parse.c

这是著名的TCPMP播放器在WINDWOWS,和WINCE下编译通过的源程序.笔者对其中的LIBMAD库做了针对ARM MPU的优化. 并增加了词幕功能.

			    samples[ch][i] = 0;
		    }
		i++;
		continue;

	    case -1:
		if (quant->q1_ptr >= 0) {
		    cplcoeff = quant->q1[quant->q1_ptr--];
		    break;
		} else {
		    int code;

		    code = bitstream_get (state, 5);

		    quant->q1_ptr = 1;
		    quant->q1[0] = q_1_2[code];
		    quant->q1[1] = q_1_1[code];
		    cplcoeff = q_1_0[code];
		    break;
		}

	    case -2:
		if (quant->q2_ptr >= 0) {
		    cplcoeff = quant->q2[quant->q2_ptr--];
		    break;
		} else {
		    int code;

		    code = bitstream_get (state, 7);

		    quant->q2_ptr = 1;
		    quant->q2[0] = q_2_2[code];
		    quant->q2[1] = q_2_1[code];
		    cplcoeff = q_2_0[code];
		    break;
		}

	    case 3:
		cplcoeff = q_3[bitstream_get (state, 3)];
		break;

	    case -3:
		if (quant->q4_ptr == 0) {
		    quant->q4_ptr = -1;
		    cplcoeff = quant->q4;
		    break;
		} else {
		    int code;

		    code = bitstream_get (state, 7);

		    quant->q4_ptr = 0;
		    quant->q4 = q_4_1[code];
		    cplcoeff = q_4_0[code];
		    break;
		}

	    case 4:
		cplcoeff = q_5[bitstream_get (state, 4)];
		break;

	    default:
		cplcoeff = bitstream_get_2 (state, bapi) << (16 - bapi);
	    }
#ifndef LIBA52_FIXED
	    cplcoeff *= scale_factor[exp[i]];
#endif
	    for (ch = 0; ch < nfchans; ch++)
	       if ((state->chincpl >> ch) & 1)
#ifndef LIBA52_FIXED
		    samples[ch][i] = cplcoeff * cplco[ch];
#else
		    COEFF (samples[ch][i], cplcoeff, cplco[ch],
			   scale_factor, exp[i]);
#endif
	    i++;
	}
    }
}

int a52_block (a52_state_t * state)
{
    static const uint8_t nfchans_tbl[] = {2, 1, 2, 3, 3, 4, 4, 5, 1, 1, 2};
    static int rematrix_band[4] = {25, 37, 61, 253};
    int i, nfchans, chaninfo;
    uint8_t cplexpstr, chexpstr[5], lfeexpstr, do_bit_alloc, done_cpl;
    uint8_t blksw[5], dithflag[5];
    level_t coeff[5];
    int chanbias;
    quantizer_set_t quant;
    sample_t * samples;

    nfchans = nfchans_tbl[state->acmod];

    for (i = 0; i < nfchans; i++)
	blksw[i] = bitstream_get (state, 1);

    for (i = 0; i < nfchans; i++)
	dithflag[i] = bitstream_get (state, 1);

    chaninfo = !state->acmod;
    do {
	if (bitstream_get (state, 1)) {	/* dynrnge */
	    int dynrng;

	    dynrng = bitstream_get_2 (state, 8);
	    if (state->dynrnge) {
		level_t range;

#if !defined(LIBA52_FIXED)
		range = ((((dynrng & 0x1f) | 0x20) << 13) *
			 scale_factor[3 - (dynrng >> 5)]);
#else
		range = ((dynrng & 0x1f) | 0x20) << (21 + (dynrng >> 5));
#endif
		if (state->dynrngcall)
		    range = state->dynrngcall (range, state->dynrngdata);
		state->dynrng = MUL_L (state->level, range);
	    }
	}
    } while (chaninfo--);

    if (bitstream_get (state, 1)) {	/* cplstre */
	state->chincpl = 0;
	if (bitstream_get (state, 1)) {	/* cplinu */
	    static uint8_t bndtab[16] = {31, 35, 37, 39, 41, 42, 43, 44,
					 45, 45, 46, 46, 47, 47, 48, 48};
	    int cplbegf;
	    int cplendf;
	    int ncplsubnd;

	    for (i = 0; i < nfchans; i++)
		state->chincpl |= bitstream_get (state, 1) << i;
	    switch (state->acmod) {
	    case 0: case 1:
		return 1;
	    case 2:
		state->phsflginu = bitstream_get (state, 1);
	    }
	    cplbegf = bitstream_get (state, 4);
	    cplendf = bitstream_get (state, 4);

	    if (cplendf + 3 - cplbegf < 0)
		return 1;
	    state->ncplbnd = ncplsubnd = cplendf + 3 - cplbegf;
	    state->cplstrtbnd = bndtab[cplbegf];
	    state->cplstrtmant = cplbegf * 12 + 37;
	    state->cplendmant = cplendf * 12 + 73;

	    state->cplbndstrc = 0;
	    for (i = 0; i < ncplsubnd - 1; i++)
		if (bitstream_get (state, 1)) {
		    state->cplbndstrc |= 1 << i;
		    state->ncplbnd--;
		}
	}
    }

    if (state->chincpl) {	/* cplinu */
	int j, cplcoe;

	cplcoe = 0;
	for (i = 0; i < nfchans; i++)
	    if ((state->chincpl) >> i & 1)
		if (bitstream_get (state, 1)) {	/* cplcoe */
		    int mstrcplco, cplcoexp, cplcomant;

		    cplcoe = 1;
		    mstrcplco = 3 * bitstream_get (state, 2);
		    for (j = 0; j < state->ncplbnd; j++) {
			cplcoexp = bitstream_get (state, 4);
			cplcomant = bitstream_get (state, 4);
			if (cplcoexp == 15)
			    cplcomant <<= 14;
			else
			    cplcomant = (cplcomant | 0x10) << 13;
#ifndef LIBA52_FIXED
			state->cplco[i][j] =
			    cplcomant * scale_factor[cplcoexp + mstrcplco];
#else
			state->cplco[i][j] = (cplcomant << 11) >> (cplcoexp + mstrcplco);
#endif

		    }
		}
	if ((state->acmod == 2) && state->phsflginu && cplcoe)
	    for (j = 0; j < state->ncplbnd; j++)
		if (bitstream_get (state, 1))	/* phsflg */
		    state->cplco[1][j] = -state->cplco[1][j];
    }

    if ((state->acmod == 2) && (bitstream_get (state, 1))) {	/* rematstr */
	int end;

	state->rematflg = 0;
	end = (state->chincpl) ? state->cplstrtmant : 253;	/* cplinu */
	i = 0;
	do
	    state->rematflg |= bitstream_get (state, 1) << i;
	while (rematrix_band[i++] < end);
    }

    cplexpstr = EXP_REUSE;
    lfeexpstr = EXP_REUSE;
    if (state->chincpl)	/* cplinu */
	cplexpstr = bitstream_get (state, 2);
    for (i = 0; i < nfchans; i++)
	chexpstr[i] = bitstream_get (state, 2);
    if (state->lfeon) 
	lfeexpstr = bitstream_get (state, 1);

    for (i = 0; i < nfchans; i++)
	if (chexpstr[i] != EXP_REUSE) {
	    if ((state->chincpl >> i) & 1)
		state->endmant[i] = state->cplstrtmant;
	    else {
		int chbwcod;

		chbwcod = bitstream_get (state, 6);
		if (chbwcod > 60)
		    return 1;
		state->endmant[i] = chbwcod * 3 + 73;
	    }
	}

    do_bit_alloc = 0;

    if (cplexpstr != EXP_REUSE) {
	int cplabsexp, ncplgrps;

	do_bit_alloc = 64;
	ncplgrps = ((state->cplendmant - state->cplstrtmant) /
		    (3 << (cplexpstr - 1)));
	cplabsexp = bitstream_get (state, 4) << 1;
	if (parse_exponents (state, cplexpstr, ncplgrps, cplabsexp,
			     state->cpl_expbap.exp + state->cplstrtmant))
	    return 1;
    }
    for (i = 0; i < nfchans; i++)
	if (chexpstr[i] != EXP_REUSE) {
	    int grp_size, nchgrps;

	    do_bit_alloc |= 1 << i;
	    grp_size = 3 << (chexpstr[i] - 1);
	    nchgrps = (state->endmant[i] + grp_size - 4) / grp_size;
	    state->fbw_expbap[i].exp[0] = bitstream_get (state, 4);
	    if (parse_exponents (state, chexpstr[i], nchgrps,
				 state->fbw_expbap[i].exp[0],
				 state->fbw_expbap[i].exp + 1))
		return 1;
	    bitstream_get (state, 2);	/* gainrng */
	}
    if (lfeexpstr != EXP_REUSE) {
	do_bit_alloc |= 32;
	state->lfe_expbap.exp[0] = bitstream_get (state, 4);
	if (parse_exponents (state, lfeexpstr, 2, state->lfe_expbap.exp[0],
			     state->lfe_expbap.exp + 1))
	    return 1;
    }

    if (bitstream_get (state, 1)) {	/* baie */
	do_bit_alloc = 127;
	state->bai = bitstream_get (state, 11);
    }
    if (bitstream_get (state, 1)) {	/* snroffste */
	do_bit_alloc = 127;
	state->csnroffst = bitstream_get (state, 6);
	if (state->chincpl)	/* cplinu */
	    state->cplba.bai = bitstream_get (state, 7);
	for (i = 0; i < nfchans; i++)
	    state->ba[i].bai = bitstream_get (state, 7);
	if (state->lfeon)
	    state->lfeba.bai = bitstream_get (state, 7);
    }
    if ((state->chincpl) && (bitstream_get (state, 1))) { /* cplleake */
	do_bit_alloc |= 64;
	state->cplfleak = 9 - bitstream_get (state, 3);
	state->cplsleak = 9 - bitstream_get (state, 3);
    }

    if (bitstream_get (state, 1)) {	/* deltbaie */
	do_bit_alloc = 127;
	if (state->chincpl)	/* cplinu */
	    state->cplba.deltbae = bitstream_get (state, 2);
	for (i = 0; i < nfchans; i++)
	    state->ba[i].deltbae = bitstream_get (state, 2);
	if (state->chincpl &&	/* cplinu */
	    (state->cplba.deltbae == DELTA_BIT_NEW) &&
	    parse_deltba (state, state->cplba.deltba))
	    return 1;
	for (i = 0; i < nfchans; i++)
	    if ((state->ba[i].deltbae == DELTA_BIT_NEW) &&
		parse_deltba (state, state->ba[i].deltba))
		return 1;
    }

    if (do_bit_alloc) {
	if (zero_snr_offsets (nfchans, state)) {
	    memset (state->cpl_expbap.bap, 0, sizeof (state->cpl_expbap.bap));
	    for (i = 0; i < nfchans; i++)
		memset (state->fbw_expbap[i].bap, 0,
			sizeof (state->fbw_expbap[i].bap));
	    memset (state->lfe_expbap.bap, 0, sizeof (state->lfe_expbap.bap));
	} else {
	    if (state->chincpl && (do_bit_alloc & 64))	/* cplinu */
		a52_bit_allocate (state, &state->cplba, state->cplstrtbnd,
				  state->cplstrtmant, state->cplendmant,
				  state->cplfleak << 8, state->cplsleak << 8,
				  &state->cpl_expbap);
	    for (i = 0; i < nfchans; i++)
		if (do_bit_alloc & (1 << i))
		    a52_bit_allocate (state, state->ba + i, 0, 0,
				      state->endmant[i], 0, 0,
				      state->fbw_expbap +i);
	    if (state->lfeon && (do_bit_alloc & 32)) {
		state->lfeba.deltbae = DELTA_BIT_NONE;
		a52_bit_allocate (state, &state->lfeba, 0, 0, 7, 0, 0,
				  &state->lfe_expbap);
	    }
	}
    }

    if (bitstream_get (state, 1)) {	/* skiple */
	i = bitstream_get (state, 9);	/* skipl */
	while (i--)
	    bitstream_get (state, 8);
    }

    samples = state->samples;
    if (state->output & A52_LFE)
	samples += 256;	/* shift for LFE channel */

    chanbias = a52_downmix_coeff (coeff, state->acmod, state->output,
				  state->dynrng, state->clev, state->slev);

    quant.q1_ptr = quant.q2_ptr = quant.q4_ptr = -1;
    done_cpl = 0;

    for (i = 0; i < nfchans; i++) {
	int j;

	coeff_get (state, samples + 256 * i, state->fbw_expbap +i, &quant,
		   coeff[i], dithflag[i], state->endmant[i]);

	if ((state->chincpl >> i) & 1) {
	    if (!done_cpl) {
		done_cpl = 1;
		coeff_get_coupling (state, nfchans, coeff,
				    (sample_t (*)[256])samples, &quant,
				    dithflag);
	    }
	    j = state->cplendmant;
	} else
	    j = state->endmant[i];
	do
	    (samples + 256 * i)[j] = 0;
	while (++j < 256);
    }

    if (state->acmod == 2) {
	int j, end, band, rematflg;

	end = ((state->endmant[0] < state->endmant[1]) ?
	       state->endmant[0] : state->endmant[1]);

	i = 0;
	j = 13;
	rematflg = state->rematflg;
	do {
	    if (! (rematflg & 1)) {
		rematflg >>= 1;
		j = rematrix_band[i++];
		continue;
	    }
	    rematflg >>= 1;
	    band = rematrix_band[i++];
	    if (band > end)
		band = end;
	    do {
		sample_t tmp0, tmp1;

		tmp0 = samples[j];
		tmp1 = (samples+256)[j];
		samples[j] = tmp0 + tmp1;
		(samples+256)[j] = tmp0 - tmp1;
	    } while (++j < band);
	} while (j < end);
    }

    if (state->lfeon) {
	if (state->output & A52_LFE) {
	    coeff_get (state, samples - 256, &state->lfe_expbap, &quant,
		       state->dynrng, 0, 7);
	    for (i = 7; i < 256; i++)
		(samples-256)[i] = 0;
	    a52_imdct_512 (samples - 256, samples + 1536 - 256, state->bias);
	} else {
	    /* just skip the LFE coefficients */
	    coeff_get (state, samples + 1280, &state->lfe_expbap, &quant,
		       0, 0, 7);
	}
    }

    i = 0;
    if (nfchans_tbl[state->output & A52_CHANNEL_MASK] < nfchans)
	for (i = 1; i < nfchans; i++)
	    if (blksw[i] != blksw[0])
		break;

    if (i < nfchans) {
	if (state->downmixed) {
	    state->downmixed = 0;
	    a52_upmix (samples + 1536, state->acmod, state->output);
	}

	for (i = 0; i < nfchans; i++) {
	    sample_t bias;

	    bias = 0;
	    if (!(chanbias & (1 << i)))
		bias = state->bias;

	    if (coeff[i]) {
		if (blksw[i])
		    a52_imdct_256 (samples + 256 * i, samples + 1536 + 256 * i,
				   bias);
		else 
		    a52_imdct_512 (samples + 256 * i, samples + 1536 + 256 * i,
				   bias);
	    } else {
		int j;

		for (j = 0; j < 256; j++)
		    (samples + 256 * i)[j] = bias;
	    }
	}

	a52_downmix (samples, state->acmod, state->output, state->bias,
		     state->clev, state->slev);
    } else {
	nfchans = nfchans_tbl[state->output & A52_CHANNEL_MASK];

	a52_downmix (samples, state->acmod, state->output, 0,
		     state->clev, state->slev);

	if (!state->downmixed) {
	    state->downmixed = 1;
	    a52_downmix (samples + 1536, state->acmod, state->output, 0,
			 state->clev, state->slev);
	}

	if (blksw[0])
	    for (i = 0; i < nfchans; i++)
		a52_imdct_256 (samples + 256 * i, samples + 1536 + 256 * i,
			       state->bias);
	else 
	    for (i = 0; i < nfchans; i++)
		a52_imdct_512 (samples + 256 * i, samples + 1536 + 256 * i,
			       state->bias);
    }

    return 0;
}

void a52_free (a52_state_t * state)
{
    free (state->samples);
    free (state);
}