/*

 * Common mpeg video decoding code

 * Copyright (c) 2000,2001 Fabrice Bellard

 * Copyright (c) 2002-2004 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 <limits.h>

#include "config_components.h"

#include "libavutil/avassert.h"

#include "libavutil/emms.h"

#include "libavutil/imgutils.h"

#include "libavutil/internal.h"

#include "libavutil/video_enc_params.h"

#include "avcodec.h"

#include "decode.h"

#include "h264chroma.h"

#include "internal.h"

#include "mpegutils.h"

#include "mpegvideo.h"

#include "mpegvideodec.h"

#include "mpeg4videodec.h"

#include "refstruct.h"

#include "thread.h"

#include "threadprogress.h"

#include "wmv2dec.h"

int ff_mpv_decode_init(MpegEncContext *s, AVCodecContext *avctx)

{

    enum ThreadingStatus thread_status;

    ff_mpv_common_defaults(s);

    s->avctx           = avctx;

    s->width           = avctx->coded_width;

    s->height          = avctx->coded_height;

    s->codec_id        = avctx->codec->id;

    s->workaround_bugs = avctx->workaround_bugs;

    /* convert fourcc to upper case */

    s->codec_tag       = ff_toupper4(avctx->codec_tag);

    ff_mpv_idct_init(s);

    ff_h264chroma_init(&s->h264chroma, 8); //for lowres

    if (s->picture_pool)  // VC-1 can call this multiple times

        return 0;

    thread_status = ff_thread_sync_ref(avctx, offsetof(MpegEncContext, picture_pool));

    if (thread_status != FF_THREAD_IS_COPY) {

        s->picture_pool = ff_mpv_alloc_pic_pool(thread_status != FF_THREAD_NO_FRAME_THREADING);

        if (!s->picture_pool)

            return AVERROR(ENOMEM);

    }

    return 0;

}

int ff_mpeg_update_thread_context(AVCodecContext *dst,

                                  const AVCodecContext *src)

{

    MpegEncContext *const s1 = src->priv_data;

    MpegEncContext *const s  = dst->priv_data;

    int ret;

    if (dst == src)

        return 0;

    av_assert0(s != s1);

    // FIXME can parameters change on I-frames?

    // in that case dst may need a reinit

    if (!s->context_initialized) {

        void *private_ctx = s->private_ctx;

        int err;

        memcpy(s, s1, sizeof(*s));

        s->context_initialized   = 0;

        s->context_reinit        = 0;

        s->avctx                 = dst;

        s->private_ctx           = private_ctx;

        s->bitstream_buffer      = NULL;

        s->bitstream_buffer_size = s->allocated_bitstream_buffer_size = 0;

        if (s1->context_initialized) {

            if ((err = ff_mpv_common_init(s)) < 0)

                return err;

        }

    }

    if (s->height != s1->height || s->width != s1->width || s->context_reinit) {

        s->height = s1->height;

        s->width  = s1->width;

        if ((ret = ff_mpv_common_frame_size_change(s)) < 0)

            return ret;

    }

    s->quarter_sample       = s1->quarter_sample;

    s->picture_number       = s1->picture_number;

    ff_mpv_replace_picture(&s->cur_pic,  &s1->cur_pic);

    ff_mpv_replace_picture(&s->last_pic, &s1->last_pic);

    ff_mpv_replace_picture(&s->next_pic, &s1->next_pic);

    s->linesize   = s1->linesize;

    s->uvlinesize = s1->uvlinesize;

    // Error/bug resilience

    s->workaround_bugs      = s1->workaround_bugs;

    s->padding_bug_score    = s1->padding_bug_score;

    // MPEG-4 timing info

    memcpy(&s->last_time_base, &s1->last_time_base,

           (char *) &s1->pb_field_time + sizeof(s1->pb_field_time) -

           (char *) &s1->last_time_base);

    // B-frame info

    s->max_b_frames = s1->max_b_frames;

    s->low_delay    = s1->low_delay;

    // DivX handling (doesn't work)

    s->divx_packed  = s1->divx_packed;

    if (s1->bitstream_buffer) {

        av_fast_padded_malloc(&s->bitstream_buffer,

                              &s->allocated_bitstream_buffer_size,

                              s1->bitstream_buffer_size);

        if (!s->bitstream_buffer) {

            s->bitstream_buffer_size = 0;

            return AVERROR(ENOMEM);

        }

        s->bitstream_buffer_size = s1->bitstream_buffer_size;

        memcpy(s->bitstream_buffer, s1->bitstream_buffer,

               s1->bitstream_buffer_size);

    }

    // MPEG-2/interlacing info

    memcpy(&s->progressive_sequence, &s1->progressive_sequence,

           (char *) &s1->rtp_mode - (char *) &s1->progressive_sequence);

    return 0;

}

int ff_mpv_decode_close(AVCodecContext *avctx)

{

    MpegEncContext *s = avctx->priv_data;

    ff_refstruct_pool_uninit(&s->picture_pool);

    ff_mpv_common_end(s);

    return 0;

}

int ff_mpv_common_frame_size_change(MpegEncContext *s)

{

    int err = 0;

    if (!s->context_initialized)

        return AVERROR(EINVAL);

    ff_mpv_free_context_frame(s);

    ff_mpv_unref_picture(&s->last_pic);

    ff_mpv_unref_picture(&s->next_pic);

    ff_mpv_unref_picture(&s->cur_pic);

    if ((s->width || s->height) &&

        (err = av_image_check_size(s->width, s->height, 0, s->avctx)) < 0)

        goto fail;

    /* set chroma shifts */

    err = av_pix_fmt_get_chroma_sub_sample(s->avctx->pix_fmt,

                                           &s->chroma_x_shift,

                                           &s->chroma_y_shift);

    if (err < 0)

        goto fail;

    if ((err = ff_mpv_init_context_frame(s)))

        goto fail;

    memset(s->thread_context, 0, sizeof(s->thread_context));

    s->thread_context[0]   = s;

    if (s->width && s->height) {

        err = ff_mpv_init_duplicate_contexts(s);

        if (err < 0)

            goto fail;

    }

    s->context_reinit = 0;

    return 0;

 fail:

    ff_mpv_free_context_frame(s);

    s->context_reinit = 1;

    return err;

}

static int alloc_picture(MpegEncContext *s, MPVWorkPicture *dst, int reference)

{

    AVCodecContext *avctx = s->avctx;

    MPVPicture *pic = ff_refstruct_pool_get(s->picture_pool);

    int ret;

    if (!pic)

        return AVERROR(ENOMEM);

    dst->ptr = pic;

    pic->reference = reference;

    /* WM Image / Screen codecs allocate internal buffers with different

     * dimensions / colorspaces; ignore user-defined callbacks for these. */

    if (avctx->codec_id != AV_CODEC_ID_WMV3IMAGE &&

        avctx->codec_id != AV_CODEC_ID_VC1IMAGE  &&

        avctx->codec_id != AV_CODEC_ID_MSS2) {

        ret = ff_thread_get_buffer(avctx, pic->f,

                                   reference ? AV_GET_BUFFER_FLAG_REF : 0);

    } else {

        pic->f->width  = avctx->width;

        pic->f->height = avctx->height;

        pic->f->format = avctx->pix_fmt;

        ret = avcodec_default_get_buffer2(avctx, pic->f, 0);

    }

    if (ret < 0)

        goto fail;

    ret = ff_mpv_pic_check_linesize(avctx, pic->f, &s->linesize, &s->uvlinesize);

    if (ret < 0)

        goto fail;

    ret = ff_hwaccel_frame_priv_alloc(avctx, &pic->hwaccel_picture_private);

    if (ret < 0)

        goto fail;

    av_assert1(s->mb_width  == s->buffer_pools.alloc_mb_width);

    av_assert1(s->mb_height == s->buffer_pools.alloc_mb_height ||

               FFALIGN(s->mb_height, 2) == s->buffer_pools.alloc_mb_height);

    av_assert1(s->mb_stride == s->buffer_pools.alloc_mb_stride);

    ret = ff_mpv_alloc_pic_accessories(s->avctx, dst, &s->sc,

                                       &s->buffer_pools, s->mb_height);

    if (ret < 0)

        goto fail;

    return 0;

fail:

    ff_mpv_unref_picture(dst);

    return ret;

}

static int av_cold alloc_dummy_frame(MpegEncContext *s, MPVWorkPicture *dst)

{

    MPVPicture *pic;

    int ret = alloc_picture(s, dst, 1);

    if (ret < 0)

        return ret;

    pic = dst->ptr;

    pic->dummy = 1;

    ff_thread_progress_report(&pic->progress, INT_MAX);

    return 0;

}

static void color_frame(AVFrame *frame, int luma)

{

    int h_chroma_shift, v_chroma_shift;

    for (int i = 0; i < frame->height; i++)

        memset(frame->data[0] + frame->linesize[0] * i, luma, frame->width);

    if (!frame->data[1])

        return;

    av_pix_fmt_get_chroma_sub_sample(frame->format, &h_chroma_shift, &v_chroma_shift);

    for (int i = 0; i < AV_CEIL_RSHIFT(frame->height, v_chroma_shift); i++) {

        memset(frame->data[1] + frame->linesize[1] * i,

               0x80, AV_CEIL_RSHIFT(frame->width, h_chroma_shift));

        memset(frame->data[2] + frame->linesize[2] * i,

               0x80, AV_CEIL_RSHIFT(frame->width, h_chroma_shift));

    }

}

int ff_mpv_alloc_dummy_frames(MpegEncContext *s)

{

    AVCodecContext *avctx = s->avctx;

    int ret;

    av_assert1(!s->last_pic.ptr || s->last_pic.ptr->f->buf[0]);

    av_assert1(!s->next_pic.ptr || s->next_pic.ptr->f->buf[0]);

    if (!s->last_pic.ptr && s->pict_type != AV_PICTURE_TYPE_I) {

        if (s->pict_type == AV_PICTURE_TYPE_B && s->next_pic.ptr)

            av_log(avctx, AV_LOG_DEBUG,

                   "allocating dummy last picture for B frame\n");

        else if (s->codec_id != AV_CODEC_ID_H261 /* H.261 has no keyframes */ &&

                 (s->picture_structure == PICT_FRAME || s->first_field))

            av_log(avctx, AV_LOG_ERROR,

                   "warning: first frame is no keyframe\n");

        /* Allocate a dummy frame */

        ret = alloc_dummy_frame(s, &s->last_pic);

        if (ret < 0)

            return ret;

        if (!avctx->hwaccel) {

            int luma_val = s->codec_id == AV_CODEC_ID_FLV1 || s->codec_id == AV_CODEC_ID_H263 ? 16 : 0x80;

            color_frame(s->last_pic.ptr->f, luma_val);

        }

    }

    if (!s->next_pic.ptr && s->pict_type == AV_PICTURE_TYPE_B) {

        /* Allocate a dummy frame */

        ret = alloc_dummy_frame(s, &s->next_pic);

        if (ret < 0)

            return ret;

    }

    av_assert0(s->pict_type == AV_PICTURE_TYPE_I || (s->last_pic.ptr &&

                                                 s->last_pic.ptr->f->buf[0]));

    return 0;

}

/**

 * generic function called after decoding

 * the header and before a frame is decoded.

 */

int ff_mpv_frame_start(MpegEncContext *s, AVCodecContext *avctx)

{

    int ret;

    s->mb_skipped = 0;

    if (!ff_thread_can_start_frame(avctx)) {

        av_log(avctx, AV_LOG_ERROR, "Attempt to start a frame outside SETUP state\n");

        return AVERROR_BUG;

    }

    ff_mpv_unref_picture(&s->cur_pic);

    ret = alloc_picture(s, &s->cur_pic,

                        s->pict_type != AV_PICTURE_TYPE_B && !s->droppable);

    if (ret < 0)

        return ret;

    s->cur_pic.ptr->f->flags |= AV_FRAME_FLAG_TOP_FIELD_FIRST * !!s->top_field_first;

    s->cur_pic.ptr->f->flags |= AV_FRAME_FLAG_INTERLACED *

                                (!s->progressive_frame && !s->progressive_sequence);

    s->cur_pic.ptr->field_picture = s->picture_structure != PICT_FRAME;

    s->cur_pic.ptr->f->pict_type = s->pict_type;

    if (s->pict_type == AV_PICTURE_TYPE_I)

        s->cur_pic.ptr->f->flags |= AV_FRAME_FLAG_KEY;

    else

        s->cur_pic.ptr->f->flags &= ~AV_FRAME_FLAG_KEY;

    if (s->pict_type != AV_PICTURE_TYPE_B) {

        ff_mpv_workpic_from_pic(&s->last_pic, s->next_pic.ptr);

        if (!s->droppable)

            ff_mpv_workpic_from_pic(&s->next_pic, s->cur_pic.ptr);

    }

    ff_dlog(s->avctx, "L%p N%p C%p L%p N%p C%p type:%d drop:%d\n",

            (void*)s->last_pic.ptr, (void*)s->next_pic.ptr, (void*)s->cur_pic.ptr,

            s->last_pic.ptr ? s->last_pic.ptr->f->data[0] : NULL,

            s->next_pic.ptr ? s->next_pic.ptr->f->data[0] : NULL,

            s->cur_pic.ptr  ? s->cur_pic.ptr->f->data[0]  : NULL,

            s->pict_type, s->droppable);

    ret = ff_mpv_alloc_dummy_frames(s);

    if (ret < 0)

        return ret;

    if (s->avctx->debug & FF_DEBUG_NOMC)

        color_frame(s->cur_pic.ptr->f, 0x80);

    return 0;

}

/* called after a frame has been decoded. */

void ff_mpv_frame_end(MpegEncContext *s)

{

    emms_c();

    if (s->cur_pic.reference)

        ff_thread_progress_report(&s->cur_pic.ptr->progress, INT_MAX);

}

void ff_print_debug_info(const MpegEncContext *s, const MPVPicture *p, AVFrame *pict)

{

    ff_print_debug_info2(s->avctx, pict, p->mb_type,

                         p->qscale_table, p->motion_val,

                         s->mb_width, s->mb_height, s->mb_stride, s->quarter_sample);

}

int ff_mpv_export_qp_table(const MpegEncContext *s, AVFrame *f,

                           const MPVPicture *p, int qp_type)

{

    AVVideoEncParams *par;

    int mult = (qp_type == FF_MPV_QSCALE_TYPE_MPEG1) ? 2 : 1;

    unsigned int nb_mb = p->mb_height * p->mb_width;

    if (!(s->avctx->export_side_data & AV_CODEC_EXPORT_DATA_VIDEO_ENC_PARAMS))

        return 0;

    par = av_video_enc_params_create_side_data(f, AV_VIDEO_ENC_PARAMS_MPEG2, nb_mb);

    if (!par)

        return AVERROR(ENOMEM);

    for (unsigned y = 0; y < p->mb_height; y++)

        for (unsigned x = 0; x < p->mb_width; x++) {

            const unsigned int block_idx = y * p->mb_width + x;

            const unsigned int     mb_xy = y * p->mb_stride + x;

            AVVideoBlockParams *const b = av_video_enc_params_block(par, block_idx);

            b->src_x = x * 16;

            b->src_y = y * 16;

            b->w     = 16;

            b->h     = 16;

            b->delta_qp = p->qscale_table[mb_xy] * mult;

        }

    return 0;

}

void ff_mpeg_draw_horiz_band(MpegEncContext *s, int y, int h)

{

    ff_draw_horiz_band(s->avctx, s->cur_pic.ptr->f,

                       s->last_pic.ptr ? s->last_pic.ptr->f : NULL,

                       y, h, s->picture_structure,

                       s->first_field, s->low_delay);

}

void ff_mpeg_flush(AVCodecContext *avctx)

{

    MpegEncContext *const s = avctx->priv_data;

    ff_mpv_unref_picture(&s->cur_pic);

    ff_mpv_unref_picture(&s->last_pic);

    ff_mpv_unref_picture(&s->next_pic);

    s->mb_x = s->mb_y = 0;

    s->bitstream_buffer_size = 0;

    s->pp_time = 0;

}

void ff_mpv_report_decode_progress(MpegEncContext *s)

{

    if (s->pict_type != AV_PICTURE_TYPE_B && !s->partitioned_frame && !s->er.error_occurred)

        ff_thread_progress_report(&s->cur_pic.ptr->progress, s->mb_y);

}

static inline int hpel_motion_lowres(MpegEncContext *s,

                                     uint8_t *dest, const uint8_t *src,

                                     int field_based, int field_select,

                                     int src_x, int src_y,

                                     int width, int height, ptrdiff_t stride,

                                     int h_edge_pos, int v_edge_pos,

                                     int w, int h, const h264_chroma_mc_func *pix_op,

                                     int motion_x, int motion_y)

{

    const int lowres   = s->avctx->lowres;

    const int op_index = lowres;

    const int s_mask   = (2 << lowres) - 1;

    int emu = 0;

    int sx, sy;

    av_assert2(op_index <= 3);

    if (s->quarter_sample) {

        motion_x /= 2;

        motion_y /= 2;

    }

    sx = motion_x & s_mask;

    sy = motion_y & s_mask;

    src_x += motion_x >> lowres + 1;

    src_y += motion_y >> lowres + 1;

    src   += src_y * stride + src_x;

    if ((unsigned)src_x > FFMAX( h_edge_pos - (!!sx) - w,                 0) ||

        (unsigned)src_y > FFMAX((v_edge_pos >> field_based) - (!!sy) - h, 0)) {

        s->vdsp.emulated_edge_mc(s->sc.edge_emu_buffer, src,

                                 s->linesize, s->linesize,

                                 w + 1, (h + 1) << field_based,

                                 src_x, src_y * (1 << field_based),

                                 h_edge_pos, v_edge_pos);

        src = s->sc.edge_emu_buffer;

        emu = 1;

    }

    sx = (sx << 2) >> lowres;

    sy = (sy << 2) >> lowres;

    if (field_select)

        src += s->linesize;

    pix_op[op_index](dest, src, stride, h, sx, sy);

    return emu;

}

/* apply one mpeg motion vector to the three components */

static av_always_inline void mpeg_motion_lowres(MpegEncContext *s,

                                                uint8_t *dest_y,

                                                uint8_t *dest_cb,

                                                uint8_t *dest_cr,

                                                int field_based,

                                                int bottom_field,

                                                int field_select,

                                                uint8_t *const *ref_picture,

                                                const h264_chroma_mc_func *pix_op,

                                                int motion_x, int motion_y,

                                                int h, int mb_y)

{

    const uint8_t *ptr_y, *ptr_cb, *ptr_cr;

    int mx, my, src_x, src_y, uvsrc_x, uvsrc_y, sx, sy, uvsx, uvsy;

    ptrdiff_t uvlinesize, linesize;

    const int lowres     = s->avctx->lowres;

    const int op_index   = lowres - 1 + s->chroma_x_shift;

    const int block_s    = 8 >> lowres;

    const int s_mask     = (2 << lowres) - 1;

    const int h_edge_pos = s->h_edge_pos >> lowres;

    const int v_edge_pos = s->v_edge_pos >> lowres;

    int hc = s->chroma_y_shift ? (h+1-bottom_field)>>1 : h;

    av_assert2(op_index <= 3);

    linesize   = s->cur_pic.linesize[0] << field_based;

    uvlinesize = s->cur_pic.linesize[1] << field_based;

    // FIXME obviously not perfect but qpel will not work in lowres anyway

    if (s->quarter_sample) {

        motion_x /= 2;

        motion_y /= 2;

    }

    if (field_based) {

        motion_y += (bottom_field - field_select)*((1 << lowres)-1);

    }

    sx = motion_x & s_mask;

    sy = motion_y & s_mask;

    src_x = s->mb_x * 2 * block_s + (motion_x >> lowres + 1);

    src_y = (mb_y * 2 * block_s >> field_based) + (motion_y >> lowres + 1);

    if (s->out_format == FMT_H263) {

        uvsx    = ((motion_x >> 1) & s_mask) | (sx & 1);

        uvsy    = ((motion_y >> 1) & s_mask) | (sy & 1);

        uvsrc_x = src_x >> 1;

        uvsrc_y = src_y >> 1;

    } else if (s->out_format == FMT_H261) {

        // even chroma mv's are full pel in H261

        mx      = motion_x / 4;

        my      = motion_y / 4;

        uvsx    = (2 * mx) & s_mask;

        uvsy    = (2 * my) & s_mask;

        uvsrc_x = s->mb_x * block_s + (mx >> lowres);

        uvsrc_y =    mb_y * block_s + (my >> lowres);

    } else {

        if (s->chroma_y_shift) {

            mx      = motion_x / 2;

            my      = motion_y / 2;

            uvsx    = mx & s_mask;

            uvsy    = my & s_mask;

            uvsrc_x = s->mb_x * block_s                 + (mx >> lowres + 1);

            uvsrc_y =   (mb_y * block_s >> field_based) + (my >> lowres + 1);

        } else {

            if (s->chroma_x_shift) {

            //Chroma422

                mx = motion_x / 2;

                uvsx = mx & s_mask;

                uvsy = motion_y & s_mask;

                uvsrc_y = src_y;

                uvsrc_x = s->mb_x*block_s               + (mx >> (lowres+1));

            } else {

            //Chroma444

                uvsx = motion_x & s_mask;

                uvsy = motion_y & s_mask;

                uvsrc_x = src_x;

                uvsrc_y = src_y;

            }

        }

    }

    ptr_y  = ref_picture[0] + src_y   * linesize   + src_x;

    ptr_cb = ref_picture[1] + uvsrc_y * uvlinesize + uvsrc_x;

    ptr_cr = ref_picture[2] + uvsrc_y * uvlinesize + uvsrc_x;

    if ((unsigned) src_x > FFMAX( h_edge_pos - (!!sx) - 2 * block_s,       0) || uvsrc_y<0 ||

        (unsigned) src_y > FFMAX((v_edge_pos >> field_based) - (!!sy) - FFMAX(h, hc<<s->chroma_y_shift), 0)) {

        s->vdsp.emulated_edge_mc(s->sc.edge_emu_buffer, ptr_y,

                                 linesize >> field_based, linesize >> field_based,

                                 17, 17 + field_based,

                                src_x, src_y * (1 << field_based), h_edge_pos,

                                v_edge_pos);

        ptr_y = s->sc.edge_emu_buffer;

        if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {

            uint8_t *ubuf = s->sc.edge_emu_buffer + 18 * s->linesize;

            uint8_t *vbuf =ubuf + 10 * s->uvlinesize;

            if (s->workaround_bugs & FF_BUG_IEDGE)

                vbuf -= s->uvlinesize;

            s->vdsp.emulated_edge_mc(ubuf,  ptr_cb,

                                     uvlinesize >> field_based, uvlinesize >> field_based,

                                     9, 9 + field_based,

                                    uvsrc_x, uvsrc_y * (1 << field_based),

                                    h_edge_pos >> 1, v_edge_pos >> 1);

            s->vdsp.emulated_edge_mc(vbuf,  ptr_cr,

                                     uvlinesize >> field_based,uvlinesize >> field_based,

                                     9, 9 + field_based,

                                    uvsrc_x, uvsrc_y * (1 << field_based),

                                    h_edge_pos >> 1, v_edge_pos >> 1);

            ptr_cb = ubuf;

            ptr_cr = vbuf;

        }

    }

    // FIXME use this for field pix too instead of the obnoxious hack which changes picture.f->data

    if (bottom_field) {

        dest_y  += s->linesize;

        dest_cb += s->uvlinesize;

        dest_cr += s->uvlinesize;

    }

    if (field_select) {

        ptr_y   += s->linesize;

        ptr_cb  += s->uvlinesize;

        ptr_cr  += s->uvlinesize;

    }

    sx = (sx << 2) >> lowres;

    sy = (sy << 2) >> lowres;

    pix_op[lowres - 1](dest_y, ptr_y, linesize, h, sx, sy);

    if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY)) {

        uvsx = (uvsx << 2) >> lowres;

        uvsy = (uvsy << 2) >> lowres;

        if (hc) {

            pix_op[op_index](dest_cb, ptr_cb, uvlinesize, hc, uvsx, uvsy);

            pix_op[op_index](dest_cr, ptr_cr, uvlinesize, hc, uvsx, uvsy);

        }

    }

    // FIXME h261 lowres loop filter

}

static inline void chroma_4mv_motion_lowres(MpegEncContext *s,

                                            uint8_t *dest_cb, uint8_t *dest_cr,

                                            uint8_t *const *ref_picture,

                                            const h264_chroma_mc_func * pix_op,

                                            int mx, int my)

{

    const int lowres     = s->avctx->lowres;

    const int op_index   = lowres;

    const int block_s    = 8 >> lowres;

    const int s_mask     = (2 << lowres) - 1;

    const int h_edge_pos = s->h_edge_pos >> lowres + 1;

    const int v_edge_pos = s->v_edge_pos >> lowres + 1;

    int emu = 0, src_x, src_y, sx, sy;

    ptrdiff_t offset;

    const uint8_t *ptr;

    av_assert2(op_index <= 3);

    if (s->quarter_sample) {

        mx /= 2;

        my /= 2;

    }

    /* In case of 8X8, we construct a single chroma motion vector

       with a special rounding */

    mx = ff_h263_round_chroma(mx);

    my = ff_h263_round_chroma(my);

    sx = mx & s_mask;

    sy = my & s_mask;

    src_x = s->mb_x * block_s + (mx >> lowres + 1);

    src_y = s->mb_y * block_s + (my >> lowres + 1);

    offset = src_y * s->uvlinesize + src_x;

    ptr = ref_picture[1] + offset;

    if ((unsigned) src_x > FFMAX(h_edge_pos - (!!sx) - block_s, 0) ||

        (unsigned) src_y > FFMAX(v_edge_pos - (!!sy) - block_s, 0)) {

        s->vdsp.emulated_edge_mc(s->sc.edge_emu_buffer, ptr,

                                 s->uvlinesize, s->uvlinesize,

                                 9, 9,

                                 src_x, src_y, h_edge_pos, v_edge_pos);

        ptr = s->sc.edge_emu_buffer;

        emu = 1;

    }

    sx = (sx << 2) >> lowres;

    sy = (sy << 2) >> lowres;

    pix_op[op_index](dest_cb, ptr, s->uvlinesize, block_s, sx, sy);

    ptr = ref_picture[2] + offset;

    if (emu) {

        s->vdsp.emulated_edge_mc(s->sc.edge_emu_buffer, ptr,

                                 s->uvlinesize, s->uvlinesize,

                                 9, 9,

                                 src_x, src_y, h_edge_pos, v_edge_pos);

        ptr = s->sc.edge_emu_buffer;

    }

    pix_op[op_index](dest_cr, ptr, s->uvlinesize, block_s, sx, sy);

}

/**

 * motion compensation of a single macroblock

 * @param s context

 * @param dest_y luma destination pointer

 * @param dest_cb chroma cb/u destination pointer

 * @param dest_cr chroma cr/v destination pointer

 * @param dir direction (0->forward, 1->backward)

 * @param ref_picture array[3] of pointers to the 3 planes of the reference picture

 * @param pix_op halfpel motion compensation function (average or put normally)

 * the motion vectors are taken from s->mv and the MV type from s->mv_type

 */

static inline void MPV_motion_lowres(MpegEncContext *s,

                                     uint8_t *dest_y, uint8_t *dest_cb,

                                     uint8_t *dest_cr,

                                     int dir, uint8_t *const *ref_picture,

                                     const h264_chroma_mc_func *pix_op)

{

    int mx, my;

    int mb_x, mb_y;

    const int lowres  = s->avctx->lowres;

    const int block_s = 8 >>lowres;

    mb_x = s->mb_x;

    mb_y = s->mb_y;

    switch (s->mv_type) {

    case MV_TYPE_16X16:

        mpeg_motion_lowres(s, dest_y, dest_cb, dest_cr,

                           0, 0, 0,

                           ref_picture, pix_op,

                           s->mv[dir][0][0], s->mv[dir][0][1],

                           2 * block_s, mb_y);

        break;

    case MV_TYPE_8X8:

        mx = 0;

        my = 0;

        for (int i = 0; i < 4; i++) {

            hpel_motion_lowres(s, dest_y + ((i & 1) + (i >> 1) *

                               s->linesize) * block_s,

                               ref_picture[0], 0, 0,

                               (2 * mb_x + (i & 1)) * block_s,

                               (2 * mb_y + (i >> 1)) * block_s,

                               s->width, s->height, s->linesize,

                               s->h_edge_pos >> lowres, s->v_edge_pos >> lowres,

                               block_s, block_s, pix_op,

                               s->mv[dir][i][0], s->mv[dir][i][1]);

            mx += s->mv[dir][i][0];

            my += s->mv[dir][i][1];

        }

        if (!CONFIG_GRAY || !(s->avctx->flags & AV_CODEC_FLAG_GRAY))

            chroma_4mv_motion_lowres(s, dest_cb, dest_cr, ref_picture,

                                     pix_op, mx, my);

        break;

    case MV_TYPE_FIELD:

        if (s->picture_structure == PICT_FRAME) {

            /* top field */

            mpeg_motion_lowres(s, dest_y, dest_cb, dest_cr,

                               1, 0, s->field_select[dir][0],

                               ref_picture, pix_op,

                               s->mv[dir][0][0], s->mv[dir][0][1],

                               block_s, mb_y);

            /* bottom field */

            mpeg_motion_lowres(s, dest_y, dest_cb, dest_cr,

                               1, 1, s->field_select[dir][1],

                               ref_picture, pix_op,

                               s->mv[dir][1][0], s->mv[dir][1][1],

                               block_s, mb_y);

        } else {

            if (s->picture_structure != s->field_select[dir][0] + 1 &&

                s->pict_type != AV_PICTURE_TYPE_B && !s->first_field) {

                ref_picture = s->cur_pic.ptr->f->data;

            }

            mpeg_motion_lowres(s, dest_y, dest_cb, dest_cr,

                               0, 0, s->field_select[dir][0],

                               ref_picture, pix_op,

                               s->mv[dir][0][0],

                               s->mv[dir][0][1], 2 * block_s, mb_y >> 1);

            }

        break;

    case MV_TYPE_16X8:

        for (int i = 0; i < 2; i++) {

            uint8_t *const *ref2picture;

            if (s->picture_structure == s->field_select[dir][i] + 1 ||

                s->pict_type == AV_PICTURE_TYPE_B || s->first_field) {

                ref2picture = ref_picture;

            } else {

                ref2picture = s->cur_pic.ptr->f->data;

            }

            mpeg_motion_lowres(s, dest_y, dest_cb, dest_cr,

                               0, 0, s->field_select[dir][i],

                               ref2picture, pix_op,

                               s->mv[dir][i][0], s->mv[dir][i][1] +

                               2 * block_s * i, block_s, mb_y >> 1);

            dest_y  +=  2 * block_s *  s->linesize;

            dest_cb += (2 * block_s >> s->chroma_y_shift) * s->uvlinesize;

            dest_cr += (2 * block_s >> s->chroma_y_shift) * s->uvlinesize;

        }

        break;

    case MV_TYPE_DMV:

        if (s->picture_structure == PICT_FRAME) {

            for (int i = 0; i < 2; i++) {

                for (int j = 0; j < 2; j++) {

                    mpeg_motion_lowres(s, dest_y, dest_cb, dest_cr,

                                       1, j, j ^ i,

                                       ref_picture, pix_op,

                                       s->mv[dir][2 * i + j][0],

                                       s->mv[dir][2 * i + j][1],

                                       block_s, mb_y);

                }

                pix_op = s->h264chroma.avg_h264_chroma_pixels_tab;

            }

        } else {

            for (int i = 0; i < 2; i++) {

                mpeg_motion_lowres(s, dest_y, dest_cb, dest_cr,

                                   0, 0, s->picture_structure != i + 1,

                                   ref_picture, pix_op,

                                   s->mv[dir][2 * i][0],s->mv[dir][2 * i][1],

                                   2 * block_s, mb_y >> 1);

                // after put we make avg of the same block

                pix_op = s->h264chroma.avg_h264_chroma_pixels_tab;

                // opposite parity is always in the same

                // frame if this is second field

                if (!s->first_field) {

                    ref_picture = s->cur_pic.ptr->f->data;

                }

            }

        }

        break;

    default:

        av_assert2(0);

    }

}

/**

 * find the lowest MB row referenced in the MVs

 */

static int lowest_referenced_row(MpegEncContext *s, int dir)

{

    int my_max = INT_MIN, my_min = INT_MAX, qpel_shift = !s->quarter_sample;

    int off, mvs;

    if (s->picture_structure != PICT_FRAME || s->mcsel)

        goto unhandled;

    switch (s->mv_type) {

        case MV_TYPE_16X16:

            mvs = 1;

            break;

        case MV_TYPE_16X8:

            mvs = 2;

            break;

        case MV_TYPE_8X8:

            mvs = 4;

            break;

        default:

            goto unhandled;

    }

    for (int i = 0; i < mvs; i++) {

        int my = s->mv[dir][i][1];

        my_max = FFMAX(my_max, my);

        my_min = FFMIN(my_min, my);

    }

    off = ((FFMAX(-my_min, my_max) << qpel_shift) + 63) >> 6;

    return av_clip(s->mb_y + off, 0, s->mb_height - 1);

unhandled:

    return s->mb_height - 1;

}

/* add block[] to dest[] */

static inline void add_dct(MpegEncContext *s,

                           int16_t *block, int i, uint8_t *dest, int line_size)

{

    if (s->block_last_index[i] >= 0) {

        s->idsp.idct_add(dest, line_size, block);

    }

}

#define IS_ENCODER 0

#include "mpv_reconstruct_mb_template.c"

void ff_mpv_reconstruct_mb(MpegEncContext *s, int16_t block[12][64])

{

    if (s->avctx->debug & FF_DEBUG_DCT_COEFF) {

       /* print DCT coefficients */

       av_log(s->avctx, AV_LOG_DEBUG, "DCT coeffs of MB at %dx%d:\n", s->mb_x, s->mb_y);

       for (int i = 0; i < 6; i++) {

           for (int j = 0; j < 64; j++) {

               av_log(s->avctx, AV_LOG_DEBUG, "%5d",

                      block[i][s->idsp.idct_permutation[j]]);

           }

           av_log(s->avctx, AV_LOG_DEBUG, "\n");

       }

    }

    av_assert2((s->out_format <= FMT_H261) == (s->out_format == FMT_H261 || s->out_format == FMT_MPEG1));

    if (!s->avctx->lowres) {

#if !CONFIG_SMALL

        if (s->out_format <= FMT_H261)

            mpv_reconstruct_mb_internal(s, block, 0, DEFINITELY_MPEG12_H261);

        else

            mpv_reconstruct_mb_internal(s, block, 0, NOT_MPEG12_H261);

#else

        mpv_reconstruct_mb_internal(s, block, 0, MAY_BE_MPEG12_H261);

#endif

    } else

        mpv_reconstruct_mb_internal(s, block, 1, MAY_BE_MPEG12_H261);

}