lavc: VP9 decoder

Originally written by Ronald S. Bultje <rsbultje@gmail.com> and
Clément Bœsch <u@pkh.me>

Further contributions by:
Anton Khirnov <anton@khirnov.net>
Diego Biurrun <diego@biurrun.de>
Luca Barbato <lu_zero@gentoo.org>
Martin Storsjö <martin@martin.st>
Signed-off-by: Luca Barbato <lu_zero@gentoo.org>
Signed-off-by: Anton Khirnov <anton@khirnov.net>

Changelog

@@ -47,6 +47,7 @@ version 10:
 - Live HDS muxer
 - setsar/setdar filters now support variables in ratio expressions
 - dar variable in the scale filter now returns the actual DAR (i.e. a * sar)
+- VP9 decoder
 
 
 version 9:

configure

@@ -1702,6 +1702,7 @@ vp6_decoder_select="h264chroma hpeldsp huffman videodsp vp3dsp"
 vp6a_decoder_select="vp6_decoder"
 vp6f_decoder_select="vp6_decoder"
 vp8_decoder_select="h264pred videodsp"
+vp9_decoder_select="videodsp"
 webp_decoder_select="vp8_decoder"
 wmapro_decoder_select="mdct sinewin"
 wmav1_decoder_select="mdct sinewin"

doc/general.texi

@@ -594,6 +594,8 @@ following image formats are supported:
     @tab fourcc: VP60,VP61,VP62
 @item VP8                    @tab  E  @tab  X
     @tab fourcc: VP80, encoding supported through external library libvpx
+@item VP9                    @tab  E  @tab  X
+    @tab Encoding supported through external library libvpx
 @item planar RGB             @tab     @tab  X
     @tab fourcc: 8BPS
 @item Q-team QPEG            @tab     @tab  X

libavcodec/Makefile

@@ -392,6 +392,8 @@ OBJS-$(CONFIG_VP5_DECODER)             += vp5.o vp56.o vp56data.o vp56dsp.o \
 OBJS-$(CONFIG_VP6_DECODER)             += vp6.o vp56.o vp56data.o vp56dsp.o \
                                           vp6dsp.o vp56rac.o
 OBJS-$(CONFIG_VP8_DECODER)             += vp8.o vp8dsp.o vp56rac.o
+OBJS-$(CONFIG_VP9_DECODER)             += vp9.o vp9data.o vp9dsp.o \
+                                          vp9block.o vp9prob.o vp9mvs.o vp56rac.o
 OBJS-$(CONFIG_VQA_DECODER)             += vqavideo.o
 OBJS-$(CONFIG_WAVPACK_DECODER)         += wavpack.o
 OBJS-$(CONFIG_WEBP_DECODER)            += webp.o

libavcodec/allcodecs.c

@@ -257,6 +257,7 @@ void avcodec_register_all(void)
     REGISTER_DECODER(VP6A,              vp6a);
     REGISTER_DECODER(VP6F,              vp6f);
     REGISTER_DECODER(VP8,               vp8);
+    REGISTER_DECODER(VP9,               vp9);
     REGISTER_DECODER(VQA,               vqa);
     REGISTER_DECODER(WEBP,              webp);
     REGISTER_ENCDEC (WMV1,              wmv1);

libavcodec/version.h

@@ -27,7 +27,7 @@
  */
 
 #define LIBAVCODEC_VERSION_MAJOR 55
-#define LIBAVCODEC_VERSION_MINOR 27
+#define LIBAVCODEC_VERSION_MINOR 28
 #define LIBAVCODEC_VERSION_MICRO  0
 
 #define LIBAVCODEC_VERSION_INT  AV_VERSION_INT(LIBAVCODEC_VERSION_MAJOR, \

libavcodec/vp9.h

+/*
+ * VP9 compatible video decoder
+ *
+ * Copyright (C) 2013 Ronald S. Bultje <rsbultje gmail com>
+ * Copyright (C) 2013 Clément Bœsch <u pkh me>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_VP9_H
+#define AVCODEC_VP9_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+#include "libavutil/internal.h"
+
+#include "avcodec.h"
+#include "vp56.h"
+
+enum TxfmMode {
+    TX_4X4,
+    TX_8X8,
+    TX_16X16,
+    TX_32X32,
+    N_TXFM_SIZES,
+    TX_SWITCHABLE = N_TXFM_SIZES,
+    N_TXFM_MODES
+};
+
+enum TxfmType {
+    DCT_DCT,
+    DCT_ADST,
+    ADST_DCT,
+    ADST_ADST,
+    N_TXFM_TYPES
+};
+
+enum IntraPredMode {
+    VERT_PRED,
+    HOR_PRED,
+    DC_PRED,
+    DIAG_DOWN_LEFT_PRED,
+    DIAG_DOWN_RIGHT_PRED,
+    VERT_RIGHT_PRED,
+    HOR_DOWN_PRED,
+    VERT_LEFT_PRED,
+    HOR_UP_PRED,
+    TM_VP8_PRED,
+    LEFT_DC_PRED,
+    TOP_DC_PRED,
+    DC_128_PRED,
+    DC_127_PRED,
+    DC_129_PRED,
+    N_INTRA_PRED_MODES
+};
+
+enum FilterMode {
+    FILTER_8TAP_SMOOTH,
+    FILTER_8TAP_REGULAR,
+    FILTER_8TAP_SHARP,
+    FILTER_BILINEAR,
+    FILTER_SWITCHABLE,
+};
+
+enum BlockPartition {
+    PARTITION_NONE,    // [ ] <-.
+    PARTITION_H,       // [-]   |
+    PARTITION_V,       // [|]   |
+    PARTITION_SPLIT,   // [+] --'
+};
+
+enum InterPredMode {
+    NEARESTMV = 10,
+    NEARMV    = 11,
+    ZEROMV    = 12,
+    NEWMV     = 13,
+};
+
+enum MVJoint {
+    MV_JOINT_ZERO,
+    MV_JOINT_H,
+    MV_JOINT_V,
+    MV_JOINT_HV,
+};
+
+typedef struct ProbContext {
+    uint8_t y_mode[4][9];
+    uint8_t uv_mode[10][9];
+    uint8_t filter[4][2];
+    uint8_t mv_mode[7][3];
+    uint8_t intra[4];
+    uint8_t comp[5];
+    uint8_t single_ref[5][2];
+    uint8_t comp_ref[5];
+    uint8_t tx32p[2][3];
+    uint8_t tx16p[2][2];
+    uint8_t tx8p[2];
+    uint8_t skip[3];
+    uint8_t mv_joint[3];
+    struct {
+        uint8_t sign;
+        uint8_t classes[10];
+        uint8_t class0;
+        uint8_t bits[10];
+        uint8_t class0_fp[2][3];
+        uint8_t fp[3];
+        uint8_t class0_hp;
+        uint8_t hp;
+    } mv_comp[2];
+    uint8_t partition[4][4][3];
+} ProbContext;
+
+typedef void (*vp9_mc_func)(uint8_t *dst, const uint8_t *ref,
+                            ptrdiff_t dst_stride,
+                            ptrdiff_t ref_stride,
+                            int h, int mx, int my);
+
+typedef struct VP9DSPContext {
+    /*
+     * dimension 1: 0=4x4, 1=8x8, 2=16x16, 3=32x32
+     * dimension 2: intra prediction modes
+     *
+     * dst/left/top is aligned by transform-size (i.e. 4, 8, 16 or 32 pixels)
+     * stride is aligned by 16 pixels
+     * top[-1] is top/left; top[4,7] is top-right for 4x4
+     */
+    // FIXME(rbultje) maybe replace left/top pointers with HAVE_TOP/
+    // HAVE_LEFT/HAVE_TOPRIGHT flags instead, and then handle it in-place?
+    // also needs to fit in with what h264/vp8/etc do
+    void (*intra_pred[N_TXFM_SIZES][N_INTRA_PRED_MODES])(uint8_t *dst,
+                                                         ptrdiff_t stride,
+                                                         const uint8_t *left,
+                                                         const uint8_t *top);
+
+    /*
+     * dimension 1: 0=4x4, 1=8x8, 2=16x16, 3=32x32, 4=lossless (3-4=dct only)
+     * dimension 2: 0=dct/dct, 1=dct/adst, 2=adst/dct, 3=adst/adst
+     *
+     * dst is aligned by transform-size (i.e. 4, 8, 16 or 32 pixels)
+     * stride is aligned by 16 pixels
+     * block is 16-byte aligned
+     * eob indicates the position (+1) of the last non-zero coefficient,
+     * in scan-order. This can be used to write faster versions, e.g. a
+     * dc-only 4x4/8x8/16x16/32x32, or a 4x4-only (eob<10) 8x8/16x16/32x32,
+     * etc.
+     */
+    // FIXME also write idct_add_block() versions for whole (inter) pred
+    // blocks, so we can do 2 4x4s at once
+    void (*itxfm_add[N_TXFM_SIZES + 1][N_TXFM_TYPES])(uint8_t *dst,
+                                                      ptrdiff_t stride,
+                                                      int16_t *block, int eob);
+
+    /*
+     * dimension 1: width of filter (0=4, 1=8, 2=16)
+     * dimension 2: 0=col-edge filter (h), 1=row-edge filter (v)
+     *
+     * dst/stride are aligned by 8
+     */
+    void (*loop_filter_8[3][2])(uint8_t *dst, ptrdiff_t stride,
+                                int mb_lim, int lim, int hev_thr);
+
+    /*
+     * dimension 1: 0=col-edge filter (h), 1=row-edge filter (v)
+     *
+     * The width of filter is assumed to be 16; dst/stride are aligned by 16
+     */
+    void (*loop_filter_16[2])(uint8_t *dst, ptrdiff_t stride,
+                              int mb_lim, int lim, int hev_thr);
+
+    /*
+     * dimension 1/2: width of filter (0=4, 1=8) for each filter half
+     * dimension 3: 0=col-edge filter (h), 1=row-edge filter (v)
+     *
+     * dst/stride are aligned by operation size
+     * this basically calls loop_filter[d1][d3][0](), followed by
+     * loop_filter[d2][d3][0]() on the next 8 pixels
+     * mb_lim/lim/hev_thr contain two values in the lowest two bytes of the
+     * integer.
+     */
+    // FIXME perhaps a mix4 that operates on 32px (for AVX2)
+    void (*loop_filter_mix2[2][2][2])(uint8_t *dst, ptrdiff_t stride,
+                                      int mb_lim, int lim, int hev_thr);
+
+    /*
+     * dimension 1: hsize (0: 64, 1: 32, 2: 16, 3: 8, 4: 4)
+     * dimension 2: filter type (0: smooth, 1: regular, 2: sharp, 3: bilin)
+     * dimension 3: averaging type (0: put, 1: avg)
+     * dimension 4: x subpel interpolation (0: none, 1: 8tap/bilin)
+     * dimension 5: y subpel interpolation (1: none, 1: 8tap/bilin)
+     *
+     * dst/stride are aligned by hsize
+     */
+    vp9_mc_func mc[5][4][2][2][2];
+} VP9DSPContext;
+
+enum CompPredMode {
+    PRED_SINGLEREF,
+    PRED_COMPREF,
+    PRED_SWITCHABLE,
+};
+
+typedef struct VP9MVRefPair {
+    VP56mv mv[2];
+    int8_t ref[2];
+} VP9MVRefPair;
+
+typedef struct VP9Filter {
+    uint8_t level[8 * 8];
+    uint8_t /* bit=col */ mask[2 /* 0=y, 1=uv */][2 /* 0=col, 1=row */]
+                              [8 /* rows */][4 /* 0=16, 1=8, 2=4, 3=inner4 */];
+} VP9Filter;
+
+enum BlockLevel {
+    BL_64X64,
+    BL_32X32,
+    BL_16X16,
+    BL_8X8,
+};
+
+enum BlockSize {
+    BS_64x64,
+    BS_64x32,
+    BS_32x64,
+    BS_32x32,
+    BS_32x16,
+    BS_16x32,
+    BS_16x16,
+    BS_16x8,
+    BS_8x16,
+    BS_8x8,
+    BS_8x4,
+    BS_4x8,
+    BS_4x4,
+    N_BS_SIZES,
+};
+
+typedef struct VP9Block {
+    uint8_t seg_id, intra, comp, ref[2], mode[4], uvmode, skip;
+    enum FilterMode filter;
+    VP56mv mv[4 /* b_idx */][2 /* ref */];
+    enum BlockSize bs;
+    enum TxfmMode tx, uvtx;
+
+    int row, row7, col, col7;
+    uint8_t *dst[3];
+    ptrdiff_t y_stride, uv_stride;
+} VP9Block;
+
+typedef struct VP9Context {
+    VP9DSPContext dsp;
+    VideoDSPContext vdsp;
+    GetBitContext gb;
+    VP56RangeCoder c;
+    VP56RangeCoder *c_b;
+    unsigned c_b_size;
+    VP9Block b;
+
+    // bitstream header
+    uint8_t profile;
+    uint8_t keyframe, last_keyframe;
+    uint8_t invisible;
+    uint8_t use_last_frame_mvs;
+    uint8_t errorres;
+    uint8_t colorspace;
+    uint8_t fullrange;
+    uint8_t intraonly;
+    uint8_t resetctx;
+    uint8_t refreshrefmask;
+    uint8_t highprecisionmvs;
+    enum FilterMode filtermode;
+    uint8_t allowcompinter;
+    uint8_t fixcompref;
+    uint8_t refreshctx;
+    uint8_t parallelmode;
+    uint8_t framectxid;
+    uint8_t refidx[3];
+    uint8_t signbias[3];
+    uint8_t varcompref[2];
+    AVFrame *refs[8];
+    AVFrame *cur_frame;
+
+    struct {
+        uint8_t level;
+        int8_t sharpness;
+        uint8_t lim_lut[64];
+        uint8_t mblim_lut[64];
+    } filter;
+    struct {
+        uint8_t enabled;
+        int8_t mode[2];
+        int8_t ref[4];
+    } lf_delta;
+    uint8_t yac_qi;
+    int8_t ydc_qdelta, uvdc_qdelta, uvac_qdelta;
+    uint8_t lossless;
+    struct {
+        uint8_t enabled;
+        uint8_t temporal;
+        uint8_t absolute_vals;
+        uint8_t update_map;
+        struct {
+            uint8_t q_enabled;
+            uint8_t lf_enabled;
+            uint8_t ref_enabled;
+            uint8_t skip_enabled;
+            uint8_t ref_val;
+            int16_t q_val;
+            int8_t lf_val;
+            int16_t qmul[2][2];
+            uint8_t lflvl[4][2];
+        } feat[8];
+    } segmentation;
+    struct {
+        unsigned log2_tile_cols, log2_tile_rows;
+        unsigned tile_cols, tile_rows;
+        unsigned tile_row_start, tile_row_end, tile_col_start, tile_col_end;
+    } tiling;
+    unsigned sb_cols, sb_rows, rows, cols;
+    struct {
+        ProbContext p;
+        uint8_t coef[4][2][2][6][6][3];
+    } prob_ctx[4];
+    struct {
+        ProbContext p;
+        uint8_t coef[4][2][2][6][6][11];
+        uint8_t seg[7];
+        uint8_t segpred[3];
+    } prob;
+    struct {
+        unsigned y_mode[4][10];
+        unsigned uv_mode[10][10];
+        unsigned filter[4][3];
+        unsigned mv_mode[7][4];
+        unsigned intra[4][2];
+        unsigned comp[5][2];
+        unsigned single_ref[5][2][2];
+        unsigned comp_ref[5][2];
+        unsigned tx32p[2][4];
+        unsigned tx16p[2][3];
+        unsigned tx8p[2][2];
+        unsigned skip[3][2];
+        unsigned mv_joint[4];
+        struct {
+            unsigned sign[2];
+            unsigned classes[11];
+            unsigned class0[2];
+            unsigned bits[10][2];
+            unsigned class0_fp[2][4];
+            unsigned fp[4];
+            unsigned class0_hp[2];
+            unsigned hp[2];
+        } mv_comp[2];
+        unsigned partition[4][4][4];
+        unsigned coef[4][2][2][6][6][3];
+        unsigned eob[4][2][2][6][6][2];
+    } counts;
+    enum TxfmMode txfmmode;
+    enum CompPredMode comppredmode;
+
+    // contextual (left/above) cache
+    uint8_t left_partition_ctx[8], *above_partition_ctx;
+    uint8_t left_mode_ctx[16], *above_mode_ctx;
+    // FIXME maybe merge some of the below in a flags field?
+    uint8_t left_y_nnz_ctx[16], *above_y_nnz_ctx;
+    uint8_t left_uv_nnz_ctx[2][8], *above_uv_nnz_ctx[2];
+    uint8_t left_skip_ctx[8], *above_skip_ctx; // 1bit
+    uint8_t left_txfm_ctx[8], *above_txfm_ctx; // 2bit
+    uint8_t left_segpred_ctx[8], *above_segpred_ctx; // 1bit
+    uint8_t left_intra_ctx[8], *above_intra_ctx; // 1bit
+    uint8_t left_comp_ctx[8], *above_comp_ctx; // 1bit
+    uint8_t left_ref_ctx[8], *above_ref_ctx; // 2bit
+    uint8_t left_filter_ctx[8], *above_filter_ctx;
+    VP56mv left_mv_ctx[16][2], (*above_mv_ctx)[2];
+
+    // whole-frame cache
+    uint8_t *intra_pred_data[3];
+    uint8_t *segmentation_map;
+    VP9MVRefPair *mv[2];
+    VP9Filter *lflvl;
+    DECLARE_ALIGNED(32, uint8_t, edge_emu_buffer)[71 * 80];
+
+    // block reconstruction intermediates
+    DECLARE_ALIGNED(32, int16_t, block)[4096];
+    DECLARE_ALIGNED(32, int16_t, uvblock)[2][1024];
+    uint8_t eob[256];
+    uint8_t uveob[2][64];
+    VP56mv min_mv, max_mv;
+    DECLARE_ALIGNED(32, uint8_t, tmp_y)[64 * 64];
+    DECLARE_ALIGNED(32, uint8_t, tmp_uv)[2][32 * 32];
+} VP9Context;
+
+void ff_vp9dsp_init(VP9DSPContext *dsp);
+
+void ff_vp9dsp_init_x86(VP9DSPContext *dsp);
+
+void ff_vp9_fill_mv(VP9Context *s, VP56mv *mv, int mode, int sb);
+
+void ff_vp9_adapt_probs(VP9Context *s);
+
+int ff_vp9_decode_block(AVCodecContext *avctx, int row, int col,
+                        VP9Filter *lflvl, ptrdiff_t yoff, ptrdiff_t uvoff,
+                        enum BlockLevel bl, enum BlockPartition bp);
+
+#endif /* AVCODEC_VP9_H */

libavcodec/vp9data.h

+/*
+ * Copyright (C) 2013 Ronald S. Bultje <rsbultje gmail com>
+ * Copyright (C) 2013 Clément Bœsch <u pkh me>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#ifndef AVCODEC_VP9DATA_H
+#define AVCODEC_VP9DATA_H
+
+#include <stdint.h>
+
+#include "vp9.h"
+
+extern const int8_t ff_vp9_partition_tree[3][2];
+extern const uint8_t ff_vp9_default_kf_partition_probs[4][4][3];
+extern const int8_t ff_vp9_segmentation_tree[7][2];
+extern const int8_t ff_vp9_intramode_tree[9][2];
+extern const uint8_t ff_vp9_default_kf_ymode_probs[10][10][9];
+extern const uint8_t ff_vp9_default_kf_uvmode_probs[10][9];
+extern const int8_t ff_vp9_inter_mode_tree[3][2];
+extern const int8_t ff_vp9_filter_tree[2][2];
+extern const enum FilterMode ff_vp9_filter_lut[3];
+extern const int16_t ff_vp9_dc_qlookup[256];
+extern const int16_t ff_vp9_ac_qlookup[256];
+extern const enum TxfmType ff_vp9_intra_txfm_type[14];
+extern const int16_t ff_vp9_default_scan_4x4[16];
+extern const int16_t ff_vp9_col_scan_4x4[16];
+extern const int16_t ff_vp9_row_scan_4x4[16];
+extern const int16_t ff_vp9_default_scan_8x8[64];
+extern const int16_t ff_vp9_col_scan_8x8[64];
+extern const int16_t ff_vp9_row_scan_8x8[64];
+extern const int16_t ff_vp9_default_scan_16x16[256];
+extern const int16_t ff_vp9_col_scan_16x16[256];
+extern const int16_t ff_vp9_row_scan_16x16[256];
+extern const int16_t ff_vp9_default_scan_32x32[1024];
+extern const int16_t *ff_vp9_scans[5][4];
+extern const int16_t ff_vp9_default_scan_4x4_nb[16][2];
+extern const int16_t ff_vp9_col_scan_4x4_nb[16][2];
+extern const int16_t ff_vp9_row_scan_4x4_nb[16][2];
+extern const int16_t ff_vp9_default_scan_8x8_nb[64][2];
+extern const int16_t ff_vp9_col_scan_8x8_nb[64][2];
+extern const int16_t ff_vp9_row_scan_8x8_nb[64][2];
+extern const int16_t ff_vp9_default_scan_16x16_nb[256][2];
+extern const int16_t ff_vp9_col_scan_16x16_nb[256][2];
+extern const int16_t ff_vp9_row_scan_16x16_nb[256][2];
+extern const int16_t ff_vp9_default_scan_32x32_nb[1024][2];
+extern const int16_t (*ff_vp9_scans_nb[5][4])[2];
+extern const uint8_t ff_vp9_model_pareto8[256][8];
+extern const ProbContext ff_vp9_default_probs;
+extern const uint8_t ff_vp9_default_coef_probs[4][2][2][6][6][3];
+extern const int8_t ff_vp9_mv_joint_tree[3][2];
+extern const int8_t ff_vp9_mv_class_tree[10][2];
+extern const int8_t ff_vp9_mv_fp_tree[3][2];
+
+#endif /* AVCODEC_VP9DATA_H */

libavcodec/vp9mvs.c

+/*
+ * VP9 compatible video decoder
+ *
+ * Copyright (C) 2013 Ronald S. Bultje <rsbultje gmail com>
+ * Copyright (C) 2013 Clément Bœsch <u pkh me>
+ *
+ * This file is part of Libav.
+ *
+ * Libav 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.
+ *
+ * Libav 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 Libav; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+#include "internal.h"
+#include "vp56.h"
+#include "vp9.h"
+#include "vp9data.h"
+
+static av_always_inline void clamp_mv(VP56mv *dst, const VP56mv *src,
+                                      VP9Context *s)
+{
+    dst->x = av_clip(src->x, s->min_mv.x, s->max_mv.x);
+    dst->y = av_clip(src->y, s->min_mv.y, s->max_mv.y);
+}
+
+static void find_ref_mvs(VP9Context *s,
+                         VP56mv *pmv, int ref, int z, int idx, int sb)
+{
+    static const int8_t mv_ref_blk_off[N_BS_SIZES][8][2] = {
+        [BS_64x64] = { {  3, -1 }, { -1,  3 }, {  4, -1 }, { -1,  4 },
+                       { -1, -1 }, {  0, -1 }, { -1,  0 }, {  6, -1 } },
+        [BS_64x32] = { {  0, -1 }, { -1,  0 }, {  4, -1 }, { -1,  2 },
+                       { -1, -1 }, {  0, -3 }, { -3,  0 }, {  2, -1 } },
+        [BS_32x64] = { { -1,  0 }, {  0, -1 }, { -1,  4 }, {  2, -1 },
+                       { -1, -1 }, { -3,  0 }, {  0, -3 }, { -1,  2 } },
+        [BS_32x32] = { {  1, -1 }, { -1,  1 }, {  2, -1 }, { -1,  2 },
+                       { -1, -1 }, {  0, -3 }, { -3,  0 }, { -3, -3 } },
+        [BS_32x16] = { {  0, -1 }, { -1,  0 }, {  2, -1 }, { -1, -1 },
+                       { -1,  1 }, {  0, -3 }, { -3,  0 }, { -3, -3 } },
+        [BS_16x32] = { { -1,  0 }, {  0, -1 }, { -1,  2 }, { -1, -1 },
+                       {  1, -1 }, { -3,  0 }, {  0, -3 }, { -3, -3 } },
+        [BS_16x16] = { {  0, -1 }, { -1,  0 }, {  1, -1 }, { -1,  1 },
+                       { -1, -1 }, {  0, -3 }, { -3,  0 }, { -3, -3 } },
+        [BS_16x8]  = { {  0, -1 }, { -1,  0 }, {  1, -1 }, { -1, -1 },
+                       {  0, -2 }, { -2,  0 }, { -2, -1 }, { -1, -2 } },
+        [BS_8x16]  = { { -1,  0 }, {  0, -1 }, { -1,  1 }, { -1, -1 },
+                       { -2,  0 }, {  0, -2 }, { -1, -2 }, { -2, -1 } },
+        [BS_8x8]   = { {  0, -1 }, { -1,  0 }, { -1, -1 }, {  0, -2 },
+                       { -2,  0 }, { -1, -2 }, { -2, -1 }, { -2, -2 } },