Harsh, "aliased" sound with digital TV converter box.

The audibility of lossy codecs varies with the quality of the playback
system. Over my computer speakers (Monsoon planar magnetics),
KUOW sounds fine. Not only is it clean and transparent, but I've never
heard anything that I interpreted as an artifact. (This is the Microsoft
codec.)

What are you trying to say? Are you saying the lossiness of DD would
be audible over your computer speakers or not?

No, I'm saying that the Monsoons, good as they are, aren't Apogees.

In article ,
"William Sommerwerck" wrote:

The first time I decoded a Dolby Digital signal ("The Incredibles") I could
hear the difference -- flat, grainy, dry, blah sound.

Ooo, nice description.

--
Star Trek 09:

No Shat, No Show.
http://www.disneysub.com/board/noshat.jpg

In article "William Sommerwerck" writes:

No, I'm talking objective fact. Color-difference signals require less
bandwidth than color-primary signals.

I rather doubt that. Even small changes in small areas would produce the
same bandwidth. However, the magnitude of the signal may be less.

The critical thing is that *because of the limitations of human vision*,
one can get away with reducing the bandwidth of the color difference signals.

The original color difference signal may well have full bandwidth --
since the color difference signals vary with hue variation, even when
the saturation remains the same. (They also vary with saturation change
even with hue remaining the same.)

Alan

"Alan" wrote in message
...
In article "William Sommerwerck" writes:

No, I'm talking objective fact. Color-difference signals require less
bandwidth than color-primary signals.

I rather doubt that. Even small changes in small areas would produce the
same bandwidth. However, the magnitude of the signal may be less.

Correct. But color-difference signals DON'T HAVE THOSE SMALL CHANGES.


The critical thing is that *because of the limitations of human vision*,
one can get away with reducing the bandwidth of the color difference
signals.

Not so. Think about it. Saturation (which is what the amplitude of the
color-difference signal represents) "never" (well, hardly ever) changes as
rapidly as luminance.


The original color difference signal may well have full bandwidth --
since the color difference signals vary with hue variation, even when
the saturation remains the same. (They also vary with saturation change
even with hue remaining the same.)

See above.

This is the typical knee-jerk reaction to something someone hasn't bothered
to think through.

Arny Krueger wrote:
"trotsky" wrote in message
news:[email protected]_s21
Arny Krueger wrote:
"trotsky" wrote in message
news:[email protected]_s22
Arny Krueger wrote:
"William Sommerwerck"
wrote in message

"Arny Krueger" wrote in message
...
"William Sommerwerck"
wrote in
message

Yes, it's brilliant. (It's one of the great 20th
century inventions.) But -- and I will keep
repeating this ad nauseum -- the reason color TV
systems (of all sorts) can "get away" with reduced
chroma bandwidth
If we extrapolate this discussion to audio, then we
have Willaim Sommerwerck, MP3 advocate! ;-)
God, no. I hate compressed audio. (Dolby Digital, at
least.)
(1) Dolby Digital is really old-old tech, predating MP3
by lots.
What difference does it make when it was created?
Perceptual coding was and is a work in progress.
Progress was pretty rapid at the time that DD was
introduced and the decade following it. Dolby AC-3 AKA Dolby Digital was
introduced in 1991. It
is a proprietary standard, and has not changed a lot
over the years. MP3 has remained a work in progress since 1989. The rate
at which MP3 coders were improved slowed down quite a
bit after ca. 1998, but improvement may still be
possible.

You're not making sense.

Please clarify, because the questions that follow are not requests for
clarification.

Did Dolby do their homework and
do sufficient blind tests to "prove" that their codec was
transparent to people?

AFAIK, Dolby never claimed that DD was perfectly transparent.


And your working definition for "perfectly transparent" is what, exactly?


The MPEG group
coder tests in the late 1990s showed that Dolby Digital was not sonically
transparent and generally inferior to other, more modern codecs.


At all bit rates? And again, what is the definition or "sonically
transparent"--when people with Radio Shack stereos can tell the difference?


Maybe you're a different Arny Krueger

Nope. Just older and wiser. ;-)


Yeah, I'll buy the older part. If you're saying blind test results have
to be taken with a grain of salt then I'll buy the wiser part.


and have come to realize that these blind tests are ineffective.

How so? The fact that AC-3 was a substandard codec based on the MPEG
Group's blind tests was pretty well publicized by the MPEG and the AES.


Perhaps you can show us a cite for these results, then.


This
was no doubt a bit of an embarrassment to Dolby. Dolby has been doing their
own blind tests for decades.

Dolby subsequently came out with a new multimodal system for coding and
decoding audio known as Dolby TrueHD. In some modes, TrueHD is definitely
sonically transparent.


Again, you are using a term without defining its meaning.

"trotsky" wrote in message
news%[email protected]_s21
Arny Krueger wrote:
"trotsky" wrote in message
news:[email protected]_s21

Did Dolby do their homework and
do sufficient blind tests to "prove" that their codec
was transparent to people?

AFAIK, Dolby never claimed that DD was perfectly
transparent.

And your working definition for "perfectly transparent"
is what, exactly?

Passes a bypass test with under any relevant test condition without audible
alternation.

The MPEG group
coder tests in the late 1990s showed that Dolby Digital
was not sonically transparent and generally inferior to
other, more modern codecs.

At all bit rates?

As typically used.

And again, what is the definition or
"sonically transparent"--when people with Radio Shack
stereos can tell the difference?

Relevant tests are used with selected, trained listeners. Listener
sensitivity is essential. Please see ITU recommendation BS 1116, which is
availble through the web.

Maybe you're a different Arny Krueger

Nope. Just older and wiser. ;-)


Yeah, I'll buy the older part. If you're saying blind
test results have to be taken with a grain of salt then
I'll buy the wiser part.

Let's put it this way - every test result must be considered in its context.
Sighted tests for signal quality are generally so invalid that they need not
be taken seriously at all. Blind test results are at least worth
considering.

and have come to realize that these blind tests are
ineffective.

How so? The fact that AC-3 was a substandard codec
based on the MPEG Group's blind tests was pretty well
publicized by the MPEG and the AES.

Perhaps you can show us a cite for these results, then.

Check the AES web site. They were published in the JAES some years back.

This
was no doubt a bit of an embarrassment to Dolby. Dolby
has been doing their own blind tests for decades.

Dolby subsequently came out with a new multimodal system
for coding and decoding audio known as Dolby TrueHD. In
some modes, TrueHD is definitely sonically transparent.

Again, you are using a term without defining its meaning.

Which term? I've used tons of them. I would expect that the readers of the
newsgroups we are posting to know what most common audio terms mean.

"Arny Krueger" wrote in message

"trotsky" wrote in message
news%[email protected]_s21
Arny Krueger wrote:
"trotsky" wrote in message
news:[email protected]_s21

Did Dolby do their homework and
do sufficient blind tests to "prove" that their codec
was transparent to people?

AFAIK, Dolby never claimed that DD was perfectly
transparent.

And your working definition for "perfectly transparent"
is what, exactly?

Passes a bypass test with under any relevant test
condition without audible alternation.

Correction:

Passes a bypass test with under any relevant test
condition without audible alteration.

On Feb 29, 7:15 am, "William Sommerwerck"
wrote:

snip

Not so. Think about it. Saturation (which is what the amplitude of the
color-difference signal represents) "never" (well, hardly ever) changes as
rapidly as luminance.

You need to be careful here. While saturation is a function of color
differences, it needs to be normalized by the intensity. Simple color
differences are functions of both saturation and luminosity. Consider,
for example, calculating saturation in the HSI coordinate system as
illustrated in this link:

http://homepages.inf.ed.ac.uk/rbf/CV....html#tth_sEc3

Similar examples for other coordinate systems can be found he

http://en.wikipedia.org/wiki/Saturation_(color_theory)

Not so. Think about it. Saturation (which is what the amplitude of the
color-difference signal represents) "never" (well, hardly ever) changes
as
rapidly as luminance.

You need to be careful here. While saturation is a function of color
differences, it needs to be normalized by the intensity.

That is PRECISELY the point. Subtracting Y from R, G, or B provides the
normalization and produces a saturation -- color-difference -- signal from
which brightness information has been removed. This is what we want.

More than 50 years ago, Electronics magazine published pictures of the NTSC
color signals, based on real scenes. The colors are completely "flat" --
they are of constant saturation, with no variation in brightness.

It's important to understand that NTSC and PAL are non-redundant systems.
None of the three signals contains information present in another.

Arny Krueger wrote:
"trotsky" wrote in message
news%[email protected]_s21
Arny Krueger wrote:
"trotsky" wrote in message
news:[email protected]_s21

Did Dolby do their homework and
do sufficient blind tests to "prove" that their codec
was transparent to people?

AFAIK, Dolby never claimed that DD was perfectly
transparent.

And your working definition for "perfectly transparent"
is what, exactly?

Passes a bypass test with under any relevant test condition without audible
alternation.


A) That sentence makes no sense grammatically, and B) you have provided
no definition for "passes a bypass test". You keep making the same
mistakes over and over.


The MPEG group
coder tests in the late 1990s showed that Dolby Digital
was not sonically transparent and generally inferior to
other, more modern codecs.

At all bit rates?

As typically used.

And again, what is the definition or
"sonically transparent"--when people with Radio Shack
stereos can tell the difference?

Relevant tests are used with selected, trained listeners. Listener
sensitivity is essential. Please see ITU recommendation BS 1116, which is
availble through the web.


This is silly. I'll ask again: can you define what you're talking
about? What's a passing grade for "sonically transparent"--100%? 90%?
If 80% of the trained listeners can't tell the difference, is it then
"sonically transparent"?

Then there's Bill Somerwerck's point: how good is the resolution of the
equipment they're using? If the speakers are mediocre, that will skew
the results.


Maybe you're a different Arny Krueger
Nope. Just older and wiser. ;-)

Yeah, I'll buy the older part. If you're saying blind
test results have to be taken with a grain of salt then
I'll buy the wiser part.

Let's put it this way - every test result must be considered in its context.
Sighted tests for signal quality are generally so invalid that they need not
be taken seriously at all. Blind test results are at least worth
considering.


Sure, if you believe in Jesus I guess you can believe in the vagaries of
blind testing.


and have come to realize that these blind tests are
ineffective.

How so? The fact that AC-3 was a substandard codec
based on the MPEG Group's blind tests was pretty well
publicized by the MPEG and the AES.

Perhaps you can show us a cite for these results, then.

Check the AES web site. They were published in the JAES some years back.


Nice try, Arny. AES charges $5 for members and $20 for non-members for
each paper on the topic. Again, please provide a cite for what you're
talking about.


This
was no doubt a bit of an embarrassment to Dolby. Dolby
has been doing their own blind tests for decades.

Dolby subsequently came out with a new multimodal system
for coding and decoding audio known as Dolby TrueHD. In
some modes, TrueHD is definitely sonically transparent.

Again, you are using a term without defining its meaning.

Which term? I've used tons of them. I would expect that the readers of the
newsgroups we are posting to know what most common audio terms mean.


You have no working definition of "sonically transparent".
Intellectually, you are about as credible as a crack addict. Are you a
crack addict?