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ANN: Fixed point OpenLPC codec released under LGPL

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Phil Frisbie, Jr.

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Oct 19, 2005, 5:37:32 PM10/19/05
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I am pleased to announce that my commercial fixed point OpenLPC codec will now
be dual licensed as LGPL or commercial software. The fixed point version of the
OpenLPC codec is suitable to run on hand-held devices with CPUs that do not
support hardware floating point math such as Arm, Intel PXA250, and other 32 bit
CPUs. The fixed point codec is fully interoperable with the floating point
codec, so developers can continue to use the floating point codec on desktop
computers or servers. It can be downloaded now as a separate archive, and it
will be included in the next release of HawkVoiceDI.

Go to the HawkVoice page at http://www.hawksoft.com/hawkvoice/ for the latest
information, and http://www.hawksoft.com/download/ to download the source code.

--
Phil Frisbie, Jr.
Hawk Software
http://www.hawksoft.com

Jim Leonard

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Oct 20, 2005, 12:01:24 AM10/20/05
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Phil Frisbie, Jr. wrote:
> I am pleased to announce that my commercial fixed point OpenLPC codec will now
> be dual licensed as LGPL or commercial software. The fixed point version of the
> OpenLPC codec is suitable to run on hand-held devices with CPUs that do not
> support hardware floating point math such as Arm, Intel PXA250, and other 32 bit
> CPUs. The fixed point codec is fully interoperable with the floating point
> codec, so developers can continue to use the floating point codec on desktop
> computers or servers. It can be downloaded now as a separate archive, and it
> will be included in the next release of HawkVoiceDI.

180 bytes per second LPC is quite impressive.

In the code, you write: "...analysis and synthesis takes each about 6
- 8% of the CPU cycles on a Cy686/166, when the code is compiled with
MSVC++ 4.2 with /Ox or gcc with -O3. However, a floating point unit is
absolutely required." If these numbers hold for the floating-point
version, what is the cpu utilization of the fixed-point code?

Phil Frisbie, Jr.

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Oct 20, 2005, 11:59:33 AM10/20/05
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Jim Leonard wrote:

That is a quote from the original floating point code written over 8 years ago.
I left that block of text in because it explains the stream format and a little
about how the codec works. I will look at that block again and edit out the old
irrelevant information to avoid future confusion ;)

From the HawkVoice codecs page, http://www.hawksoft.com/hawkvoice/codecs.shtml
, this is the performance:

Here are some performance results for fixed point codecs on a Pocket PC with a
PXA250 400MHz X-Scale (ARM) CPU using the long 25 second voice sample above:

CPU cycles per second for 8KHz sample rate sound.

encode decode
LPC-10: 19.0M 13.2M
OpenLPC 1.8K: 8.1M 9.8M
OpenLPC 1.4K: 8.2M 9.8M

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