static int decode_nal_unit(HEVCContext *s, const uint8_t *nal, int length)
{
    HEVCLocalContext *lc = &s->HEVClc;
    GetBitContext *gb    = &lc->gb;
    int ctb_addr_ts, ret;

    ret = init_get_bits8(gb, nal, length);
    if (ret < 0)
        return ret;

    ret = hls_nal_unit(s);
    if (ret < 0) {
        av_log(s->avctx, AV_LOG_ERROR, "Invalid NAL unit %d, skipping.\n",
               s->nal_unit_type);
        if (s->avctx->err_recognition & AV_EF_EXPLODE)
            return ret;
        return 0;
    } else if (!ret)
        return 0;

    switch (s->nal_unit_type) {
    case NAL_VPS:
        ret = ff_hevc_decode_nal_vps(s);
        if (ret < 0)
            return ret;
        break;
    case NAL_SPS:
        ret = ff_hevc_decode_nal_sps(s);
        if (ret < 0)
            return ret;
        break;
    case NAL_PPS:
        ret = ff_hevc_decode_nal_pps(s);
        if (ret < 0)
            return ret;
        break;
    case NAL_SEI_PREFIX:
    case NAL_SEI_SUFFIX:
        ret = ff_hevc_decode_nal_sei(s);
        if (ret < 0)
            return ret;
        break;
    case NAL_TRAIL_R:
    case NAL_TRAIL_N:
    case NAL_TSA_N:
    case NAL_TSA_R:
    case NAL_STSA_N:
    case NAL_STSA_R:
    case NAL_BLA_W_LP:
    case NAL_BLA_W_RADL:
    case NAL_BLA_N_LP:
    case NAL_IDR_W_RADL:
    case NAL_IDR_N_LP:
    case NAL_CRA_NUT:
    case NAL_RADL_N:
    case NAL_RADL_R:
    case NAL_RASL_N:
    case NAL_RASL_R:
        ret = hls_slice_header(s);
        if (ret < 0)
            return ret;

        if (s->max_ra == INT_MAX) {
            if (s->nal_unit_type == NAL_CRA_NUT || IS_BLA(s)) {
                s->max_ra = s->poc;
            } else {
                if (IS_IDR(s))
                    s->max_ra = INT_MIN;
            }
        }

        if ((s->nal_unit_type == NAL_RASL_R || s->nal_unit_type == NAL_RASL_N) &&
            s->poc <= s->max_ra) {
            s->is_decoded = 0;
            break;
        } else {
            if (s->nal_unit_type == NAL_RASL_R && s->poc > s->max_ra)
                s->max_ra = INT_MIN;
        }

        if (s->sh.first_slice_in_pic_flag) {
            ret = hevc_frame_start(s);
            if (ret < 0)
                return ret;
        } else if (!s->ref) {
            av_log(s->avctx, AV_LOG_ERROR, "First slice in a frame missing.\n");
            return AVERROR_INVALIDDATA;
        }

        if (s->nal_unit_type != s->first_nal_type) {
            av_log(s->avctx, AV_LOG_ERROR,
                   "Non-matching NAL types of the VCL NALUs: %d %d\n",
                   s->first_nal_type, s->nal_unit_type);
            return AVERROR_INVALIDDATA;
        }

        if (!s->sh.dependent_slice_segment_flag &&
            s->sh.slice_type != I_SLICE) {
            ret = ff_hevc_slice_rpl(s);
            if (ret < 0) {
                av_log(s->avctx, AV_LOG_WARNING,
                       "Error constructing the reference lists for the current slice.\n");
                if (s->avctx->err_recognition & AV_EF_EXPLODE)
                    return ret;
            }
        }

        ctb_addr_ts = hls_slice_data(s);
        if (ctb_addr_ts >= (s->sps->ctb_width * s->sps->ctb_height)) {
            s->is_decoded = 1;
            if ((s->pps->transquant_bypass_enable_flag ||
                 (s->sps->pcm.loop_filter_disable_flag && s->sps->pcm_enabled_flag)) &&
                s->sps->sao_enabled)
                restore_tqb_pixels(s);
        }

        if (ctb_addr_ts < 0)
            return ctb_addr_ts;
        break;
    case NAL_EOS_NUT:
    case NAL_EOB_NUT:
        s->seq_decode = (s->seq_decode + 1) & 0xff;
        s->max_ra     = INT_MAX;
        break;
    case NAL_AUD:
    case NAL_FD_NUT:
        break;
    default:
        av_log(s->avctx, AV_LOG_INFO,
               "Skipping NAL unit %d\n", s->nal_unit_type);
    }

    return 0;
}
static int decode_nal_unit(HEVCContext *s, const uint8_t *nal, int length)
{
    HEVCLocalContext *lc = &s->HEVClc;
    GetBitContext *gb    = &lc->gb;
    int ctb_addr_ts, ret;

    ret = init_get_bits8(gb, nal, length);
    if (ret < 0)
        return ret;

    ret = hls_nal_unit(s);
    if (ret < 0) {
        av_log(s->avctx, AV_LOG_ERROR, "Invalid NAL unit %d, skipping.\n",
               s->nal_unit_type);
        if (s->avctx->err_recognition & AV_EF_EXPLODE)
            return ret;
        return 0;
    } else if (!ret)
        return 0;

    switch (s->nal_unit_type) {
    case NAL_VPS:
        ret = ff_hevc_decode_nal_vps(s);
        if (ret < 0)
            return ret;
        break;
    case NAL_SPS:
        ret = ff_hevc_decode_nal_sps(s);
        if (ret < 0)
            return ret;
        break;
    case NAL_PPS:
        ret = ff_hevc_decode_nal_pps(s);
        if (ret < 0)
            return ret;
        break;
    case NAL_SEI_PREFIX:
    case NAL_SEI_SUFFIX:
        ret = ff_hevc_decode_nal_sei(s);
        if (ret < 0)
            return ret;
        break;
    case NAL_TRAIL_R:
    case NAL_TRAIL_N:
    case NAL_TSA_N:
    case NAL_TSA_R:
    case NAL_STSA_N:
    case NAL_STSA_R:
    case NAL_BLA_W_LP:
    case NAL_BLA_W_RADL:
    case NAL_BLA_N_LP:
    case NAL_IDR_W_RADL:
    case NAL_IDR_N_LP:
    case NAL_CRA_NUT:
    case NAL_RADL_N:
    case NAL_RADL_R:
    case NAL_RASL_N:
    case NAL_RASL_R:
        ret = hls_slice_header(s);
        if (ret < 0)
            return ret;

        if (s->max_ra == INT_MAX) {
            if (s->nal_unit_type == NAL_CRA_NUT || IS_BLA(s)) {
                s->max_ra = s->poc;
            } else {
                if (IS_IDR(s))
                    s->max_ra = INT_MIN;
            }
        }

        if ((s->nal_unit_type == NAL_RASL_R || s->nal_unit_type == NAL_RASL_N) &&
            s->poc <= s->max_ra) {
            s->is_decoded = 0;
            break;
        } else {
            if (s->nal_unit_type == NAL_RASL_R && s->poc > s->max_ra)
                s->max_ra = INT_MIN;
        }

        if (s->sh.first_slice_in_pic_flag) {
            ret = hevc_frame_start(s);
            if (ret < 0)
                return ret;
        } else if (!s->ref) {
            av_log(s->avctx, AV_LOG_ERROR, "First slice in a frame missing.\n");
            return AVERROR_INVALIDDATA;
        }

        if (s->nal_unit_type != s->first_nal_type) {
            av_log(s->avctx, AV_LOG_ERROR,
                   "Non-matching NAL types of the VCL NALUs: %d %d\n",
                   s->first_nal_type, s->nal_unit_type);
            return AVERROR_INVALIDDATA;
        }

        if (!s->sh.dependent_slice_segment_flag &&
            s->sh.slice_type != I_SLICE) {
            ret = ff_hevc_slice_rpl(s);
            if (ret < 0) {
                av_log(s->avctx, AV_LOG_WARNING,
                       "Error constructing the reference lists for the current slice.\n");
                if (s->avctx->err_recognition & AV_EF_EXPLODE)
                    return ret;
            }
        }

        ctb_addr_ts = hls_slice_data(s);
        if (ctb_addr_ts >= (s->sps->ctb_width * s->sps->ctb_height)) {
            s->is_decoded = 1;
            if ((s->pps->transquant_bypass_enable_flag ||
                 (s->sps->pcm.loop_filter_disable_flag && s->sps->pcm_enabled_flag)) &&
                s->sps->sao_enabled)
                restore_tqb_pixels(s);
        }

        if (ctb_addr_ts < 0)
            return ctb_addr_ts;
        break;
    case NAL_EOS_NUT:
    case NAL_EOB_NUT:
        s->seq_decode = (s->seq_decode + 1) & 0xff;
        s->max_ra     = INT_MAX;
        break;
    case NAL_AUD:
    case NAL_FD_NUT:
        break;
    default:
        av_log(s->avctx, AV_LOG_INFO,
               "Skipping NAL unit %d\n", s->nal_unit_type);
    }

    return 0;
}