EasyG722 is an implementation of ITU
G.722. EasyG722 support
multiple channels concurrent. There is no limit in concurrent channels and
it can up to thousands channels.
EasyG722 is an 64kbps coder that encodes/decodes speech signal.
Mode | 7kHz audio coding bit
rate | Auxiliary data channel bit
rate
-------------------------------------------------------------------------------
1
|
64 kbit/s
|
0 kbit/s
2
|
56 kbit/s
|
8 kbit/s
3
|
48 kbit/s
|
16kbit/s
The coder operates
on speech frames of 10 ms, corresponding to 160 samples at a sampling
rate of 16000 samples/sec. In addition to the 10 ms speech frame
duration, there is also a look-ahead delay of 0.125 ms, resulting in a total initial algorithmic delay
of 10.125 ms.
EasyG722 codec specifications
|
|
Bit rate (kbps)
|
64
|
Speech
sampling rate(Hz)
|
16000
|
Frame
duration (ms)
|
10
|
Look-ahead
delay (ms)
|
0.125
|
Samples in one Frame
|
160
|
Frame size before encode(bytes)
|
320
|
Frame size after encode(bytes)
|
80
|
EasyG722 has a binary release version
on Windows and Linux. The source code of EasyG722 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
EasyG722.pdf
|
This
document
|
EasyG722.lib
|
Win32
statically linkable library of G722 for Pentium and compatible
processors.
|
libG722.a
|
Linux
statically linkable library of G722 for Pentium and compatible
processors.
|
EasyG722.h
|
API
prototypes and constants declarations required by the sample programs.
|
test_encode
directory
|
Microsoft
VC6.0 sample application and Linux GCC sample application.
Demonstrating encoder API calls to the codec for encoding a speech
file.
|
test_decode
directory
|
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 16000 Hz as input, i.e.,
without any header information. For every speech frame, consisting of
160*16 bit (320 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 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):
EasyG722_encoder
infile bitstream
EasyG722_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.
EasyG722 API FUNCTIONS
EasyG722_init_encoder
|
|||
Description
|
Initializes the memory needed by the encoding
process. This function must be called prior to opening or re-opening a
channel.
|
||
Syntax
|
#include “EasyG722.h”
CODER_HANDLE EasyG722_init_encoder(
);
|
||
Arguments
|
none
|
||
Returned value
|
Return a handle that represent an encode
channel, this value will used at EasyG722_encoder and
EasyG722_release_encoder
|
||
EasyG722_encoder
|
|||
Description
|
Encode an 160 words
speech frame into a 80 bytes packed bit stream.
|
||
Syntax
|
#include “EasyG722.h”
bool EasyG722_encoder(CODER_HANDLE
hEncoder, short *speech, unsigned char *bitstream);
|
||
Arguments
|
hEncoder
The coder handle returned by EasyG722_init_encoder
speech
Input speech buffer containing one frame of 16-bit PCM speech
data.
Bitstream Output bit stream
buffer containing packed bit stream.
|
||
Returned value
|
Return true if successful, return
false if failed.
|
||
EasyG722_release_encoder
|
|||
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.
|
||
Syntax
|
#include “EasyG722.h”
bool
EasyG722_release_encoder(CODER_HANDLE hEncoder);
|
||
Arguments
|
hEncoder The
coder handle returned by EasyG722_init_encoder
|
||
Returned value
|
Return true if successful, return
false if failed.
|
||
EasyG722_init_decoder
|
|||
Description
|
Initializes the memory needed by the decoding
process. This function must be called prior to opening or re-opening a
channel.
|
||
Syntax
|
#include “EasyG722.h”
CODER_HANDLE EasyG722_init_decoder(
);
|
||
Arguments
|
None
|
||
Returned value
|
Return a handle that represent an decode
channel, this value will used at EasyG722_decoder and
EasyG722_release_decoder
|
||
EasyG722_decoder
|
|||
Description
|
Decodes a 80 bytes packed bit stream into an 160 words speech
frame.
|
||
Syntax
|
#include “EasyG722.h”
bool EasyG722_decoder(CODER_HANDLE
hDecoder, unsigned char *bitstream, short *synth_short );
|
||
Arguments
|
hDecoder
The decoder handle returned by EasyG722_init_decoder
bitstream
Input buffer containing packed bit-stream.
synth_short Output buffer
containing one frame of decoded 16 bits PCM.
|
||
Returned value
|
Return true if successful, return
false if failed.
|
||
EasyG722_release_decoder
|
|||
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 “EasyG722.h”
bool
EasyG722_release_decoder(CODER_HANDLE hDecoder);
|
||
Arguments
|
hDecoder
The coder handle returned by EasyG722_init_decoder
|
||
Returned value
|
Return true if successful, return
false if failed.
|
||
FAQS
Here are some
frequently asked questions about the EasyG722.
Q — Is the implementation of G.722 interoperable with the
other company’s version?
A — The
implementation of EasyG.722 is fully conform to ITU G.722, It can
interoperate with other G.722 implementations.
Q — What type of speech input format is required?
A — Raw 16-bit mono
PCM sampled at 16000Hz. 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 16000 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
EasyG722 on other platforms, you should buy the source code of EasyG722.
Then you can compile and link.
Q — Is the EasyG722 codec able to handle multiple
channels?
A — Yes, It can
handle multiple channels. There is no limited.
Q — Is the EasyG722 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 EasyG722 codec cost?
A — The 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 Win32/Linux trial version and sample |
|
Click
to
download PPC trial version and sample |
|
Click
to
download Windows and Linux 64bits trial version and samples |
|
Click
to
download Mac 32bits trial version and samples |
|
Click
to
download Mac 64bits trial version and samples |
|
Click
to
download the document |
|
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 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 |
|
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the Windows 64bits binary library(no time limitation) |
|
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Linux 64bits binary library(no time limitation) |
|
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to buy the
Mac 32bits binary library(no time limitation) |
|
Click
to buy the
Mac 64bits binary library(no time limitation) |
|
Click
to buy
the 64bits source code |
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