Dear
Gary,
I
was pleased to see that in your October (Issue 65) editorial you made mention of
MPEG-4 (in connection with the hoped-for HD-DVD standard).
It seems to me that MPEG-4 is being treated by some players in the video
technology market as some sort of rogue technology, rather than the outcome of
years of serious work by the industry’s respected group of experts (i.e. the
MPEG). Steve Jobs and Apple seem to
be the only players openly supporting and praising MPEG-4. Other
players seem to want to brand it as “that thing that video pirates are using
to exchange ripped videos over the Internet”.
And Microsoft’s message to the MPEG regarding MPEG-4 seems to be
“Thank you for all your hard work, guys, but we’ll take it from here.” It is not clear what deals Microsoft is striking with the
other players, particularly the studios, but it seems possible that they are
along the lines of: “We will build rock-solid copy protection into the
compression algorithm and you will support the use of a Microsoft algorithm so
we can make billions of dollars in licensing fees, just as we did with
Windows.”
While
I agree with you that the present red laser approach, with an average bit rate
of 5 Mbps, combined with the best possible compression algorithm, is not going
to give us the HD quality that we want (Warner’s approach), those other
manufacturers that are proposing to use Blu-ray discs in combination with MPEG-2
must be crazy. Why would anyone opt
to use MPEG-2 after the MPEG spent almost a decade developing the improvements
and additions to MPEG-2 that resulted in MPEG-4?
If the industry had followed similar logic in moving from laserdiscs to
DVDs, then DVDs would be using analog video!
Surely the HD-DVD standard should combine the best available hardware and
software elements, namely 20 to 30 Mbps bit rate Blu-ray discs with the MPEG-4
algorithm? In very rough terms this
would give us an overall quality improvement factor versus DVDs of something
like 16 to 24 (based on bit rate improvement of 4 to 6 multiplied by an
estimated compression efficiency improvement factor of 4).
On
this last point (compression efficiency) it seems that there is a general
reluctance to publish independent comparisons of MPEG-2 versus MPEG-4 using
useful bit rates. Claims in various
articles and on various websites about the efficiency of MPEG-4 versus MPEG-2
vary wildly, from 3:1 to 10:1, and are presumably not based on tests performed
under carefully controlled conditions. It
is important to know the real number so that we can have some idea what to
expect when we read about the bit rate of a particular proposed disc, cable,
satellite, or tape technology that is going to be used in combination with
MPEG-4. Interesting and useful
comparisons might be:
(a)
MPEG-2 at 5 Mbps (the present DVD standard) versus MPEG-4 at various bit rates
over the range 0.75 Mbps to 2Mbps, in order to find the average bit rate at
which DVD-like quality is obtained using MPEG-4; and
(b) MPEG-2 at 28.2 Mbps with HD content viewed on an HD display (D-VHS) versus MPEG-4 with the same content at various bit rates from 5 Mbps upwards, to find the “yes, this really is HD” point for MPEG-4.
Malcolm
Hamer, New York, New York
malcolmhamer@hotmail.com
Editor-In-Chief Gary Reber Comments:
Malcolm, thank you for your thought-provoking letter.
This is exactly the prying that is needed to move the development of a HD
version of DVD to the best possible performance level.
I hope that in future issues of Widescreen Review we can explore some of
the issues you raise and serve our readers by expressing our desire for “the
best that it can be” in a HD-DVD format that will also be backward compatible
with present-day DVD.