readme_usage

MPEG2/MPEG4编解码参考程序(实现了MPEG4的部分功能)

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***              MPEG-4 Audio Reference Software                   ***
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Content of README_usage
=======================

MPEG-4 Version 1:
0   General
1   HVXC
2   CELP
3   TwinVQ
4   AAC scalable


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0  General
==========

As soon as the MPEG-4 file format specification will be stable

  mp4audec -mp4ff bitstreamfilename -o ouputfilename          

will decode files in ".mp4" file format as specified in MPEG-4 Version 2.
No further swiches are necessary for paricular decoders since all necessary 
information is in the file itself.

Please note that the ".mp4" file format is not supported in the
MPEG-4 Version 1 Audio Reference Software!


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1   HVXC
========


HVXC encoding/decoding is carried out using the reference software.

Show below is example usages of the reference software
as a HVXC encoder/decoder.


1. Fixed rate 2000bps

Encode:
mp4auenc -eo .aif -r 2000 -c "m=hvx dm=0" -m par -pb encbit2k filename.aif 
Decode:
mp4audec -ed .aif -sf 1.0 -pf 1.0 -r 2000 -c "dm=1" encbit2k/filename.mp4 -o decout2k.aif


input:filename.aif
encoded bitstream: encbit2k/filename.mp4
decoded output: decout2k.aif
dm=0: low dealy mode encode
dm=1: normal delay mode decode
-pf: pitch control factor (default=1.0)
-sf: speed control factor (default=1.0)


2. Fixed rate 4000bps

Encode:
mp4auenc -eo .aif -r 4000 -c "m=hvx dm=0" -m par -pb encbit4k filename.aif  
Decode:
mp4audec -ed .aif -sf 1.0 -pf 1.0 -r 4000 -c "dm=1" encbit4k/filename.mp4 -o decout4k.aif

input:filename.aif
encoded bitstream: encbit4k/filename.mp4
decoded output: decout4k.aif
dm=0: low dealy mode encode
dm=1: normal delay mode decode
-pf: pitch control factor (default=1.0)
-sf: speed control factor (default=1.0)


3. Variable rate

Encode:
mp4auenc -eo .aif -vr -r 2000 -c "m=hvx dm=0 vr=1 ed=1" -m par -pb encbitvar filename.aif
Decode:
mp4audec -ed .aif -sf 1.0 -pf 1.0 -r 2000 -c "dm=1" encbitvar/filename.mp4 -o decout2k.aif

input:filename.au
encoded bitstream: encbitvar/filename.mp4
decoded output: decout2k.aif


4. Scalable decode

Encoded bitstream at 4000 bps can also be decoded at 2000 bps, where a subset of
4000 bps bitstream is used for decoding.

Encode:
mp4auenc -eo .aif -r 4000 -c "m=hvx dm=0" -m par -pb encbit4k filename.aif  
Decode:
mp4audec -ed .aif -r 2000 -sf 1.0 -pf 1.0 -c "dm=1" encbit4k/filename.mp4 -o decout2k.aif

input:filename.aif
encoded bitstream: encbit4k/filename.mp4
decoded output: decout2k.aif


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Shown below are the lists you can see by executing mp4auenc -h or mp4audec -h


Encoder switches:

usage: mp4auenc -switches <audio file(s)>
switches: -h        print help
          -m <x>    codec mode (par, lpc, tf, g729, g723) (dflt: par)
          -r <x>    bit rate [bit/s] (dflt: 6000)
          -vr       enable variable bit rate
          -b <x>    bit reservoir size [bit] (dflt: 0)
          -bi <x>   initial bit reservoir bits
                    (dflt: bit reservoir size)
          -c <x>    encoder parameter string (dflt: )
          -ts <x>   start time of encoded region [sec] (dflt: 0)
          -td <x>   duration of encoded region [sec]
                    (dflt: until end of file)
          -o <x>    output file name
          -n <x>    number of audio channels for bit stream header
                    (0=as input file) (dflt: 0)
          -s <x>    sampling frequency [Hz] for bit stream header
                    (0=as input file) (dflt: 0)
          -po <x>   default path original audio files (dflt: $MP4_ORI_PATH)
          -pb <x>   default path bit stream files (dflt: $MP4_BIT_PATH)
          -eo <x>   original audio file extension
                    supported file formats: .au, .snd, .wav, .aif, .raw
                    (dflt: $MP4_ORI_FORMAT / .au)
                    (raw format: $MP4_RAWAUDIOFILE)
          -eb <x>   bit stream file extension (dflt: .mp4)
          -ni       disable bit info string
          -nh       disable mp4 bit stream header
          -ms <x>   bit stream magic string (dflt: .mp4)
          -d <x>    main debug level (dflt: 0)
          -da <x>   audio file debug level (dflt: 0)
          -db <x>   bit stream debug level (dflt: 0)
          -dc <x>   cmd line debug level (dflt: 0)
          -dq <x>   quantizer  debug level (dflt: 0)

parametric encoder core V5.0 12-nov-97
encoder parameter string format:
  list of tokens (tokens separated by characters in " ,=")

token list format: switches
switches: h          print help
          m <x>      parametric codec mode (hvx, il, swit, mix) (dflt: il)
          dm <x>     HVXC delay mode (0=short 1=long) (dflt: 0)
          vr <x>     HVXC variable rate mode (0=fixed 1=var)
                     (set frame work option -vr) (dflt: 0)
          mm <x>     HVXC/IL mix mode (2ch: L=HVXC R=IL, use with -n 1)
                     (0=HVXC 1=HVXC2+IL 2=HVXC4+IL 3=IL  -=cycle periode)
                     (dflt: 1)
          dl <x>     debug level (dflt: 0)
          dli <x>    debug level individual lines (dflt: 0)
          fd <x>     frame duration [sec] (dflt: 0.032)
          mnl <x>    max num individual lines
          mlf <x>    max line frequency
          me <x>     max num envelopes (1=il/harm 2=+noise) (dflt: 1)
          mh <x>     max num harmonic tones (dflt: 1)
          mhl <x>    max num lines of harmonic tone (dflt: 64)
          mn <x>     max num noise paramters (dflt: 16)
          hie <x>    harm/indi enha flag (0=basic 1=enha) (dflt: 0)
          hibr <x>   harm/indi basic bit rate (dflt: full rate)
          hiq <x>    harm/indi quant mode (-1=auto 0..3) (dflt: -1)
          hieq <x>   harm/indi enha quant mode (-1=auto 0..3) (dflt: -1)
          hicm <x>   harm/indi continue mode (0=hi, 1=hi&ii) (dflt: 0)
          iecm <x>   indi encoder continue mode (0=cont 1=no-cont) (dflt: 0)
          bsf <x>    HILN bitstream format (0=VM 1=9705 2=CD) (dflt: 2)
          clas <x>   for test only
                     (classifier mode 0=pause req. 1=no pause req.) (dflt: 0)
          test <x>   for test only
                     (hvxc/il alternate periode +=IL/HVXC/.. -=HVXC/IL/..)
                     (dflt: 0)
          ed <x>     HVXC only mode encoder delay comp.: 0=0/20ms 1=6/26ms
                     (dflt: 0)


Decoded Switches:

usage: mp4audec -switches <bit stream file(s)>
switches: -h          print help
          -r <x>      decoder bit rate for scalability [bit/s]
                      (dflt: encoder bit rate)
          -n <x>      number of audio channels (0=as original) (dflt: 0)
          -s <x>      sampling frequency [Hz] (0=as original) (dflt: 0)
          -sf <x>     speed change factor (dflt: 1)
          -pf <x>     pitch change factor (dflt: 1)
          -c <x>      decoder parameter string ("-c h" for help) (dflt: )
          -ts <x>     start time of decoded region [sec] (dflt: 0)
          -td <x>     duration of decoded region [sec]
                      (dflt: until end of bit stream)
          -o <x>      output file name
          -pb <x>     default path bit stream files (dflt: $MP4_BIT_PATH)
          -pd <x>     default path decoded audio files (dflt: $MP4_DEC_PATH)
          -eb <x>     bit stream file extension (dflt: .mp4)
          -ed <x>     decoded audio file extension
                      supported file formats: .au, .snd, .wav, .aif, .raw
                      (dflt: $MP4_DEC_FORMAT / .au)
                      (raw format: integer16, native)
          -t          test bit stream (decoder disabled)
          -d <x>      main debug level (dflt: 0)
          -da <x>     audio file debug level (dflt: 0)
          -db <x>     bit stream debug level (dflt: 0)
          -dc <x>     cmd line debug level (dflt: 0)
          -daac <x>   [a-Z] Debug Options for aac-Decoder (dflt: )
          -picola     speed control by PICOLA
          -aaceof     AAC bitstream end detection

parametric decoder core V5.0 12-nov-97
decoder parameter string format:
  list of tokens (tokens separated by characters in " ,=")

token list format: switches
switches: h          print help
          dm <x>     HVXC delay mode (0=short 1=long) (dflt: 0)
          dl <x>     debug level (dflt: 0)
          dli <x>    debug level individual lines (dflt: 0)
          noi        disable indiline synthesis
          noh        disable harm synthesis
          non        disable noise synthesis
          npf <x>    noise para factor (dflt: 1.0)
          hie <x>    harm/indi enha flag
                     (0=basic 1=enha 2=no-scalable-enha) (dflt: 0)
          pnl <x>    initial number of prev. indilines
                     (-1=unknown for start at arbitrary frame) (dflt: 0)
          hicm <x>   harm/indi continue mode
                     (-1=bitstream 0=hi, 1=hi&ii) (dflt: -1)
          bsf <x>    HILN bitstream format (0=VM 1=9705 2=CD) (dflt: 2)
          nos        disable stretching
          cdf <x>    line continuation df (dflt: 1.05)
          cda <x>    line continuation da (dflt: 4.0)
          rsp <x>    random startphase (0=sin(0) 1=sin(rnd)) (dflt: 1)
          test <x>   for test only (1=hvxc 2=il) (dflt: 0)



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[HVXC update 990218]

     usage of newly implemented HVXC core.
    (HVXC in parametric core still exists)

    [fixed rate 2kbps]
    mp4auenc -m hvxc -r 2000 -c "dm=0" -o <bitstream file> <input file(.au)> 
    mp4audec -sf 1.0 -pf 1.0 -c "dm=1" -o <output file(.au)> <bitstream file>

    encode: short delay mode
    decode: normal delay mode, speed change factor=1, pitch change factor=1
            speed change factor can be given by using option "-sf <x>".
	    (possible variation is from 0.5 to 2.0)
            pitch change factor can be given by using option "-pf <x>".
	    (possible variation is from 0.5 to 2.0)

    [fixed rate 4kbps]
    mp4auenc -m hvxc -r 4000 -c "dm=0" -o <bitstream file> <input file(.au)> 
    mp4audec -sf 1.0 -pf 1.0 -c "dm=1" -o <output file(.au)> <bitstream file>

    [variable rate]
    mp4auenc -m hvxc -vr -r 2000 -c "dm=0" -o <bitstream file> <input file(.au)> 
    mp4audec -sf 1.0 -pf 1.0 -c "dm=1" -o <output file(.au)> <bitstream file>

    [scalable decode]
    mp4auenc -m hvxc -r 4000 -c "dm=0" -o <bitstream file> <input file(.au)> 
    mp4audec -sf 1.0 -pf 1.0 -r 2000 -c "dm=1" -o <output file(.au)> <bitstream file>
 
    encoded bitstream at 4000 bps can also be decoded at 2000 bps, where a subset of
    4000 bps bitstream is used for decoding.

[HVXC update 990616]
switches:
    -hvxc_sys	encode/decode system interface(flexmux)

    usage of encode/decode with system interface(flexmux)
    (only single layer of HVXC supported)

    [fixed rate 2kbps]
    mp4auenc -m hvxc -r 2000 -c "-hvxc_sys" -o <bitstream file> <input file> 
    mp4audec -sf 1.0 -pf 1.0 -c "-hvxc_sys" -o <output file> <bitstream file>

    [fixed rate 4kbps]
    mp4auenc -m hvxc -r 4000 -c "-hvxc_sys" -o <bitstream file> <input file> 
    mp4audec -sf 1.0 -pf 1.0 -c "-hvxc_sys" -o <output file> <bitstream file>

    [variable rate]
    mp4auenc -m hvxc -r 2000 -vr -c "-hvxc_sys vr=1" -o <bitstream file> <input file> 
    mp4audec -sf 1.0 -pf 1.0 -c "-hvxc_sys" -o <output file> <bitstream file>

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2   CELP
========


Usage of the MPEG-4 Reference Software - CELP RPE modes
-------------------------------------------------------

CELP ENCODER (RPE modes)

To use the MPEG-4 Reference Software to encode MPEG-4 CELP bitstreams,
the following CELP specific encoder parameter string options are available:

       e <0/1> : Multi-Pulse Excitation (0) or Regular-Pulse Excitation (1)
       f <0/1> : Fine Rate Control OFF (0) or ON (1)
       p <0/1> : Pre-processing OFF (0) or ON (1)
       d <0/1> : Debug Level OFF (0) or ON (1)

The input must be a file with one channel of PCM audio sampled at 16 kHz.

When FineRate Control is ON, the -vr switch is required in order to
enable variable bitrate. In this case, the -b option must be used to
indicate the input buffer size (expressed in bits) that will be
required in the MPEG-4 decoder. The default value is -b 6000.

The table below lists some examples on how to use the MPEG-4 Audio
Reference Software to create MPEG-4 CELP bitstreams at several
bitrates. Note that when FineRate Control is OFF, only one bitrate is
available for each RPE Configuration. When FineRate Control is ON, the
bitrate can be selected within a limited range for each RPE
Configuration. For detailed information, please refer to ISO/IEC
14496-3 Subpart 3, MPEG-4 CELP Audio.


RPE                          FineRate     Example
Configuration:  Bitrate:     Control:     invokement:
-------------------------------------------------------------------------------------------------------------------------
   0            14400 bps    OFF          mp4auenc -m lpc -o .\out.mp4 .\in.wav -c "e 1 f 0 p 1" -r 14400 -b 0 -d 1
   1            16000 bps    OFF          mp4auenc -m lpc -o .\out.mp4 .\in.wav -c "e 1 f 0 p 1" -r 16000 -b 0 -d 1
   2            18667 bps    OFF          mp4auenc -m lpc -o .\out.mp4 .\in.wav -c "e 1 f 0 p 1" -r 18667 -b 0 -d 1
   3            22533 bps    OFF          mp4auenc -m lpc -o .\out.mp4 .\in.wav -c "e 1 f 0 p 1" -r 22533 -b 0 -d 1

   0            13500 bps    ON           mp4auenc -m lpc -o .\out.mp4 .\in.wav -c "e 1 f 1 p 1" -r 13500 -vr -b 8000 -d 1
   1            15400 bps    ON           mp4auenc -m lpc -o .\out.mp4 .\in.wav -c "e 1 f 1 p 1" -r 15400 -vr -b 8000 -d 1
   2            18000 bps    ON           mp4auenc -m lpc -o .\out.mp4 .\in.wav -c "e 1 f 1 p 1" -r 18000 -vr -b 8000 -d 1
   3            21500 bps    ON           mp4auenc -m lpc -o .\out.mp4 .\in.wav -c "e 1 f 1 p 1" -r 21500 -vr -b 8000 -d 1


CELP DECODER (RPE modes)

To use the MPEG-4 Reference Software to decode MPEG-4 CELP bitstreams,
the following CELP specific decoder parameter string options are
available:

       p <0/1>         : Post filter OFF (0) or ON (1). Default: OFF
       d <0/1>         : Debug Level OFF (0) or ON (1). Default: OFF

The output will be a file with one channel of PCM audio at 16 kHz
sampling rate.

The table below lists some examples on how to use the MPEG-4 Audio
Reference Software to decode MPEG-4 CELP bitstreams. The operation of
the optional postfilter can be selected by the p parameter.

Postfiter:      Example invokement:
----------------------------------------------------------------
  OFF           mp4audec -o .\out.wav .\in.mp4 -c "p 0" -d 1
  ON            mp4audec -o .\out.wav .\in.mp4 -c "p 1" -d 1


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