HD Fans Crying Foul Over Compressed Signals
Tony Calguire
MINNEAPOLIS (AP) -- In Brent Swanson's basement home theater, there should
be nothing drab about "Battlestar Galactica." He's got a high-end projector
that beams the picture onto a wall painted like a silver screen, and
speakers loom in the corners, flanking two big subwoofers.
Yet when he tuned in Sci Fi HD for a recent episode filmed in high
definition, the image was soft and the darkest parts broke up into large
blocks with no definition. Explosions, he said, were just dull.
"It kind of looked like they took the standard definition and just blew it
up," said Swanson, a 33-year-old graphic designer and videographer who
subscribes to Comcast Corp.'s TV service. "I couldn't really tell if what I
was seeing was really better than what I saw on regular television."
As cable TV companies pack ever more HD channels into limited bandwidth,
some owners of pricey plasma, projector and LCD TVs are complaining that
they're not getting the high-def quality they paid for. They blame the
increased signal compression being used to squeeze three digital HD signals
into the bandwidth of one analog station.
The problem is viewers want more HD channels at a time when many cable and
satellite providers are at the limits of their capacity, said Jim Willcox,
a technology editor for Consumer Reports magazine.
"They have to figure out a way to deliver more HD content through their
distribution networks," he said.
Compressing the signal is cheaper than costly infrastructure upgrades to
increase capacity. Satellite TV providers -- including DirecTV Group Inc.
and Dish Network Corp. -- also have the option of launching satellites to
boost the number of HD channels on their systems.
While information is nearly always lost when signals are compressed and
then uncompressed, the process can theoretically be made unnoticeable to
eyes and ears -- and Comcast says it should be.
But some viewers say they can see it. Willcox said complaints about
compression have been showing up on Web forums, including the AV Science
Forum, a site for serious audio visual enthusiasts.
"It's not exclusively Comcast, although Comcast, being the largest cable
provider, is probably the largest target," he said.
Derek Harrar, a Comcast senior vice president in charge of video, said the
company recently began using new technology on some channels to compress
three HD channels into the bandwidth of one analog station. Other channels
continue to get the previous 2-to-1 compression.
In a posting on the AV Science Forum, Ken Fowler of Arlington, Va. compared
Comcast signals with those on Verizon Communications Inc.'s all-fiber-optic
network, which doesn't have the same capacity limitations. Fowler found the
higher-compressed HD stations, including Sci Fi, Animal Planet, the
Discovery Channel, the Food Network and A&E, fared particularly poorly.
He analyzed the signals by recording them on a digital recorder, then
transferring them to a personal computer for analysis. He found there was
much less data, measured in bit rates, flowing to some channels than
others.
For example, Discovery's bit rate was 14.16 megabits per second on
Verizon's FiOS system but only 10.43 Mbps on Comcast; A&E HD was 18.66 Mbps
on FiOS compared to 14.48 Mbps on Comcast. The FiOS system didn't offer Sci
Fi HD, which Fowler's testing showed at 12.59 Mbps on Comcast.
He found the signals from the major networks and ESPN weren't getting the
increased compression.
In an interview, Fowler said he reran his analysis about two weeks ago and
found "basically the same thing."
Comcast wouldn't identify specific signals that are 3-to-1 compressed, and
a Sci Fi channel spokeswoman referred questions back to Comcast.
Harrar said the company works to make sure any new compression technology
is invisible to consumers, but Comcast is "constantly monitoring our
network and making adjustments" for best picture quality. The company has
been rolling out the new compression technology at different times around
the country.
In fact, postings on the AV Science Forum from early April suggest the
Comcast network has improved in some places.
And there are other reasons a high-definition picture can appear subpar:
The source image might not have been recorded in HD or the television's
settings, the viewing angle and even the ambient lighting in the room could
be the cause.
New York-based Time Warner Cable has avoided many of the criticisms aimed
at Comcast, although the companies are technologically similar and face the
same capacity limits.
Time Warner spokesman Alex Dudley attributed it to his company's testing
procedures. He said that before Time Warner rolls out new technology that
may affect image quality it sets up two identical televisions in a lab, one
with the old signal and one with the new. Technicians make adjustments
until the pictures can't be told apart.
"The testers are our engineers who we call 'golden eyes,' who have a proven
track record of picking up subtle differences in picture quality," he said.
Verizon's FiOS doesn't compress the signal once it receives it, and Willcox
said it's considered the picture quality "benchmark." Verizon said the
system is growing but is now available only in parts of 17 states and has
just over a million subscribers -- compared to more than 24 million for
Comcast.
He said two possible solutions are on the horizon, an improved version of
compression, called MPEG-4, and something called "switched digital video."
Comcast and Time Warner Cable have introduced switched video on a trial
basis across their networks. In concept, it's like on-demand videos. The
company sends only the channels the viewer is watching, instead of all the
channels at once.
But switched video has its own issues, including possible slower channel
switching times and compatibility problems with digital video recorders.
Willcox said cable providers can't afford to ignore quality complaints.
Many customers are already picky about quality after paying $800 to $3,500
for an average-sized, HD-ready LCD television.
Swanson, the "Battlestar Galactica" fan, is sticking with Comcast for now.
"It hasn't gotten bad enough for me to consider changing," he said.
Taylor
===
Rogers Cable set to begin compressing HD Signals
http://www.digitalhome.ca/forum/showthread.php?t=84134
===
http://www.digitalhome.ca/content/view/2426/206/
Rogers Cable set to begin compressing HD Signals
Thursday, 03 April 2008
In news that is sure to instill anger among Canadian high definition
television lovers, Digital Home Canada has learned that effective
April 9th, Rogers Cable will begin compressing the high definition
(HD) television signals it sends out to its Rogers Personal TV
customers.
In a technical briefing sent out by Rogers Network Engineering and
Operations that was passed on to Digital Home Canada, the company said
it would begin compressing parts of its high definition line-up in
order to deliver more HD channels without having to use more
bandwidth.
Channels on the Rogers Digital Cable system facing compression
include:
* HD PBS Buffalo
* HD WGN
* HD The Score
* HD Showcase
* HD National Geographic
* HD Mpix
* HD Discovery
* HD MORE
* HD TMN
* HD NBC Seattle
* HD SUN
* HD RAP
* HDA&E
* HDCNN
* HDNET
Channels not on the list include the big American network feeds and
Canadian networks such as CTV, CBC, Global and specialty sports
station TSN. No mention is why some popular stations such as PBS and
HD Discovery are going face compression, while stations like CTV and
Global, which duplicate much of the U.S. primetime schedule are left
unaffected.
Related: Overview of QAM and HD signal compression
Rogers is not the first cable company in North America to attempt to
serve up more HD signals without gobbling up more bandwidth. Recently,
in the U.S., Comcast Cable has recently begun compressing its signals
by using the same techniques to be employed by Rogers.
This Gizmodo article clearly shows the results have been disastrous.
The article which compares the HD signals from Comcast and FIOS, which
does not compress its signals, clearly shows how compression results
in pictures that are “grainy and blocky and full of artifacts—a result
of shoving three channels into a space where only two previously
occupied.”
The technical briefing sent out by Rogers Engineering is quite
complex, however, the bottom line is clear. In an effort to deliver
more HD channels to Rogers digital cable customers, the company is
going to compress its HD signals.
Discuss and learn more:
Discuss this story in our Rogers Digital Cable forum in the Digital
Forum. Membership in the forum is free and with over 75 interest
groups and 47,000 members, there is always something new and
interesting to discuss.
~consul
>> "It kind of looked like they took the standard definition and just blew it
>> up," said Swanson, a 33-year-old graphic designer and videographer who
>> subscribes to Comcast Corp.'s TV service. "I couldn't really tell if what I
>> was seeing was really better than what I saw on regular television."
Is that why when I tape different shows on the same or different channel, I get different MB sizes for the same amount of time? Some hour shows range from 4-7MB in size.
--
"... respect, all good works are not done by only good folk. For here, at the end of all things, we shall do what needs to be done."
--till next time, consul -x- <<poetry.dolphins-cove.com>>
Anim8rFSK
~consul <con...@dolphins-coveINVALID.com> wrote:
> and thus Taylor inscribed ...
> > On Apr 18, 6:59 pm, Tony Calguire <calgu...@tcfreenet.invalid> wrote:
> >> "It kind of looked like they took the standard definition and just blew it
> >> up," said Swanson, a 33-year-old graphic designer and videographer who
> >> subscribes to Comcast Corp.'s TV service. "I couldn't really tell if what
> >> I
> >> was seeing was really better than what I saw on regular television."
>
> Is that why when I tape different shows on the same or different channel, I
> get different MB sizes for the same amount of time? Some hour shows range
> from 4-7MB in size.
uh
an hour show in 4mb?
I don't think so.
--
Star Trek 09:
No Shat, No Show.
http://www.disneysub.com/board/noshat.jpg
~consul
>> Is that why when I tape different shows on the same or different channel, I
>> get different MB sizes for the same amount of time? Some hour shows range
>> from 4-7MB in size.
> uh
> an hour show in 4mb?
> I don't think so.
Oops, where is the 1/2? I coulda sworn I wrote it. And in GB. :)
WWEHD which is 2 hours, gives me about 15.5 GB. I gotta check when I get home, but I do get different file sizes for same length shows. I notice it more w/ the 1/2 shows than the hour long ones.