h263.c

Trolltech公司发布的图形界面操作系统。可在qt-embedded-2.3.7平台上编译为嵌入式图形界面操作系统。

    while(time_incr--)
        put_bits(&s->pb, 1, 1);
        
    put_bits(&s->pb, 1, 0);

    put_bits(&s->pb, 1, 1);	/* marker */
    put_bits(&s->pb, s->time_increment_bits, time_mod);	/* time increment */
    put_bits(&s->pb, 1, 1);	/* marker */
    put_bits(&s->pb, 1, 1);	/* vop coded */
    if (    s->pict_type == P_TYPE 
        || (s->pict_type == S_TYPE && s->vol_sprite_usage==GMC_SPRITE)) {
        s->no_rounding ^= 1;
	put_bits(&s->pb, 1, s->no_rounding);	/* rounding type */
    }
    put_bits(&s->pb, 3, 0);	/* intra dc VLC threshold */
    if(!s->progressive_sequence){
         put_bits(&s->pb, 1, s->top_field_first);
         put_bits(&s->pb, 1, s->alternate_scan);
    }
    //FIXME sprite stuff

    put_bits(&s->pb, 5, s->qscale);

    if (s->pict_type != I_TYPE)
	put_bits(&s->pb, 3, s->f_code);	/* fcode_for */
    if (s->pict_type == B_TYPE)
	put_bits(&s->pb, 3, s->b_code);	/* fcode_back */
    //    printf("****frame %d\n", picture_number);

     s->y_dc_scale_table= ff_mpeg4_y_dc_scale_table; //FIXME add short header support 
     s->c_dc_scale_table= ff_mpeg4_c_dc_scale_table;
     s->h_edge_pos= s->width;
     s->v_edge_pos= s->height;
}

/**
 * change qscale by given dquant and update qscale dependant variables.
 */
static void change_qscale(MpegEncContext * s, int dquant)
{
    s->qscale += dquant;

    if (s->qscale < 1)
        s->qscale = 1;
    else if (s->qscale > 31)
        s->qscale = 31;

    s->y_dc_scale= s->y_dc_scale_table[ s->qscale ];
    s->c_dc_scale= s->c_dc_scale_table[ s->qscale ];
}

static inline int ff_mpeg4_pred_dc(MpegEncContext * s, int n, UINT16 **dc_val_ptr, int *dir_ptr)
{
    int a, b, c, wrap, pred, scale;
    UINT16 *dc_val;
    int dummy;

    /* find prediction */
    if (n < 4) {
	scale = s->y_dc_scale;
    } else {
	scale = s->c_dc_scale;
    }
    wrap= s->block_wrap[n];
    dc_val = s->dc_val[0] + s->block_index[n];

    /* B C
     * A X 
     */
    a = dc_val[ - 1];
    b = dc_val[ - 1 - wrap];
    c = dc_val[ - wrap];

    /* outside slice handling (we cant do that by memset as we need the dc for error resilience) */
    if(s->first_slice_line && n!=3){
        if(n!=2) b=c= 1024;
        if(n!=1 && s->mb_x == s->resync_mb_x) b=a= 1024;
    }
    if(s->mb_x == s->resync_mb_x && s->mb_y == s->resync_mb_y+1){
        if(n==0 || n==4 || n==5)
            b=1024;
    }

    if (abs(a - b) < abs(b - c)) {
	pred = c;
        *dir_ptr = 1; /* top */
    } else {
	pred = a;
        *dir_ptr = 0; /* left */
    }
    /* we assume pred is positive */
#ifdef ARCH_X86
	asm volatile (
		"xorl %%edx, %%edx	\n\t"
		"mul %%ecx		\n\t"
		: "=d" (pred), "=a"(dummy)
		: "a" (pred + (scale >> 1)), "c" (inverse[scale])
	);
#else
    pred = (pred + (scale >> 1)) / scale;
#endif

    /* prepare address for prediction update */
    *dc_val_ptr = &dc_val[0];

    return pred;
}

void mpeg4_pred_ac(MpegEncContext * s, INT16 *block, int n,
                   int dir)
{
    int i;
    INT16 *ac_val, *ac_val1;

    /* find prediction */
    ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
    ac_val1 = ac_val;
    if (s->ac_pred) {
        if (dir == 0) {
            const int xy= s->mb_x-1 + s->mb_y*s->mb_width;
            /* left prediction */
            ac_val -= 16;
            
            if(s->mb_x==0 || s->qscale == s->qscale_table[xy] || n==1 || n==3){
                /* same qscale */
                for(i=1;i<8;i++) {
                    block[s->idct_permutation[i<<3]] += ac_val[i];
                }
            }else{
                /* different qscale, we must rescale */
                for(i=1;i<8;i++) {
                    block[s->idct_permutation[i<<3]] += ROUNDED_DIV(ac_val[i]*s->qscale_table[xy], s->qscale);
                }
            }
        } else {
            const int xy= s->mb_x + s->mb_y*s->mb_width - s->mb_width;
            /* top prediction */
            ac_val -= 16 * s->block_wrap[n];

            if(s->mb_y==0 || s->qscale == s->qscale_table[xy] || n==2 || n==3){
                /* same qscale */
                for(i=1;i<8;i++) {
                    block[s->idct_permutation[i]] += ac_val[i + 8];
                }
            }else{
                /* different qscale, we must rescale */
                for(i=1;i<8;i++) {
                    block[s->idct_permutation[i]] += ROUNDED_DIV(ac_val[i + 8]*s->qscale_table[xy], s->qscale);
                }
            }
        }
    }
    /* left copy */
    for(i=1;i<8;i++)
        ac_val1[i    ] = block[s->idct_permutation[i<<3]];

    /* top copy */
    for(i=1;i<8;i++)
        ac_val1[8 + i] = block[s->idct_permutation[i   ]];

}

static void mpeg4_inv_pred_ac(MpegEncContext * s, INT16 *block, int n,
                              int dir)
{
    int i;
    INT16 *ac_val;

    /* find prediction */
    ac_val = s->ac_val[0][0] + s->block_index[n] * 16;
 
    if (dir == 0) {
        const int xy= s->mb_x-1 + s->mb_y*s->mb_width;
        /* left prediction */
        ac_val -= 16;
        if(s->mb_x==0 || s->qscale == s->qscale_table[xy] || n==1 || n==3){
            /* same qscale */
            for(i=1;i<8;i++) {
                block[s->idct_permutation[i<<3]] -= ac_val[i];
            }
        }else{
            /* different qscale, we must rescale */
            for(i=1;i<8;i++) {
                block[s->idct_permutation[i<<3]] -= ROUNDED_DIV(ac_val[i]*s->qscale_table[xy], s->qscale);
            }
        }
    } else {
        const int xy= s->mb_x + s->mb_y*s->mb_width - s->mb_width;
        /* top prediction */
        ac_val -= 16 * s->block_wrap[n];
        if(s->mb_y==0 || s->qscale == s->qscale_table[xy] || n==2 || n==3){
            /* same qscale */
            for(i=1;i<8;i++) {
                block[s->idct_permutation[i]] -= ac_val[i + 8];
            }
        }else{
            /* different qscale, we must rescale */
            for(i=1;i<8;i++) {
                block[s->idct_permutation[i]] -= ROUNDED_DIV(ac_val[i + 8]*s->qscale_table[xy], s->qscale);
            }
        }
    }
}

static inline void mpeg4_encode_dc(PutBitContext * s, int level, int n)
{
#if 1
//    if(level<-255 || level>255) printf("dc overflow\n");
    level+=256;
    if (n < 4) {
	/* luminance */
	put_bits(s, uni_DCtab_lum[level][1], uni_DCtab_lum[level][0]);
    } else {
	/* chrominance */
	put_bits(s, uni_DCtab_chrom[level][1], uni_DCtab_chrom[level][0]);
    }
#else
    int size, v;
    /* find number of bits */
    size = 0;
    v = abs(level);
    while (v) {
	v >>= 1;
	size++;
    }

    if (n < 4) {
	/* luminance */
	put_bits(&s->pb, DCtab_lum[size][1], DCtab_lum[size][0]);
    } else {
	/* chrominance */
	put_bits(&s->pb, DCtab_chrom[size][1], DCtab_chrom[size][0]);
    }

    /* encode remaining bits */
    if (size > 0) {
	if (level < 0)
	    level = (-level) ^ ((1 << size) - 1);
	put_bits(&s->pb, size, level);
	if (size > 8)
	    put_bits(&s->pb, 1, 1);
    }
#endif
}
#ifdef CONFIG_ENCODERS
static inline void mpeg4_encode_block(MpegEncContext * s, DCTELEM * block, int n, int intra_dc, 
                               UINT8 *scan_table, PutBitContext *dc_pb, PutBitContext *ac_pb)
{
    int i, last_non_zero;
#if 0 //variables for the outcommented version
    int code, sign, last;
#endif
    const RLTable *rl;
    UINT32 *bits_tab;
    UINT8 *len_tab;
    const int last_index = s->block_last_index[n];

    if (s->mb_intra) { //Note gcc (3.2.1 at least) will optimize this away
	/* mpeg4 based DC predictor */
	mpeg4_encode_dc(dc_pb, intra_dc, n);
        if(last_index<1) return;
	i = 1;
        rl = &rl_intra;
        bits_tab= uni_mpeg4_intra_rl_bits;
        len_tab = uni_mpeg4_intra_rl_len;
    } else {
        if(last_index<0) return;
	i = 0;
        rl = &rl_inter;
        bits_tab= uni_mpeg4_inter_rl_bits;
        len_tab = uni_mpeg4_inter_rl_len;
    }

    /* AC coefs */
    last_non_zero = i - 1;
#if 1
    for (; i < last_index; i++) {
	int level = block[ scan_table[i] ];
	if (level) {
	    int run = i - last_non_zero - 1;
            level+=64;
            if((level&(~127)) == 0){
                const int index= UNI_MPEG4_ENC_INDEX(0, run, level);
                put_bits(ac_pb, len_tab[index], bits_tab[index]);
            }else{ //ESC3
                put_bits(ac_pb, 7+2+1+6+1+12+1, (3<<23)+(3<<21)+(0<<20)+(run<<14)+(1<<13)+(((level-64)&0xfff)<<1)+1);
            }
	    last_non_zero = i;
	}
    }
    /*if(i<=last_index)*/{
	int level = block[ scan_table[i] ];
        int run = i - last_non_zero - 1;
        level+=64;
        if((level&(~127)) == 0){
            const int index= UNI_MPEG4_ENC_INDEX(1, run, level);
            put_bits(ac_pb, len_tab[index], bits_tab[index]);
        }else{ //ESC3
            put_bits(ac_pb, 7+2+1+6+1+12+1, (3<<23)+(3<<21)+(1<<20)+(run<<14)+(1<<13)+(((level-64)&0xfff)<<1)+1);
        }
    }
#else
    for (; i <= last_index; i++) {
	const int slevel = block[ scan_table[i] ];
	if (slevel) {
            int level;
	    int run = i - last_non_zero - 1;
	    last = (i == last_index);
	    sign = 0;
	    level = slevel;
	    if (level < 0) {
		sign = 1;
		level = -level;
	    }
            code = get_rl_index(rl, last, run, level);
            put_bits(ac_pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
            if (code == rl->n) {
                int level1, run1;
                level1 = level - rl->max_level[last][run];
                if (level1 < 1) 
                    goto esc2;
                code = get_rl_index(rl, last, run, level1);
                if (code == rl->n) {
                esc2:
                    put_bits(ac_pb, 1, 1);
                    if (level > MAX_LEVEL)
                        goto esc3;
                    run1 = run - rl->max_run[last][level] - 1;
                    if (run1 < 0)
                        goto esc3;
                    code = get_rl_index(rl, last, run1, level);
                    if (code == rl->n) {
                    esc3:
                        /* third escape */
                        put_bits(ac_pb, 1, 1);
                        put_bits(ac_pb, 1, last);
                        put_bits(ac_pb, 6, run);
                        put_bits(ac_pb, 1, 1);
                        put_bits(ac_pb, 12, slevel & 0xfff);
                        put_bits(ac_pb, 1, 1);
                    } else {
                        /* second escape */
                        put_bits(ac_pb, 1, 0);
                        put_bits(ac_pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
                        put_bits(ac_pb, 1, sign);
                    }
                } else {
                    /* first escape */
                    put_bits(ac_pb, 1, 0);
                    put_bits(ac_pb, rl->table_vlc[code][1], rl->table_vlc[code][0]);
                    put_bits(ac_pb, 1, sign);
                }
            } else {
                put_bits(ac_pb, 1, sign);
            }
	    last_non_zero = i;
	}
    }
#endif
}
#endif


/***********************************************/
/* decoding */

static VLC intra_MCBPC_vlc;
static VLC inter_MCBPC_vlc;
static VLC cbpy_vlc;
static VLC mv_vlc;
static VLC dc_lum, dc_chrom;
static VLC sprite_trajectory;
static VLC mb_type_b_vlc;

void init_rl(RLTable *rl)
{
    INT8 max_level[MAX_RUN+1], max_run[MAX_LEVEL+1];
    UINT8 index_run[MAX_RUN+1];
    int last, run, level, start, end, i;

    /* compute max_level[], max_run[] and index_run[] */
    for(last=0;last<2;last++) {
        if (last == 0) {
            start = 0;
            end = rl->last;
        } else {
            start = rl->last;
            end = rl->n;
        }

        memset(max_level, 0, MAX_RUN + 1);
        memset(max_run, 0, MAX_LEVEL + 1);
        memset(index_run, rl->n, MAX_RUN + 1);
        for(i=start;i<end;i++) {
            run = rl->table_run[i];
            level = rl->table_level[i];
            if (index_run[run] == rl->n)
                index_run[run] = i;
            if (level > max_level[run])
                max_level[run] = level;
            if (run > max_run[level])