WCAI on WGBH HD

[Brian Vita]

I just tuned in to WGBH from Peabody and even though I'm seeing a strong
signal the tuner did not see an HD carrier at all.

Brian Vita, President
Cinema Service & Supply, Inc.
77 Walnut St - Ste 4
Peabody, MA  01960-5691
 
Office:  (978)538-7575
Fax:     (978)538-7550


> -----Original Message-----
> From: boston-radio-interest-bounces@tsornin.BostonRadio.org 
> [mailto:boston-radio-interest-bounces@tsornin.BostonRadio.org]
>  On Behalf Of Garrett Wollman
> Sent: Thursday, October 04, 2007 6:17 PM
> To: Dan.Strassberg
> Cc: boston-radio-interest@rolinin.bostonradio.org
> Subject: Re: WCAI on WGBH HD
> 
> 
> <<On Thu, 4 Oct 2007 16:45:51 -0400, "Dan.Strassberg" 
> <dan.strassberg@att.net> said:
> 
> > I was under the impression that in FM-band HD, the 
> aggregate bit rate 
> > of the main channel plus all ND-n channels was limited to 96 kbps.
> 
> Extended hybrid mode adds 12.5, 25, or 50 kbit/s of 
> additional capacity over standard hybrid mode.  Thus, a 
> station running full extended-hybrid could carry their main 
> service at 64 kbit/s, a second audio service at 48 kbit/s, 
> and a third audio service at 32 kbit/s, leaving 2 kbit/s for 
> PAD and other signalling.
> 
> > bandwidth. I find it hard to believe that a stereo HD stream at the 
> > same 48-kbps rate could have bandwidth any narrower than what I'm 
> > listening to. If it did, I think it would sound so bad that nobody 
> > would be likely to listen. But I suspect that it would be 
> quite a feat 
> > to squeeze the same audio bandwidth into a STEREO stream at half of 
> > the bit rate of the mono stream I am listening to.
> 
> None of these codecs implement lossless stereo.  The standard 
> technique (I don't think HE-AAC aka "HDC" actually does this) 
> is to compute a source-direction vector for each subband in 
> the encoder, and then quantize it down to just a few bits per 
> block of audio.
> 
> -GAWollman
> 
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