EasyG726 is an implementation of ITU
G.726. EasyG726 support
multiple channels concurrent. There is no limit in concurrent channels and
it can up to thousands channels.
EasyG726 has 4 different bit rates, it has
16kbps/24kbps/32kbps/40kbps coder that encodes/decodes speech signal. The coder
operates on speech frames is based on each frame.
EasyG726 codec specifications
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|
Bit rate (kbps)
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16,24,32,40
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Speech
sampling rate(Hz)
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8000
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EasyG726 has a binary release version
on Windows and Linux. The source code of EasyG726 is written by C, so you
can easily port it to UNIX, PPC,DSP, Vxworks or other operation system that
support C.
PACKAGE CONTENTS
EasyG726.pdf
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This
document
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EasyG726.lib
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Win32
statically linkable library of G726 for Pentium and compatible
processors.
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libG726.a
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Linux
statically linkable library of G726 for Pentium and compatible processors.
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EasyG726.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.
|
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, only include one
sample(2 bytes)
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 less than 1% CPU time
Decoder less than 1% 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):
EasyG726_encoder
infile bitstream
EasyG726_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.
EasyG726 API FUNCTIONS
EasyG726_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 “EasyG726.h”
CODER_HANDLE EasyG726_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 EasyG726_encoder and
EasyG726_release_encoder
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EasyG726_encoder
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Description
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Encode a sample(16bits)
into a bit stream.
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Syntax
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#include “EasyG726.h”
int EasyG726_encoder(CODER_HANDLE
hEncoder, short *speech, unsigned char *bitstream, int in_coding, int
bitsPerSample );
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Arguments
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hEncoder
The coder handle returned by EasyG726_init_encoder
speech
Input speech buffer containing one sample of 16-bit PCM speech
data.
bitstream Output bit stream
buffer containing packed bit stream.
in_coding:
1
AUDIO_ENCODING_ULAW
ISDN u-law
2 AUDIO_ENCODING_ALAW
ISDN A-law
3 AUDIO_ENCODING_LINEAR
PCM 2's-complement (0-center)
bitsPerSample
2 16kbps
3 24kbps
4 32kbps
5 40kbps
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Returned value
|
Return 0 if successful, return –1 if failed.
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EasyG726_release_encoder
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Description
|
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 “EasyG726.h”
int
EasyG726_release_encoder(CODER_HANDLE hEncoder);
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Arguments
|
hEncoder The
coder handle returned by EasyG726_init_encoder
|
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Returned value
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Return 0 if successful, return –1 if failed.
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EasyG726_init_decoder
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|||
Description
|
Initializes the memory needed by the
decoding process. This function must be called prior to opening or
re-opening a channel.
|
||
Syntax
|
#include “EasyG726.h”
CODER_HANDLE EasyG726_init_decoder(
);
|
||
Arguments
|
None
|
||
Returned value
|
Return a handle that represent an decode
channel, this value will used at EasyG726_decoder and
EasyG726_release_decoder
|
||
EasyG726_decoder
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Description
|
Decodes a packed bit stream into a sample(16bits).
|
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Syntax
|
#include “EasyG726.h”
int EasyG726_decoder(CODER_HANDLE
hDecoder, unsigned char *bitstream, short *speech, int out_coding, int
bitsPerSample );
|
||
Arguments
|
HDecoder
The decoder handle returned by EasyG726_init_decoder
bitstream
Input buffer containing packed bit-stream.
speech
Output buffer containing one sample 16 bits PCM.
out_coding:
1
AUDIO_ENCODING_ULAW
ISDN u-law
2 AUDIO_ENCODING_ALAW
ISDN A-law
3 AUDIO_ENCODING_LINEAR
PCM 2's-complement (0-center)
bitsPerSample
2 16kbps
3 24kbps
4 32kbps
5 40kbps
|
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Returned value
|
Return 0 if successful, return –1 if failed.
|
||
EasyG726_release_decoder
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|||
Description
|
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.
|
||
Syntax
|
#include “EasyG726.h”
int
EasyG726_release_decoder(CODER_HANDLE hDecoder);
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Arguments
|
hDecoder The
coder handle returned by EasyG726_init_decoder
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Returned value
|
Return 0 if successful, return -1
if failed.
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||
FAQS
Here are some
frequently asked questions about the EasyG726.
Q — Is the implementation of G.726 interoperable with the
other company’s version?
A — The
implementation of EasyG.726 is fully conform to ITU G.726, It can
interoperate with other G.726 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
EasyG726 on other platforms, you should buy the source code of EasyG726.
Then you can compile and link.
Q — Is the EasyG726 codec able to handle multiple
channels?
A — Yes, It can
handle multiple channels. There is no limited.
Q — Is the EasyG726 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 EasyG726 codec cost?
A — The 32bits/64bits object code
of Windows or Linux is $5,000. The source code is $40000. You can buy it
from www.imtelephone.com.
Click
 to download the Win32/Linux trial version and sample |
|
Click
to download the PPC trial version and sample |
|
Click
to download the Windows and Linux 64bits version and sample |
|
Click
to
download the document |
|
Click
 to buy
the Win32 binary library(no time limitation) |
|
Click
to buy
the Linux binary library(no time limitation) |
|
Click
to buy
the source code |
|
Click
to buy
the Windoes 64bits binary library(no time limitation) |
|
Click
to buy
the Linux 64bits binary library(no time limitation) |
|
Click
to buy
the 64bits source code |
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