Linear predictive coding in mixed excitation linear predictive coder melp
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Linear Predictive Coding in Mixed-Excitation Linear Predictive Coder - MELP. MELP LPC LSFs demonstration Subject: Adaptive Digital Signal Processing Scientific Postgraduate Study of Electronics, FESB, University of Split Professor: dr. sc. Dinko Begušić Student: Zoran Sambol.

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Linear Predictive Coding in Mixed-Excitation Linear Predictive Coder - MELP

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Linear predictive coding in mixed excitation linear predictive coder melp

Linear Predictive Coding in Mixed-Excitation Linear Predictive Coder - MELP

MELP LPC LSFs demonstration

Subject: Adaptive Digital Signal Processing

Scientific Postgraduate Study of Electronics, FESB, University of Split

Professor: dr. sc. Dinko Begušić Student: Zoran Sambol

LPC impact on MELP


Adaptive dsp study

Adaptive DSP - Study

  • Subject program

    • Literature - Simon Haykin: Adaptive filter theory,

      Prentice Hall, 1991.

  • Practical work based on MELP codec

    • Study subject – Speech coding - Presentation

  • Three phases

    • Adaptive Filter theory – Seminar documents

    • MELP codec adjustment - coding

    • LPC LSF impact on MELP – today presentation

LPC impact on MELP


Lpc show impact on melp

LPC – show impact on MELP

  • Task was given during MELP codec presentation – September 2002.

  • MELP codec is based on Linear Predictive Coding.

    • Its LPC coder has 10th order

  • My task was to show impact of LPC coder on overall MELP algorithm

LPC impact on MELP


Lpc web resources

LPC web & resources

  • MELP documents - MELP Presentation page 3.

    • DDVPC Homepage, Standard draft, ASPI digital – Polycom, Texas Instruments and Noam Amir educational site.

  • Most of the resources has samples coded in Matlab

  • Google groups search – Line Spectrum Pairs (LSP)

    • Cite – William M. Wiese Jr. [ In the real world, if two adjoining LSF values are equal we separate them by some small value like 35 – 50 Hz.]

      What will happen if I change LSF that minimum

      distance is greater or less than 50 Hz?

LPC impact on MELP


Encoder melp lpc

Encoder MELP – LPC

LPC impact on MELP


Decoder melp lpc

Parameters

Voiced

Unvoiced

LSF’s

25

25

Fourier Magnitudes

8

-

Gain (2 per frame)

8

8

Pitch (overall voicing)

7

7

Bandpass voicing

4

-

Aperiodic Flag

1

-

Error protection

-

13

Sync Bit

1

1

Total bits/ 22.5 ms Frame

54

54

Decoder MELP - LPC

44/54 = 81.48%

LPC impact on MELP


Melp codec

MELP codec

  • Windows console application

  • What were changed?

    • Command prompt – additional argument

      • ConsoleMelp –a –i dam9.bin –o dam9.ccl –f 150

      • Parse function - void parse(int argc,char **argv)

      • Clamping function (sort LSFs and minimum separation)

        • int lpc_clmp(float *w, float delta, int p);

    • Minimum LSF separation

      • #define BWMIN (50.0*2/FSAMP) /* minimum LSF separation */

      • Changed with float fLSFFrequency variable

LPC impact on MELP


Recorder player

Recorder - Player

  • Windows MELPCodec application

    • Known interface

  • Equalizer dialog

    • 50 Hz default value

    • Check button

    • Log slider

    • Easy canceling

Equalizer

LPC impact on MELP


Batch console applications

Batch – Console applications

  • Four different console application integrated using DOS Batch files

    • Waveopt, ConsoleMelp, CCRemover and CCInserter

  • Console applications with input and output parameters – files

    • ConsoleMelp –a –i dam9.bin –o dam9.ccl –f 150

    • Waveopt syntax:

      • Waveopt.exe [*.bin | *.wav]

  • Easy deleting, renaming, directory creating –

    • Read Me file.

LPC impact on MELP


Testing

Testing

  • Well known record

  • Using MelpCodec application as a recorder and my own voice.

LPC impact on MELP


Results

Results

  • Subjective measurements

  • Overvoicing

  • Quality degradation – Male and Female

  • 180 samples segments impact on parameters

  • Real measurement – MOS (ITU)

LPC impact on MELP


Windows melp codec

Opening WAV and MELP (Channel coded) files

Playing files

Recording and storing waves in MELP useful format

Recording Channel coded and MELP files

Size comparison - Explorer utility

Useful Equalizer

Windows – MELP Codec

LPC impact on MELP


Melpcodec with equalizer

MelpCodec with Equalizer

Education

  • Useful adjustable tool:

    • Statistics (MOS, DAM, DRT measurement)

    • Vocoder example for FEC

    • Internet and database connection

    • Visualization, Skins and additional GUI components

  • Laboratory exercise – Voice Coding subject

  • Digital Signal Adaptive Processing - Subject

  • Gathering measurement results

  • Symposium article (IEEE, SoftCOM, ELMAR, MiPRO)

  • Experience for some other voice and no-voice LP algorithms

LPC impact on MELP


Thanks for your time

Thanks for your time!

Contact:

Zoran Sambol, Siemens d.d. Put Brodarice 6, 21000 Split

Tel. +385 21 390 936

[email protected], [email protected]

LPC impact on MELP


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