bitstream.h

用MPEG-4对YUV视频文件编码压缩成divx视频文件

 /******************************************************************************
  *                                                                            *
  *  This file is part of XviD, a free MPEG-4 video encoder/decoder            *
  *                                                                            *
  *  XviD is an implementation of a part of one or more MPEG-4 Video tools     *
  *  as specified in ISO/IEC 14496-2 standard.  Those intending to use this    *
  *  software module in hardware or software products are advised that its     *
  *  use may infringe existing patents or copyrights, and any such use         *
  *  would be at such party's own risk.  The original developer of this        *
  *  software module and his/her company, and subsequent editors and their     *
  *  companies, will have no liability for use of this software or             *
  *  modifications or derivatives thereof.                                     *
  *                                                                            *
  *  XviD is free software; you can redistribute it and/or modify it           *
  *  under the terms of the GNU General Public License as published by         *
  *  the Free Software Foundation; either version 2 of the License, or         *
  *  (at your option) any later version.                                       *
  *                                                                            *
  *  XviD is distributed in the hope that it will be useful, but               *
  *  WITHOUT ANY WARRANTY; without even the implied warranty of                *
  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             *
  *  GNU General Public License for more details.                              *
  *                                                                            *
  *  You should have received a copy of the GNU General Public License         *
  *  along with this program; if not, write to the Free Software               *
  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA  *
  *                                                                            *
  ******************************************************************************/

 /******************************************************************************
  *                                                                            *
  *  bitstream.h                                                               *
  *                                                                            *
  *  Copyright (C) 2001 - Peter Ross <[e-mail]>                    *
  *                                                                            *
  *  For more information visit the XviD homepage: http://www.xvid.org         *
  *                                                                            *
  ******************************************************************************/

 /******************************************************************************
  *																			   *	
  *  Revision history:                                                         *
  *                                                                            *
  *  28.06.2002 addded BitstreamNumBitsToByteAlign()                           *
  *                    BitstreamShowBitsFromByteAlign()                        *
  *  26.03.2002 interlacing support - modified putvol/vopheaders paramters     *
  *  04.03.2002 putbits speedup (Isibaar)                                      *
  *  03.03.2002 merged BITREADER and BITWRITER (Isibaar)                       *
  *	 16.12.2001	inital version                                           	   *
  *																			   *
  ******************************************************************************/

#ifndef _BITSTREAM_H_
#define _BITSTREAM_H_

#include "../portab.h"

#include "../encoder.h"

 /* comment any #defs we dont use*/

#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_CODE	0x1b6

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


/*== 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

/*==========write vol,vop,userdata into buffer ==========================*/
void BitstreamWriteVolHeader(Bitstream * const bs,
							 const MBParam * pParam,
							 const FRAMEINFO * frame);

void BitstreamWriteVopHeader(Bitstream * const bs,
							 const MBParam * pParam,
							 const FRAMEINFO * frame,
							 int vop_coded);

void BitstreamWriteUserData(Bitstream * const bs, 
							uint8_t * data, 
							const int length);


/*!
 ************************************************************************
 * \brief
 *    initialise bitstream structure
 ************************************************************************
 */
static void __inline
BitstreamInit(Bitstream * const bs,     /*<--> bitstream buffer */
			  void *const bitstream,	/*<--  actual bitstream buffer address */
			  uint32_t length)			/*<--  the used len of the buffer */
{
	uint32_t tmp;

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

	tmp = *(uint32_t *) bitstream;
#ifndef ARCH_IS_BIG_ENDIAN
	BSWAP(tmp);
#endif
	bs->bufa = tmp;

	tmp = *((uint32_t *) bitstream + 1);
#ifndef ARCH_IS_BIG_ENDIAN
	BSWAP(tmp);
#endif
	bs->bufb = tmp;

	bs->buf = 0;
	bs->pos = 0;
	bs->length = length;
}

/*!
 ************************************************************************
 * \brief
 *    skip n bits forward in bitstream 
 ************************************************************************
 */
static __inline void
BitstreamSkip(Bitstream * const bs,		/*<--> bitstream buffer */
			  const uint32_t bits)		/*<--  skip how many bits */
{
	bs->pos += bits;

	if (bs->pos >= 32) {
		uint32_t tmp;

		bs->bufa = bs->bufb;
		tmp = *((uint32_t *) bs->tail + 2);
#ifndef ARCH_IS_BIG_ENDIAN
		BSWAP(tmp);
#endif
		bs->bufb = tmp;
		bs->tail++;
		bs->pos -= 32;
	}
}

/*!
 ************************************************************************
 * \brief
 *    number of bits to next byte alignment 
 ************************************************************************
 */
static __inline uint32_t 
BitstreamNumBitsToByteAlign(Bitstream *bs)
{
	uint32_t n = (32 - bs->pos) % 8;
	return n == 0 ? 8 : n;
}


/*!
 ************************************************************************
 * \brief
 *    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;*/
    return ( ( ( ptr_t )bs->tail - ( ptr_t )bs->start ) << 3 )+ bs->pos ;

}


/*!
 ************************************************************************
 * \brief
 *    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) {
		uint32_t b = bs->buf;

#ifndef ARCH_IS_BIG_ENDIAN
		BSWAP(b);
#endif
		*bs->tail = b;

		/*	len += (bs->pos + 7) / 8;*/
	    len +=(bs->pos+7)>>3;
	}

	return len;
}

/*!
 ************************************************************************
 * \brief
 * move bitstream position forward by n bits and write out buffer if needed
 ************************************************************************
 */
static void __inline
BitstreamForward(Bitstream * const bs,
				 const uint32_t bits)
{
	bs->pos += bits;

	if (bs->pos >= 32) {
		uint32_t b = bs->buf;

#ifndef ARCH_IS_BIG_ENDIAN
		BSWAP(b);
#endif
		*bs->tail++ = b;
		bs->buf = 0;
		bs->pos -= 32;
	}
}

/*!
 ************************************************************************
 * \brief
 * pad bitstream to the next byte boundary
 ************************************************************************
 */
static void __inline
BitstreamPad(Bitstream * const bs)
{
	uint32_t remainder = bs->pos % 8;

	if (remainder) {
		BitstreamForward(bs, 8 - remainder);
	}
}

/*!
 ************************************************************************
 * \brief
 * write single bit to bitstream
 ************************************************************************
 */

static void __inline
BitstreamPutBit(Bitstream * const bs,
				const uint32_t bit)
{
	if (bit)
		bs->buf |= (0x80000000 >> bs->pos);

	BitstreamForward(bs, 1);
}


/*!
 ************************************************************************
 * \brief
 * write n bits to bitstream
 ************************************************************************
 */
static void __inline
BitstreamPutBits(Bitstream * const bs,
				 const uint32_t value,
				 const uint32_t size)
{
	uint32_t shift = 32 - bs->pos - size;

	if (shift <= 32) {
		bs->buf |= value << shift;
		BitstreamForward(bs, size);
	} else {
		uint32_t remainder;

		shift = size - (32 - bs->pos);
		bs->buf |= value >> shift;
		BitstreamForward(bs, size - shift);
		remainder = shift;

		shift = 32 - shift;

		bs->buf |= value << shift;
		BitstreamForward(bs, remainder);
	}
}

#endif							/* _BITSTREAM_H_ */