Fwd: WinDRM, DRMDV, FDMDV mo longer available -- and may be illegal for hams to use
- ----- Forwarded Message ----
From: Gary Pearce KN4AQ <kn4aq@...>
Sent: Monday, July 21, 2008 6:31:10 AM
Subject: Windows HF DV programs pulled from distribution
I think D-STAR fans will be interested to note that the
Windows/sound-card based Digital Voice programs - WinDRM, DRMDV, FDMDV -
have been pulled from distribution. They are no longer available for
download. These programs were written by Cesko HB9TLK, and distributed
primarily by Jason N1SU through his web site.
The problem is licensing, or lack of it, for the MELP codec that all the
programs shared. The codec was developed for the US military and NASA,
but was never licensed for free distribution. Several companies share
the "IPR" (Intellectual Property Rights) for various forms of MELP. Some
of those companies do not permit unlicensed use.
MELP was designed for high quality, low data-rate voice communication,
and is particularly well suited for HF radio applications. WinDRM
occupies about 2.5 kHz of spectrum and sounds like FM with few artifacts
when signals are good. Cesko's newest program, FDMDV, used only 1.1 kHz
of spectrum. It sounds a little rougher, but still remarkable for that
low bandwidth. It works closer to the noise level, and has almost no
latency. All the programs use OFDM (multiple carrier) modulation schemes.
Some hams have been aware that MELP's legal status was murky at best.
Most users probably had no idea. One web site I read said that hams
were using a "pirated" copy of the MELP dll. I can't offer a legal
opinion, but it appears that use, not just distribution, of the MELP
codec violates the IPR license.
The AOR digital voice modems use the AMBE 2020 vocoder, and are not
affected by the MELP situation.
I don't know if any specific legal action or threat precipitated the
removal of the Windows programs (not just the codec) from distribution,
or if the hams involved just changed their minds on participation.
ARVN: Amateur Radio//Video News
Gary Pearce KN4AQ
508 Spencer Crest Ct.
Cary, NC 27513