[Speex-dev] problem: The decoded frame is not as the original one

[Arthurc]

1. Sound encoding and decoding is a lossy process.
2. To determine that it is working correctly, you either play it back or look at he wave form.

Arthur

On 2012年3月12日, at 上午1:17, Mashal al-shboul <shboul8989 at yahoo.com> wrote:

> Hi All,
> i need your help in determining the problem in the following sample code (taken from speex manual) for fixed point encoding.
> i tested encoding a 160 sample frame and then decoding it back But The problem is that the decoded frame is totally different from the original frame(see output below).What is the possible reason for this?.thanks for any help
> 
> #include<stdio.h>
> #include"intel16.h"
> #include <speex/speex.h>
> 
> #define FRAME_SIZE 160
> #define MAX_NB_BYTES 25
> SpeexBits bits;
> void *enc_state;
> int quality=4;       
> int nbBytes;
> int byte_ptr;
> int frame_size;
> short frame[FRAME_SIZE];  
> char outBuffer[20];
> 
> SpeexBits decBits;
> void *dec_state;
> short decFrame[FRAME_SIZE];
> /*===========END ===============================*/
> 
> 
> int z=0;
> int frame_size;
> 
> 
> int main (int argc,char **argv)
> {
> for( z=0;z<160;z++)
>     {
>     frame[z]=intel_theme[z];  //array of short from "intel16" header file
>     }
>  printf("\n =================================== \n");
> 
>  for( z=0;z<160;z++)
>     {
>         printf("%i",frame[z]);
>     printf ("  ");
>         }
> 
> /*===============================ENCODING==============================================*/
> 
>      speex_bits_init(&bits);
>      enc_state = speex_encoder_init(&speex_nb_mode);
>      speex_encoder_ctl(enc_state,SPEEX_GET_FRAME_SIZE,&frame_size);
>      speex_encoder_ctl(enc_state,SPEEX_SET_QUALITY,&quality);
>      speex_bits_reset(&bits);
>  
> //-----------TWO CALLS FOR ENCODING-------------------
>      speex_encode_int(enc_state, frame, &bits);                // encoding from frame to &bits
>      nbBytes = speex_bits_write(&bits, outBuffer, MAX_NB_BYTES); //writing from &bits to outBuffer
> //----------------------------------------------------
>      
>      speex_bits_destroy(&bits);
>      speex_encoder_destroy(enc_state);    
> 
> printf("\n outBuffer: ");
> for(z=0;z<20;z++)
> {
> printf("%c",outBuffer[z]);
> }
> printf("\n \n");
> /*===============================END OF ENCODING=========================================*/
> 
> 
> /*===============================DECODING==============================================*/
> 
> speex_bits_init(&decBits);
> dec_state=speex_decoder_init(&speex_nb_mode);
> speex_decoder_ctl(dec_state, SPEEX_GET_FRAME_SIZE, &frame_size);
> 
> //-----------TWO CALLS FOR DECODING-------------------
> speex_bits_read_from(&decBits,outBuffer,nbBytes);
> speex_decode_int(dec_state,&decBits,decFrame);
> //----------------------------------------------------
> printf("\n BUFFER DECODED BACK \n");
> 
> for(z=0;z<160;z++)
> {
> printf("%i",decFrame[z]);
> printf ("  ");
> }
> 
> speex_bits_destroy(&decBits);
> speex_decoder_destroy(dec_state);
> /*===============================END OF DECODING==============================================*/
> printf("\n nbBytes: ");
> printf("%i",nbBytes);
> printf("\n frame_size= ");
> printf("%i",frame_size);
> printf ("\n");
> //-----------------
> printf("end of run!");
> 
> return 0;
> }
> 
> OUTPUT:
> //the original frame
> 1  -512  16384  512  -768  -2048  -1280  256  -1024  12288  0  8192  253  256  -768  12288  0  -16  -768  -512  -1  0  -512  -768  -1536  -512  -512  -768  16384  0  8192  -512  16384  512  -768  -2048  -1280  256  -1024  12288  0  8192  253  256  -768  12288  0  -16  -768  -512  -1  0  -512  -768  -1536  -512  -512  -768  16384  0  8192  -512  16384  512  -768  -2048  -1280  256  -1024  12288  0  8192  253  256  -768  12288  0  -16  -768  -512  -1  0  -512  -768  -1536  -512  -512  -768  16384  0  8192  -512  16384  512  -768  -2048  -1280  256  -1024  12288  0  8192  253  256  -768  12288  0  -16  -768  -512  -1  0  -512  -768  -1536  -512  -512  -768  16384  0  8192  -512  16384  512  -768  -2048  -1280  256  -1024  12288  0  8192  253  256  -768  12288  0  -16  -768  -512  -1  0  -512  -768  -1536  -512  -512  -768  16384  0  -1  0  -512  -768  -1536  -512  -512  -768  16384  -1  
>  =================================== 
> 
>  outBuffer: ╴9╴p╴C╴╴m╴Cx6╴╴
>  
> //the decoded frame .totally different
>  BUFFER DECODED BACK 
> 0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  2838  -3982  4801  -4136  432  -1945  610  1035  -1090  2752  -558  1431  -2320  -1016  789  5084  -2395  -2916  -225  -311  -703  586  1110  -557  -1152  1096  229  425  5825  -933  3922  -6289  7423  -6636  -793  -2123  -354  991  -1947  3958  -1070  1380  -2120  -2777  -679  9010  -2451  -4210  -1845  229  -1687  317  1443  -1355  -2818  214  721  -313  9997  -60  3489  -5953  9277  -6990  -2716  -1642  -792  477  -2417  5801  -1200  1055  -1744  -2927  -2053  10273  -1913  -4342  -2718  427  
>  nbBytes: 20
>  frame_size= 160
> 
> 
> 
> 
> 
> 
> 
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