In article ,
(Mark Zenier) wrote:

In article
,
Telamon wrote:
In article ,
(Mark Zenier) wrote:

As much as I dislike giving Mr. Gleason arguement points, you have to
consider that the psycho-acoustic compression schemes used in IBOC-AM
reduce the equivalent analog bandwidth down to a telcom grade signal,
(32-36 kBps = 3 kHz at [mumble 40 dB?] signal to noise ratio). Compared
to the 16-18 kHz of a high-fi AM broadcast signal. (Not than anybody
seems to bother anymore...).

On the other hand, there's going to be a quality loss with all the
gargling kazoo sound effects and other crap from de/compression.
Somebody need to come up with a formula that equates that distortion
to a Signal to Noise ratio.

Oh, that has been worked out and the codecs used by HD are an
intentional form of distortion.

Seriously, there needs to be a way of equating artifact distortion to
bandwidth to keep the media managers from adding more and more channels
to the point where it all sounds (or looks) like crap. The "free market"
won't work, here, because the viewer/listener is either, 1) in the case of
subscription media, trapped in a monopoly situation, or 2) for advertiser
supported media, is not the customer but instead "is the product" (or,
if the wrong age, "not in the demographic" and doesn't count at all).

Every codec can compress audio/video/pictures to a certain extent to
transmit the data in less bandwidth. The no-loss ones don't do enough so
people employ ones that distort the data in acceptable ways. Whether the
distortion is "acceptable" or not depends upon the listener/viewer and
the material that is compressed. The situation is actually a very
complex mix of the depth or detail of the program material and the
person that is hearing or viewing the material. Some combinations will
work well but others poorly. Personally I have a low tolerance of audio
and video artifacts.

I think that what people should understand is that when a codec is
employed it is similar to adding noise to the program material in a
psycho-acoustic way(for radio). It just kills me when some goober comes
along and touts the use of a compression codec as an "improvement" in
the transmit/receive system.

--
Telamon
Ventura, California

In article ,
Telamon wrote:
Every codec can compress audio/video/pictures to a certain extent to
transmit the data in less bandwidth. The no-loss ones don't do enough so
people employ ones that distort the data in acceptable ways. Whether the
distortion is "acceptable" or not depends upon the listener/viewer and
the material that is compressed. The situation is actually a very
complex mix of the depth or detail of the program material and the
person that is hearing or viewing the material. Some combinations will
work well but others poorly. Personally I have a low tolerance of audio
and video artifacts.

I think that what people should understand is that when a codec is
employed it is similar to adding noise to the program material in a
psycho-acoustic way(for radio). It just kills me when some goober comes
along and touts the use of a compression codec as an "improvement" in
the transmit/receive system.

Well, I guess what I'm saying is that somebody needs to come up with
"some real world but worst possible" test cases that can be used to
come up with a quantitative number for distortion, instead of the media
manglers being able to say "It sounds ok to 50% of our audience, so what's
your problem".

One thing that bothers me is that there are probably certain program
materials that get censored by default because they look or sound bad
when passed through the compression, so that the broadcasters or DVD
distributors just won't bother to run or sell them.

Mark Zenier
Googleproofaddress(account:mzenier provider:eskimo domain:com)