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I just got my first Superbit titile 'The Fifth Element'. Comparisson
against the original R1 DVD. (I also have the new R2 SE DVD, which
has several issues and is far subpar IMO to both R1 versions.)
Detail:
The SB version has a fair bit more horizontal detail in ALL scenes,
but in SOME the difference is HUGE. There is no increase in vertical
detail at all. The increase in horizontal resolution is NOT DIRECTLY
due to the higher bitrate, but rater INDIRECTLY. Let me explain:
DVDs are usually slightly filtered to remove the highest frequencies,
thus limiting the finest detail.
1) In the vertical dimension this is done to minimize interlace
flicker artefacts on regular TVs. This wouldn't be necessary if
DVDs where optimized for progressive output.
2) In the horizontal dimension its done to minimize aliasing artefacts
in the DVD players output stage. Not all DVD players can fully resolve
6.75Mhz patterns, some show heavy aliasing if such frequencies are
present.
But there is another, more important reason why filtering high
frequency information (in both dimensions) is used: it reduce the
ENTROPY (real information, detail) of the image. And the lower the
entropy of the encoded material, the lower the MPEG bitrate can
be, without yielding a considerable amount of compression artefacts.
Think of it like this. There is a consensus about a certain threshold
of compression artefacts that you don't want to surpass. On the
other hand, going far beyond this threshold isn't necessary, because
there is a point of diminishing returns.
Now, if you encode your transfer and choose the bitrate in each
scene in a way, that you are always reasonably above this artefact
threshold, the result will be certain amount of space that you need
(average bitrate * running time). If you simply don't have the space
for this on the DVD (due to extras, single layer or whatever), you
need to make a decision:
a) Either you save bitrate in several scenes, thus surpass the
artefact threshold which results in visible MPEG blocking (esp.
in darker scenes) and mosquito noise artefacts.This is obviously
a bad choice, but if used carefully isn't too obvious, especially
if you have your black-level calibrated properly, becaues blocking
is most noticable in the lowest IRE levels, which are hardly distinguishable
once calibrated.
b) Or you reduce the overall entropy of the image by filtering
away the highest frequencies. Now, as mentioned above, a lower entropy
means that you need less bitrate to achieve that same artefact threshold!
So you can now lower the bitrate slightly in all scenes without
introducing any blocking or mosquito noise, but get a slightly softer
picture. Like so many things, its a tradeoff.
But, if you have the space available, like on the extra-less superbit
titles, you can use the opposite reasoning. You can choose NOT to
filter the content at all, leaving the original entropy intact.
If you do so, you will need to raise the bitrate in most scenes
to a higher level to achieve an artefact free image. If you have
a full dual-layer disc to spare for a movie with not-too-long running
time, you can even run the bitrate close to its possible maximum
most of the time.
Col/Tri's transfers from day one used route b) to dodge compression
artefacts. Their transfers are always slightly soft, never quite
reaching the highest amount of achievable detail as Criterion's
'The Rock' , Warner's 'The Pledge' or Fox's 'X-Men'. On top of that,
their encoder is said to be the most efficient, thus yielding the
least amount of artefacts for a given bitrate. Combine these two
issues and you will understand why Col/Tri transfers over the years
constanty yielded among the least amount of compression artefacts.
Compare early (1997-98) Warner transfers to Col/Tri and you will
see what i mean.
Now, given the above, why in gods name would Columbia introduce
'Superbit' titles (which have higher bitrates) if their transfers
are among the least compression artefact plagued off all? Easy:
the higher bitrate allows them to open the throttle on detail while
remaining their picky standards for compression artefacts. As easy
as that.
At least thats what i hoped for in theory. But thats exactly what
happened on Fifth Element SB. The horizontal resolution, that was
filtered on the old transfer is now completely unfiltered, yielding
the highest amount of detail possible on DVD, and indeed, it matches
the magnificent transfer of 'The Rock' in this regard.
Edge Enhancement:
Probably to compensate for their slight filtered softness, Col/Tri
transfers always show an unpleasing amount of edge enhancement.
Read my EE guide if you
want more info.
While i was quite certain (or at least hopefull) that Col/Tri would
open the throttle on detail on their SB titles, the first thing
that popped into my mind was "maybe they reduce the EE while
they are at it!". Note that i tried to clarify in some recent
threads that by simply increasing the bitrate, you don't affect
the amount of EE artefacts at all. You decrease a different edge
artefact called mosquito noise, but the trace-contoured halos that
us videophiles hate so much, stay where they are.
But i am ULTRA happy to report that at least on the Fifth Element
Superbit DVD, they did indeed reduce at least the horizontal EE
a considerable amoung. Fifth Element never was one of the very strong
EE contenders anyway, it was just a bit too much for the most picky
souls like me.
A concrete analysis of the improvement is that the amplitude of
the ringing stays the same, but the frequency increased by a fair
amount, which means that the halos are less disturbing, because
they are thinner.
Hoooray!
Everything else:
The Fifth Element transfer has always been reference quality in
every other aspect: Shadow detail, contrast delineation, black level,
color tone and saturation. Perfect. And the new SB transfer does
indeed inherent all these characteristics. In all these aspects
they look almost identical.
I have read reviews where people found a difference in shadow detail,
better colors (esp. in the faces) etc... Must be a psychological
thing, because the measured difference is never more than 1-2%.
Apart from the higher resolution and less compression artefacts
in darker areas (remember Fifth Element was a single layer disc),
the discs look basically completely alike. Print defects etc. are
the same as well, so the same master was used.
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