[opendtv] Re: New Philips HDD/DVD recorder

A 5.1-channel audio package might take 384 kbps (I prefer 448). Mono audio might be 64 kbps.
So, a 5.1-channel VI package (audio for the visually impaired) takes 384 kbps, and a 5.1-channel undescribed CM (complete mix) package takes 384 kbps. Together, they take 768 kbps out of the channel. On the other hand, a mono description (VI) added to a 5.1-channel complete mix (CM) is just 448 kbps, a savings of 320 kbps.
Now consider other viewers. A 5.1-channel music & effects package (ME) might take 384 kbps, which, combined with a 64 kbps English-language dialogue (D) channel comes to 448 kbps, worse than just the CM. But add Spanish 5.1, and the two CMs would take 768 kbps; 2D+ME is just 512 kbps. Add French to that (as you might want to do in Miami, where the three languages are commonly spoken), and it's 3CM at 1.2 Mbps versus 3D+ME at 576 kbps. Add more languages, and the bit-rate advantage increases for the dual decoders. 

Or try a science show with multiple commentary channels.
But broadcasters cannot do it, even though it's perfectly okay in the standard, because (unless things have changed recently) not a single dual-stream audio decoder has been sold. 

TTFN,
Mark


Adam Goldberg wrote:

Can someone explain this to me.

In order to have a program with descriptive audio, you must produce the
program without descriptive audio; also then produce the descriptive audio.

After our 'mini-failure', in order to broadcast a program with descriptive
audio (optional), you need to send two complete audios (one without, one
with the descriptive audio).  Decoders with only one decoder merely select
the right one somehow.

Without the 'mini-failure', in order to broadcast a program with descriptive
audio (optional), you'd need to send one complete audio and one mezzanine
audio with just the description.  Decoders would need to select & decode the
mezzanine for those that want it.

What functionality exactly is missing given our state of having a
'mini-failure'?

Adam Goldberg
adam_g@xxxxxxxxx

-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx] On
Behalf Of Mark Schubin
Sent: Thursday, December 27, 2007 3:40 PM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: New Philips HDD/DVD recorder

John Willkie wrote:

I suspect that you disagree with the effective banning of dual audio as
being a mini-failure. 
I see it as making 4 or more of the bsmod services unusable and making
descriptive video service (if that becomes mandatory per the FCC at some
point in the future) 'rather difficult.' (Blind people won't be able to
select how much source audio they hear in relation to video descriptions.)

Agreed.

TTFN,
Mark
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