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>

1 files changed, 344 insertions, 0 deletions

diff --git a/libavcodec/vp9mvs.c b/libavcodec/vp9mvs.c
new file mode 100644
index 0000000000..2f37755046
--- /dev/null
+++ b/libavcodec/vp9mvs.c
@@ -0,0 +1,344 @@
+/*
+ * 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 } },
+        [BS_8x4]   = { {  0, -1 }, { -1,  0 }, { -1, -1 }, {  0, -2 },
+                       { -2,  0 }, { -1, -2 }, { -2, -1 }, { -2, -2 } },
+        [BS_4x8]   = { {  0, -1 }, { -1,  0 }, { -1, -1 }, {  0, -2 },
+                       { -2,  0 }, { -1, -2 }, { -2, -1 }, { -2, -2 } },
+        [BS_4x4]   = { {  0, -1 }, { -1,  0 }, { -1, -1 }, {  0, -2 },
+                       { -2,  0 }, { -1, -2 }, { -2, -1 }, { -2, -2 } },
+    };
+    VP9Block *const b = &s->b;
+    int row = b->row, col = b->col, row7 = b->row7;
+    const int8_t (*p)[2] = mv_ref_blk_off[b->bs];
+#define INVALID_MV 0x80008000U
+    uint32_t mem = INVALID_MV;
+    int i;
+
+#define RETURN_DIRECT_MV(mv)                    \
+    do {                                        \
+        uint32_t m = AV_RN32A(&mv);             \
+        if (!idx) {                             \
+            AV_WN32A(pmv, m);                   \
+            return;                             \
+        } else if (mem == INVALID_MV) {         \
+            mem = m;                            \
+        } else if (m != mem) {                  \
+            AV_WN32A(pmv, m);                   \
+            return;                             \
+        }                                       \
+    } while (0)
+
+    if (sb >= 0) {
+        if (sb == 2 || sb == 1) {
+            RETURN_DIRECT_MV(b->mv[0][z]);
+        } else if (sb == 3) {
+            RETURN_DIRECT_MV(b->mv[2][z]);
+            RETURN_DIRECT_MV(b->mv[1][z]);
+            RETURN_DIRECT_MV(b->mv[0][z]);
+        }
+
+#define RETURN_MV(mv)                           \
+    do {                                        \
+        if (sb > 0) {                           \
+            VP56mv tmp;                         \
+            uint32_t m;                         \
+            clamp_mv(&tmp, &mv, s);             \
+            m = AV_RN32A(&tmp);                 \
+            if (!idx) {                         \
+                AV_WN32A(pmv, m);               \
+                return;                         \
+            } else if (mem == INVALID_MV) {     \
+                mem = m;                        \
+            } else if (m != mem) {              \
+                AV_WN32A(pmv, m);               \
+                return;                         \
+            }                                   \
+        } else {                                \
+            uint32_t m = AV_RN32A(&mv);         \
+            if (!idx) {                         \
+                clamp_mv(pmv, &mv, s);          \
+                return;                         \
+            } else if (mem == INVALID_MV) {     \
+                mem = m;                        \
+            } else if (m != mem) {              \
+                clamp_mv(pmv, &mv, s);          \
+                return;                         \
+            }                                   \
+        }                                       \
+    } while (0)
+
+        if (row > 0) {
+            VP9MVRefPair *mv = &s->mv[0][(row - 1) * s->sb_cols * 8 + col];
+
+            if (mv->ref[0] == ref)
+                RETURN_MV(s->above_mv_ctx[2 * col + (sb & 1)][0]);
+            else if (mv->ref[1] == ref)
+                RETURN_MV(s->above_mv_ctx[2 * col + (sb & 1)][1]);
+        }
+        if (col > s->tiling.tile_col_start) {
+            VP9MVRefPair *mv = &s->mv[0][row * s->sb_cols * 8 + col - 1];
+
+            if (mv->ref[0] == ref)
+                RETURN_MV(s->left_mv_ctx[2 * row7 + (sb >> 1)][0]);
+            else if (mv->ref[1] == ref)
+                RETURN_MV(s->left_mv_ctx[2 * row7 + (sb >> 1)][1]);
+        }
+        i = 2;
+    } else {
+        i = 0;
+    }
+
+    // previously coded MVs in the neighborhood, using same reference frame
+    for (; i < 8; i++) {
+        int c = p[i][0] + col, r = p[i][1] + row;
+
+        if (c >= s->tiling.tile_col_start && c < s->cols &&
+            r >= 0 && r < s->rows) {
+            VP9MVRefPair *mv = &s->mv[0][r * s->sb_cols * 8 + c];
+
+            if (mv->ref[0] == ref)
+                RETURN_MV(mv->mv[0]);
+            else if (mv->ref[1] == ref)
+                RETURN_MV(mv->mv[1]);
+        }
+    }
+
+    // MV at this position in previous frame, using same reference frame
+    if (s->use_last_frame_mvs) {
+        VP9MVRefPair *mv = &s->mv[1][row * s->sb_cols * 8 + col];
+
+        if (mv->ref[0] == ref)
+            RETURN_MV(mv->mv[0]);
+        else if (mv->ref[1] == ref)
+            RETURN_MV(mv->mv[1]);
+    }
+
+#define RETURN_SCALE_MV(mv, scale)              \
+    do {                                        \
+        if (scale) {                            \
+            VP56mv mv_temp = { -mv.x, -mv.y };  \
+            RETURN_MV(mv_temp);                 \
+        } else {                                \
+            RETURN_MV(mv);                      \
+        }                                       \
+    } while (0)
+
+    // previously coded MVs in the neighborhood, using different reference frame
+    for (i = 0; i < 8; i++) {
+        int c = p[i][0] + col, r = p[i][1] + row;
+
+        if (c >= s->tiling.tile_col_start && c < s->cols &&
+            r >= 0 && r < s->rows) {
+            VP9MVRefPair *mv = &s->mv[0][r * s->sb_cols * 8 + c];
+
+            if (mv->ref[0] != ref && mv->ref[0] >= 0)
+                RETURN_SCALE_MV(mv->mv[0],
+                                s->signbias[mv->ref[0]] != s->signbias[ref]);
+            if (mv->ref[1] != ref && mv->ref[1] >= 0)
+                RETURN_SCALE_MV(mv->mv[1],
+                                s->signbias[mv->ref[1]] != s->signbias[ref]);
+        }
+    }
+
+    // MV at this position in previous frame, using different reference frame
+    if (s->use_last_frame_mvs) {
+        VP9MVRefPair *mv = &s->mv[1][row * s->sb_cols * 8 + col];
+
+        if (mv->ref[0] != ref && mv->ref[0] >= 0)
+            RETURN_SCALE_MV(mv->mv[0],
+                            s->signbias[mv->ref[0]] != s->signbias[ref]);
+        if (mv->ref[1] != ref && mv->ref[1] >= 0)
+            RETURN_SCALE_MV(mv->mv[1],
+                            s->signbias[mv->ref[1]] != s->signbias[ref]);
+    }
+
+    AV_ZERO32(pmv);
+#undef INVALID_MV
+#undef RETURN_MV
+#undef RETURN_SCALE_MV
+}
+
+static av_always_inline int read_mv_component(VP9Context *s, int idx, int hp)
+{
+    int bit, sign = vp56_rac_get_prob(&s->c, s->prob.p.mv_comp[idx].sign);
+    int n, c = vp8_rac_get_tree(&s->c, ff_vp9_mv_class_tree,
+                                s->prob.p.mv_comp[idx].classes);
+
+    s->counts.mv_comp[idx].sign[sign]++;
+    s->counts.mv_comp[idx].classes[c]++;
+    if (c) {
+        int m;
+
+        for (n = 0, m = 0; m < c; m++) {
+            bit = vp56_rac_get_prob(&s->c, s->prob.p.mv_comp[idx].bits[m]);
+            n  |= bit << m;
+            s->counts.mv_comp[idx].bits[m][bit]++;
+        }
+        n <<= 3;
+        bit = vp8_rac_get_tree(&s->c, ff_vp9_mv_fp_tree,
+                               s->prob.p.mv_comp[idx].fp);
+        n  |= bit << 1;
+        s->counts.mv_comp[idx].fp[bit]++;
+        if (hp) {
+            bit = vp56_rac_get_prob(&s->c, s->prob.p.mv_comp[idx].hp);
+            s->counts.mv_comp[idx].hp[bit]++;
+            n |= bit;
+        } else {
+            n |= 1;
+            // bug in libvpx - we count for bw entropy purposes even if the
+            // bit wasn't coded
+            s->counts.mv_comp[idx].hp[1]++;
+        }
+        n += 8 << c;
+    } else {
+        n = vp56_rac_get_prob(&s->c, s->prob.p.mv_comp[idx].class0);
+        s->counts.mv_comp[idx].class0[n]++;
+        bit = vp8_rac_get_tree(&s->c, ff_vp9_mv_fp_tree,
+                               s->prob.p.mv_comp[idx].class0_fp[n]);
+        s->counts.mv_comp[idx].class0_fp[n][bit]++;
+        n = (n << 3) | (bit << 1);
+        if (hp) {
+            bit = vp56_rac_get_prob(&s->c, s->prob.p.mv_comp[idx].class0_hp);
+            s->counts.mv_comp[idx].class0_hp[bit]++;
+            n |= bit;
+        } else {
+            n |= 1;
+            // bug in libvpx - we count for bw entropy purposes even if the
+            // bit wasn't coded
+            s->counts.mv_comp[idx].class0_hp[1]++;
+        }
+    }
+
+    return sign ? -(n + 1) : (n + 1);
+}
+
+void ff_vp9_fill_mv(VP9Context *s, VP56mv *mv, int mode, int sb)
+{
+    VP9Block *const b = &s->b;
+
+    if (mode == ZEROMV) {
+        memset(mv, 0, sizeof(*mv) * 2);
+    } else {
+        int hp;
+
+        // FIXME cache this value and reuse for other subblocks
+        find_ref_mvs(s, &mv[0], b->ref[0], 0, mode == NEARMV,
+                     mode == NEWMV ? -1 : sb);
+        // FIXME maybe move this code into find_ref_mvs()
+        if ((mode == NEWMV || sb == -1) &&
+            !(hp = s->highprecisionmvs &&
+              abs(mv[0].x) < 64 && abs(mv[0].y) < 64)) {
+            if (mv[0].y & 1) {
+                if (mv[0].y < 0)
+                    mv[0].y++;
+                else
+                    mv[0].y--;
+            }
+            if (mv[0].x & 1) {
+                if (mv[0].x < 0)
+                    mv[0].x++;
+                else
+                    mv[0].x--;
+            }
+        }
+        if (mode == NEWMV) {
+            enum MVJoint j = vp8_rac_get_tree(&s->c, ff_vp9_mv_joint_tree,
+                                              s->prob.p.mv_joint);
+
+            s->counts.mv_joint[j]++;
+            if (j >= MV_JOINT_V)
+                mv[0].y += read_mv_component(s, 0, hp);
+            if (j & 1)
+                mv[0].x += read_mv_component(s, 1, hp);
+        }
+
+        if (b->comp) {
+            // FIXME cache this value and reuse for other subblocks
+            find_ref_mvs(s, &mv[1], b->ref[1], 1, mode == NEARMV,
+                         mode == NEWMV ? -1 : sb);
+            if ((mode == NEWMV || sb == -1) &&
+                !(hp = s->highprecisionmvs &&
+                  abs(mv[1].x) < 64 && abs(mv[1].y) < 64)) {
+                if (mv[1].y & 1) {
+                    if (mv[1].y < 0)
+                        mv[1].y++;
+                    else
+                        mv[1].y--;
+                }
+                if (mv[1].x & 1) {
+                    if (mv[1].x < 0)
+                        mv[1].x++;
+                    else
+                        mv[1].x--;
+                }
+            }
+            if (mode == NEWMV) {
+                enum MVJoint j = vp8_rac_get_tree(&s->c, ff_vp9_mv_joint_tree,
+                                                  s->prob.p.mv_joint);
+
+                s->counts.mv_joint[j]++;
+                if (j >= MV_JOINT_V)
+                    mv[1].y += read_mv_component(s, 0, hp);
+                if (j & 1)
+                    mv[1].x += read_mv_component(s, 1, hp);
+            }
+        }
+    }
+}