g726.c

读取SD卡存储的adpcm码

#include "stdio.h"
#include "memory.h"
#include "g72x.h"

extern void g726_Encode(unsigned char *speech,char *bitstream)
{
	g726_state state_ptr;
	short temp[480];
	int i;
	//char c;

	g726_init_state(&state_ptr);
	/*for(i=0;i<480;i++)
	{
		c=*(speech+i*2);
		*(speech+i*2)=*(speech+i*2+1);
		*(speech+i*2+1)=c;
	}*/
	memcpy(temp,speech,960);
	
	for(i=0;i<120;i++)
	{
		*(bitstream+i)=(((char)(g726_16_encoder(temp[i*4],AUDIO_ENCODING_LINEAR,&state_ptr)))<<6)|(((char)(g726_16_encoder(temp[i*4+1],AUDIO_ENCODING_LINEAR,&state_ptr)))<<4)|(((char)(g726_16_encoder(temp[i*4+2],AUDIO_ENCODING_LINEAR,&state_ptr)))<<2)|(((char)(g726_16_encoder(temp[i*4+3],AUDIO_ENCODING_LINEAR,&state_ptr))));
	}
}

extern void g726_Decode(char *Adpcm,short *pcm)
{
/*	g726_state state_ptr;
	int i;
	int in;
	short temp;

	g726_init_state(&state_ptr);*/
g726_state state_ptr;
g726_init_state(&state_ptr);

int in;
		int i;
short temp;
	for(i=0;i<512;i++)
	{
		in=(int)((*(Adpcm+i))&(char)0x0f);
		temp=g726_32_decoder(in,AUDIO_ENCODING_LINEAR,&state_ptr);
		*(pcm+2*i)=temp;
		in=(int)(((*(Adpcm+i))&(char)0x0f0)>>4);
		temp=g726_32_decoder(in,AUDIO_ENCODING_LINEAR,&state_ptr);
		*(pcm+2*i+1)=temp;
	}
}