Wednesday, February 26, 2014

Exclusive interview with Lars Liljeryd!

In light of the press release from the new Digital Radio Sweden initiative, I decided to reach-out and here is the result! Lars Liljeryd, pioneer in the audio codec world, generously gave us some of his time and we have what I feel to be an excellent, in-depth interview of the man. Enjoy the interview, but wait around here only long enough to read it -  then whisk yourself off to Lars' own page of accomplishments! This guy ROCKS!

Lars, please give us some background about yourself. Tell us what you feel are your greatest accomplishments.

I am a somewhat eccentric technologist and entrepreneur having worked in many areas from hydro acoustics and medtech to satellite technology. My biggest accomplishment is that I initiated the basic ideas of SBR (Spectral Band Replication) and PS (Parametric Stereo) that made the extremely efficient HE-AAC codec a reality and a worldwide success. This lead to a trade sale of my company "Coding Technologies" to Dolby Laboratories, a sale that created quite some international attention in 2007.

Briefly outline the Swedish digital radio situation and your current plans.

Sweden was an early pioneer in digital broadcasting, starting with the first
small-scale introduction of DAB, which was initiated in the 1990's. In those days,
the main message and teaser to the public was to create added value by
offering CD-quality sound. However, this concept may have been a bit simple
and naive - as DAB never made it to take-off, merely getting a flat tire at
the runway! Ever since, more and more features were added to DAB (including the HE-AAC codec)
and DRM. Thus DAB+ and DRM+ became more or less equal in function for the consumer.
However for the broadcaster it was a different story...

OK Lars, what are the technical differences?

Well, DAB+ uses a wideband fixed multiplex of 1500 kHz bandwidth and DRM+ uses a
narrowband mini-multiplex of 96 kHz bandwidth. Therefore DAB+ is more
suitable for large nationwide broadcasters like Swedish Radio (run by
the government) and larger commercial broadcasters that can fill-up such a large multiplex.
Small-scale broadcasters (like local commercial broadcasters and community radio broadcasters) would be reluctant to join a large multiplex community run by a major government organization. Typically
they would rather run their own transmitter and antenna tower (so typical
for American broadcasters) and do not want a government organization to
interfere or to have their finger on the power switch!

Therefore the small local and community broadcasters need a solution
when deciding to go digital. DRM+ is an excellent alternative in this
respect but has so far been neglected, not identified and somewhat
discredited in the broadcast digitization discussions by the DAB lobby organizations
here in Europe. This may have been due to political reasons, simply being unaware, fear or
even plain stupidity. That is why my influential friends and I have started up
a non-profit organization "Digital Radio Sweden" in order to create
awareness and to push for an alternative or complementary digital radio
standard using DRM+. Some rather suspicious individuals have asked me what I plan to get out of this,
due to the fact that I have patents in HE-AAC technology. My answer is
that those patents are now owned by Dolby and I am no longer getting any kind
of return for my initial engagement and investments. I'm doing this only for
philanthropic and democratic reasons.

Great background Lars. So why DRM+ and Why DRM30 on VHF band II? (I do think this is great idea to
test, by the way!)

Broadcasting has existed on the FM band for many decades now. I think it
is totally natural to have the transition from analog to digital broadcasting on
this band, and DRM+ works great here! However in major cities within
Europe and elsewhere, the FM band is typically crammed with transmitters and
it is therefore difficult or entirely impossible to find space for additional
transmitters, in particular if a broadcaster wants to simulcast DRM+ with an
adjacent FM channel. In many cases there is simply no space left. Making a cold switch from
analog to digital is not an option as the broadcaster would lose many if not most
listeners. A soft or graceful transition to digital is certainly the way to go, but is not
simple (or even possible) in an area with a congested FM band.

So my basic idea is to see if it is possible to squeeze in a relatively narrow
bandwidth (20 kHz) DRM30 signal together with the analog FM signal (using simulcast mode)
within the standard ETSI FM spectral mask. If possible, this would mean that the
broadcaster would not need to apply for an additional frequency spectrum
permit (especially as spectrum may not be available), but could run simulcast
legally within the same FM spectral mask. DRM30 is my only option to test
this idea as the DRM+ RF bandwidth is 96 kHz and a narrower mode does not
(yet) exist. However running DRM30 in a 20 kHz bandwidth mode would not
work practically for mobile listeners as the Doppler shift would likely kill the DRM30
reception at even moderate vehicle speeds (since truly the DRM30 mode is not
designed for the high frequency FM band). However it would worth a try to test
the idea to see if it would work. So far, my close-range lab-tests indicate that
there is a good possibility for success and that DRM30 works reasonably well
for stationary reception in this band. One must understand the
drawbacks, however. Even if DRM+ would be redesigned with additional
lower bandwidth modes, lower RF bandwidth is closely connected with lower
bitrate and thus lower overall sound quality. Certainly DRM30 sound quality has proven
it self to be good and more than acceptable in the AM bands and sound quality would not be
worse than that in this theoretical mode. During a transitional period
from analog to full-digital, this may be the only available option in dense FM
areas and would enable digital broadcasters or simulcasters to gradually
move to 96 kHz bandwidth with higher quality digital broadcasting and
eventually to turn off their old analog FM transmitters.

Regarding DRM30 (my chief interest) do you think it has any hope of
developing worldwide as an alternative to traditional DSB/AM? or perhaps
will it only serve intra-country such as the work currently going on in India?

I am certainly not a political expert to give any opinions on
intercontinental broadcasting using DRM30, but as India is already reaching out
worldwide with their DRM30 broadcasts (in fact, I can receive their broadcasts here in
Stockholm) this is certainly an interesting topic, and an interesting
alternative to Internet broadcasting. I guess India fully understands the
political impact their broadcasts may have the day we all can buy cheap DRM
receivers (due to India's transition). This is a powerful concept that
should not be overlooked. You can always turn off Internet or cut fiber-optic cables,
but it is extremely difficult to block or jam a high-power
digital transmission, in particular if it is using NVIS for shorter ranges or
ionospheric reflection for long-jumps. Who knows, India may inspire others
on the introduction of DRM30 on AM!

Do you think DRM30 has proven itself (technically) via the decade-plus of HF/SW and
AM/MW (and LW) testing?

Yes, I certainly do. India is an excellent proof for that fact.

Have you been following the "AM revitalization" discussion in the USA?
Any thoughts, especially the fitness of iBiquity HD for MW (as well as for
FM/VHF band II)?

No, not much, sorry. I think analog FM and AM are ok as long as they last, but
without a doubt, FM and AM will die eventually and digital broadcasting will take over.
Despite the fact of "added value" for the consumer when going digital, the RF
space is getting more and more sparse as there is less space for new
technologies and new applications as more advanced wireless systems see the
daylight in many technical areas. The demand for RF bandwidth is therefore
growing exponentially. It is in my opinion unwise and unfair to use
life-support on a dying and spectrally very inefficient technology such as
analog AM and FM. Going digital will preserve RF bandwidth and preserve
energy due to higher spectral and electrical efficiencies.
To my understanding, iBiquity's "only" problem is output power. As the inherent
design of HD-Radio is simulcast, they are as well very dependent on people
going digital so they can operate using full-digital power and no longer have to care about
FM reception issues and analog-digital crosstalk.

Can you give us any insight (or opinions) on recent codec developments such as Opus and codec2?

I think these are fine and developed by enthusiastic engineers who want to
save the world from greedy companies asking for patent licensing! I have
used codec2 in FMDV experiments and it works great, my hat off to
developer and to FMDV and similar digital ham projects. The Opus codec is
another good codec that has higher aims and is said to be royalty free. I
applaud these guys, as they offer good codecs to the open source community and
similar non-commercial projects. It is however the one who has the best
patent lawyers who wins the patent battles, so this is a very unsecure "grey
zone" that has not seen major battles yet. As this "grey zone" patent
situation exists and this technology is not any threat to commercial
competition, peace may persist. But it would be unwise for anybody to use
and invest in such "royalty-free" technologies commercially without doing
serious and costly due-diligence research on the entire IP situation.
Therefore most major commercial corporations stay out of this presumptive minefield and instead
use licenced codecs.

However technically, the progress is on-going in patent licenced (mine
cleared) codec areas as well. The HE-AAC codec has recently been introduced
in an improved and upgraded version (where the improvement is mainly for
extremely low bitrates) the xHE-AAC (I am a co-inventor!). This is by far
the world's most efficient codec (again) and gives fully acceptable sound
quality in stereo at 12 kb/s(!) and improved voice quality down to 8 kb/s.
This will most likely be standardized as an amendment to the DRM30 and DRM+
standard. This step will certainly improve the low-bitrate performance for
DRM30 for long-range and intercontinental broadcasting. You can listen to a demo here .

Wow Lars, what a whirlwind trip into Digital Broadcasting, Codecs and the mind
of a self described "eccentric technologist". We at DRMNA are grateful not only for your work,
but the for the time you took to answer some questions for us!

Thanks for your interest.