/*

 * HEVC video decoder

 *

 * Copyright (C) 2012 - 2013 Guillaume Martres

 * Copyright (C) 2012 - 2013 Gildas Cocherel

 *

 * 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 "libavutil/container_fifo.h"

#include "libavutil/mem.h"

#include "libavutil/stereo3d.h"

#include "decode.h"

#include "hevc.h"

#include "hevcdec.h"

#include "progressframe.h"

#include "thread.h"

#include "libavutil/refstruct.h"

void ff_hevc_unref_frame(HEVCFrame *frame, int flags)

{

    frame->flags &= ~flags;

    if (!(frame->flags & ~HEVC_FRAME_FLAG_CORRUPT))

        frame->flags = 0;

    if (!frame->flags) {

        ff_progress_frame_unref(&frame->tf);

        av_frame_unref(frame->frame_grain);

        frame->needs_fg = 0;

        av_refstruct_unref(&frame->pps);

        av_refstruct_unref(&frame->tab_mvf);

        av_refstruct_unref(&frame->rpl);

        frame->nb_rpl_elems = 0;

        av_refstruct_unref(&frame->rpl_tab);

        frame->refPicList = NULL;

        av_refstruct_unref(&frame->hwaccel_picture_private);

    }

}

const RefPicList *ff_hevc_get_ref_list(const HEVCFrame *ref, int x0, int y0)

{

    const HEVCSPS *sps = ref->pps->sps;

    int x_cb         = x0 >> sps->log2_ctb_size;

    int y_cb         = y0 >> sps->log2_ctb_size;

    int pic_width_cb = sps->ctb_width;

    int ctb_addr_ts  = ref->pps->ctb_addr_rs_to_ts[y_cb * pic_width_cb + x_cb];

    return &ref->rpl_tab[ctb_addr_ts]->refPicList[0];

}

void ff_hevc_clear_refs(HEVCLayerContext *l)

{

    int i;

    for (i = 0; i < FF_ARRAY_ELEMS(l->DPB); i++)

        ff_hevc_unref_frame(&l->DPB[i],

                            HEVC_FRAME_FLAG_SHORT_REF |

                            HEVC_FRAME_FLAG_LONG_REF);

}

void ff_hevc_flush_dpb(HEVCContext *s)

{

    for (int layer = 0; layer < FF_ARRAY_ELEMS(s->layers); layer++) {

        HEVCLayerContext *l = &s->layers[layer];

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

            ff_hevc_unref_frame(&l->DPB[i], ~0);

    }

}

static int replace_alpha_plane(AVFrame *alpha, AVFrame *base)

{

    AVBufferRef *base_a = av_frame_get_plane_buffer(base, 3);

    uintptr_t data = (uintptr_t)alpha->data[0];

    int ret;

    for (int i = 0; i < FF_ARRAY_ELEMS(alpha->buf) && alpha->buf[i]; i++) {

        AVBufferRef *buf = alpha->buf[i];

        uintptr_t buf_begin = (uintptr_t)buf->data;

        if (data >=  buf_begin && data < buf_begin + buf->size) {

            ret = av_buffer_replace(&alpha->buf[i], base_a);

            if (ret < 0)

                return ret;

            alpha->linesize[0] = base->linesize[3];

            alpha->data[0] = base->data[3];

            return 0;

        }

    }

    return AVERROR_BUG;

}

static HEVCFrame *alloc_frame(HEVCContext *s, HEVCLayerContext *l)

{

    const HEVCVPS *vps = l->sps->vps;

    const int  view_id = vps->view_id[s->cur_layer];

    int i, j, ret;

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

        HEVCFrame *frame = &l->DPB[i];

        if (frame->f)

            continue;

        ret = ff_progress_frame_alloc(s->avctx, &frame->tf);

        if (ret < 0)

            return NULL;

        // Add LCEVC SEI metadata here, as it's needed in get_buffer()

        if (s->sei.common.lcevc.info) {

            HEVCSEILCEVC *lcevc = &s->sei.common.lcevc;

            ret = ff_frame_new_side_data_from_buf(s->avctx, frame->tf.f,

                                                  AV_FRAME_DATA_LCEVC, &lcevc->info);

            if (ret < 0)

                goto fail;

        }

        // add view ID side data if it's nontrivial

        if (!ff_hevc_is_alpha_video(s) && (vps->nb_layers > 1 || view_id)) {

            HEVCSEITDRDI *tdrdi = &s->sei.tdrdi;

            AVFrameSideData *sd = av_frame_side_data_new(&frame->f->side_data,

                                                         &frame->f->nb_side_data,

                                                         AV_FRAME_DATA_VIEW_ID,

                                                         sizeof(int), 0);

            if (!sd)

                goto fail;

            *(int*)sd->data = view_id;

            if (tdrdi->num_ref_displays) {

                AVStereo3D *stereo_3d;

                stereo_3d = av_stereo3d_create_side_data(frame->f);

                if (!stereo_3d)

                    goto fail;

                stereo_3d->type = AV_STEREO3D_FRAMESEQUENCE;

                if (tdrdi->left_view_id[0] == view_id)

                    stereo_3d->view = AV_STEREO3D_VIEW_LEFT;

                else if (tdrdi->right_view_id[0] == view_id)

                    stereo_3d->view = AV_STEREO3D_VIEW_RIGHT;

                else

                    stereo_3d->view = AV_STEREO3D_VIEW_UNSPEC;

            }

        }

        ret = ff_thread_get_buffer(s->avctx, frame->f, AV_GET_BUFFER_FLAG_REF);

        if (ret < 0)

            goto fail;

        frame->rpl = av_refstruct_allocz(s->pkt.nb_nals * sizeof(*frame->rpl));

        if (!frame->rpl)

            goto fail;

        frame->nb_rpl_elems = s->pkt.nb_nals;

        frame->tab_mvf = av_refstruct_pool_get(l->tab_mvf_pool);

        if (!frame->tab_mvf)

            goto fail;

        frame->rpl_tab = av_refstruct_pool_get(l->rpl_tab_pool);

        if (!frame->rpl_tab)

            goto fail;

        frame->ctb_count = l->sps->ctb_width * l->sps->ctb_height;

        for (j = 0; j < frame->ctb_count; j++)

            frame->rpl_tab[j] = frame->rpl;

        if (s->sei.picture_timing.picture_struct == AV_PICTURE_STRUCTURE_TOP_FIELD)

            frame->f->flags |= AV_FRAME_FLAG_TOP_FIELD_FIRST;

        if ((s->sei.picture_timing.picture_struct == AV_PICTURE_STRUCTURE_TOP_FIELD) ||

            (s->sei.picture_timing.picture_struct == AV_PICTURE_STRUCTURE_BOTTOM_FIELD))

            frame->f->flags |= AV_FRAME_FLAG_INTERLACED;

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

        if (ret < 0)

            goto fail;

        frame->pps = av_refstruct_ref_c(s->pps);

        if (l != &s->layers[0] && ff_hevc_is_alpha_video(s)) {

            AVFrame *alpha = frame->f;

            AVFrame *base = s->layers[0].cur_frame->f;

            ret = replace_alpha_plane(alpha, base);

            if (ret < 0)

                goto fail;

        }

        return frame;

fail:

        ff_hevc_unref_frame(frame, ~0);

        return NULL;

    }

    av_log(s->avctx, AV_LOG_ERROR, "Error allocating frame, DPB full.\n");

    return NULL;

}

int ff_hevc_set_new_ref(HEVCContext *s, HEVCLayerContext *l, int poc)

{

    HEVCFrame *ref;

    int i;

    int no_output;

    /* check that this POC doesn't already exist */

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

        HEVCFrame *frame = &l->DPB[i];

        if (frame->f && frame->poc == poc) {

            av_log(s->avctx, AV_LOG_ERROR, "Duplicate POC in a sequence: %d.\n",

                   poc);

            return AVERROR_INVALIDDATA;

        }

    }

    ref = alloc_frame(s, l);

    if (!ref)

        return AVERROR(ENOMEM);

    s->cur_frame = ref;

    l->cur_frame = ref;

    s->collocated_ref = NULL;

    ref->base_layer_frame = (l != &s->layers[0] && s->layers[0].cur_frame) ?

                            s->layers[0].cur_frame - s->layers[0].DPB : -1;

    no_output = !IS_IRAP(s) && (s->poc < s->recovery_poc) &&

                !(s->avctx->flags & AV_CODEC_FLAG_OUTPUT_CORRUPT) &&

                !(s->avctx->flags2 & AV_CODEC_FLAG2_SHOW_ALL);

    if (s->sh.pic_output_flag && !no_output)

        ref->flags = HEVC_FRAME_FLAG_OUTPUT | HEVC_FRAME_FLAG_SHORT_REF;

    else

        ref->flags = HEVC_FRAME_FLAG_SHORT_REF;

    ref->poc      = poc;

    ref->f->crop_left   = l->sps->output_window.left_offset;

    ref->f->crop_right  = l->sps->output_window.right_offset;

    ref->f->crop_top    = l->sps->output_window.top_offset;

    ref->f->crop_bottom = l->sps->output_window.bottom_offset;

    return 0;

}

static void unref_missing_refs(HEVCLayerContext *l)

{

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

         HEVCFrame *frame = &l->DPB[i];

         if (frame->flags & HEVC_FRAME_FLAG_UNAVAILABLE) {

             ff_hevc_unref_frame(frame, ~0);

         }

    }

}

int ff_hevc_output_frames(HEVCContext *s,

                          unsigned layers_active_decode, unsigned layers_active_output,

                          unsigned max_output, unsigned max_dpb, int discard)

{

    while (1) {

        int nb_dpb[HEVC_VPS_MAX_LAYERS] = { 0 };

        int nb_output = 0;

        int min_poc   = INT_MAX;

        int min_layer = -1;

        int min_idx, ret = 0;

        for (int layer = 0; layer < FF_ARRAY_ELEMS(s->layers); layer++) {

            HEVCLayerContext *l = &s->layers[layer];

            if (!(layers_active_decode & (1 << layer)))

                continue;

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

                HEVCFrame *frame = &l->DPB[i];

                if (frame->flags & HEVC_FRAME_FLAG_OUTPUT) {

                    // nb_output counts AUs with an output-pending frame

                    // in at least one layer

                    if (!(frame->base_layer_frame >= 0 &&

                          (s->layers[0].DPB[frame->base_layer_frame].flags & HEVC_FRAME_FLAG_OUTPUT)))

                        nb_output++;

                    if (min_layer < 0 || frame->poc < min_poc) {

                        min_poc = frame->poc;

                        min_idx = i;

                        min_layer = layer;

                    }

                }

                nb_dpb[layer] += !!frame->flags;

            }

        }

        if (nb_output > max_output ||

            (nb_output &&

             (nb_dpb[0] > max_dpb || nb_dpb[1] > max_dpb))) {

            HEVCFrame *frame = &s->layers[min_layer].DPB[min_idx];

            AVFrame *f = frame->needs_fg ? frame->frame_grain : frame->f;

            int output = !discard && (layers_active_output & (1 << min_layer));

            if (output) {

                if (frame->flags & HEVC_FRAME_FLAG_CORRUPT)

                    f->flags |= AV_FRAME_FLAG_CORRUPT;

                f->pkt_dts = s->pkt_dts;

                ret = av_container_fifo_write(s->output_fifo, f, AV_CONTAINER_FIFO_FLAG_REF);

            }

            ff_hevc_unref_frame(frame, HEVC_FRAME_FLAG_OUTPUT);

            if (ret < 0)

                return ret;

            av_log(s->avctx, AV_LOG_DEBUG, "%s frame with POC %d/%d.\n",

                   output ? "Output" : "Discarded", min_layer, frame->poc);

            continue;

        }

        return 0;

    }

}

static int init_slice_rpl(HEVCContext *s)

{

    HEVCFrame *frame = s->cur_frame;

    int ctb_count    = frame->ctb_count;

    int ctb_addr_ts  = s->pps->ctb_addr_rs_to_ts[s->sh.slice_segment_addr];

    int i;

    if (s->slice_idx >= frame->nb_rpl_elems)

        return AVERROR_INVALIDDATA;

    for (i = ctb_addr_ts; i < ctb_count; i++)

        frame->rpl_tab[i] = frame->rpl + s->slice_idx;

    frame->refPicList = (RefPicList *)frame->rpl_tab[ctb_addr_ts];

    return 0;

}

int ff_hevc_slice_rpl(HEVCContext *s)

{

    SliceHeader *sh = &s->sh;

    uint8_t nb_list = sh->slice_type == HEVC_SLICE_B ? 2 : 1;

    uint8_t list_idx;

    int i, j, ret;

    ret = init_slice_rpl(s);

    if (ret < 0)

        return ret;

    if (!(s->rps[ST_CURR_BEF].nb_refs + s->rps[ST_CURR_AFT].nb_refs +

          s->rps[LT_CURR].nb_refs +

          s->rps[INTER_LAYER0].nb_refs + s->rps[INTER_LAYER1].nb_refs) &&

        !s->pps->pps_curr_pic_ref_enabled_flag) {

        av_log(s->avctx, AV_LOG_ERROR, "Zero refs in the frame RPS.\n");

        return AVERROR_INVALIDDATA;

    }

    for (list_idx = 0; list_idx < nb_list; list_idx++) {

        RefPicList  rpl_tmp = { { 0 } };

        RefPicList *rpl     = &s->cur_frame->refPicList[list_idx];

        /* The order of the elements is

         * ST_CURR_BEF - INTER_LAYER0 - ST_CURR_AFT - LT_CURR - INTER_LAYER1 for the L0 and

         * ST_CURR_AFT - INTER_LAYER1 - ST_CURR_BEF - LT_CURR - INTER_LAYER0 for the L1 */

        int cand_lists[] = { list_idx ? ST_CURR_AFT : ST_CURR_BEF,

                             list_idx ? INTER_LAYER1 : INTER_LAYER0,

                             list_idx ? ST_CURR_BEF : ST_CURR_AFT,

                             LT_CURR,

                             list_idx ? INTER_LAYER0 : INTER_LAYER1

        };

        /* concatenate the candidate lists for the current frame */

        while (rpl_tmp.nb_refs < sh->nb_refs[list_idx]) {

            for (i = 0; i < FF_ARRAY_ELEMS(cand_lists); i++) {

                RefPicList *rps = &s->rps[cand_lists[i]];

                for (j = 0; j < rps->nb_refs && rpl_tmp.nb_refs < HEVC_MAX_REFS; j++) {

                    rpl_tmp.list[rpl_tmp.nb_refs]       = rps->list[j];

                    rpl_tmp.ref[rpl_tmp.nb_refs]        = rps->ref[j];

                    // multiview inter-layer refs are treated as long-term here,

                    // cf. G.8.1.3

                    rpl_tmp.isLongTerm[rpl_tmp.nb_refs] = cand_lists[i] == LT_CURR ||

                                                          cand_lists[i] == INTER_LAYER0 ||

                                                          cand_lists[i] == INTER_LAYER1;

                    rpl_tmp.nb_refs++;

                }

            }

            // Construct RefPicList0, RefPicList1 (8-8, 8-10)

            if (s->pps->pps_curr_pic_ref_enabled_flag && rpl_tmp.nb_refs < HEVC_MAX_REFS) {

                rpl_tmp.list[rpl_tmp.nb_refs]           = s->cur_frame->poc;

                rpl_tmp.ref[rpl_tmp.nb_refs]            = s->cur_frame;

                rpl_tmp.isLongTerm[rpl_tmp.nb_refs]     = 1;

                rpl_tmp.nb_refs++;

            }

        }

        /* reorder the references if necessary */

        if (sh->rpl_modification_flag[list_idx]) {

            for (i = 0; i < sh->nb_refs[list_idx]; i++) {

                int idx = sh->list_entry_lx[list_idx][i];

                if (idx >= rpl_tmp.nb_refs) {

                    av_log(s->avctx, AV_LOG_ERROR, "Invalid reference index.\n");

                    return AVERROR_INVALIDDATA;

                }

                rpl->list[i]       = rpl_tmp.list[idx];

                rpl->ref[i]        = rpl_tmp.ref[idx];

                rpl->isLongTerm[i] = rpl_tmp.isLongTerm[idx];

                rpl->nb_refs++;

            }

        } else {

            memcpy(rpl, &rpl_tmp, sizeof(*rpl));

            rpl->nb_refs = FFMIN(rpl->nb_refs, sh->nb_refs[list_idx]);

        }

        // 8-9

        if (s->pps->pps_curr_pic_ref_enabled_flag &&

            !sh->rpl_modification_flag[list_idx] &&

            rpl_tmp.nb_refs > sh->nb_refs[L0]) {

            rpl->list[sh->nb_refs[L0] - 1] = s->cur_frame->poc;

            rpl->ref[sh->nb_refs[L0] - 1]  = s->cur_frame;

        }

        if (sh->collocated_list == list_idx &&

            sh->collocated_ref_idx < rpl->nb_refs)

            s->collocated_ref = rpl->ref[sh->collocated_ref_idx];

    }

    return 0;

}

static HEVCFrame *find_ref_idx(HEVCContext *s, HEVCLayerContext *l,

                               int poc, uint8_t use_msb)

{

    int mask = use_msb ? ~0 : (1 << l->sps->log2_max_poc_lsb) - 1;

    int i;

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

        HEVCFrame *ref = &l->DPB[i];

        if (ref->f) {

            if ((ref->poc & mask) == poc && (use_msb || ref->poc != s->poc))

                return ref;

        }

    }

    if (s->nal_unit_type != HEVC_NAL_CRA_NUT && !IS_BLA(s))

        av_log(s->avctx, AV_LOG_ERROR,

               "Could not find ref with POC %d\n", poc);

    return NULL;

}

static void mark_ref(HEVCFrame *frame, int flag)

{

    frame->flags &= ~(HEVC_FRAME_FLAG_LONG_REF | HEVC_FRAME_FLAG_SHORT_REF);

    frame->flags |= flag;

}

static HEVCFrame *generate_missing_ref(HEVCContext *s, HEVCLayerContext *l, int poc)

{

    HEVCFrame *frame;

    int i, y;

    frame = alloc_frame(s, l);

    if (!frame)

        return NULL;

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

        if (!l->sps->pixel_shift) {

            for (i = 0; frame->f->data[i]; i++)

                memset(frame->f->data[i], 1 << (l->sps->bit_depth - 1),

                       frame->f->linesize[i] * AV_CEIL_RSHIFT(l->sps->height, l->sps->vshift[i]));

        } else {

            for (i = 0; frame->f->data[i]; i++)

                for (y = 0; y < (l->sps->height >> l->sps->vshift[i]); y++) {

                    uint8_t *dst = frame->f->data[i] + y * frame->f->linesize[i];

                    AV_WN16(dst, 1 << (l->sps->bit_depth - 1));

                    av_memcpy_backptr(dst + 2, 2, 2*(l->sps->width >> l->sps->hshift[i]) - 2);

                }

        }

    }

    frame->poc      = poc;

    frame->flags    = HEVC_FRAME_FLAG_UNAVAILABLE;

    if (s->avctx->active_thread_type == FF_THREAD_FRAME)

        ff_progress_frame_report(&frame->tf, INT_MAX);

    return frame;

}

/* add a reference with the given poc to the list and mark it as used in DPB */

static int add_candidate_ref(HEVCContext *s, HEVCLayerContext *l,

                             RefPicList *list,

                             int poc, int ref_flag, uint8_t use_msb)

{

    HEVCFrame *ref = find_ref_idx(s, l, poc, use_msb);

    if (ref == s->cur_frame || list->nb_refs >= HEVC_MAX_REFS)

        return AVERROR_INVALIDDATA;

    if (!IS_IRAP(s)) {

        int ref_corrupt = !ref || ref->flags & (HEVC_FRAME_FLAG_CORRUPT |

                                                HEVC_FRAME_FLAG_UNAVAILABLE);

        int recovering = HEVC_IS_RECOVERING(s);

        if (ref_corrupt && !recovering) {

            if (!(s->avctx->flags & AV_CODEC_FLAG_OUTPUT_CORRUPT) &&

                !(s->avctx->flags2 & AV_CODEC_FLAG2_SHOW_ALL))

                return AVERROR_INVALIDDATA;

            s->cur_frame->flags |= HEVC_FRAME_FLAG_CORRUPT;

        }

    }

    if (!ref) {

        ref = generate_missing_ref(s, l, poc);

        if (!ref)

            return AVERROR(ENOMEM);

    }

    list->list[list->nb_refs] = ref->poc;

    list->ref[list->nb_refs]  = ref;

    list->nb_refs++;

    mark_ref(ref, ref_flag);

    return 0;

}

int ff_hevc_frame_rps(HEVCContext *s, HEVCLayerContext *l)

{

    const ShortTermRPS *short_rps = s->sh.short_term_rps;

    const LongTermRPS  *long_rps  = &s->sh.long_term_rps;

    RefPicList               *rps = s->rps;

    int i, ret = 0;

    unref_missing_refs(l);

    /* clear the reference flags on all frames except the current one */

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

        HEVCFrame *frame = &l->DPB[i];

        if (frame == s->cur_frame)

            continue;

        mark_ref(frame, 0);

    }

    for (i = 0; i < NB_RPS_TYPE; i++)

        rps[i].nb_refs = 0;

    if (!short_rps)

        goto inter_layer;

    /* add the short refs */

    for (i = 0; i < short_rps->num_delta_pocs; i++) {

        int poc = s->poc + short_rps->delta_poc[i];

        int list;

        if (!(short_rps->used & (1 << i)))

            list = ST_FOLL;

        else if (i < short_rps->num_negative_pics)

            list = ST_CURR_BEF;

        else

            list = ST_CURR_AFT;

        ret = add_candidate_ref(s, l, &rps[list], poc,

                                HEVC_FRAME_FLAG_SHORT_REF, 1);

        if (ret < 0)

            goto fail;

    }

    /* add the long refs */

    for (i = 0; i < long_rps->nb_refs; i++) {

        int poc  = long_rps->poc[i];

        int list = long_rps->used[i] ? LT_CURR : LT_FOLL;

        ret = add_candidate_ref(s, l, &rps[list], poc,

                                HEVC_FRAME_FLAG_LONG_REF, long_rps->poc_msb_present[i]);

        if (ret < 0)

            goto fail;

    }

inter_layer:

    /* add inter-layer refs */

    if (s->sh.inter_layer_pred) {

        HEVCLayerContext *l0 = &s->layers[0];

        av_assert0(l != l0);

        /* Given the assumption of at most two layers, refPicSet0Flag is

         * always 1, so only RefPicSetInterLayer0 can ever contain a frame. */

        if (l0->cur_frame) {

            // inter-layer refs are treated as short-term here, cf. F.8.1.6

            ret = add_candidate_ref(s, l0, &rps[INTER_LAYER0], l0->cur_frame->poc,

                                    HEVC_FRAME_FLAG_SHORT_REF, 1);

            if (ret < 0)

                goto fail;

        }

    }

fail:

    /* release any frames that are now unused */

    for (i = 0; i < FF_ARRAY_ELEMS(l->DPB); i++)

        ff_hevc_unref_frame(&l->DPB[i], 0);

    return ret;

}

int ff_hevc_frame_nb_refs(const SliceHeader *sh, const HEVCPPS *pps,

                          unsigned layer_idx)

{

    int ret = 0;

    int i;

    const ShortTermRPS     *rps = sh->short_term_rps;

    const LongTermRPS *long_rps = &sh->long_term_rps;

    if (rps) {

        for (i = 0; i < rps->num_negative_pics; i++)

            ret += !!(rps->used & (1 << i));

        for (; i < rps->num_delta_pocs; i++)

            ret += !!(rps->used & (1 << i));

    }

    if (long_rps) {

        for (i = 0; i < long_rps->nb_refs; i++)

            ret += !!long_rps->used[i];

    }

    if (sh->inter_layer_pred) {

        av_assert0(pps->sps->vps->num_direct_ref_layers[layer_idx] < 2);

        ret++;

    }

    if (pps->pps_curr_pic_ref_enabled_flag)

        ret++;

    return ret;

}