bitstream.h

基于Linux的ffmepg decoder

/**
 *  @file bitstream.h
 *  @brief This file contains some operations for bitstream manipulation.
 *
 */
#ifndef _BITSTREAM_H_
#define _BITSTREAM_H_
#include "portab.h"
#include "ftmcp100.h"
#include "decoder.h"
#include "encoder.h"


/*****************************************************************************
 * Constants
 ****************************************************************************/

// comment any #defs we dont use
#define VIDO_RESYN_MARKER 0x1
#define VIDOBJ_START_CODE		0x00000100	/* ..0x0000011f  */
#define VIDOBJLAY_START_CODE		0x00000120	/* ..0x0000012f */
#define VISOBJSEQ_START_CODE		0x000001b0
#define VISOBJSEQ_STOP_CODE		0x000001b1	/* ??? */
#define USERDATA_START_CODE		0x000001b2
#define GRPOFVOP_START_CODE		0x000001b3
//#define VIDSESERR_ERROR_CODE  	0x000001b4
#define VISOBJ_START_CODE		0x000001b5
//#define SLICE_START_CODE      	0x000001b7
//#define EXT_START_CODE        	0x000001b8


#define VISOBJ_TYPE_VIDEO				1
//#define VISOBJ_TYPE_STILLTEXTURE      2
//#define VISOBJ_TYPE_MESH              3
//#define VISOBJ_TYPE_FBA               4
//#define VISOBJ_TYPE_3DMESH            5


#define VIDOBJLAY_TYPE_SIMPLE			1
//#define VIDOBJLAY_TYPE_SIMPLE_SCALABLE    2
#define VIDOBJLAY_TYPE_CORE				3
#define VIDOBJLAY_TYPE_MAIN				4


//#define VIDOBJLAY_AR_SQUARE           1
//#define VIDOBJLAY_AR_625TYPE_43       2
//#define VIDOBJLAY_AR_525TYPE_43       3
//#define VIDOBJLAY_AR_625TYPE_169      8
//#define VIDOBJLAY_AR_525TYPE_169      9
#define VIDOBJLAY_AR_EXTPAR				15


#define VIDOBJLAY_SHAPE_RECTANGULAR		0
#define VIDOBJLAY_SHAPE_BINARY			1
#define VIDOBJLAY_SHAPE_BINARY_ONLY		2
#define VIDOBJLAY_SHAPE_GRAYSCALE		3

#define VO_START_CODE	0x8
#define VOL_START_CODE	0x12
#define VOP_START_CODE0	0x0
#define VOP_START_CODE1	0x1b6
#define VIDO_SHORT_HEADER 0x20
#define VIDO_SHORT_HEADER_END 0x3f

//#define READ_MARKER()	BitstreamSkip(bs, 1)
#define WRITE_MARKER()	BitstreamPutBit(1,pCodec)

// vop coding types 
// intra, prediction, backward, sprite, not_coded
#define I_VOP	0
#define P_VOP	1
#define B_VOP	2
#define S_VOP	3
#define N_VOP	4

// resync-specific
#define NUMBITS_VP_RESYNC_MARKER  17
#define RESYNC_MARKER 1

static const int stuffing_codes[8] =
{
	        /* nbits     stuffing code */
	0,		/* 1          0 */
	1,		/* 2          01 */
	3,		/* 3          011 */
	7,		/* 4          0111 */
	0xf,	/* 5          01111 */
	0x1f,	/* 6          011111 */
	0x3f,   /* 7          0111111 */
	0x7f,	/* 8          01111111 */
};

/*****************************************************************************
 * Prototypes
 ****************************************************************************/

void BitstreamWriteVolHeader(const MBParam * pParam,
			 const FRAMEINFO * frame,FTMCP100_CODEC *pCodec);

void BitstreamWriteVopHeader(const MBParam * pParam,
			 const FRAMEINFO * frame,
			 int vop_coded,FTMCP100_CODEC *pCodec);
			 
void BitstreamWriteShortHeader(MBParam * pParam,
						const FRAMEINFO * frame,
						int vop_coded,FTMCP100_CODEC *pCodec);

/*****************************************************************************
 * Inlined functions
 ****************************************************************************/

/* initialise bitstream structure */

static void __inline
BitstreamInit(Bitstream * const bs,
			  void *const bitstream,
			  uint32_t length)
{

	bs->start = bs->tail = (uint32_t *) bitstream;

//	bs->bufa = *(uint32_t *) bitstream;
//	bs->bufb = *((uint32_t *) bitstream + 1);
//	bs->buf = 0;
//	bs->pos = 0;

	bs->length = length;
}

/* bitstream length (unit bits) */

//static uint32_t __inline BitstreamPos(const Bitstream * const bs)
//{
//	return 8 * ((ptr_t)bs->tail - (ptr_t)bs->start) + bs->pos;
//}


/*	flush the bitstream & return length (unit bytes)
	NOTE: assumes no futher bitstream functions will be called.
 */

//static uint32_t __inline
//BitstreamLength(Bitstream * const bs)
//{
//	uint32_t len = (ptr_t) bs->tail - (ptr_t) bs->start;
//
//	if (bs->pos) {
//		len += (bs->pos + 7) >> 3;
//		*bs->tail = bs->buf;
//	}
//	return len;
//}


/* pad bitstream to the next byte boundary */


/* write n bits to bitstream */

static void __inline
BitstreamPutBits(const uint32_t value,
				 const uint32_t size,FTMCP100_CODEC *pCodec)
{
    DECLARE_MP4_PTR
    
	SET_BADR(value)
	SET_BALR(size)
}


/* pad bitstream to the next byte boundary */

static void __inline
BitstreamPad(FTMCP100_CODEC *pCodec)
{
	int bits;
	uint32_t code;
	DECLARE_MP4_PTR
	
	
	FA526_DrainWriteBuffer();
	
	READ_VOADR(bits)
	bits = 8 - (bits & 0x7);			//		bits % 8
	code =  stuffing_codes[bits - 1];
	if (bits < 8) {
		SET_BADR(code)
		SET_BALR(bits)
	}
}

static void __inline
BitstreamPadAlways(FTMCP100_CODEC *pCodec)
{
	int bits;
	uint32_t code;
	
	DECLARE_MP4_PTR
	
	#ifdef CORE_VERSION_2
	    int32_t cpsts;
	    // check VLC done
	    do {
	      READ_CPSTS(cpsts)
	    } while (!(cpsts&0x08000));
	    FA526_DrainWriteBuffer();
	#endif
	
	
	READ_VOADR(bits)					/// 弄