Doing more with less” is a common refrain in business. But it's
never been more of a necessity than it is now for telcos launching TV services
and satellite operators wrestling with new HD programming, as both try to
squeeze as many video streams as possible into as little bandwidth as
necessary.
The IBC show in Amsterdam (Sept. 7-12) should bring some relief, as
various manufacturers unveil new encoders using the MPEG-4 Advanced Video
Compression (AVC/H.264) standard. MPEG-4 AVC encoders promise the same picture
quality as MPEG-2 in less than half the bit rate. New models go even beyond
that.
Tandberg Television is introducing its next generation of MPEG-4 AVC HD
and SD encoders at IBC. Tandberg has deployed more than 1,000 high-def MPEG-4
AVC encoders, giving the company an estimated 95% share of the high-def AVC
market, and some 4,000 MPEG-4 AVC encoders overall. Big customers include
DirecTV, Swisscom and Premiere in Germany.
Big bandwidth improvements
Tandberg says its new encoders, the EN8030 for SD and the EN8090 for
SD/HD operation, provide bandwidth improvements of up to 50% over its
first-generation MPEG-4 AVC gear. While MPEG-2 encoders could compress high-def
video down to the 16 to 18 megabit-per-second (Mb/s) range, early-generation
AVC encoders could deliver the same quality in 10 Mb/s.
“Now we're looking at five to six megabits per second for
high-motion sports at 1080i resolution, and maybe 4 megabits per second for
720p film material,” says Matthew Goldman, Tandberg's VP of technology, for
compression systems.
That improvement means IPTV operators can fit two full-resolution HD
channels over an ADSL2+ (advanced DSL) pipe, or that satellite broadcasters
could fit up to 8 HD channels on a 36 megahertz (MHz) transponder.
Tandberg is also introducing MPEG-4 AVC encoding modules for its Plex
brand encoders. Those are aimed squarely at telco IPTV customers and based on
technology Tandberg gained when it acquired SkyStream last February.
Tandberg's MPEG-4 AVC's improved chip technology allows for
“single-slice” video processing; the encoder is able to process an entire
HD picture in a single slice instead of having to break it down into smaller
slices. That frees up computational power for other functions.
The new Tandberg encoders can generate three channels from a single HDTV
input: a full-resolution HD channel; a full-resolution SD channel, and a
low-res “micro” channel for picture-in-picture applications. The
high-density Plex systems can deliver up to 12 simultaneous channels from a
one-rack-unit device: 4 HDs plus 4 SDs plus 4 low-res channels.
Harmonic has trailed Tandberg in the MPEG-4 market, delaying the release
of its first high-def MPEG-4 AVC encoder until this year. But the Sunnyvale,
Calif.-based company is ramping up production, bringing new HD and SD MPEG-4
AVC products to IBC. After introducing the DiviCom Electra 7000 high-def MPEG-4
AVC unit in July, Harmonic's latest entry is the standard-def Electra 5400
multichannel model, which can deliver four simultaneous SD channels with
corresponding low-res versions for picture-in-picture or mobile video
applications. (The company already has orders for the Electra 7000 from five
satellite and telco customers spread across North America and Europe.)
Harmonic claims the third-generation Electra 5400 can deliver the same
quality at bit-rates 30% lower than encoders currently deployed in the market;
Harmonic VP Nimrod Ben-Natan says the 5400 will deliver full-resolution SD
quality at rates from 1.5 to 1.75 Mb/s. First customer shipments are scheduled
to begin in September.
Like Tandberg, Harmonic is taking advantage of improved processing chips
to perform single-slice encoding of HD pictures. And like Tandberg, it says it
can deliver high-quality HD at bit rates as low as 6 or 7 Mb/s.
Struggling to deliver high-def
“Our customers are telling us this is really a breakthrough for them
and is changing the business models in some cases,” says Ben-Natan. “Some
of the telco providers have been struggling with the network bandwidth
requirements to deliver high-def.”
Other compression vendors including Scientific-Atlanta and Modulus Video
are bringing new and/or improved MPEG-4 AVC encoders to IBC. These products are
primarily focused on telco and satellite operators distributing MPEG-4 to the
home, where the pictures will be decoded by MPEG-4 set-tops.
But broadcasters are increasingly interested in using MPEG-4 AVC for
newscasts. Network engineers say that MPEG-4 products for professional use
aren't really available yet, a point which encoder vendors concede. But that
is slowly changing.
At IBC, Tandberg will also be introducing new MPEG-4 AVC systems for
digital satellite newsgathering (DSNG) and digital electronic newsgathering
applications (DENG), including the EN5940, which combines MPEG-4 AVC
compression with a DVB-S2 satellite modulator. That product can uplink HD video
feeds in the same amount of bandwidth used for an MPEG-2 SD feed.
Another vendor showing DSNG solutions at IBC is San Francisco-based
Envivio. The company has already sold a large quantity of MPEG-4 AVC
compression gear to Mexican broadcaster Televisa, including 40 4Caster B3
standard-def encoders and 10 4View D1 professional decoders. Says William
Aguirre, Televisa's director of satellite operations, “The performance is
very good, and the quality of video is totally acceptable.”
