dsp_mp4svp_stream.c

来自「mpeg-4 SVP程序」· C语言 代码 · 共 67 行

//#include <stdio.h>
//#include <stdlib.h>
//#include <iostream.h>
#include <string.h>

#include "dsp_mp4svp_type.h"
#include "dsp_mp4svp_global.h"
#include "dsp_mp4svp_stream.h"

void initBuffer()
{
	pbfr = buffer;
	ByteBfr = 0;
	leftcnt = 8;
	bytecnt = 0;


}
void BitstreamPutBits(UInt val, UChar nbits)
{
	char i;
	UInt mask;
	if (nbits==0)
		return;

	mask = 1 << (nbits-1);							  /* selects first (leftmost) bit */

	for (i=0; i<nbits; i++)
	{
		ByteBfr <<= 1;

		if (val & mask)
			ByteBfr|= 1;

		mask >>= 1;				  /* select next bit */
		leftcnt--;

		if (leftcnt==0)			  /* 8 bit buffer full */
		{
			*(pbfr++) = ByteBfr;
			leftcnt = 8;
			bytecnt++;
			if( (bytecnt%256) == 0 )
			{
				memcpy (pstream, buffer, 256);//dma
				pstream +=256;
				pbfr = buffer;
			
			}

		}
	}

}
void stuffingBitstrm()
{
	char i,n;
	n = leftcnt;
	BitstreamPutBits(0,1);
	n--;//before leftcnt--,leftcnt can not be 0,this is ensured by BitstreamPutBits(UInt val, UChar nbits)
	for(i=0; i<n; i++)
	{
		BitstreamPutBits(1,1);
	}

}