[opendtv] Re: Video compression artifacts and MPEG noise reduction

  • From: dan.grimes@xxxxxxxx
  • To: opendtv@xxxxxxxxxxxxx
  • Date: Mon, 16 Jun 2008 12:42:15 -0700

Both analogies make their point.  However, as typical with analogies, they
cannot exactly replicate the situation they are to mimic.

The analogy of the change in the automobile wheel standard is a good one.
However, the analogy could be taken further.  I would like to point out a
few things:

1.  The Michelin system was (arguably) superior.  As to whether it should
have been adopted or not could be debated.

2.  The standard for the tire has been changed many times.  As cars became
faster and highways allowed faster speeds, the tire and the rim developed
and standards changed.  The same could be said for other specifications
such as load and traction ratings.

3.  The beauty about our road system is that it has become better and
better, yet allows both a Ford Model A wheel and the Michelin TRX to use

Please don't read any more into the analogy than is right there in the
words.  I don't intend for every intricate detail of the highway system to
match our data delivery systems by any means.


             "Manfredi, Albert                                         
             <albert.e.manfred                                          To
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             eelists.org                                           Subject
                                       [opendtv] Re: Video compression 
                                       artifacts and MPEG noise reduction
             06/16/2008 11:15                                          
             Please respond to                                         

Kon Wilms wrote:

> Let's also abandon cars and bring back the horse and
> buggy while we're at it.

Wrong analogy, but there actually is a very close car-related analogy.

In the mid 1970s, Michelin introduced a tire with ellyptical
cross-section, called the TRX. The goal was to create high pressure, low
aspect ratio tires, without introducing too much ride harshness. This
was to provide better directional stability and fuel economy. Stresses
were supposed to be better distributed throughout the sidewall.

Because the cross section was ellyptical, standard wheel rims could not
be used. The surfcaes of the rim that mate to the tire were not
parallel, as they are in normal wheels. So while they were at it,
Michelin introduced a wheel rim with metric dimensions. TRX tires were
specified all-metric. Such as, 220/55-390.

Great. So in order to benefit from this innovation, everyone would have
to change tires AND rims.

Instead what happened was that other tire companies managed to change
their sidewall designs in such a way as to offer high pressure, very low
aspect ratios (soon even less than the 65 and 55 ratios of TRX tires),
without having to use a different standard of rim design.

If you can get away with it, it's usually better to extend the existing
standard. If you can do it, it's far easier to tweak MPEG-2 than to
introduce a new codec, for existing, deployed broadcast applications.


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