slice.c

mpeg2 decoder filter过滤服务端

/*
 * slice.c
 * Copyright (C) 2000-2003 Michel Lespinasse <[e-mail]>
 * Copyright (C) 2003      Peter Gubanov <[e-mail]>
 * Copyright (C) 1999-2000 Aaron Holtzman <[e-mail]>
 *
 * This file is part of mpeg2dec, a free MPEG-2 video stream decoder.
 * See http://libmpeg2.sourceforge.net/ for updates.
 *
 * mpeg2dec 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.
 *
 * mpeg2dec 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
 */

#include "config.h"

#include <inttypes.h>

#include "mpeg2.h"
#include "attributes.h"
#include "mpeg2_internal.h"

extern mpeg2_mc_t mpeg2_mc;
extern void (* mpeg2_idct_copy) (int16_t * block, uint8_t * dest, int stride);
extern void (* mpeg2_idct_add) (int last, int16_t * block,
				uint8_t * dest, int stride);
extern void (* mpeg2_cpu_state_save) (cpu_state_t * state);
extern void (* mpeg2_cpu_state_restore) (cpu_state_t * state);

#include "vlc.h"

static inline int get_macroblock_modes (mpeg2_decoder_t * const decoder)
{
#define bit_buf (decoder->bitstream_buf)
#define bits (decoder->bitstream_bits)
#define bit_ptr (decoder->bitstream_ptr)
    int macroblock_modes;
    const MBtab * tab;

    switch (decoder->coding_type) {
    case I_TYPE:

	tab = MB_I + UBITS (bit_buf, 1);
	DUMPBITS (bit_buf, bits, tab->len);
	macroblock_modes = tab->modes;

	if ((! (decoder->frame_pred_frame_dct)) &&
	    (decoder->picture_structure == FRAME_PICTURE)) {
	    macroblock_modes |= UBITS (bit_buf, 1) * DCT_TYPE_INTERLACED;
	    DUMPBITS (bit_buf, bits, 1);
	}

	return macroblock_modes;

    case P_TYPE:

	tab = MB_P + UBITS (bit_buf, 5);
	DUMPBITS (bit_buf, bits, tab->len);
	macroblock_modes = tab->modes;

	if (decoder->picture_structure != FRAME_PICTURE) {
	    if (macroblock_modes & MACROBLOCK_MOTION_FORWARD) {
		macroblock_modes |= UBITS (bit_buf, 2) << MOTION_TYPE_SHIFT;
		DUMPBITS (bit_buf, bits, 2);
	    }
	    return macroblock_modes | MACROBLOCK_MOTION_FORWARD;
	} else if (decoder->frame_pred_frame_dct) {
	    if (macroblock_modes & MACROBLOCK_MOTION_FORWARD)
		macroblock_modes |= MC_FRAME << MOTION_TYPE_SHIFT;
	    return macroblock_modes | MACROBLOCK_MOTION_FORWARD;
	} else {
	    if (macroblock_modes & MACROBLOCK_MOTION_FORWARD) {
		macroblock_modes |= UBITS (bit_buf, 2) << MOTION_TYPE_SHIFT;
		DUMPBITS (bit_buf, bits, 2);
	    }
	    if (macroblock_modes & (MACROBLOCK_INTRA | MACROBLOCK_PATTERN)) {
		macroblock_modes |= UBITS (bit_buf, 1) * DCT_TYPE_INTERLACED;
		DUMPBITS (bit_buf, bits, 1);
	    }
	    return macroblock_modes | MACROBLOCK_MOTION_FORWARD;
	}

    case B_TYPE:

	tab = MB_B + UBITS (bit_buf, 6);
	DUMPBITS (bit_buf, bits, tab->len);
	macroblock_modes = tab->modes;

	if (decoder->picture_structure != FRAME_PICTURE) {
	    if (! (macroblock_modes & MACROBLOCK_INTRA)) {
		macroblock_modes |= UBITS (bit_buf, 2) << MOTION_TYPE_SHIFT;
		DUMPBITS (bit_buf, bits, 2);
	    }
	    return macroblock_modes;
	} else if (decoder->frame_pred_frame_dct) {
	    /* if (! (macroblock_modes & MACROBLOCK_INTRA)) */
	    macroblock_modes |= MC_FRAME << MOTION_TYPE_SHIFT;
	    return macroblock_modes;
	} else {
	    if (macroblock_modes & MACROBLOCK_INTRA)
		goto intra;
	    macroblock_modes |= UBITS (bit_buf, 2) << MOTION_TYPE_SHIFT;
	    DUMPBITS (bit_buf, bits, 2);
	    if (macroblock_modes & (MACROBLOCK_INTRA | MACROBLOCK_PATTERN)) {
	    intra:
		macroblock_modes |= UBITS (bit_buf, 1) * DCT_TYPE_INTERLACED;
		DUMPBITS (bit_buf, bits, 1);
	    }
	    return macroblock_modes;
	}

    case D_TYPE:

	DUMPBITS (bit_buf, bits, 1);
	return MACROBLOCK_INTRA;

    default:
	return 0;
    }
#undef bit_buf
#undef bits
#undef bit_ptr
}

static inline void get_quantizer_scale (mpeg2_decoder_t * const decoder)
{
#define bit_buf (decoder->bitstream_buf)
#define bits (decoder->bitstream_bits)
#define bit_ptr (decoder->bitstream_ptr)

    int quantizer_scale_code;

    quantizer_scale_code = UBITS (bit_buf, 5);
    DUMPBITS (bit_buf, bits, 5);

    decoder->quantizer_matrix[0] =
	decoder->quantizer_prescale[0][quantizer_scale_code];
    decoder->quantizer_matrix[1] =
	decoder->quantizer_prescale[1][quantizer_scale_code];
    decoder->quantizer_matrix[2] =
	decoder->chroma_quantizer[0][quantizer_scale_code];
    decoder->quantizer_matrix[3] =
	decoder->chroma_quantizer[1][quantizer_scale_code];
#undef bit_buf
#undef bits
#undef bit_ptr
}

static inline int get_motion_delta (mpeg2_decoder_t * const decoder,
				    const int f_code)
{
#define bit_buf (decoder->bitstream_buf)
#define bits (decoder->bitstream_bits)
#define bit_ptr (decoder->bitstream_ptr)

    int delta;
    int sign;
    const MVtab * tab;

    if (bit_buf & 0x80000000) {
	DUMPBITS (bit_buf, bits, 1);
	return 0;
    } else if (bit_buf >= 0x0c000000) {

	tab = MV_4 + UBITS (bit_buf, 4);
	delta = (tab->delta << f_code) + 1;
	bits += tab->len + f_code + 1;
	bit_buf <<= tab->len;

	sign = SBITS (bit_buf, 1);
	bit_buf <<= 1;

	if (f_code)
	    delta += UBITS (bit_buf, f_code);
	bit_buf <<= f_code;

	return (delta ^ sign) - sign;

    } else {

	tab = MV_10 + UBITS (bit_buf, 10);
	delta = (tab->delta << f_code) + 1;
	bits += tab->len + 1;
	bit_buf <<= tab->len;

	sign = SBITS (bit_buf, 1);
	bit_buf <<= 1;

	if (f_code) {
	    NEEDBITS (bit_buf, bits, bit_ptr);
	    delta += UBITS (bit_buf, f_code);
	    DUMPBITS (bit_buf, bits, f_code);
	}

	return (delta ^ sign) - sign;

    }
#undef bit_buf
#undef bits
#undef bit_ptr
}

static inline int bound_motion_vector (const int vector, const int f_code)
{
    return ((int32_t)vector << (27 - f_code)) >> (27 - f_code);
}

static inline int get_dmv (mpeg2_decoder_t * const decoder)
{
#define bit_buf (decoder->bitstream_buf)
#define bits (decoder->bitstream_bits)
#define bit_ptr (decoder->bitstream_ptr)

    const DMVtab * tab;

    tab = DMV_2 + UBITS (bit_buf, 2);
    DUMPBITS (bit_buf, bits, tab->len);
    return tab->dmv;
#undef bit_buf
#undef bits
#undef bit_ptr
}

static inline int get_coded_block_pattern (mpeg2_decoder_t * const decoder)
{
#define bit_buf (decoder->bitstream_buf)
#define bits (decoder->bitstream_bits)
#define bit_ptr (decoder->bitstream_ptr)

    const CBPtab * tab;

    NEEDBITS (bit_buf, bits, bit_ptr);

    if (bit_buf >= 0x20000000) {

	tab = CBP_7 + (UBITS (bit_buf, 7) - 16);
	DUMPBITS (bit_buf, bits, tab->len);
	return tab->cbp;

    } else {

	tab = CBP_9 + UBITS (bit_buf, 9);
	DUMPBITS (bit_buf, bits, tab->len);
	return tab->cbp;
    }

#undef bit_buf
#undef bits
#undef bit_ptr
}

static inline int get_luma_dc_dct_diff (mpeg2_decoder_t * const decoder)
{
#define bit_buf (decoder->bitstream_buf)
#define bits (decoder->bitstream_bits)
#define bit_ptr (decoder->bitstream_ptr)
    const DCtab * tab;
    int size;
    int dc_diff;

    if (bit_buf < 0xf8000000) {
	tab = DC_lum_5 + UBITS (bit_buf, 5);
	size = tab->size;
	if (size) {
	    bits += tab->len + size;
	    bit_buf <<= tab->len;
	    dc_diff =
		UBITS (bit_buf, size) - UBITS (SBITS (~bit_buf, 1), size);
	    bit_buf <<= size;
	    return dc_diff << decoder->intra_dc_precision;
	} else {
	    DUMPBITS (bit_buf, bits, 3);
	    return 0;
	}
    } else {
	tab = DC_long + (UBITS (bit_buf, 9) - 0x1e0);
	size = tab->size;
	DUMPBITS (bit_buf, bits, tab->len);
	NEEDBITS (bit_buf, bits, bit_ptr);
	dc_diff = UBITS (bit_buf, size) - UBITS (SBITS (~bit_buf, 1), size);
	DUMPBITS (bit_buf, bits, size);
	return dc_diff << decoder->intra_dc_precision;
    }
#undef bit_buf
#undef bits
#undef bit_ptr
}

static inline int get_chroma_dc_dct_diff (mpeg2_decoder_t * const decoder)
{
#define bit_buf (decoder->bitstream_buf)
#define bits (decoder->bitstream_bits)
#define bit_ptr (decoder->bitstream_ptr)
    const DCtab * tab;
    int size;
    int dc_diff;

    if (bit_buf < 0xf8000000) {
	tab = DC_chrom_5 + UBITS (bit_buf, 5);
	size = tab->size;
	if (size) {
	    bits += tab->len + size;
	    bit_buf <<= tab->len;
	    dc_diff =
		UBITS (bit_buf, size) - UBITS (SBITS (~bit_buf, 1), size);
	    bit_buf <<= size;
	    return dc_diff << decoder->intra_dc_precision;
	} else {
	    DUMPBITS (bit_buf, bits, 2);
	    return 0;
	}
    } else {
	tab = DC_long + (UBITS (bit_buf, 10) - 0x3e0);
	size = tab->size;
	DUMPBITS (bit_buf, bits, tab->len + 1);
	NEEDBITS (bit_buf, bits, bit_ptr);
	dc_diff = UBITS (bit_buf, size) - UBITS (SBITS (~bit_buf, 1), size);
	DUMPBITS (bit_buf, bits, size);
	return dc_diff << decoder->intra_dc_precision;
    }
#undef bit_buf
#undef bits
#undef bit_ptr
}

#define SATURATE(val)				\
do {						\
    val <<= 4;					\
    if (unlikely (val != (int16_t) val))	\
	val = (SBITS (val, 1) ^ 2047) << 4;	\
} while (0)

static void get_intra_block_B14 (mpeg2_decoder_t * const decoder,
				 const uint16_t * const quant_matrix)
{
    int i;
    int j;
    int val;
    const uint8_t * const scan = decoder->scan;
    int mismatch;
    const DCTtab * tab;
    uint32_t bit_buf;
    int bits;
    const uint8_t * bit_ptr;
    int16_t * const dest = decoder->DCTblock;

    i = 0;
    mismatch = ~dest[0];

    bit_buf = decoder->bitstream_buf;
    bits = decoder->bitstream_bits;
    bit_ptr = decoder->bitstream_ptr;

    NEEDBITS (bit_buf, bits, bit_ptr);

    while (1) {
	if (bit_buf >= 0x28000000) {

	    tab = DCT_B14AC_5 + (UBITS (bit_buf, 5) - 5);

	    i += tab->run;
	    if (i >= 64)
		break;	/* end of block */

	normal_code:
	    j = scan[i];
	    bit_buf <<= tab->len;
	    bits += tab->len + 1;
	    val = (tab->level * quant_matrix[j]) >> 4;

	    /* if (bitstream_get (1)) val = -val; */
	    val = (val ^ SBITS (bit_buf, 1)) - SBITS (bit_buf, 1);

	    SATURATE (val);
	    dest[j] = val;
	    mismatch ^= val;

	    bit_buf <<= 1;