/*

 * VVC video decoder

 *

 * Copyright (C) 2021 Nuo Mi

 * Copyright (C) 2022 Xu Mu

 *

 * 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 "libavcodec/bytestream.h"

#include "libavcodec/codec_internal.h"

#include "libavcodec/decode.h"

#include "libavcodec/hwaccel_internal.h"

#include "libavcodec/hwconfig.h"

#include "libavcodec/profiles.h"

#include "libavutil/refstruct.h"

#include "libavcodec/aom_film_grain.h"

#include "libavcodec/thread.h"

#include "libavutil/cpu.h"

#include "libavutil/mem.h"

#include "libavutil/thread.h"

#include "libavutil/film_grain_params.h"

#include "dec.h"

#include "ctu.h"

#include "data.h"

#include "refs.h"

#include "thread.h"

#include "config_components.h"

#define TAB_MAX 32

typedef struct Tab {

    void **tab;

    size_t size;

} Tab;

typedef struct TabList {

    Tab tabs[TAB_MAX];

    int nb_tabs;

    int zero;

    int realloc;

} TabList;

#define TL_ADD(t, s) do {                                \

    av_assert0(l->nb_tabs < TAB_MAX);                    \

    l->tabs[l->nb_tabs].tab  = (void**)&fc->tab.t;       \

    l->tabs[l->nb_tabs].size = sizeof(*fc->tab.t) * (s); \

    l->nb_tabs++;                                        \

} while (0)

static void tl_init(TabList *l, const int zero, const int realloc)

{

    l->nb_tabs = 0;

    l->zero = zero;

    l->realloc = realloc;

}

static int tl_free(TabList *l)

{

    for (int i = 0; i < l->nb_tabs; i++)

        av_freep(l->tabs[i].tab);

    return 0;

}

static int tl_create(TabList *l)

{

    if (l->realloc) {

        tl_free(l);

        for (int i = 0; i < l->nb_tabs; i++) {

            Tab *t = l->tabs + i;

            *t->tab = l->zero ? av_mallocz(t->size) : av_malloc(t->size);

            if (!*t->tab)

                return AVERROR(ENOMEM);

        }

    }

    return 0;

}

static int tl_zero(TabList *l)

{

    if (l->zero) {

        for (int i = 0; i < l->nb_tabs; i++) {

            Tab *t = l->tabs + i;

            memset(*t->tab, 0, t->size);

        }

    }

    return 0;

}

static void ctu_nz_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCSPS *sps   = fc->ps.sps;

    const VVCPPS *pps   = fc->ps.pps;

    const int ctu_size  = sps ? (1 << sps->ctb_log2_size_y << sps->ctb_log2_size_y) : 0;

    const int ctu_count = pps ? pps->ctb_count : 0;

    const int changed   = fc->tab.sz.ctu_count != ctu_count || fc->tab.sz.ctu_size != ctu_size;

    tl_init(l, 0, changed);

    TL_ADD(cus,     ctu_count);

    TL_ADD(ctus,    ctu_count);

    TL_ADD(deblock, ctu_count);

    TL_ADD(sao,     ctu_count);

    TL_ADD(alf,     ctu_count);

    TL_ADD(slice_idx, ctu_count);

    TL_ADD(coeffs,    ctu_count * ctu_size * VVC_MAX_SAMPLE_ARRAYS);

}

static void min_cb_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCPPS *pps            = fc->ps.pps;

    const int pic_size_in_min_cb = pps ? pps->min_cb_width * pps->min_cb_height : 0;

    const int changed            = fc->tab.sz.pic_size_in_min_cb != pic_size_in_min_cb;

    tl_init(l, 1, changed);

    TL_ADD(imf,  pic_size_in_min_cb);

    for (int i = LUMA; i <= CHROMA; i++)

        TL_ADD(cb_width[i],  pic_size_in_min_cb);   //is_a0_available requires this

}

static void min_cb_nz_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCPPS *pps            = fc->ps.pps;

    const int pic_size_in_min_cb = pps ? pps->min_cb_width * pps->min_cb_height : 0;

    const int changed            = fc->tab.sz.pic_size_in_min_cb != pic_size_in_min_cb;

    tl_init(l, 0, changed);

    TL_ADD(skip, pic_size_in_min_cb);

    TL_ADD(ipm,  pic_size_in_min_cb);

    for (int i = LUMA; i <= CHROMA; i++) {

        TL_ADD(cqt_depth[i], pic_size_in_min_cb);

        TL_ADD(cb_pos_x[i],  pic_size_in_min_cb);

        TL_ADD(cb_pos_y[i],  pic_size_in_min_cb);

        TL_ADD(cb_height[i], pic_size_in_min_cb);

        TL_ADD(cp_mv[i],     pic_size_in_min_cb * MAX_CONTROL_POINTS);

        TL_ADD(cpm[i],       pic_size_in_min_cb);

        TL_ADD(pcmf[i],      pic_size_in_min_cb);

    }

    // For luma, qp can only change at the CU level, so the qp tab size is related to the CU.

    TL_ADD(qp[LUMA], pic_size_in_min_cb);

}

static void min_pu_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCPPS *pps            = fc->ps.pps;

    const int pic_size_in_min_pu = pps ? pps->min_pu_width * pps->min_pu_height : 0;

    const int changed            = fc->tab.sz.pic_size_in_min_pu != pic_size_in_min_pu;

    tl_init(l, 1, changed);

    TL_ADD(iaf, pic_size_in_min_pu);

}

static void min_pu_nz_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCPPS *pps            = fc->ps.pps;

    const int pic_size_in_min_pu = pps ? pps->min_pu_width * pps->min_pu_height : 0;

    const int changed            = fc->tab.sz.pic_size_in_min_pu != pic_size_in_min_pu;

    tl_init(l, 0, changed);

    TL_ADD(msf, pic_size_in_min_pu);

    TL_ADD(mmi, pic_size_in_min_pu);

    TL_ADD(mvf, pic_size_in_min_pu);

}

static void min_tu_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCPPS *pps            = fc->ps.pps;

    const int pic_size_in_min_tu = pps ? pps->min_tu_width * pps->min_tu_height : 0;

    const int changed            = fc->tab.sz.pic_size_in_min_tu != pic_size_in_min_tu;

    tl_init(l, 1, changed);

    TL_ADD(tu_joint_cbcr_residual_flag, pic_size_in_min_tu);

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

        TL_ADD(tu_coded_flag[i], pic_size_in_min_tu);

        for (int vertical = 0; vertical < 2; vertical++)

            TL_ADD(bs[vertical][i], pic_size_in_min_tu);

    }

}

static void min_tu_nz_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCPPS *pps            = fc->ps.pps;

    const int pic_size_in_min_tu = pps ? pps->min_tu_width * pps->min_tu_height : 0;

    const int changed            = fc->tab.sz.pic_size_in_min_tu != pic_size_in_min_tu;

    tl_init(l, 0, changed);

    for (int i = LUMA; i <= CHROMA; i++) {

        TL_ADD(tb_width[i],  pic_size_in_min_tu);

        TL_ADD(tb_height[i], pic_size_in_min_tu);

    }

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

        TL_ADD(max_len_p[vertical], pic_size_in_min_tu);

        TL_ADD(max_len_q[vertical], pic_size_in_min_tu);

    }

    // For chroma, considering the joint CbCr, the QP tab size is related to the TU.

    for (int i = CB; i < VVC_MAX_SAMPLE_ARRAYS; i++)

        TL_ADD(qp[i], pic_size_in_min_tu);

}

static void pixel_buffer_nz_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCSPS *sps    = fc->ps.sps;

    const VVCPPS *pps    = fc->ps.pps;

    const int width      = pps ? pps->width : 0;

    const int height     = pps ? pps->height : 0;

    const int ctu_width  = pps ? pps->ctb_width : 0;

    const int ctu_height = pps ? pps->ctb_height : 0;

    const int chroma_idc = sps ? sps->r->sps_chroma_format_idc : 0;

    const int ps         = sps ? sps->pixel_shift : 0;

    const int c_end      = chroma_idc ? VVC_MAX_SAMPLE_ARRAYS : 1;

    const int changed    = fc->tab.sz.chroma_format_idc != chroma_idc ||

        fc->tab.sz.width != width || fc->tab.sz.height != height ||

        fc->tab.sz.ctu_width != ctu_width || fc->tab.sz.ctu_height != ctu_height ||

        fc->tab.sz.pixel_shift != ps;

    tl_init(l, 0, changed);

    for (int c_idx = 0; c_idx < c_end; c_idx++) {

        const int w = width  >> (sps ? sps->hshift[c_idx] : 0);

        const int h = height >> (sps ? sps->vshift[c_idx] : 0);

        TL_ADD(sao_pixel_buffer_h[c_idx], (w * 2 * ctu_height) << ps);

        TL_ADD(sao_pixel_buffer_v[c_idx], (h * 2 * ctu_width)  << ps);

    }

    for (int c_idx = 0; c_idx < c_end; c_idx++) {

        const int w = width  >> (sps ? sps->hshift[c_idx] : 0);

        const int h = height >> (sps ? sps->vshift[c_idx] : 0);

        const int border_pixels = c_idx ? ALF_BORDER_CHROMA : ALF_BORDER_LUMA;

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

            TL_ADD(alf_pixel_buffer_h[c_idx][i], (w * border_pixels * ctu_height) << ps);

            TL_ADD(alf_pixel_buffer_v[c_idx][i], h * ALF_PADDING_SIZE * ctu_width);

        }

    }

}

static void msm_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCPPS *pps = fc->ps.pps;

    const int w32     = pps ? AV_CEIL_RSHIFT(pps->width,  5) : 0;

    const int h32     = pps ? AV_CEIL_RSHIFT(pps->height, 5) : 0;

    const int changed = AV_CEIL_RSHIFT(fc->tab.sz.width,  5) != w32 ||

        AV_CEIL_RSHIFT(fc->tab.sz.height,  5) != h32;

    tl_init(l, 1, changed);

    for (int i = LUMA; i <= CHROMA; i++)

        TL_ADD(msm[i], w32 * h32);

}

static void ispmf_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCPPS *pps = fc->ps.pps;

    const int w64     = pps ? AV_CEIL_RSHIFT(pps->width,  6) : 0;

    const int h64     = pps ? AV_CEIL_RSHIFT(pps->height, 6) : 0;

    const int changed = AV_CEIL_RSHIFT(fc->tab.sz.width,  6) != w64 ||

        AV_CEIL_RSHIFT(fc->tab.sz.height,  6) != h64;

    tl_init(l, 1, changed);

    TL_ADD(ispmf, w64 * h64);

}

static void ibc_tl_init(TabList *l, VVCFrameContext *fc)

{

    const VVCSPS *sps    = fc->ps.sps;

    const VVCPPS *pps    = fc->ps.pps;

    const int ctu_height = pps ? pps->ctb_height : 0;

    const int ctu_size   = sps ? sps->ctb_size_y : 0;

    const int ps         = sps ? sps->pixel_shift : 0;

    const int chroma_idc = sps ? sps->r->sps_chroma_format_idc : 0;

    const int has_ibc    = sps ? sps->r->sps_ibc_enabled_flag : 0;

    const int changed    = fc->tab.sz.chroma_format_idc != chroma_idc ||

        fc->tab.sz.ctu_height != ctu_height ||

        fc->tab.sz.ctu_size != ctu_size ||

        fc->tab.sz.pixel_shift != ps;

    fc->tab.sz.ibc_buffer_width = ctu_size ? 2 * MAX_CTU_SIZE * MAX_CTU_SIZE / ctu_size : 0;

    tl_init(l, has_ibc, changed);

    for (int i = LUMA; i < VVC_MAX_SAMPLE_ARRAYS; i++) {

        const int hs = sps ? sps->hshift[i] : 0;

        const int vs = sps ? sps->vshift[i] : 0;

        TL_ADD(ibc_vir_buf[i], fc->tab.sz.ibc_buffer_width * ctu_size * ctu_height << ps >> hs >> vs);

    }

}

typedef void (*tl_init_fn)(TabList *l, VVCFrameContext *fc);

static int frame_context_for_each_tl(VVCFrameContext *fc, int (*unary_fn)(TabList *l))

{

    const tl_init_fn init[] = {

        ctu_nz_tl_init,

        min_cb_tl_init,

        min_cb_nz_tl_init,

        min_pu_tl_init,

        min_pu_nz_tl_init,

        min_tu_tl_init,

        min_tu_nz_tl_init,

        pixel_buffer_nz_tl_init,

        msm_tl_init,

        ispmf_tl_init,

        ibc_tl_init,

    };

    for (int i = 0; i < FF_ARRAY_ELEMS(init); i++) {

        TabList l;

        int ret;

        init[i](&l, fc);

        ret = unary_fn(&l);

        if (ret < 0)

            return ret;

    }

    return 0;

}

static void free_cus(VVCFrameContext *fc)

{

    if (fc->tab.cus) {

        for (int i = 0; i < fc->tab.sz.ctu_count; i++)

            ff_vvc_ctu_free_cus(fc->tab.cus + i);

    }

}

static void pic_arrays_free(VVCFrameContext *fc)

{

    free_cus(fc);

    frame_context_for_each_tl(fc, tl_free);

    av_refstruct_pool_uninit(&fc->rpl_tab_pool);

    av_refstruct_pool_uninit(&fc->tab_dmvr_mvf_pool);

    memset(&fc->tab.sz, 0, sizeof(fc->tab.sz));

}

static int pic_arrays_init(VVCContext *s, VVCFrameContext *fc)

{

    const VVCSPS *sps            = fc->ps.sps;

    const VVCPPS *pps            = fc->ps.pps;

    const int ctu_count          = pps->ctb_count;

    const int pic_size_in_min_pu = pps->min_pu_width * pps->min_pu_height;

    int ret;

    free_cus(fc);

    ret = frame_context_for_each_tl(fc, tl_create);

    if (ret < 0)

        return ret;

    // for error handling case, we may call free_cus before VVC_TASK_STAGE_INIT, so we need to set cus to 0 here

    memset(fc->tab.cus, 0, sizeof(*fc->tab.cus) * ctu_count);

    memset(fc->tab.slice_idx, -1, sizeof(*fc->tab.slice_idx) * ctu_count);

    if (fc->tab.sz.ctu_count != ctu_count) {

        av_refstruct_pool_uninit(&fc->rpl_tab_pool);

        fc->rpl_tab_pool = av_refstruct_pool_alloc(ctu_count * sizeof(RefPicListTab), 0);

        if (!fc->rpl_tab_pool)

            return AVERROR(ENOMEM);

    }

    if (fc->tab.sz.pic_size_in_min_pu != pic_size_in_min_pu) {

        av_refstruct_pool_uninit(&fc->tab_dmvr_mvf_pool);

        fc->tab_dmvr_mvf_pool = av_refstruct_pool_alloc(

            pic_size_in_min_pu * sizeof(MvField), AV_REFSTRUCT_POOL_FLAG_ZERO_EVERY_TIME);

        if (!fc->tab_dmvr_mvf_pool)

            return AVERROR(ENOMEM);

    }

    fc->tab.sz.ctu_count          = pps->ctb_count;

    fc->tab.sz.ctu_size           = 1 << sps->ctb_log2_size_y << sps->ctb_log2_size_y;

    fc->tab.sz.pic_size_in_min_cb = pps->min_cb_width * pps->min_cb_height;

    fc->tab.sz.pic_size_in_min_pu = pic_size_in_min_pu;

    fc->tab.sz.pic_size_in_min_tu = pps->min_tu_width * pps->min_tu_height;

    fc->tab.sz.width              = pps->width;

    fc->tab.sz.height             = pps->height;

    fc->tab.sz.ctu_width          = pps->ctb_width;

    fc->tab.sz.ctu_height         = pps->ctb_height;

    fc->tab.sz.chroma_format_idc  = sps->r->sps_chroma_format_idc;

    fc->tab.sz.pixel_shift        = sps->pixel_shift;

    return 0;

}

int ff_vvc_per_frame_init(VVCFrameContext *fc)

{

    return frame_context_for_each_tl(fc, tl_zero);

}

static int min_positive(const int idx, const int diff, const int min_diff)

{

    return diff > 0 && (idx < 0 || diff < min_diff);

}

static int max_negtive(const int idx, const int diff, const int max_diff)

{

    return diff < 0 && (idx < 0 || diff > max_diff);

}

typedef int (*smvd_find_fxn)(const int idx, const int diff, const int old_diff);

static int8_t smvd_find(const VVCFrameContext *fc, const SliceContext *sc, int lx, smvd_find_fxn find)

{

    const H266RawSliceHeader *rsh = sc->sh.r;

    const RefPicList *rpl         = sc->rpl + lx;

    const int poc                 = fc->ref->poc;

    int8_t idx                    = -1;

    int old_diff                  = -1;

    for (int i = 0; i < rsh->num_ref_idx_active[lx]; i++) {

        if (!rpl->refs[i].is_lt) {

            int diff = poc - rpl->refs[i].poc;

            if (find(idx, diff, old_diff)) {

                idx = i;

                old_diff = diff;

            }

        }

    }

    return idx;

}

static void smvd_ref_idx(const VVCFrameContext *fc, SliceContext *sc)

{

    VVCSH *sh = &sc->sh;

    if (IS_B(sh->r)) {

        sh->ref_idx_sym[0] = smvd_find(fc, sc, 0, min_positive);

        sh->ref_idx_sym[1] = smvd_find(fc, sc, 1, max_negtive);

        if (sh->ref_idx_sym[0] == -1 || sh->ref_idx_sym[1] == -1) {

            sh->ref_idx_sym[0] = smvd_find(fc, sc, 0, max_negtive);

            sh->ref_idx_sym[1] = smvd_find(fc, sc, 1, min_positive);

        }

    }

}

static void eps_free(SliceContext *slice)

{

    av_freep(&slice->eps);

    slice->nb_eps = 0;

}

static void slices_free(VVCFrameContext *fc)

{

    if (fc->slices) {

        for (int i = 0; i < fc->nb_slices_allocated; i++) {

            SliceContext *slice = fc->slices[i];

            if (slice) {

                av_refstruct_unref(&slice->ref);

                av_refstruct_unref(&slice->sh.r);

                eps_free(slice);

                av_free(slice);

            }

        }

        av_freep(&fc->slices);

    }

    fc->nb_slices_allocated = 0;

    fc->nb_slices = 0;

}

static int slices_realloc(VVCFrameContext *fc)

{

    void *p;

    const int size = (fc->nb_slices_allocated + 1) * 3 / 2;

    if (fc->nb_slices < fc->nb_slices_allocated)

        return 0;

    p = av_realloc_array(fc->slices, size, sizeof(*fc->slices));

    if (!p)

        return AVERROR(ENOMEM);

    fc->slices = p;

    for (int i = fc->nb_slices_allocated; i < size; i++) {

        fc->slices[i] = av_mallocz(sizeof(*fc->slices[0]));

        if (!fc->slices[i]) {

            fc->nb_slices_allocated = i;

            return AVERROR(ENOMEM);

        }

        fc->slices[i]->slice_idx = i;

    }

    fc->nb_slices_allocated = size;

    return 0;

}

static int get_ep_size(const H266RawSliceHeader *rsh, const GetByteContext *gb,

                       const H2645NAL *nal, const int header_size, const int ep_index)

{

    int size;

    if (ep_index < rsh->num_entry_points) {

        int skipped = 0;

        int64_t start = bytestream2_tell(gb);

        int64_t end = start + rsh->sh_entry_point_offset_minus1[ep_index] + 1;

        while (skipped < nal->skipped_bytes && nal->skipped_bytes_pos[skipped] <= start + header_size) {

            skipped++;

        }

        while (skipped < nal->skipped_bytes && nal->skipped_bytes_pos[skipped] <= end + header_size) {

            end--;

            skipped++;

        }

        size = end - start;

        size = av_clip(size, 0, bytestream2_get_bytes_left(gb));

    } else {

        size = bytestream2_get_bytes_left(gb);

    }

    return size;

}

static int ep_init_cabac_decoder(EntryPoint *ep, GetByteContext *gb, const int size)

{

    int ret;

    av_assert0(size <= bytestream2_get_bytes_left(gb));

    ret = ff_init_cabac_decoder(&ep->cc, gb->buffer, size);

    if (ret < 0)

        return ret;

    bytestream2_skipu(gb, size);

    return 0;

}

static int ep_init(EntryPoint *ep, const int ctu_addr, const int ctu_end,

                   GetByteContext *gb, const int size)

{

    const int ret = ep_init_cabac_decoder(ep, gb, size);

    if (ret < 0)

        return ret;

    ep->ctu_start = ctu_addr;

    ep->ctu_end   = ctu_end;

    for (int c_idx = LUMA; c_idx <= CR; c_idx++)

        ep->pp[c_idx].size = 0;

    return 0;

}

static int slice_init_entry_points(SliceContext *sc,

    VVCFrameContext *fc, const H2645NAL *nal, const CodedBitstreamUnit *unit)

{

    const VVCSH *sh           = &sc->sh;

    const H266RawSlice *slice = unit->content_ref;

    int nb_eps                = sh->r->num_entry_points + 1;

    int ctu_addr              = 0;

    GetByteContext gb;

    int ret;

    if (sc->nb_eps != nb_eps) {

        eps_free(sc);

        sc->eps = av_calloc(nb_eps, sizeof(*sc->eps));

        if (!sc->eps)

            return AVERROR(ENOMEM);

        sc->nb_eps = nb_eps;

    }

    bytestream2_init(&gb, slice->data, slice->data_size);

    for (int i = 0; i < sc->nb_eps; i++)

    {

        const int size    = get_ep_size(sc->sh.r, &gb, nal, slice->header_size, i);

        const int ctu_end = (i + 1 == sc->nb_eps ? sh->num_ctus_in_curr_slice : sh->entry_point_start_ctu[i]);

        EntryPoint *ep    = sc->eps + i;

        ret = ep_init(ep, ctu_addr, ctu_end, &gb, size);

        if (ret < 0)

            return ret;

        for (int j = ep->ctu_start; j < ep->ctu_end; j++) {

            const int rs = sc->sh.ctb_addr_in_curr_slice[j];

            fc->tab.slice_idx[rs] = sc->slice_idx;

        }

        if (i + 1 < sc->nb_eps)

            ctu_addr = sh->entry_point_start_ctu[i];

    }

    return 0;

}

static VVCFrameContext* get_frame_context(const VVCContext *s, const VVCFrameContext *fc, const int delta)

{

    const int size = s->nb_fcs;

    const int idx  = (fc - s->fcs + delta  + size) % size;

    return s->fcs + idx;

}

static int ref_frame(VVCFrame *dst, const VVCFrame *src)

{

    int ret;

    ret = av_frame_ref(dst->frame, src->frame);

    if (ret < 0)

        return ret;

    av_refstruct_replace(&dst->sps, src->sps);

    av_refstruct_replace(&dst->pps, src->pps);

    if (src->needs_fg) {

        ret = av_frame_ref(dst->frame_grain, src->frame_grain);

        if (ret < 0)

            return ret;

        dst->needs_fg = src->needs_fg;

    }

    av_refstruct_replace(&dst->progress, src->progress);

    av_refstruct_replace(&dst->tab_dmvr_mvf, src->tab_dmvr_mvf);

    av_refstruct_replace(&dst->rpl_tab, src->rpl_tab);

    av_refstruct_replace(&dst->rpl, src->rpl);

    av_refstruct_replace(&dst->hwaccel_picture_private,

                          src->hwaccel_picture_private);

    dst->nb_rpl_elems = src->nb_rpl_elems;

    dst->poc = src->poc;

    dst->ctb_count = src->ctb_count;

    dst->scaling_win = src->scaling_win;

    dst->ref_width   = src->ref_width;

    dst->ref_height  = src->ref_height;

    dst->flags = src->flags;

    dst->sequence = src->sequence;

    return 0;

}

static av_cold void frame_context_free(VVCFrameContext *fc)

{

    slices_free(fc);

    av_refstruct_pool_uninit(&fc->tu_pool);

    av_refstruct_pool_uninit(&fc->cu_pool);

    for (int i = 0; i < FF_ARRAY_ELEMS(fc->DPB); i++) {

        ff_vvc_unref_frame(fc, &fc->DPB[i], ~0);

        av_frame_free(&fc->DPB[i].frame);

        av_frame_free(&fc->DPB[i].frame_grain);

    }

    ff_vvc_frame_thread_free(fc);

    pic_arrays_free(fc);

    av_frame_free(&fc->output_frame);

    ff_vvc_frame_ps_free(&fc->ps);

    ff_vvc_sei_reset(&fc->sei);

}

static av_cold int frame_context_init(VVCFrameContext *fc, AVCodecContext *avctx)

{

    fc->log_ctx = avctx;

    fc->output_frame = av_frame_alloc();

    if (!fc->output_frame)

        return AVERROR(ENOMEM);

    for (int j = 0; j < FF_ARRAY_ELEMS(fc->DPB); j++) {

        fc->DPB[j].frame = av_frame_alloc();

        if (!fc->DPB[j].frame)

            return AVERROR(ENOMEM);

        fc->DPB[j].frame_grain = av_frame_alloc();

        if (!fc->DPB[j].frame_grain)

            return AVERROR(ENOMEM);

    }

    fc->cu_pool = av_refstruct_pool_alloc(sizeof(CodingUnit), 0);

    if (!fc->cu_pool)

        return AVERROR(ENOMEM);

    fc->tu_pool = av_refstruct_pool_alloc(sizeof(TransformUnit), 0);

    if (!fc->tu_pool)

        return AVERROR(ENOMEM);

    return 0;

}

static int frame_context_setup(VVCFrameContext *fc, VVCContext *s)

{

    int ret;

    // copy refs from the last frame

    if (s->nb_frames && s->nb_fcs > 1) {

        VVCFrameContext *prev = get_frame_context(s, fc, -1);

        for (int i = 0; i < FF_ARRAY_ELEMS(fc->DPB); i++) {

            ff_vvc_unref_frame(fc, &fc->DPB[i], ~0);

            if (prev->DPB[i].frame->buf[0]) {

                ret = ref_frame(&fc->DPB[i], &prev->DPB[i]);

                if (ret < 0)

                    return ret;

            }

        }

        ret = ff_vvc_sei_replace(&fc->sei, &prev->sei);

        if (ret < 0)

            return ret;

    }

    if (IS_IDR(s)) {

        ff_vvc_clear_refs(fc);

    }

    ret = pic_arrays_init(s, fc);

    if (ret < 0)

        return ret;

    ff_vvc_dsp_init(&fc->vvcdsp, fc->ps.sps->bit_depth);

    ff_videodsp_init(&fc->vdsp, fc->ps.sps->bit_depth);

    return 0;

}

/* SEI does not affect decoding, so we ignore the return value */

static void decode_prefix_sei(VVCFrameContext *fc, VVCContext *s)

{

    CodedBitstreamFragment *frame = &s->current_frame;

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

        const CodedBitstreamUnit *unit = frame->units + i;

        if (unit->type == VVC_PREFIX_SEI_NUT) {

            int ret = ff_vvc_sei_decode(&fc->sei, unit->content_ref, fc);

            if (ret < 0)

                return;

        }

    }

}

static int set_side_data(VVCContext *s, VVCFrameContext *fc)

{

    AVFrame *out = fc->ref->frame;

    return ff_h2645_sei_to_frame(out, &fc->sei.common, AV_CODEC_ID_VVC, s->avctx,

        NULL, fc->ps.sps->bit_depth, fc->ps.sps->bit_depth, fc->ref->poc);

}

static int check_film_grain(VVCContext *s, VVCFrameContext *fc)

{

    int ret;

    fc->ref->needs_fg = (fc->sei.common.film_grain_characteristics &&

        fc->sei.common.film_grain_characteristics->present ||

        fc->sei.common.aom_film_grain.enable) &&

        !(s->avctx->export_side_data & AV_CODEC_EXPORT_DATA_FILM_GRAIN) &&

        !s->avctx->hwaccel;

    if (fc->ref->needs_fg &&

        (fc->sei.common.film_grain_characteristics &&

         fc->sei.common.film_grain_characteristics->present &&

            !ff_h274_film_grain_params_supported(fc->sei.common.film_grain_characteristics->model_id,

                fc->ref->frame->format) ||

            !av_film_grain_params_select(fc->ref->frame))) {

        av_log_once(s->avctx, AV_LOG_WARNING, AV_LOG_DEBUG, &s->film_grain_warning_shown,

            "Unsupported film grain parameters. Ignoring film grain.\n");

        fc->ref->needs_fg = 0;

    }

    if (fc->ref->needs_fg) {

        fc->ref->frame_grain->format = fc->ref->frame->format;

        fc->ref->frame_grain->width  = fc->ref->frame->width;

        fc->ref->frame_grain->height = fc->ref->frame->height;

        ret = ff_thread_get_buffer(s->avctx, fc->ref->frame_grain, 0);

        if (ret < 0)

            return ret;

        return av_frame_copy_props(fc->ref->frame_grain, fc->ref->frame);

    }

    return 0;

}

static int frame_start(VVCContext *s, VVCFrameContext *fc, SliceContext *sc)

{

    const VVCPH *ph                 = &fc->ps.ph;

    const H266RawSliceHeader *rsh   = sc->sh.r;

    int ret;

    // 8.3.1 Decoding process for picture order count

    if (!s->temporal_id && !ph->r->ph_non_ref_pic_flag && !(IS_RASL(s) || IS_RADL(s)))

        s->poc_tid0 = ph->poc;

    decode_prefix_sei(fc, s);

    if ((ret = ff_vvc_set_new_ref(s, fc, &fc->frame)) < 0)

        goto fail;

    ret = set_side_data(s, fc);

    if (ret < 0)

        goto fail;

    ret = check_film_grain(s, fc);

    if (ret < 0)

        goto fail;

    if (!IS_IDR(s))

        ff_vvc_bump_frame(s, fc);

    av_frame_unref(fc->output_frame);

    if ((ret = ff_vvc_output_frame(s, fc, fc->output_frame,rsh->sh_no_output_of_prior_pics_flag, 0)) < 0)

        goto fail;

    if ((ret = ff_vvc_frame_rpl(s, fc, sc)) < 0)

        goto fail;

    if ((ret = ff_vvc_frame_thread_init(fc)) < 0)

        goto fail;

    return 0;

fail:

    if (fc->ref)

        ff_vvc_unref_frame(fc, fc->ref, ~0);

    fc->ref = NULL;

    return ret;

}

static int slice_start(SliceContext *sc, VVCContext *s, VVCFrameContext *fc,

    const CodedBitstreamUnit *unit, const int is_first_slice)

{

    VVCSH *sh = &sc->sh;

    int ret;

    ret = ff_vvc_decode_sh(sh, &fc->ps, unit);

    if (ret < 0)

        return ret;

    if (is_first_slice) {

        ret = frame_start(s, fc, sc);

        if (ret < 0)

            return ret;

    } else if (fc->ref) {

        if (!IS_I(sh->r)) {

            ret = ff_vvc_slice_rpl(s, fc, sc);

            if (ret < 0) {

                av_log(fc->log_ctx, AV_LOG_WARNING,

                       "Error constructing the reference lists for the current slice.\n");

                return ret;

            }

        }

    } else {

        av_log(fc->log_ctx, AV_LOG_ERROR, "First slice in a frame missing.\n");

        return ret;

    }

    if (!IS_I(sh->r))

        smvd_ref_idx(fc, sc);

    return 0;

}

static enum AVPixelFormat get_format(AVCodecContext *avctx, const VVCSPS *sps)

{

#define HWACCEL_MAX CONFIG_VVC_VAAPI_HWACCEL

    enum AVPixelFormat pix_fmts[HWACCEL_MAX + 2], *fmt = pix_fmts;

    switch (sps->pix_fmt) {

    case AV_PIX_FMT_YUV420P:

#if CONFIG_VVC_VAAPI_HWACCEL

        *fmt++ = AV_PIX_FMT_VAAPI;

#endif

        break;

    case AV_PIX_FMT_YUV420P10:

#if CONFIG_VVC_VAAPI_HWACCEL

        *fmt++ = AV_PIX_FMT_VAAPI;

#endif

        break;

    }

    *fmt++ = sps->pix_fmt;

    *fmt = AV_PIX_FMT_NONE;

    return ff_get_format(avctx, pix_fmts);

}

static int export_frame_params(VVCContext *s, const VVCFrameContext *fc)

{

    AVCodecContext *c = s->avctx;

    const VVCSPS *sps = fc->ps.sps;

    const VVCPPS *pps = fc->ps.pps;

    // Reset the format if pix_fmt/w/h change.

    if (c->sw_pix_fmt != sps->pix_fmt || c->coded_width != pps->width || c->coded_height != pps->height) {

        c->coded_width  = pps->width;

        c->coded_height = pps->height;

        c->sw_pix_fmt   = sps->pix_fmt;

        c->pix_fmt      = get_format(c, sps);

        if (c->pix_fmt < 0)

            return AVERROR_INVALIDDATA;

    }

    c->width  = pps->width  - ((pps->r->pps_conf_win_left_offset + pps->r->pps_conf_win_right_offset) << sps->hshift[CHROMA]);

    c->height = pps->height - ((pps->r->pps_conf_win_top_offset + pps->r->pps_conf_win_bottom_offset) << sps->vshift[CHROMA]);

    return 0;

}

static int frame_setup(VVCFrameContext *fc, VVCContext *s)

{

    int ret = ff_vvc_decode_frame_ps(fc, s);

    if (ret < 0)

        return ret;

    ret = frame_context_setup(fc, s);

    if (ret < 0)

        return ret;

    ret = export_frame_params(s, fc);

    if (ret < 0)

        return ret;

    return 0;

}

static int decode_slice(VVCContext *s, VVCFrameContext *fc, AVBufferRef *buf_ref,

                        const H2645NAL *nal, const CodedBitstreamUnit *unit)

{

    int ret;

    SliceContext *sc;

    const int is_first_slice = !fc->nb_slices;

    ret = slices_realloc(fc);

    if (ret < 0)

        return ret;

    sc = fc->slices[fc->nb_slices];

    av_refstruct_replace(&sc->ref, unit->content_ref);

    s->vcl_unit_type = nal->type;

    if (is_first_slice) {

        ret = frame_setup(fc, s);

        if (ret < 0)

            return ret;

    }

    ret = slice_start(sc, s, fc, unit, is_first_slice);

    if (ret < 0)

        return ret;

    ret = slice_init_entry_points(sc, fc, nal, unit);

    if (ret < 0)

        return ret;

    if (s->avctx->hwaccel) {

        if (is_first_slice) {

            ret = FF_HW_CALL(s->avctx, start_frame, buf_ref, NULL, 0);

            if (ret < 0)

                return ret;

        }

        ret = FF_HW_CALL(s->avctx, decode_slice,

                         nal->raw_data, nal->raw_size);

        if (ret < 0)

            return ret;

    }

    fc->nb_slices++;

    return 0;

}

static int decode_nal_unit(VVCContext *s, VVCFrameContext *fc, AVBufferRef *buf_ref,

                           const H2645NAL *nal, const CodedBitstreamUnit *unit)

{

    int  ret;

    s->temporal_id = nal->temporal_id;

    if (nal->nuh_layer_id > 0) {

        avpriv_report_missing_feature(fc->log_ctx,

                "Decoding of multilayer bitstreams");

        return AVERROR_PATCHWELCOME;

    }

    switch (unit->type) {

    case VVC_VPS_NUT:

    case VVC_SPS_NUT:

    case VVC_PPS_NUT:

        /* vps, sps, sps cached by s->cbc */

        break;

    case VVC_TRAIL_NUT:

    case VVC_STSA_NUT:

    case VVC_RADL_NUT:

    case VVC_RASL_NUT:

    case VVC_IDR_W_RADL:

    case VVC_IDR_N_LP:

    case VVC_CRA_NUT:

    case VVC_GDR_NUT:

        ret = decode_slice(s, fc, buf_ref, nal, unit);

        if (ret < 0)

            return ret;

        break;