diff --git a/libavcodec/vvc/vvcdec.c b/libavcodec/vvc/vvcdec.c
index 8d027af0b9..c85b7fac8c 100644
--- a/libavcodec/vvc/vvcdec.c
+++ b/libavcodec/vvc/vvcdec.c
@@ -24,32 +24,1055 @@
 
 #include "libavcodec/codec_internal.h"
 #include "libavcodec/decode.h"
-#include "libavcodec/golomb.h"
 #include "libavcodec/profiles.h"
 #include "libavcodec/vvc.h"
 
 #include "libavutil/cpu.h"
 
 #include "vvcdec.h"
+#include "vvc_ctu.h"
+#include "vvc_data.h"
+#include "vvc_refs.h"
+#include "vvc_thread.h"
+
+static int vvc_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;
+
+    if ((ret = ff_vvc_set_new_ref(s, fc, &fc->frame)) < 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 void ctb_arrays_free(VVCFrameContext *fc)
+{
+    av_freep(&fc->tab.deblock);
+    av_freep(&fc->tab.sao);
+    av_freep(&fc->tab.alf);
+    av_freep(&fc->tab.slice_idx);
+    av_freep(&fc->tab.coeffs);
+    if (fc->tab.ctus) {
+        for (int i = 0; i < fc->tab.ctu_count; i++)
+            ff_vvc_ctu_free_cus(fc->tab.ctus + i);
+        av_freep(&fc->tab.ctus);
+    }
+    av_buffer_pool_uninit(&fc->rpl_tab_pool);
+}
+
+static int ctb_arrays_init(VVCFrameContext *fc, const int ctu_count, const int ctu_size)
+{
+    if (fc->tab.ctu_count != ctu_count || fc->tab.ctu_size != ctu_size) {
+        ctb_arrays_free(fc);
+        fc->tab.deblock         = av_calloc(ctu_count, sizeof(*fc->tab.deblock));
+        fc->tab.sao             = av_calloc(ctu_count, sizeof(*fc->tab.sao));
+        fc->tab.alf             = av_calloc(ctu_count, sizeof(*fc->tab.alf));
+        fc->tab.ctus            = av_calloc(ctu_count, sizeof(*fc->tab.ctus));
+        fc->tab.slice_idx       = av_malloc(ctu_count * sizeof(*fc->tab.slice_idx));
+        if (!fc->tab.deblock || !fc->tab.sao || !fc->tab.alf || !fc->tab.ctus || !fc->tab.slice_idx )
+            return AVERROR(ENOMEM);
+        fc->tab.coeffs = av_malloc(ctu_count * sizeof(*fc->tab.coeffs) * ctu_size * VVC_MAX_SAMPLE_ARRAYS);
+        if (!fc->tab.coeffs)
+            return AVERROR(ENOMEM);
+        fc->rpl_tab_pool = av_buffer_pool_init(ctu_count * sizeof(RefPicListTab), av_buffer_allocz);
+        if (!fc->rpl_tab_pool)
+            return AVERROR(ENOMEM);
+    } else {
+        memset(fc->tab.deblock, 0, ctu_count * sizeof(*fc->tab.deblock));
+        memset(fc->tab.sao, 0, ctu_count * sizeof(*fc->tab.sao));
+        memset(fc->tab.alf, 0, ctu_count * sizeof(*fc->tab.alf));
+        for (int i = 0; i < fc->tab.ctu_count; i++)
+            ff_vvc_ctu_free_cus(fc->tab.ctus + i);
+        memset(fc->tab.ctus, 0, ctu_count * sizeof(*fc->tab.ctus));
+    }
+    memset(fc->tab.slice_idx, -1, ctu_count * sizeof(*fc->tab.slice_idx));
+
+    return 0;
+}
+
+static void min_cb_arrays_free(VVCFrameContext *fc)
+{
+    for (int i = LUMA; i <= CHROMA; i++) {
+        av_freep(&fc->tab.cb_pos_x[i]);
+        av_freep(&fc->tab.cb_pos_y[i]);
+        av_freep(&fc->tab.cb_width[i]);
+        av_freep(&fc->tab.cb_height[i]);
+        av_freep(&fc->tab.cqt_depth[i]);
+        av_freep(&fc->tab.cpm[i]);
+        av_freep(&fc->tab.cp_mv[i]);
+    }
+
+    av_freep(&fc->tab.ipm);
+    av_freep(&fc->tab.imf);
+    av_freep(&fc->tab.imtf);
+    av_freep(&fc->tab.imm);
+    av_freep(&fc->tab.skip);
+}
+
+static int min_cb_arrays_init(VVCFrameContext *fc, const int pic_size_in_min_cb)
+{
+    if (fc->tab.pic_size_in_min_cb != pic_size_in_min_cb) {
+        min_cb_arrays_free(fc);
+        for (int i = LUMA; i <= CHROMA; i++) {
+            fc->tab.cb_pos_x[i]  = av_mallocz(pic_size_in_min_cb * sizeof(int));
+            fc->tab.cb_pos_y[i]  = av_mallocz(pic_size_in_min_cb * sizeof(int));
+            fc->tab.cb_width[i]  = av_mallocz(pic_size_in_min_cb);
+            fc->tab.cb_height[i] = av_mallocz(pic_size_in_min_cb);
+            fc->tab.cqt_depth[i] = av_mallocz(pic_size_in_min_cb);
+            if (!fc->tab.cb_pos_x[i] || !fc->tab.cb_pos_y[i] || !fc->tab.cb_width[i] || !fc->tab.cb_height[i] || !fc->tab.cqt_depth[i])
+                return AVERROR(ENOMEM);
+
+            fc->tab.cpm[i]   = av_mallocz(pic_size_in_min_cb);
+            fc->tab.cp_mv[i] = av_mallocz(pic_size_in_min_cb * sizeof(Mv) * MAX_CONTROL_POINTS);
+            if (!fc->tab.cpm[i] || !fc->tab.cp_mv[i])
+                return AVERROR(ENOMEM);
+        }
+
+        fc->tab.ipm  = av_mallocz(pic_size_in_min_cb);
+        fc->tab.imf  = av_mallocz(pic_size_in_min_cb);
+        fc->tab.imtf = av_mallocz(pic_size_in_min_cb);
+        fc->tab.imm  = av_mallocz(pic_size_in_min_cb);
+        fc->tab.skip = av_mallocz(pic_size_in_min_cb);
+        if (!fc->tab.ipm || !fc->tab.imf || !fc->tab.imtf || !fc->tab.imm || !fc->tab.skip)
+            return AVERROR(ENOMEM);
+    } else {
+        for (int i = LUMA; i <= CHROMA; i++) {
+            memset(fc->tab.cb_pos_x[i], 0, pic_size_in_min_cb * sizeof(int));
+            memset(fc->tab.cb_pos_y[i], 0, pic_size_in_min_cb * sizeof(int));
+            memset(fc->tab.cb_width[i], 0, pic_size_in_min_cb);
+            memset(fc->tab.cb_height[i], 0, pic_size_in_min_cb);
+            memset(fc->tab.cqt_depth[i], 0, pic_size_in_min_cb);
+            memset(fc->tab.cpm[i], 0, pic_size_in_min_cb);
+            memset(fc->tab.cp_mv[i], 0, pic_size_in_min_cb * sizeof(Mv) * MAX_CONTROL_POINTS);
+        }
+
+        memset(fc->tab.ipm, 0, pic_size_in_min_cb);
+        memset(fc->tab.imf, 0, pic_size_in_min_cb);
+        memset(fc->tab.imtf, 0, pic_size_in_min_cb);
+        memset(fc->tab.imm, 0, pic_size_in_min_cb);
+        memset(fc->tab.skip, 0, pic_size_in_min_cb);
+    }
+    return 0;
+}
+
+static void min_tu_arrays_free(VVCFrameContext *fc)
+{
+    for (int i = LUMA; i <= CHROMA; i++) {
+        av_freep(&fc->tab.tb_pos_x0[i]);
+        av_freep(&fc->tab.tb_pos_y0[i]);
+        av_freep(&fc->tab.tb_width[i]);
+        av_freep(&fc->tab.tb_height[i]);
+        av_freep(&fc->tab.pcmf[i]);
+    }
+
+    for (int i = 0; i < VVC_MAX_SAMPLE_ARRAYS; i++) {
+        av_freep(&fc->tab.qp[i]);
+        av_freep(&fc->tab.tu_coded_flag[i]);
+    }
+
+    av_freep(&fc->tab.tu_joint_cbcr_residual_flag);
+}
+
+static int min_tu_arrays_init(VVCFrameContext *fc, const int pic_size_in_min_tu)
+{
+    if (fc->tab.pic_size_in_min_tu != pic_size_in_min_tu) {
+        min_tu_arrays_free(fc);
+        for (int i = LUMA; i <= CHROMA; i++) {
+            fc->tab.tb_pos_x0[i] = av_mallocz(pic_size_in_min_tu * sizeof(*fc->tab.tb_pos_x0[0]));
+            fc->tab.tb_pos_y0[i] = av_mallocz(pic_size_in_min_tu * sizeof(*fc->tab.tb_pos_y0[0])) ;
+            fc->tab.tb_width[i]  = av_mallocz(pic_size_in_min_tu);
+            fc->tab.tb_height[i] = av_mallocz(pic_size_in_min_tu);
+            fc->tab.pcmf[i]      = av_mallocz(pic_size_in_min_tu);
+            if (!fc->tab.tb_pos_x0[i] || !fc->tab.tb_pos_y0[i] ||
+                !fc->tab.tb_width[i] || !fc->tab.tb_height[i] || !fc->tab.pcmf[i])
+                return AVERROR(ENOMEM);
+        }
+
+        for (int i = 0; i < VVC_MAX_SAMPLE_ARRAYS; i++) {
+            fc->tab.tu_coded_flag[i] = av_mallocz(pic_size_in_min_tu);
+            if (!fc->tab.tu_coded_flag[i])
+                return AVERROR(ENOMEM);
+
+            fc->tab.qp[i] = av_mallocz(pic_size_in_min_tu);
+            if (!fc->tab.qp[i])
+                return AVERROR(ENOMEM);
+        }
+
+        fc->tab.tu_joint_cbcr_residual_flag  = av_mallocz(pic_size_in_min_tu);
+        if (!fc->tab.tu_joint_cbcr_residual_flag)
+            return AVERROR(ENOMEM);
+    } else {
+        for (int i = LUMA; i <= CHROMA; i++) {
+            memset(fc->tab.tb_pos_x0[i], 0, pic_size_in_min_tu * sizeof(*fc->tab.tb_pos_x0[0]));
+            memset(fc->tab.tb_pos_y0[i], 0, pic_size_in_min_tu * sizeof(*fc->tab.tb_pos_y0[0])) ;
+            memset(fc->tab.tb_width[i], 0, pic_size_in_min_tu);
+            memset(fc->tab.tb_height[i], 0, pic_size_in_min_tu);
+            memset(fc->tab.pcmf[i], 0, pic_size_in_min_tu);
+        }
+
+        for (int i = 0; i < VVC_MAX_SAMPLE_ARRAYS; i++) {
+            memset(fc->tab.tu_coded_flag[i], 0, pic_size_in_min_tu);
+            memset(fc->tab.qp[i], 0, pic_size_in_min_tu);
+        }
+        memset(fc->tab.tu_joint_cbcr_residual_flag, 0, pic_size_in_min_tu);
+    }
+    return 0;
+}
+
+static void min_pu_arrays_free(VVCFrameContext *fc)
+{
+    av_freep(&fc->tab.mvf);
+    av_freep(&fc->tab.msf);
+    av_freep(&fc->tab.iaf);
+    av_freep(&fc->tab.mmi);
+    av_buffer_pool_uninit(&fc->tab_dmvr_mvf_pool);
+}
+
+static int min_pu_arrays_init(VVCFrameContext *fc, const int pic_size_in_min_pu)
+{
+    if (fc->tab.pic_size_in_min_pu != pic_size_in_min_pu) {
+        min_pu_arrays_free(fc);
+        fc->tab.msf  = av_mallocz(pic_size_in_min_pu);
+        fc->tab.iaf  = av_mallocz(pic_size_in_min_pu);
+        fc->tab.mmi  = av_mallocz(pic_size_in_min_pu);
+        fc->tab.mvf  = av_mallocz(pic_size_in_min_pu * sizeof(*fc->tab.mvf));
+        if (!fc->tab.msf || !fc->tab.iaf || !fc->tab.mmi || !fc->tab.mvf)
+            return AVERROR(ENOMEM);
+        fc->tab_dmvr_mvf_pool  = av_buffer_pool_init(pic_size_in_min_pu * sizeof(MvField), av_buffer_allocz);
+        if (!fc->tab_dmvr_mvf_pool)
+            return AVERROR(ENOMEM);
+    } else {
+        memset(fc->tab.msf, 0, pic_size_in_min_pu);
+        memset(fc->tab.iaf, 0, pic_size_in_min_pu);
+        memset(fc->tab.mmi, 0, pic_size_in_min_pu);
+        memset(fc->tab.mvf, 0, pic_size_in_min_pu * sizeof(*fc->tab.mvf));
+    }
+
+    return 0;
+}
+
+static void bs_arrays_free(VVCFrameContext *fc)
+{
+    for (int i = 0; i < VVC_MAX_SAMPLE_ARRAYS; i++) {
+        av_freep(&fc->tab.horizontal_bs[i]);
+        av_freep(&fc->tab.vertical_bs[i]);
+    }
+    av_freep(&fc->tab.horizontal_q);
+    av_freep(&fc->tab.horizontal_p);
+    av_freep(&fc->tab.vertical_p);
+    av_freep(&fc->tab.vertical_q);
+}
+
+static int bs_arrays_init(VVCFrameContext *fc, const int bs_width, const int bs_height)
+{
+    if (fc->tab.bs_width != bs_width || fc->tab.bs_height != bs_height) {
+        bs_arrays_free(fc);
+        for (int i = 0; i < VVC_MAX_SAMPLE_ARRAYS; i++) {
+            fc->tab.horizontal_bs[i] = av_calloc(bs_width, bs_height);
+            fc->tab.vertical_bs[i]   = av_calloc(bs_width, bs_height);
+            if (!fc->tab.horizontal_bs[i] || !fc->tab.vertical_bs[i])
+                return AVERROR(ENOMEM);
+        }
+        fc->tab.horizontal_q = av_calloc(bs_width, bs_height);
+        fc->tab.horizontal_p = av_calloc(bs_width, bs_height);
+        fc->tab.vertical_p   = av_calloc(bs_width, bs_height);
+        fc->tab.vertical_q   = av_calloc(bs_width, bs_height);
+        if (!fc->tab.horizontal_q || !fc->tab.horizontal_p || !fc->tab.vertical_p || !fc->tab.vertical_q)
+            return AVERROR(ENOMEM);
+    } else {
+        for (int i = 0; i < VVC_MAX_SAMPLE_ARRAYS; i++) {
+            memset(fc->tab.horizontal_bs[i], 0, bs_width * bs_height);
+            memset(fc->tab.vertical_bs[i], 0, bs_width * bs_height);
+        }
+        memset(fc->tab.horizontal_q, 0, bs_width * bs_height);
+        memset(fc->tab.horizontal_p, 0, bs_width * bs_height);
+        memset(fc->tab.vertical_p, 0, bs_width * bs_height);
+        memset(fc->tab.vertical_q, 0, bs_width * bs_height);
+    }
+    return 0;
+}
+
+static void pixel_buffer_free(VVCFrameContext *fc)
+{
+    for (int i = 0; i < VVC_MAX_SAMPLE_ARRAYS; i++) {
+        av_freep(&fc->tab.sao_pixel_buffer_h[i]);
+        av_freep(&fc->tab.sao_pixel_buffer_v[i]);
+        for (int j = 0; j < 2; j++) {
+            av_freep(&fc->tab.alf_pixel_buffer_h[i][j]);
+            av_freep(&fc->tab.alf_pixel_buffer_v[i][j]);
+        }
+    }
+}
+
+static int pixel_buffer_init(VVCFrameContext *fc, const int width, const int height,
+    const int ctu_width, const int ctu_height, const int chroma_format_idc, const int ps)
+{
+    const VVCSPS *sps = fc->ps.sps;
+    const int c_end   = chroma_format_idc ? VVC_MAX_SAMPLE_ARRAYS : 1;
+
+    if (fc->tab.chroma_format_idc != chroma_format_idc ||
+        fc->tab.width != width || fc->tab.height != height ||
+        fc->tab.ctu_width != ctu_width || fc->tab.ctu_height != ctu_height) {
+        pixel_buffer_free(fc);
+        for (int c_idx = 0; c_idx < c_end; c_idx++) {
+            const int w = width >> sps->hshift[c_idx];
+            const int h = height >> sps->vshift[c_idx];
+            fc->tab.sao_pixel_buffer_h[c_idx] = av_malloc((w * 2 * ctu_height) << ps);
+            fc->tab.sao_pixel_buffer_v[c_idx] = av_malloc((h * 2 * ctu_width)  << ps);
+            if (!fc->tab.sao_pixel_buffer_h[c_idx] || !fc->tab.sao_pixel_buffer_v[c_idx])
+                return AVERROR(ENOMEM);
+        }
+
+        for (int c_idx = 0; c_idx < c_end; c_idx++) {
+            const int w = width >> sps->hshift[c_idx];
+            const int h = height >> sps->vshift[c_idx];
+            const int border_pixels = c_idx ? ALF_BORDER_CHROMA : ALF_BORDER_LUMA;
+            for (int i = 0; i < 2; i++) {
+                fc->tab.alf_pixel_buffer_h[c_idx][i] = av_malloc((w * border_pixels * ctu_height) << ps);
+                fc->tab.alf_pixel_buffer_v[c_idx][i] = av_malloc(h * ALF_PADDING_SIZE * ctu_width);
+                if (!fc->tab.alf_pixel_buffer_h[c_idx][i] || !fc->tab.alf_pixel_buffer_v[c_idx][i])
+                    return AVERROR(ENOMEM);
+            }
+        }
+    }
+    return 0;
+}
+
+static void pic_arrays_free(VVCFrameContext *fc)
+{
+    ctb_arrays_free(fc);
+    min_cb_arrays_free(fc);
+    min_pu_arrays_free(fc);
+    min_tu_arrays_free(fc);
+    bs_arrays_free(fc);
+    av_buffer_pool_uninit(&fc->cu_pool);
+    av_buffer_pool_uninit(&fc->tu_pool);
+    pixel_buffer_free(fc);
+
+    for (int i = 0; i < 2; i++)
+        av_freep(&fc->tab.msm[i]);
+    av_freep(&fc->tab.ispmf);
+
+    fc->tab.ctu_count = 0;
+    fc->tab.ctu_size  = 0;
+    fc->tab.pic_size_in_min_cb = 0;
+    fc->tab.pic_size_in_min_pu = 0;
+    fc->tab.pic_size_in_min_tu = 0;
+    fc->tab.width              = 0;
+    fc->tab.height             = 0;
+    fc->tab.ctu_width          = 0;
+    fc->tab.ctu_height         = 0;
+    fc->tab.bs_width           = 0;
+    fc->tab.bs_height          = 0;
+}
+
+static int pic_arrays_init(VVCContext *s, VVCFrameContext *fc)
+{
+    const VVCSPS *sps               = fc->ps.sps;
+    const VVCPPS *pps               = fc->ps.pps;
+    const int ctu_size              = 1 << sps->ctb_log2_size_y << sps->ctb_log2_size_y;
+    const int pic_size_in_min_cb    = pps->min_cb_width * pps->min_cb_height;
+    const int pic_size_in_min_pu    = pps->min_pu_width * pps->min_pu_height;
+    const int pic_size_in_min_tu    = pps->min_tu_width * pps->min_tu_height;
+    const int w32                   = AV_CEIL_RSHIFT(pps->width,  5);
+    const int h32                   = AV_CEIL_RSHIFT(pps->height,  5);
+    const int w64                   = AV_CEIL_RSHIFT(pps->width,  6);
+    const int h64                   = AV_CEIL_RSHIFT(pps->height,  6);
+    const int bs_width              = (fc->ps.pps->width >> 2) + 1;
+    const int bs_height             = (fc->ps.pps->height >> 2) + 1;
+    int ret;
+
+    if ((ret = ctb_arrays_init(fc, pps->ctb_count, ctu_size)) < 0)
+        goto fail;
+
+    if ((ret = min_cb_arrays_init(fc, pic_size_in_min_cb)) < 0)
+        goto fail;
+
+    if ((ret = min_pu_arrays_init(fc, pic_size_in_min_pu)) < 0)
+        goto fail;
+
+    if ((ret = min_tu_arrays_init(fc, pic_size_in_min_tu)) < 0)
+        goto fail;
+
+    if ((ret = bs_arrays_init(fc, bs_width, bs_height)) < 0)
+        goto fail;
+
+    if ((ret = pixel_buffer_init(fc, pps->width, pps->height, pps->ctb_width, pps->ctb_height,
+        sps->r->sps_chroma_format_idc, sps->pixel_shift)) < 0)
+        goto fail;
+
+    if (AV_CEIL_RSHIFT(fc->tab.width,  5) != w32 || AV_CEIL_RSHIFT(fc->tab.height,  5) != h32) {
+        for (int i = LUMA; i <= CHROMA; i++) {
+            av_freep(&fc->tab.msm[i]);
+            fc->tab.msm[i] = av_calloc(w32, h32);
+            if (!fc->tab.msm[i])
+                goto fail;
+        }
+    } else {
+        for (int i = LUMA; i <= CHROMA; i++)
+            memset(fc->tab.msm[i], 0, w32 * h32);
+    }
+    if (AV_CEIL_RSHIFT(fc->tab.width,  6) != w64 || AV_CEIL_RSHIFT(fc->tab.height,  6) != h64) {
+        av_freep(&fc->tab.ispmf);
+        fc->tab.ispmf = av_calloc(w64, h64);
+        if (!fc->tab.ispmf)
+            goto fail;
+    } else {
+        memset(fc->tab.ispmf, 0, w64 * h64);
+    }
+
+    if (!fc->cu_pool) {
+        fc->cu_pool = av_buffer_pool_init(sizeof(CodingUnit), NULL);
+        if (!fc->cu_pool)
+            goto fail;
+    }
+
+    if (!fc->tu_pool) {
+        fc->tu_pool = av_buffer_pool_init(sizeof(TransformUnit), NULL);
+        if (!fc->tu_pool)
+            goto fail;
+    }
+
+    fc->tab.ctu_count = pps->ctb_count;
+    fc->tab.ctu_size  = ctu_size;
+    fc->tab.pic_size_in_min_cb = pic_size_in_min_cb;
+    fc->tab.pic_size_in_min_pu = pic_size_in_min_pu;
+    fc->tab.pic_size_in_min_tu = pic_size_in_min_tu;
+    fc->tab.width              = pps->width;
+    fc->tab.height             = pps->height;
+    fc->tab.ctu_width          = pps->ctb_width;
+    fc->tab.ctu_height         = pps->ctb_height;
+    fc->tab.chroma_format_idc  = sps->r->sps_chroma_format_idc;
+    fc->tab.pixel_shift        = sps->pixel_shift;
+    fc->tab.bs_width           = bs_width;
+    fc->tab.bs_height          = bs_height;
+
+    return 0;
+fail:
+    pic_arrays_free(fc);
+    return ret;
+}
+
+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->isLongTerm[i]) {
+            int diff = poc - rpl->list[i];
+            if (find(idx, diff, old_diff)) {
+                idx = i;
+                old_diff = diff;
+            }
+        }
+    }
+    return idx;
+}
+
+static void vvc_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)
+{
+    if (slice->eps) {
+        for (int j = 0; j < slice->nb_eps; j++)
+            av_free(slice->eps[j].parse_task);
+        av_freep(&slice->eps);
+    }
+}
+
+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_buffer_unref(&slice->sh.rref);
+                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(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_calloc(1, sizeof(*fc->slices[0]));
+        if (!fc->slices[i]) {
+            for (int j = fc->nb_slices_allocated; j < i; j++)
+                av_freep(&fc->slices[j]);
+            return AVERROR(ENOMEM);
+        }
+        fc->slices[i]->slice_idx = i;
+    }
+    fc->nb_slices_allocated = size;
+    return 0;
+}
+
+static void ep_init_cabac_decoder(SliceContext *sc, const int index, const H2645NAL *nal, GetBitContext *gb)
+{
+    const H266RawSliceHeader *rsh   = sc->sh.r;
+    EntryPoint *ep                  = sc->eps + index;
+    int size;
+
+    if (index < rsh->num_entry_points) {
+        int skipped = 0;
+        int64_t start =  (gb->index >> 3);
+        int64_t end = start + rsh->sh_entry_point_offset_minus1[index] + 1;
+        while (skipped < nal->skipped_bytes && nal->skipped_bytes_pos[skipped] <= start) {
+            skipped++;
+        }
+        while (skipped < nal->skipped_bytes && nal->skipped_bytes_pos[skipped] < end) {
+            end--;
+            skipped++;
+        }
+        size = end - start;
+    } else {
+        size = get_bits_left(gb) / 8;
+    }
+    ff_init_cabac_decoder (&ep->cc, gb->buffer + get_bits_count(gb) / 8, size);
+    skip_bits(gb, size * 8);
+}
+
+static int init_slice_context(SliceContext *sc, VVCFrameContext *fc, const H2645NAL *nal, const CodedBitstreamUnit *unit)
+{
+    const VVCSH *sh             = &sc->sh;
+    const H266RawSlice *slice   = (const H266RawSlice *)unit->content;
+    int nb_eps                  = sh->r->num_entry_points + 1;
+    int ctu_addr                = 0;
+    GetBitContext gb;
+
+    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;
+        for (int i = 0; i < sc->nb_eps; i++) {
+            EntryPoint *ep = sc->eps + i;
+            ep->parse_task = ff_vvc_task_alloc();
+            if (!ep->parse_task)
+                return AVERROR(ENOMEM);
+        }
+    }
+
+    init_get_bits8(&gb, slice->data, slice->data_size);
+    for (int i = 0; i < sc->nb_eps; i++)
+    {
+        EntryPoint *ep = sc->eps + i;
+        ff_vvc_parse_task_init(ep->parse_task, VVC_TASK_TYPE_PARSE, fc, sc, ep, ctu_addr);
+        ep->ctu_end = (i + 1 == sc->nb_eps ? sh->num_ctus_in_curr_slice : sh->entry_point_start_ctu[i]);
+        ep_init_cabac_decoder(sc, i, nal, &gb);
+        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 vvc_ref_frame(VVCFrameContext *fc, VVCFrame *dst, VVCFrame *src)
+{
+    int ret;
+
+    ret = ff_thread_ref_frame(&dst->tf, &src->tf);
+    if (ret < 0)
+        return ret;
+
+    dst->progress_buf = av_buffer_ref(src->progress_buf);
+
+    dst->tab_dmvr_mvf_buf = av_buffer_ref(src->tab_dmvr_mvf_buf);
+    if (!dst->tab_dmvr_mvf_buf)
+        goto fail;
+    dst->tab_dmvr_mvf = src->tab_dmvr_mvf;
+
+    dst->rpl_tab_buf = av_buffer_ref(src->rpl_tab_buf);
+    if (!dst->rpl_tab_buf)
+        goto fail;
+    dst->rpl_tab = src->rpl_tab;
+
+    dst->rpl_buf = av_buffer_ref(src->rpl_buf);
+    if (!dst->rpl_buf)
+        goto fail;
+
+    dst->poc = src->poc;
+    dst->ctb_count = src->ctb_count;
+    dst->flags = src->flags;
+    dst->sequence = src->sequence;
+
+    return 0;
+fail:
+    ff_vvc_unref_frame(fc, dst, ~0);
+    return AVERROR(ENOMEM);
+}
+
+static av_cold void frame_context_free(VVCFrameContext *fc)
+{
+    slices_free(fc);
+
+    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);
+    }
+
+    ff_vvc_frame_thread_free(fc);
+    pic_arrays_free(fc);
+    av_frame_free(&fc->output_frame);
+    ff_vvc_frame_ps_free(&fc->ps);
+    av_freep(&fc->avctx);
+}
+
+static av_cold int frame_context_init(VVCFrameContext *fc, AVCodecContext *avctx)
+{
+
+    fc->avctx = av_memdup(avctx, sizeof(*avctx));
+    if (!fc->avctx)
+        goto fail;
+
+    fc->output_frame = av_frame_alloc();
+    if (!fc->output_frame)
+        goto fail;
+
+    for (int j = 0; j < FF_ARRAY_ELEMS(fc->DPB); j++) {
+        fc->DPB[j].frame = av_frame_alloc();
+        if (!fc->DPB[j].frame)
+            goto fail;
+        fc->DPB[j].tf.f = fc->DPB[j].frame;
+    }
+
+    return 0;
+fail:
+    return AVERROR(ENOMEM);
+}
+
+static int frame_context_setup(VVCFrameContext *fc, VVCContext *s)
+{
+    int ret = 0;
+
+    // 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 = vvc_ref_frame(fc, &fc->DPB[i], &prev->DPB[i]);
+                if (ret < 0)
+                    goto fail;
+            }
+        }
+    }
+
+    if (IS_IDR(s)) {
+        s->seq_decode = (s->seq_decode + 1) & 0xff;
+        ff_vvc_clear_refs(fc);
+    }
+
+    ret = pic_arrays_init(s, fc);
+    if (ret < 0)
+        goto fail;
+    ff_vvc_dsp_init(&fc->vvcdsp, fc->ps.sps->bit_depth);
+    ff_videodsp_init(&fc->vdsp, fc->ps.sps->bit_depth);
+
+fail:
+    return ret;
+}
+
+static void export_frame_params(VVCFrameContext *fc)
+{
+    AVCodecContext *c   = fc->avctx;
+    const VVCSPS *sps   = fc->ps.sps;
+    const VVCPPS *pps   = fc->ps.pps;
+
+    c->pix_fmt          = sps->pix_fmt;
+    c->coded_width      = pps->width;
+    c->coded_height     = pps->height;
+    c->width            = pps->width  - pps->r->pps_conf_win_left_offset - pps->r->pps_conf_win_right_offset;
+    c->height           = pps->height - pps->r->pps_conf_win_top_offset - pps->r->pps_conf_win_bottom_offset;
+}
+
+static int decode_slice(VVCContext *s, VVCFrameContext *fc, const H2645NAL *nal, const CodedBitstreamUnit *unit)
+{
+    int ret = 0;
+    SliceContext *sc;
+    VVCSH *sh;
+    const int is_first_slice = !fc->nb_slices;
+
+    ret = slices_realloc(fc);
+    if (ret < 0)
+        return ret;
+    sc = fc->slices[fc->nb_slices];
+
+    sh = &sc->sh;
+
+    if (ret < 0)
+        goto fail;
+
+    s->vcl_unit_type = nal->type;
+    if (is_first_slice) {
+        //first slice
+        ret = ff_vvc_decode_frame_ps(&fc->ps, s);
+        if (ret < 0)
+            return ret;
+
+        ret = frame_context_setup(fc, s);
+        if (ret < 0)
+            goto fail;
+
+        export_frame_params(fc);
+    }
+
+    ret = ff_vvc_decode_sh(&sc->sh, &fc->ps, unit);
+    if (ret < 0)
+        return ret;
+
+    if (is_first_slice) {
+        ret = vvc_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->avctx, AV_LOG_WARNING,
+                       "Error constructing the reference lists for the current slice.\n");
+                return ret;
+            }
+        }
+    } else {
+        av_log(fc->avctx, AV_LOG_ERROR, "First slice in a frame missing.\n");
+        return ret;
+    }
+
+    if (!IS_I(sh->r))
+        vvc_smvd_ref_idx(fc, sc);
+
+    ret = init_slice_context(sc, fc, nal, unit);
+    if (ret < 0)
+        goto fail;
+    fc->nb_slices++;
+
+    for (int i = 0; i < (fc->ps.sps->r->sps_entropy_coding_sync_enabled_flag ? 1 : sc->nb_eps); i++)
+        ff_vvc_frame_add_task(s, sc->eps[i].parse_task);
+
+fail:
+    return ret;
+}
+
+static int decode_nal_unit(VVCContext *s, VVCFrameContext *fc, const H2645NAL *nal, const CodedBitstreamUnit *unit)
+{
+    int  ret;
+
+    s->temporal_id   = nal->temporal_id;
+
+    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, nal, unit);
+        if (ret < 0)
+            goto fail;
+        break;
+    case VVC_PREFIX_APS_NUT:
+    case VVC_SUFFIX_APS_NUT:
+        ret = ff_vvc_decode_aps(&s->ps, unit);
+        if (ret < 0)
+            goto fail;
+        break;
+    default:
+        av_log(s->avctx, AV_LOG_INFO,
+               "Skipping NAL unit %d\n", unit->type);
+    }
+
+    return 0;
+fail:
+    return ret;
+}
+
+static int decode_nal_units(VVCContext *s, VVCFrameContext *fc, AVPacket *avpkt)
+{
+    const CodedBitstreamH266Context *h266   = (const CodedBitstreamH266Context *)s->cbc->priv_data;
+    CodedBitstreamFragment *frame           = &s->current_frame;
+    int i, ret = 0;
+    int eos_at_start = 1;
+    s->last_eos = s->eos;
+    s->eos = 0;
+
+    ff_cbs_fragment_reset(frame);
+    ret = ff_cbs_read_packet(s->cbc, frame, avpkt);
+    if (ret < 0) {
+        av_log(s->avctx, AV_LOG_ERROR, "Failed to read packet.\n");
+        return ret;
+    }
+    /* decode the NAL units */
+    for (i = 0; i < frame->nb_units; i++) {
+        const H2645NAL *nal             = h266->common.read_packet.nals + i;
+        const CodedBitstreamUnit *unit  = frame->units + i;
+
+        if (unit->type == VVC_EOB_NUT || unit->type == VVC_EOS_NUT) {
+            if (eos_at_start)
+                s->last_eos = 1;
+            else
+                s->eos = 1;
+        } else {
+            ret = decode_nal_unit(s, fc, nal, unit);
+            if (ret < 0) {
+                av_log(s->avctx, AV_LOG_WARNING,
+                        "Error parsing NAL unit #%d.\n", i);
+                goto fail;
+            }
+        }
+    }
+    return 0;
+
+fail:
+    if (fc->ref)
+        ff_vvc_report_frame_finished(fc->ref);
+    return ret;
+}
+
+static int set_output_format(const VVCContext *s, const AVFrame *output)
+{
+    AVCodecContext *c = s->avctx;
+    int ret;
+
+    if (output->width != c->width || output->height != c->height) {
+        if ((ret = ff_set_dimensions(c, output->width, output->height)) < 0)
+            return ret;
+    }
+    c->pix_fmt = output->format;
+    return 0;
+}
+
+static int wait_delayed_frame(VVCContext *s, AVFrame *output, int *got_output)
+{
+    VVCFrameContext *delayed = get_frame_context(s, s->fcs, s->nb_frames - s->nb_delayed);
+    int ret = ff_vvc_frame_wait(s, delayed);
+
+    if (!ret && delayed->output_frame->buf[0]) {
+        av_frame_move_ref(output, delayed->output_frame);
+        ret = set_output_format(s, output);
+        if (!ret)
+            *got_output = 1;
+    }
+    s->nb_delayed--;
+
+    return ret;
+}
+
+static int submit_frame(VVCContext *s, VVCFrameContext *fc, AVFrame *output, int *got_output)
+{
+    int ret;
+    s->nb_frames++;
+    s->nb_delayed++;
+    if (s->nb_delayed >= s->nb_fcs) {
+        if ((ret = wait_delayed_frame(s, output, got_output)) < 0)
+            return ret;
+    }
+    return 0;
+}
 
 static int vvc_decode_frame(AVCodecContext *avctx, AVFrame *output,
     int *got_output, AVPacket *avpkt)
 {
+    VVCContext *s = avctx->priv_data;
+    VVCFrameContext *fc;
+    int ret;
+
+    if (!avpkt->size) {
+        while (s->nb_delayed) {
+            if ((ret = wait_delayed_frame(s, output, got_output)) < 0)
+                return ret;
+            if (*got_output)
+                return 0;
+        }
+        if (s->nb_frames) {
+            //we still have frames cached in dpb.
+            VVCFrameContext *last = get_frame_context(s, s->fcs, s->nb_frames - 1);
+
+            ret = ff_vvc_output_frame(s, last, output, 0, 1);
+            if (ret < 0)
+                return ret;
+            if (ret) {
+                *got_output = ret;
+                if ((ret = set_output_format(s, output)) < 0)
+                    return ret;
+            }
+        }
+        return 0;
+    }
+
+    fc = get_frame_context(s, s->fcs, s->nb_frames);
+
+    fc->nb_slices = 0;
+    fc->decode_order = s->nb_frames;
+
+    ret = decode_nal_units(s, fc, avpkt);
+    if (ret < 0)
+        return ret;
+
+    ret = submit_frame(s, fc, output, got_output);
+    if (ret < 0)
+        return ret;
+
     return avpkt->size;
 }
 
 static void vvc_decode_flush(AVCodecContext *avctx)
 {
+    VVCContext *s = avctx->priv_data;
+    int got_output;
+    AVFrame *output = av_frame_alloc();
+
+    if (output) {
+        while (s->nb_delayed) {
+            wait_delayed_frame(s, output, &got_output);
+            if (got_output) {
+                av_frame_unref(output);
+            }
+        }
+        av_frame_free(&output);
+    }
 }
 
 static av_cold int vvc_decode_free(AVCodecContext *avctx)
 {
+    VVCContext *s = avctx->priv_data;
+    int i;
+
+    ff_cbs_fragment_free(&s->current_frame);
+    vvc_decode_flush(avctx);
+    av_executor_free(&s->executor);
+    if (s->fcs) {
+        for (i = 0; i < s->nb_fcs; i++)
+            frame_context_free(s->fcs + i);
+        av_free(s->fcs);
+    }
+    ff_vvc_ps_uninit(&s->ps);
+    ff_cbs_close(&s->cbc);
+
     return 0;
 }
 
+#define VVC_MAX_FRMAE_DELAY 16
 static av_cold int vvc_decode_init(AVCodecContext *avctx)
 {
+    VVCContext *s       = avctx->priv_data;
+    int ret;
+    AVTaskCallbacks callbacks = {
+        s,
+        sizeof(VVCLocalContext),
+        ff_vvc_task_priority_higher,
+        ff_vvc_task_ready,
+        ff_vvc_task_run,
+    };
+
+    s->avctx = avctx;
+
+    if (ff_cbs_init(&s->cbc, AV_CODEC_ID_VVC, avctx))
+        goto fail;
+
+    s->nb_fcs = (avctx->flags & AV_CODEC_FLAG_LOW_DELAY) ? 1 : FFMIN(av_cpu_count(), VVC_MAX_FRMAE_DELAY);
+    s->fcs = av_calloc(s->nb_fcs, sizeof(*s->fcs));
+    if (!s->fcs)
+        goto fail;
+
+    for (int i = 0; i < s->nb_fcs; i++) {
+        VVCFrameContext *fc = s->fcs + i;
+        ret = frame_context_init(fc, avctx);
+        if (ret < 0)
+            goto fail;
+    }
+
+    s->executor = av_executor_alloc(&callbacks, s->nb_fcs);
+    s->eos = 1;
+    GDR_SET_RECOVERED(s);
+    memset(&ff_vvc_default_scale_m, 16, sizeof(ff_vvc_default_scale_m));
+
     return 0;
+
+fail:
+    vvc_decode_free(avctx);
+    return AVERROR(ENOMEM);
 }
 
 #define OFFSET(x) offsetof(VVCContext, x)
