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EasyG729A is an implementation of ITU G.729A. EasyG729A support multiple channels
concurrent. There is no limit in concurrent channels and it can up to thousands
channels.
EasyG729A
is an 8kbps coder that encodes/decodes speech signal. The coder operates on
speech frames of 10 ms, corresponding to 80 samples at a sampling rate of
8000
samples/sec. In
addition to the 10 ms speech frame duration, there is also a look-ahead
delay of 5 ms, resulting in a total initial algorithmic delay of 15ms.
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EasyG729A
codec specifications
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Bit rate (kbps)
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8
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Speech
sampling rate(Hz)
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8000
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Frame
duration (ms)
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10
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Look-ahead
delay (ms)
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5ms
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Samples in one Frame
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80
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Frame size before encode(bytes)
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160
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Frame size after encode(bytes)
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10
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EasyG729A has a binary release version
on Windows and Linux. The source code of EasyG729A is written by C/C++, so you
can easily port it to UNIX, PPC,DSP, Vxworks or other operation system
that support C/C++.
PACKAGE CONTENTS
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EasyG729A.pdf
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This
document
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EasyG729A.lib
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Win32
statically linkable library of G729A
for Pentium and compatible processors.
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libG729a.a
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Linux
statically linkable library of G729A
for Pentium and compatible processors.
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EasyG729A.h
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API
prototypes and constants declarations required by the sample programs.
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test_encode
directory
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Microsoft
VC6.0 sample application and Linux GCC sample application.
Demonstrating encoder API calls to the codec for encoding a speech
file.
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test_decode
directory
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Microsoft
VC6.0 sample application and Linux GCC sample application.
Demonstrating decoder API calls to the codec for decoding a speech
file.
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The encoder
requires raw 16-bit mono PCM speech data sampled at 8000 Hz as input,
i.e., without any header information. For every speech frame, consisting
of 80*16 bit (160 bytes) samples
CODEC COMPLEXITY
The codec
complexity is represented as percentage of CPU usage, and is as follows
when tested on an Intel 800 MHz Celeron-MMX:
Encoder 4% CPU time
Decoder 2% CPU time
ABOUT THE ENCODER/DECODER
SAMPLE PROGRAMS
The sample programs
under test_encode
directory and test_decode directory are used to simulate the encoder and decoder, and
demonstrate how to initialize and call the encoding and decoding process.
The encoder and decoder are run as follows (where infile and outfile are raw 16 bit PCM
files sampled at 8 kHz):
EasyG729A_encoder infile bitstream
EasyG729A_decoder
bitstream outfile
To build the speech
encoder (or decoder) sample programs on Windows, you can open TEST_ENCODE.dsw
or TEST_DECODE.dsw with VC6.0 or later version. After compiler and link,
it will create the execute program of test_encode.exe or test_decode.exe, you can test it
with following command.
test_encode test.pcm test.cod
test_decode test.cod
test.pcm
To build the speech
encoder (or decoder) sample programs on Linux, you only need rum make command. After you
successfully finished make command, you can run make run to test encoder and decoder.
EasyG729A
API
FUNCTIONS
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EasyG729A_init_encoder
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Description
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Initializes the memory needed by the
encoding process. This function must be called prior to opening or
re-opening a channel.
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Syntax
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#include “EasyG729A.h”
CODER_HANDLE EasyG729A_init_encoder(
);
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Arguments
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none
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Returned value
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Return a handle that represent an
encode channel, this value will used at EasyG729A_encoder and EasyG729A_release_encoder
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EasyG729A_encoder
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Description
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Encode an 80 words speech
frame into a 10 bytes packed bit stream.
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Syntax
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#include “EasyG729A.h”
bool EasyG729A_encoder(CODER_HANDLE
hEncoder, short *speech, unsigned char *bitstream);
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Arguments
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hEncoder
The coder handle returned by EasyG729A_init_encoder
speech
Input speech buffer containing one frame of 16-bit PCM speech
data.
Bitstream Output bit stream
buffer containing packed bit stream.
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Returned value
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Return true if successful, return
false if failed.
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EasyG729A_release_encoder
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Description
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release the memory allocated by the
encoding process. This function must be called before you quit your
program. If not, it will cause the memory leak.
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Syntax
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#include “EasyG729A.h”
bool EasyG729A_release_encoder(CODER_HANDLE
hEncoder);
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Arguments
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hEncoder
The coder handle returned by EasyG729A_init_encoder
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Returned value
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Return true if successful, return
false if failed.
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EasyG729A_init_decoder
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Description
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Initializes the memory needed by the
decoding process. This function must be called prior to opening or
re-opening a channel.
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Syntax
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#include “EasyG729A.h”
CODER_HANDLE EasyG729A_init_decoder(
);
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Arguments
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None
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Returned value
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Return a handle that represent an
decode channel, this value will used at EasyG729A_decoder and EasyG729A_release_decoder
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EasyG729A_decoder
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Description
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Decodes a 10 bytes packed bit stream into an 80 words speech frame.
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Syntax
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#include “EasyG729A.h”
bool EasyG729A_decoder(CODER_HANDLE
hDecoder, unsigned char *bitstream, short *synth_short );
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Arguments
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hDecoder
The decoder handle returned by EasyG729A_init_decoder
bitstream
Input buffer containing packed bit-stream.
synth_short Output buffer
containing one frame of decoded 16 bits PCM.
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Returned value
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Return true if successful, return
false if failed.
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EasyG729A_release_decoder
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Description
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release the memory allocated by the
decoding process. This function must be called before you quit your
program. If not, it will cause the memory leak.
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Syntax
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#include “EasyG729A.h”
bool EasyG729A_release_decoder(CODER_HANDLE
hDecoder);
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Arguments
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hDecoder
The coder handle returned by EasyG729A_init_decoder
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Returned value
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Return true if successful, return
false if failed.
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Here are some
frequently asked questions about the EasyG729A.
Q — Is the implementation of G.729A interoperable with the other
company’s version?
A — The
implementation of EasyG.729A
is fully conform to ITU G.729A,
It can interoperate with other G.729A
implementations.
Q — What type of speech input format is required?
A — Raw 16-bit mono
PCM sampled at 8000Hz. Do not use .WAV files. They contain a header that
will produce distortion at the start of a decoded audio sample because
the encoder interprets the header as speech data.
Q — How can I convert my .WAV files to raw 16 bit mono PCM
sampled at 8000 Hz?
A — Use an audio
editing tool such as SoX - Sound eXchange. See home.sprynet.com/~cbagwell/sox.html
for
more information
Q — Can I get link on platforms other than Pentium or
compatible?
A — The object code
provided in this package is Microsoft Win32 and Linux x86 compatible. It
is compiled for the Pentium family of processors. If you want to use
EasyG729A
on other platforms, you should buy the source code of EasyG729A. Then you
can compile and link.
Q — Is the EasyG729A
codec able to handle multiple channels?
A — Yes, It can
handle multiple channels. There is no limited.
Q — Is the EasyG729A
codec free to use?
A — No, The version
you get freely is a version only for test. If you want to use it in
commercial, you must buy it from www.imtelephone.com. This version has the same
function with the formal release version, but It can only run 60 hours
continuously.
Q — How much does the EasyG729A codec cost?
A — The object code of Windows
or Linux is $2000/year. The source code is $40000. You can buy it from www.imtelephone.com.
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Click  to
download Win32/Linux trial version and samples
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Click to
download Win32/Linux optimized trial version and samples,it is 10 times fast than unoptimized version.
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download PPC trial version and samples
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Click to
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Click to buy
the Linux optimized binary library(no time limitation)
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