mpegvideo_unquantize.c

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/*
 * Unquantize functions for mpegvideo
 * Copyright (c) 2000,2001 Fabrice Bellard
 * Copyright (c) 2002-2004 Michael Niedermayer <michaelni@gmx.at>
 *
 * 4MV & hq & B-frame encoding stuff by Michael Niedermayer <michaelni@gmx.at>
 *
 * This file is part of FFmpeg.
 *
 * FFmpeg is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * FFmpeg 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with FFmpeg; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */
 
#include <stdint.h>
 
#include "config.h"
 
#include "libavutil/attributes.h"
#include "libavutil/avassert.h"
#include "avcodec.h"
#include "mpegvideo.h"
#include "mpegvideodata.h"
#include "mpegvideo_unquantize.h"
 
av_cold void ff_init_scantable(const uint8_t *permutation, ScanTable *st,
                               const uint8_t *src_scantable)
{
    st->scantable = src_scantable;
 
    for (int i = 0, end = -1; i < 64; i++) {
        int j = src_scantable[i];
        st->permutated[i] = permutation[j];
        if (permutation[j] > end)
            end = permutation[j];
        st->raster_end[i] = end;
    }
}
 
static void dct_unquantize_mpeg1_intra_c(const MPVContext *s,
                                         int16_t *block, int n, int qscale)
{
    int i, level, nCoeffs;
    const uint16_t *quant_matrix;
 
    nCoeffs= s->block_last_index[n];
 
    block[0] *= n < 4 ? s->y_dc_scale : s->c_dc_scale;
    /* XXX: only MPEG-1 */
    quant_matrix = s->intra_matrix;
    for(i=1;i<=nCoeffs;i++) {
        int j= s->intra_scantable.permutated[i];
        level = block[j];
        if (level) {
            if (level < 0) {
                level = -level;
                level = (int)(level * qscale * quant_matrix[j]) >> 3;
                level = (level - 1) | 1;
                level = -level;
            } else {
                level = (int)(level * qscale * quant_matrix[j]) >> 3;
                level = (level - 1) | 1;
            }
            block[j] = level;
        }
    }
}
 
static void dct_unquantize_mpeg1_inter_c(const MPVContext *s,
                                         int16_t *block, int n, int qscale)
{
    int i, level, nCoeffs;
    const uint16_t *quant_matrix;
 
    nCoeffs= s->block_last_index[n];
 
    quant_matrix = s->inter_matrix;
    for(i=0; i<=nCoeffs; i++) {
        int j= s->intra_scantable.permutated[i];
        level = block[j];
        if (level) {
            if (level < 0) {
                level = -level;
                level = (((level << 1) + 1) * qscale *
                         ((int) (quant_matrix[j]))) >> 4;
                level = (level - 1) | 1;
                level = -level;
            } else {
                level = (((level << 1) + 1) * qscale *
                         ((int) (quant_matrix[j]))) >> 4;
                level = (level - 1) | 1;
            }
            block[j] = level;
        }
    }
}
 
static void dct_unquantize_mpeg2_intra_c(const MPVContext *s,
                                         int16_t *block, int n, int qscale)
{
    int i, level, nCoeffs;
    const uint16_t *quant_matrix;
 
    if (s->q_scale_type) qscale = ff_mpeg2_non_linear_qscale[qscale];
    else                 qscale <<= 1;
 
    nCoeffs= s->block_last_index[n];
 
    block[0] *= n < 4 ? s->y_dc_scale : s->c_dc_scale;
    quant_matrix = s->intra_matrix;
    for(i=1;i<=nCoeffs;i++) {
        int j= s->intra_scantable.permutated[i];
        level = block[j];
        if (level) {
            if (level < 0) {
                level = -level;
                level = (int)(level * qscale * quant_matrix[j]) >> 4;
                level = -level;
            } else {
                level = (int)(level * qscale * quant_matrix[j]) >> 4;
            }
            block[j] = level;
        }
    }
}
 
static void dct_unquantize_mpeg2_intra_bitexact(const MPVContext *s,
                                                int16_t *block, int n, int qscale)
{
    int i, level, nCoeffs;
    const uint16_t *quant_matrix;
    int sum=-1;
 
    if (s->q_scale_type) qscale = ff_mpeg2_non_linear_qscale[qscale];
    else                 qscale <<= 1;
 
    nCoeffs= s->block_last_index[n];
 
    block[0] *= n < 4 ? s->y_dc_scale : s->c_dc_scale;
    sum += block[0];
    quant_matrix = s->intra_matrix;
    for(i=1;i<=nCoeffs;i++) {
        int j= s->intra_scantable.permutated[i];
        level = block[j];
        if (level) {
            if (level < 0) {
                level = -level;
                level = (int)(level * qscale * quant_matrix[j]) >> 4;
                level = -level;
            } else {
                level = (int)(level * qscale * quant_matrix[j]) >> 4;
            }
            block[j] = level;
            sum+=level;
        }
    }
    block[63]^=sum&1;
}
 
static void dct_unquantize_mpeg2_inter_c(const MPVContext *s,
                                         int16_t *block, int n, int qscale)
{
    int i, level, nCoeffs;
    const uint16_t *quant_matrix;
    int sum=-1;
 
    if (s->q_scale_type) qscale = ff_mpeg2_non_linear_qscale[qscale];
    else                 qscale <<= 1;
 
    nCoeffs= s->block_last_index[n];
 
    quant_matrix = s->inter_matrix;
    for(i=0; i<=nCoeffs; i++) {
        int j= s->intra_scantable.permutated[i];
        level = block[j];
        if (level) {
            if (level < 0) {
                level = -level;
                level = (((level << 1) + 1) * qscale *
                         ((int) (quant_matrix[j]))) >> 5;
                level = -level;
            } else {
                level = (((level << 1) + 1) * qscale *
                         ((int) (quant_matrix[j]))) >> 5;
            }
            block[j] = level;
            sum+=level;
        }
    }
    block[63]^=sum&1;
}
 
static void dct_unquantize_h263_intra_c(const MPVContext *s,
                                        int16_t *block, int n, int qscale)
{
    int i, level, qmul, qadd;
    int nCoeffs;
 
    av_assert2(s->block_last_index[n]>=0 || s->h263_aic);
 
    qmul = qscale << 1;
 
    if (!s->h263_aic) {
        block[0] *= n < 4 ? s->y_dc_scale : s->c_dc_scale;
        qadd = (qscale - 1) | 1;
    }else{
        qadd = 0;
    }
    if(s->ac_pred)
        nCoeffs=63;
    else
        nCoeffs= s->intra_scantable.raster_end[ s->block_last_index[n] ];
 
    for(i=1; i<=nCoeffs; i++) {
        level = block[i];
        if (level) {
            if (level < 0) {
                level = level * qmul - qadd;
            } else {
                level = level * qmul + qadd;
            }
            block[i] = level;
        }
    }
}
 
static void dct_unquantize_h263_inter_c(const MPVContext *s,
                                        int16_t *block, int n, int qscale)
{
    int i, level, qmul, qadd;
    int nCoeffs;
 
    av_assert2(s->block_last_index[n]>=0);
 
    qadd = (qscale - 1) | 1;
    qmul = qscale << 1;
 
    nCoeffs= s->inter_scantable.raster_end[ s->block_last_index[n] ];
 
    for(i=0; i<=nCoeffs; i++) {
        level = block[i];
        if (level) {
            if (level < 0) {
                level = level * qmul - qadd;
            } else {
                level = level * qmul + qadd;
            }
            block[i] = level;
        }
    }
}
 
av_cold void ff_mpv_unquantize_init(MPVUnquantDSPContext *s,
                                    int bitexact, int q_scale_type)
{
    s->dct_unquantize_h263_intra  = dct_unquantize_h263_intra_c;
    s->dct_unquantize_h263_inter  = dct_unquantize_h263_inter_c;
    s->dct_unquantize_mpeg1_intra = dct_unquantize_mpeg1_intra_c;
    s->dct_unquantize_mpeg1_inter = dct_unquantize_mpeg1_inter_c;
    s->dct_unquantize_mpeg2_intra = dct_unquantize_mpeg2_intra_c;
    if (bitexact)
        s->dct_unquantize_mpeg2_intra = dct_unquantize_mpeg2_intra_bitexact;
    s->dct_unquantize_mpeg2_inter = dct_unquantize_mpeg2_inter_c;
 
#if HAVE_INTRINSICS_NEON
    ff_mpv_unquantize_init_neon(s, bitexact);
#endif
 
#if ARCH_ARM
    ff_mpv_unquantize_init_arm(s, bitexact);
#elif ARCH_PPC
    ff_mpv_unquantize_init_ppc(s, bitexact);
#elif ARCH_RISCV
    ff_mpv_unquantize_init_riscv(s, bitexact);
#elif ARCH_X86
    ff_mpv_unquantize_init_x86(s, bitexact);
#elif ARCH_MIPS
    ff_mpv_unquantize_init_mips(s, bitexact, q_scale_type);
#endif
}