily enough, today
the photographer's in to take a better shot than the one of me that appears
on page 44 of Internet Works here in the UK where I look about ten.)

I hope all that helps. This e-mail is coming to you from the London tube -
the Piccadilly Line - where it is currently very hot, very crowded, and
unusually nobody else is tapping away on anything electronic at all. Other
exciting things happening here include lots of people reading books, lots of
people reading the free newspaper, someone over there with a Sony minidisc,
and a man sitting next to me who looks as if he's just slipped through a
timewarp from the 1940s.


-- 
James Cridland, Managing Editor, Virgin Radio New Media
Better music, more of it: http://www.virginradio.co.uk/

Add us to your website: http://www.virginradio.co.uk/linktous

This message is personal, forms no part of a contract, and may not reflect
the views of Virgin Radio or SMG plc. Please do not forward this message or
post it onto newsgroups or messageboard without permission.

<p><p><p><p><p><p>-----Original Message-----
From: Lawrence Wade <vorbis at glowingplate.com>
To: vorbis at xiph.org <vorbis at xiph.org>
Sent: Wed Jun 18 00:24:43 2003
Subject: Re: [vorbis] Virgin Radio launches an Ogg stream

At 04:45 PM 6/17/2003 -0400, you wrote:
>WOW!  I just listened to the Virgin Radio Ogg Vorbis 96K stream.  It's
>currently hard to find high-quality stereo Vorbis streams right now.  This
>is the best sound quality for an internet radio station I have EVER heard!
>Most high-quality stations broadcast at 128K mp3, which to me sounds just
>about like FM.  I have to say this is much, much better, and even uses
>less of my incoming bandwidth.  Thanks for the Vorbis.

    I was impressed with the sound quality too, but I wonder if that's the 
reason - flattering as it is to Vorbis, even 128kbps MP3 doesn't sound as 
bad as most Internet radio stations.

    We have to expect a moderate increase in fidelity for a given bitrate, 
but I doubt it will be as extreme as that. Certainly Ogg vs. MP3 at 
comparable bitrates isn't *that* extreme in my experience, let alone for 
96kbps vs. 128kbps. (I use Ogg mostly because I can have the sound quality 
of a 192kbps MP3 with somewhat less size than a 160kbps MP3. When you're 
dealing in gigabytes of music, it makes a difference.)

    FM radio is highly compressed, AM even more so. Not compressed in terms 
of small data rates, compressed in terms of the dynamic range - this 
because of the comparatively high noise floor of radio as a medium. Not to 
mention the FCC doesn't like it much when you clip the modulator...

    I suspect the reason is that they're taking the output to the Internet 
"transmitter" before the compressor, while most radio stations with an 
Internet feed just put it in parallel, taking a sniff of the compressed 
output heading to the radio transmitter.

    Lawrence Wade, BOFH
    www.glowingplate.com

<p>     

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