bitstream.c

MP3编码程序和资料

/*
 *	MP3 bitstream Output interface for LAME
 *
 *	Copyright (c) 1999 Takehiro TOMINAGA
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Library General Public
 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
 * Library General Public License for more details.
 *
 * You should have received a copy of the GNU Library General Public
 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
 */

#include <stdlib.h>
#include <assert.h>
#include <stdio.h>
#include "tables.h"
#include "bitstream.h"
#include "quantize.h"
#include "quantize-pvt.h"
#include "version.h"

/* This is the scfsi_band table from 2.4.2.7 of the IS */
const int scfsi_band[5] = { 0, 6, 11, 16, 21 };



#define MAX_LENGTH      32   /* Maximum length of word written or
                                        read from bit stream */


#ifdef DEBUG
static int hoge, hogege;
#endif





const int pmask[8]={0x1, 0x3, 0x7, 0xf, 0x1f, 0x3f, 0x7f, 0xff};



void putheader_bits(lame_internal_flags *gfc,int w_ptr)
{
    Bit_stream_struc *bs;
    bs = &gfc->bs;
#ifdef DEBUG
    hoge += gfc->sideinfo_len * 8;
    hogege += gfc->sideinfo_len * 8;
#endif
    memcpy(&bs->buf[bs->buf_byte_idx], gfc->header[gfc->w_ptr].buf,
	   gfc->sideinfo_len);
    bs->buf_byte_idx += gfc->sideinfo_len;
    bs->totbit += gfc->sideinfo_len * 8;
    gfc->w_ptr = (gfc->w_ptr + 1) & (MAX_HEADER_BUF - 1);
}




/*write N bits into the bit stream */
static INLINE void
putbits2(lame_global_flags *gfp, unsigned int val, int j)
{
    lame_internal_flags *gfc=gfp->internal_flags;
    Bit_stream_struc *bs;
    bs = &gfc->bs;

    assert(j <= MAX_LENGTH);
    if (j<MAX_LENGTH)
      {
	if (val >= (1 << j)) {
	  DEBUGF("val=%ui %i \n",val,(1<<j));
	}
      assert(val < (1 << j));  /* 1 << 32 wont work on 32 bit machines */
      }

    while (j > 0) {
	int k;
	if (bs->buf_bit_idx == 0) {
	    bs->buf_bit_idx = 8;
	    bs->buf_byte_idx++;
	    assert(bs->buf_byte_idx < BUFFER_SIZE);
	    assert(gfc->header[gfc->w_ptr].write_timing >= bs->totbit);
	    if (gfc->header[gfc->w_ptr].write_timing == bs->totbit) {
	      putheader_bits(gfc,gfc->w_ptr);
	    }
	    bs->buf[bs->buf_byte_idx] = 0;
	}

	k = Min(j, bs->buf_bit_idx);

	bs->buf[bs->buf_byte_idx]
	    |= ((val >> (j-k)) & pmask[k - 1]) << (bs->buf_bit_idx - k);
	bs->buf_bit_idx -= k;
	j -= k;
	bs->totbit += k;
    }
}

/*
  Some combinations of bitrate, Fs, and stereo make it impossible to stuff
  out a frame using just main_data, due to the limited number of bits to
  indicate main_data_length. In these situations, we put stuffing bits into
  the ancillary data...
*/

static INLINE void
drain_into_ancillary(lame_global_flags *gfp,int remainingBits)
{
    lame_internal_flags *gfc=gfp->internal_flags;
    int i,bits;
    assert(remainingBits >= 0);
#ifdef DEBUG
    DEBUGF("remain %d\n",remainingBits);
    hoge += remainingBits;
    hogege += remainingBits;
#endif

    if (remainingBits >= 8) {
      putbits2(gfp,0x4c,8);
      remainingBits -= 8;
    }
    if (remainingBits >= 8) {
      putbits2(gfp,0x41,8);
      remainingBits -= 8;
    }
    if (remainingBits >= 8) {
      putbits2(gfp,0x4d,8);
      remainingBits -= 8;
    }
    if (remainingBits >= 8) {
      putbits2(gfp,0x45,8);
      remainingBits -= 8;
    }
      
    if (remainingBits >= 32) {
      char * version;
      version = get_lame_version();
      if (remainingBits >= 32) 
	for (i=0; i<strlen(version) && remainingBits >=8 ; ++i) {
	  remainingBits -= 8;
	  putbits2(gfp,(unsigned int)version[i],8);
	}
    }


    bits = remainingBits & (MAX_LENGTH - 1);
    for (i=0; i<bits; ++i) {
      putbits2(gfp,gfc->ancillary_flag,1);
      gfc->ancillary_flag = 1-gfc->ancillary_flag;
    }

    remainingBits /= MAX_LENGTH;
    for (; remainingBits > 0; remainingBits--) {
      if (gfc->ancillary_flag)
	putbits2(gfp,0xAAAAAAAA, MAX_LENGTH);
      else
	putbits2(gfp,0x55555555, MAX_LENGTH);
    }
}

/*write N bits into the header */
static INLINE void
writeheader(lame_internal_flags *gfc,unsigned int val, int j)
{
    int ptr = gfc->header[gfc->h_ptr].ptr;
    assert(j <= MAX_LENGTH);

    while (j > 0) {
	int k = Min(j, 8 - (ptr & 7));
	gfc->header[gfc->h_ptr].buf[ptr >> 3]
	    |= ((val >> (j-k)) & pmask[k-1]) << (8 - (ptr & 7) - k);
	ptr += k;
	j -= k;
    }
    gfc->header[gfc->h_ptr].ptr = ptr;
}


/* (jo) this wrapper function for BF_addEntry() updates also the crc */
static void
CRC_writeheader(lame_internal_flags *gfc,unsigned int value, int length,unsigned int *crc)
{
   unsigned int bit = 1 << length;

   while((bit >>= 1)){
      *crc <<= 1;
      if (!(*crc & 0x10000) ^ !(value & bit))
	*crc ^= CRC16_POLYNOMIAL;
   }
   *crc &= 0xffff;
   writeheader(gfc,value, length);
}

static INLINE void
encodeSideInfo2(lame_global_flags *gfp,int bitsPerFrame)
{
    lame_internal_flags *gfc=gfp->internal_flags;
    III_side_info_t *l3_side;
    int gr, ch;
    unsigned int crc;
    
    l3_side = &gfc->l3_side;
    gfc->header[gfc->h_ptr].ptr = 0;
    memset(gfc->header[gfc->h_ptr].buf, 0, gfc->sideinfo_len);
    crc = 0xffff; /* (jo) init crc16 for error_protection */
    if (gfp->out_samplerate < 16000) 
      writeheader(gfc,0xffe,                12);
    else
      writeheader(gfc,0xfff,                12);
    writeheader(gfc,(unsigned int)(gfp->version),            1);
    writeheader(gfc,4 - 3,                 2);
    writeheader(gfc,(unsigned int)(!gfp->error_protection),  1);
    /* (jo) from now on call the CRC_writeheader() wrapper to update crc */
    CRC_writeheader(gfc,(unsigned int)(gfc->bitrate_index),      4,&crc);
    CRC_writeheader(gfc,(unsigned int)(gfc->samplerate_index),   2,&crc);
    CRC_writeheader(gfc,(unsigned int)(gfc->padding),            1,&crc);
    CRC_writeheader(gfc,(unsigned int)(gfp->extension),          1,&crc);
    CRC_writeheader(gfc,(unsigned int)(gfp->mode),               2,&crc);
    CRC_writeheader(gfc,(unsigned int)(gfc->mode_ext),           2,&crc);
    CRC_writeheader(gfc,(unsigned int)(gfp->copyright),          1,&crc);
    CRC_writeheader(gfc,(unsigned int)(gfp->original),           1,&crc);
    CRC_writeheader(gfc,(unsigned int)(gfp->emphasis),           2,&crc);
    if (gfp->error_protection) {
	writeheader(gfc,0, 16); /* dummy */
    }

    if (gfp->version == 1) {
	/* MPEG1 */
	assert(l3_side->main_data_begin >= 0);
	CRC_writeheader(gfc,(unsigned int)(l3_side->main_data_begin), 9,&crc);

	if (gfc->stereo == 2)
	    CRC_writeheader(gfc,l3_side->private_bits, 3,&crc);
	else
	    CRC_writeheader(gfc,l3_side->private_bits, 5,&crc);

	for (ch = 0; ch < gfc->stereo; ch++) {
	    int band;
	    for (band = 0; band < 4; band++) {
		CRC_writeheader(gfc,l3_side->scfsi[ch][band], 1,&crc);
	    }
	}

	for (gr = 0; gr < 2; gr++) {
	    for (ch = 0; ch < gfc->stereo; ch++) {
		gr_info *gi = &l3_side->gr[gr].ch[ch].tt;
		CRC_writeheader(gfc,gi->part2_3_length,       12,&crc);
		CRC_writeheader(gfc,gi->big_values / 2,        9,&crc);
		CRC_writeheader(gfc,gi->global_gain,           8,&crc);
		CRC_writeheader(gfc,gi->scalefac_compress,     4,&crc);
		CRC_writeheader(gfc,gi->window_switching_flag, 1,&crc);

		if (gi->window_switching_flag) {
		    CRC_writeheader(gfc,gi->block_type,       2,&crc);
		    CRC_writeheader(gfc,gi->mixed_block_flag, 1,&crc);

		    if (gi->table_select[0] == 14)
			gi->table_select[0] = 16;
		    CRC_writeheader(gfc,gi->table_select[0],  5,&crc);
		    if (gi->table_select[1] == 14)
			gi->table_select[1] = 16;
		    CRC_writeheader(gfc,gi->table_select[1],  5,&crc);

		    CRC_writeheader(gfc,gi->subblock_gain[0], 3,&crc);
		    CRC_writeheader(gfc,gi->subblock_gain[1], 3,&crc);
		    CRC_writeheader(gfc,gi->subblock_gain[2], 3,&crc);
		} else {
		    assert(gi->block_type == NORM_TYPE);
		    if (gi->table_select[0] == 14)
			gi->table_select[0] = 16;
		    CRC_writeheader(gfc,gi->table_select[0], 5,&crc);
		    if (gi->table_select[1] == 14)
			gi->table_select[1] = 16;
		    CRC_writeheader(gfc,gi->table_select[1], 5,&crc);
		    if (gi->table_select[2] == 14)
			gi->table_select[2] = 16;
		    CRC_writeheader(gfc,gi->table_select[2], 5,&crc);

		    CRC_writeheader(gfc,gi->region0_count, 4,&crc);
		    CRC_writeheader(gfc,gi->region1_count, 3,&crc);
		}
		CRC_writeheader(gfc,gi->preflag,            1,&crc);
		CRC_writeheader(gfc,gi->scalefac_scale,     1,&crc);
		CRC_writeheader(gfc,gi->count1table_select, 1,&crc);
	    }
	}
    } else {
	/* MPEG2 */
	assert(l3_side->main_data_begin >= 0);
	CRC_writeheader(gfc,(unsigned int)(l3_side->main_data_begin), 8,&crc);
	CRC_writeheader(gfc,l3_side->private_bits, gfc->stereo,&crc);

	gr = 0;
	for (ch = 0; ch < gfc->stereo; ch++) {
	    gr_info *gi = &l3_side->gr[gr].ch[ch].tt;
	    CRC_writeheader(gfc,gi->part2_3_length,       12,&crc);
	    CRC_writeheader(gfc,gi->big_values / 2,        9,&crc);
	    CRC_writeheader(gfc,gi->global_gain,           8,&crc);
	    CRC_writeheader(gfc,gi->scalefac_compress,     9,&crc);
	    CRC_writeheader(gfc,gi->window_switching_flag, 1,&crc);

	    if (gi->window_switching_flag) {
		CRC_writeheader(gfc,gi->block_type,       2,&crc);
		CRC_writeheader(gfc,gi->mixed_block_flag, 1,&crc);

		if (gi->table_select[0] == 14)
		    gi->table_select[0] = 16;
		CRC_writeheader(gfc,gi->table_select[0],  5,&crc);
		if (gi->table_select[1] == 14)
		    gi->table_select[1] = 16;
		CRC_writeheader(gfc,gi->table_select[1],  5,&crc);

		CRC_writeheader(gfc,gi->subblock_gain[0], 3,&crc);
		CRC_writeheader(gfc,gi->subblock_gain[1], 3,&crc);
		CRC_writeheader(gfc,gi->subblock_gain[2], 3,&crc);
	    } else {
		if (gi->table_select[0] == 14)
		    gi->table_select[0] = 16;
		CRC_writeheader(gfc,gi->table_select[0], 5,&crc);
		if (gi->table_select[1] == 14)
		    gi->table_select[1] = 16;
		CRC_writeheader(gfc,gi->table_select[1], 5,&crc);
		if (gi->table_select[2] == 14)
		    gi->table_select[2] = 16;
		CRC_writeheader(gfc,gi->table_select[2], 5,&crc);

		CRC_writeheader(gfc,gi->region0_count, 4,&crc);
		CRC_writeheader(gfc,gi->region1_count, 3,&crc);
	    }

	    CRC_writeheader(gfc,gi->scalefac_scale,     1,&crc);
	    CRC_writeheader(gfc,gi->count1table_select, 1,&crc);
	}
    }

    if (gfp->error_protection) {
	/* (jo) error_protection: add crc16 information to header */
	gfc->header[gfc->h_ptr].buf[4] = crc >> 8;
	gfc->header[gfc->h_ptr].buf[5] = crc & 255;
    }

    {
	int old = gfc->h_ptr;
	assert(gfc->header[old].ptr == gfc->sideinfo_len * 8);

	gfc->h_ptr = (old + 1) & (MAX_HEADER_BUF - 1);
	gfc->header[gfc->h_ptr].write_timing =
	    gfc->header[old].write_timing + bitsPerFrame;

	if (gfc->h_ptr == gfc->w_ptr) {
	  /* yikes! we are out of header buffer space */
	  ERRORF("Error: MAX_HEADER_BUF too small in bitstream.c \n");
	}

    }
}



static INLINE int
huffman_coder_count1(lame_global_flags *gfp,int *ix, gr_info *gi)
{
#ifdef DEBUG
    lame_internal_flags *gfc = gfp->internal_flags;
#endif
    /* Write count1 area */
    const struct huffcodetab *h = &ht[gi->count1table_select + 32];
    int i,bits=0;
#ifdef DEBUG
    int gegebo = gfc->bs.totbit;
#endif

    ix += gi->big_values;
    assert(gi->count1table_select < 2);


    for (i = (gi->count1 - gi->big_values) / 4; i > 0; --i) {
	HUFFBITS huffbits = 0;
	int p = 0, v;

	v = ix[0];
	if (v) {
	    p += 8;
	    if (v < 0)
		huffbits++;
	    assert(-1 <= v && v <= 1);
	}

	v = ix[1];
	if (v) {
	    p += 4;
	    huffbits *= 2;
	    if (v < 0)
		huffbits++;
	    assert(-1 <= v && v <= 1);
	}

	v = ix[2];
	if (v) {
	    p += 2;
	    huffbits *= 2;
	    if (v < 0)
		huffbits++;
	    assert(-1 <= v && v <= 1);
	}

	v = ix[3];
	if (v) {
	    p++;
	    huffbits *= 2;
	    if (v < 0)
		huffbits++;