The Tor Browser: media/libvpx/vp9/encoder/vp9_encodemv.c@ac0c01689b40 (annotated)

media/libvpx/vp9/encoder/vp9_encodemv.c@ac0c01689b40 (annotated)

media/libvpx/vp9/encoder/vp9_encodemv.c

Thu, 15 Jan 2015 15:59:08 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 15:59:08 +0100
branch: TOR_BUG_9701
changeset 10: ac0c01689b40
permissions: -rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /*
  *  Copyright (c) 2010 The WebM project authors. All Rights Reserved.
  *
  *  Use of this source code is governed by a BSD-style license
  *  that can be found in the LICENSE file in the root of the source
  *  tree. An additional intellectual property rights grant can be found
  *  in the file PATENTS.  All contributing project authors may
  *  be found in the AUTHORS file in the root of the source tree.
  */
 #include <math.h>
 #include "vp9/common/vp9_common.h"
 #include "vp9/common/vp9_entropymode.h"
 #include "vp9/common/vp9_systemdependent.h"
 #include "vp9/encoder/vp9_encodemv.h"
 #ifdef ENTROPY_STATS
 extern unsigned int active_section;
 #endif
 static void encode_mv_component(vp9_writer* w, int comp,
                                 const nmv_component* mvcomp, int usehp) {
   int offset;
   const int sign = comp < 0;
   const int mag = sign ? -comp : comp;
   const int mv_class = vp9_get_mv_class(mag - 1, &offset);
   const int d = offset >> 3;                // int mv data
   const int fr = (offset >> 1) & 3;         // fractional mv data
   const int hp = offset & 1;                // high precision mv data
   assert(comp != 0);
   // Sign
   vp9_write(w, sign, mvcomp->sign);
   // Class
   write_token(w, vp9_mv_class_tree, mvcomp->classes,
               &vp9_mv_class_encodings[mv_class]);
   // Integer bits
   if (mv_class == MV_CLASS_0) {
     write_token(w, vp9_mv_class0_tree, mvcomp->class0,
                 &vp9_mv_class0_encodings[d]);
   } else {
     int i;
     const int n = mv_class + CLASS0_BITS - 1;  // number of bits
     for (i = 0; i < n; ++i)
       vp9_write(w, (d >> i) & 1, mvcomp->bits[i]);
   }
   // Fractional bits
   write_token(w, vp9_mv_fp_tree,
               mv_class == MV_CLASS_0 ?  mvcomp->class0_fp[d] : mvcomp->fp,
               &vp9_mv_fp_encodings[fr]);
   // High precision bit
   if (usehp)
     vp9_write(w, hp,
               mv_class == MV_CLASS_0 ? mvcomp->class0_hp : mvcomp->hp);
 }
 static void build_nmv_component_cost_table(int *mvcost,
                                            const nmv_component* const mvcomp,
                                            int usehp) {
   int i, v;
   int sign_cost[2], class_cost[MV_CLASSES], class0_cost[CLASS0_SIZE];
   int bits_cost[MV_OFFSET_BITS][2];
   int class0_fp_cost[CLASS0_SIZE][4], fp_cost[4];
   int class0_hp_cost[2], hp_cost[2];
   sign_cost[0] = vp9_cost_zero(mvcomp->sign);
   sign_cost[1] = vp9_cost_one(mvcomp->sign);
   vp9_cost_tokens(class_cost, mvcomp->classes, vp9_mv_class_tree);
   vp9_cost_tokens(class0_cost, mvcomp->class0, vp9_mv_class0_tree);
   for (i = 0; i < MV_OFFSET_BITS; ++i) {
     bits_cost[i][0] = vp9_cost_zero(mvcomp->bits[i]);
     bits_cost[i][1] = vp9_cost_one(mvcomp->bits[i]);
   }
   for (i = 0; i < CLASS0_SIZE; ++i)
     vp9_cost_tokens(class0_fp_cost[i], mvcomp->class0_fp[i], vp9_mv_fp_tree);
   vp9_cost_tokens(fp_cost, mvcomp->fp, vp9_mv_fp_tree);
   if (usehp) {
     class0_hp_cost[0] = vp9_cost_zero(mvcomp->class0_hp);
     class0_hp_cost[1] = vp9_cost_one(mvcomp->class0_hp);
     hp_cost[0] = vp9_cost_zero(mvcomp->hp);
     hp_cost[1] = vp9_cost_one(mvcomp->hp);
   }
   mvcost[0] = 0;
   for (v = 1; v <= MV_MAX; ++v) {
     int z, c, o, d, e, f, cost = 0;
     z = v - 1;
     c = vp9_get_mv_class(z, &o);
     cost += class_cost[c];
     d = (o >> 3);               /* int mv data */
     f = (o >> 1) & 3;           /* fractional pel mv data */
     e = (o & 1);                /* high precision mv data */
     if (c == MV_CLASS_0) {
       cost += class0_cost[d];
     } else {
       int i, b;
       b = c + CLASS0_BITS - 1;  /* number of bits */
       for (i = 0; i < b; ++i)
         cost += bits_cost[i][((d >> i) & 1)];
     }
     if (c == MV_CLASS_0) {
       cost += class0_fp_cost[d][f];
     } else {
       cost += fp_cost[f];
     }
     if (usehp) {
       if (c == MV_CLASS_0) {
         cost += class0_hp_cost[e];
       } else {
         cost += hp_cost[e];
       }
     }
     mvcost[v] = cost + sign_cost[0];
     mvcost[-v] = cost + sign_cost[1];
   }
 }
 static int update_mv(vp9_writer *w, const unsigned int ct[2], vp9_prob *cur_p,
                      vp9_prob upd_p) {
   const vp9_prob new_p = get_binary_prob(ct[0], ct[1]);
   vp9_prob mod_p = new_p | 1;
   const int cur_b = cost_branch256(ct, *cur_p);
   const int mod_b = cost_branch256(ct, mod_p);
   const int cost = 7 * 256 + (vp9_cost_one(upd_p) - vp9_cost_zero(upd_p));
   if (cur_b - mod_b > cost) {
     *cur_p = mod_p;
     vp9_write(w, 1, upd_p);
     vp9_write_literal(w, mod_p >> 1, 7);
     return 1;
   } else {
     vp9_write(w, 0, upd_p);
     return 0;
   }
 }
 static void counts_to_nmv_context(
     nmv_context_counts *nmv_count,
     int usehp,
     unsigned int (*branch_ct_joint)[2],
     unsigned int (*branch_ct_sign)[2],
     unsigned int (*branch_ct_classes)[MV_CLASSES - 1][2],
     unsigned int (*branch_ct_class0)[CLASS0_SIZE - 1][2],
     unsigned int (*branch_ct_bits)[MV_OFFSET_BITS][2],
     unsigned int (*branch_ct_class0_fp)[CLASS0_SIZE][4 - 1][2],
     unsigned int (*branch_ct_fp)[4 - 1][2],
     unsigned int (*branch_ct_class0_hp)[2],
     unsigned int (*branch_ct_hp)[2]) {
   int i, j, k;
   vp9_tree_probs_from_distribution(vp9_mv_joint_tree, branch_ct_joint,
                                    nmv_count->joints);
   for (i = 0; i < 2; ++i) {
     const uint32_t s0 = nmv_count->comps[i].sign[0];
     const uint32_t s1 = nmv_count->comps[i].sign[1];
     branch_ct_sign[i][0] = s0;
     branch_ct_sign[i][1] = s1;
     vp9_tree_probs_from_distribution(vp9_mv_class_tree,
                                     branch_ct_classes[i],
                                     nmv_count->comps[i].classes);
     vp9_tree_probs_from_distribution(vp9_mv_class0_tree,
                                      branch_ct_class0[i],
                                      nmv_count->comps[i].class0);
     for (j = 0; j < MV_OFFSET_BITS; ++j) {
       const uint32_t b0 = nmv_count->comps[i].bits[j][0];
       const uint32_t b1 = nmv_count->comps[i].bits[j][1];
       branch_ct_bits[i][j][0] = b0;
       branch_ct_bits[i][j][1] = b1;
     }
   }
   for (i = 0; i < 2; ++i) {
     for (k = 0; k < CLASS0_SIZE; ++k) {
       vp9_tree_probs_from_distribution(vp9_mv_fp_tree,
                                        branch_ct_class0_fp[i][k],
                                        nmv_count->comps[i].class0_fp[k]);
     }
     vp9_tree_probs_from_distribution(vp9_mv_fp_tree,
                                      branch_ct_fp[i],
                                      nmv_count->comps[i].fp);
   }
   if (usehp) {
     for (i = 0; i < 2; ++i) {
       const uint32_t c0_hp0 = nmv_count->comps[i].class0_hp[0];
       const uint32_t c0_hp1 = nmv_count->comps[i].class0_hp[1];
       const uint32_t hp0 = nmv_count->comps[i].hp[0];
       const uint32_t hp1 = nmv_count->comps[i].hp[1];
       branch_ct_class0_hp[i][0] = c0_hp0;
       branch_ct_class0_hp[i][1] = c0_hp1;
       branch_ct_hp[i][0] = hp0;
       branch_ct_hp[i][1] = hp1;
     }
   }
 }
 void vp9_write_nmv_probs(VP9_COMP* const cpi, int usehp, vp9_writer* const bc) {
   int i, j;
   unsigned int branch_ct_joint[MV_JOINTS - 1][2];
   unsigned int branch_ct_sign[2][2];
   unsigned int branch_ct_classes[2][MV_CLASSES - 1][2];
   unsigned int branch_ct_class0[2][CLASS0_SIZE - 1][2];
   unsigned int branch_ct_bits[2][MV_OFFSET_BITS][2];
   unsigned int branch_ct_class0_fp[2][CLASS0_SIZE][4 - 1][2];
   unsigned int branch_ct_fp[2][4 - 1][2];
   unsigned int branch_ct_class0_hp[2][2];
   unsigned int branch_ct_hp[2][2];
   nmv_context *mvc = &cpi->common.fc.nmvc;
   counts_to_nmv_context(&cpi->NMVcount, usehp,
                         branch_ct_joint, branch_ct_sign, branch_ct_classes,
                         branch_ct_class0, branch_ct_bits,
                         branch_ct_class0_fp, branch_ct_fp,
                         branch_ct_class0_hp, branch_ct_hp);
   for (j = 0; j < MV_JOINTS - 1; ++j)
     update_mv(bc, branch_ct_joint[j], &mvc->joints[j], NMV_UPDATE_PROB);
   for (i = 0; i < 2; ++i) {
     update_mv(bc, branch_ct_sign[i], &mvc->comps[i].sign, NMV_UPDATE_PROB);
     for (j = 0; j < MV_CLASSES - 1; ++j)
       update_mv(bc, branch_ct_classes[i][j], &mvc->comps[i].classes[j],
                 NMV_UPDATE_PROB);
     for (j = 0; j < CLASS0_SIZE - 1; ++j)
       update_mv(bc, branch_ct_class0[i][j], &mvc->comps[i].class0[j],
                 NMV_UPDATE_PROB);
     for (j = 0; j < MV_OFFSET_BITS; ++j)
       update_mv(bc, branch_ct_bits[i][j], &mvc->comps[i].bits[j],
                 NMV_UPDATE_PROB);
   }
   for (i = 0; i < 2; ++i) {
     for (j = 0; j < CLASS0_SIZE; ++j) {
       int k;
       for (k = 0; k < 3; ++k)
         update_mv(bc, branch_ct_class0_fp[i][j][k],
                   &mvc->comps[i].class0_fp[j][k], NMV_UPDATE_PROB);
     }
     for (j = 0; j < 3; ++j)
       update_mv(bc, branch_ct_fp[i][j], &mvc->comps[i].fp[j], NMV_UPDATE_PROB);
   }
   if (usehp) {
     for (i = 0; i < 2; ++i) {
       update_mv(bc, branch_ct_class0_hp[i], &mvc->comps[i].class0_hp,
                 NMV_UPDATE_PROB);
       update_mv(bc, branch_ct_hp[i], &mvc->comps[i].hp,
                 NMV_UPDATE_PROB);
     }
   }
 }
 void vp9_encode_mv(VP9_COMP* cpi, vp9_writer* w,
                    const MV* mv, const MV* ref,
                    const nmv_context* mvctx, int usehp) {
   const MV diff = {mv->row - ref->row,
                    mv->col - ref->col};
   const MV_JOINT_TYPE j = vp9_get_mv_joint(&diff);
   usehp = usehp && vp9_use_mv_hp(ref);
   write_token(w, vp9_mv_joint_tree, mvctx->joints, &vp9_mv_joint_encodings[j]);
   if (mv_joint_vertical(j))
     encode_mv_component(w, diff.row, &mvctx->comps[0], usehp);
   if (mv_joint_horizontal(j))
     encode_mv_component(w, diff.col, &mvctx->comps[1], usehp);
   // If auto_mv_step_size is enabled then keep track of the largest
   // motion vector component used.
   if (!cpi->dummy_packing && cpi->sf.auto_mv_step_size) {
     unsigned int maxv = MAX(abs(mv->row), abs(mv->col)) >> 3;
     cpi->max_mv_magnitude = MAX(maxv, cpi->max_mv_magnitude);
   }
 }
 void vp9_build_nmv_cost_table(int *mvjoint,
                               int *mvcost[2],
                               const nmv_context* const mvctx,
                               int usehp,
                               int mvc_flag_v,
                               int mvc_flag_h) {
   vp9_clear_system_state();
   vp9_cost_tokens(mvjoint, mvctx->joints, vp9_mv_joint_tree);
   if (mvc_flag_v)
     build_nmv_component_cost_table(mvcost[0], &mvctx->comps[0], usehp);
   if (mvc_flag_h)
     build_nmv_component_cost_table(mvcost[1], &mvctx->comps[1], usehp);
 }
 static void inc_mvs(int_mv mv[2], int_mv ref[2], int is_compound,
                     nmv_context_counts *counts) {
   int i;
   for (i = 0; i < 1 + is_compound; ++i) {
     const MV diff = { mv[i].as_mv.row - ref[i].as_mv.row,
                       mv[i].as_mv.col - ref[i].as_mv.col };
     vp9_inc_mv(&diff, counts);
   }
 }
 void vp9_update_mv_count(VP9_COMP *cpi, MACROBLOCK *x, int_mv best_ref_mv[2]) {
   MODE_INFO *mi = x->e_mbd.mi_8x8[0];
   MB_MODE_INFO *const mbmi = &mi->mbmi;
   const int is_compound = has_second_ref(mbmi);
   if (mbmi->sb_type < BLOCK_8X8) {
     const int num_4x4_w = num_4x4_blocks_wide_lookup[mbmi->sb_type];
     const int num_4x4_h = num_4x4_blocks_high_lookup[mbmi->sb_type];
     int idx, idy;
     for (idy = 0; idy < 2; idy += num_4x4_h) {
       for (idx = 0; idx < 2; idx += num_4x4_w) {
         const int i = idy * 2 + idx;
         if (mi->bmi[i].as_mode == NEWMV)
           inc_mvs(mi->bmi[i].as_mv, best_ref_mv, is_compound, &cpi->NMVcount);
       }
     }
   } else if (mbmi->mode == NEWMV) {
     inc_mvs(mbmi->mv, best_ref_mv, is_compound, &cpi->NMVcount);
   }
 }

The Tor Browser / annotate

media/libvpx/vp9/encoder/vp9_encodemv.c@ac0c01689b40 (annotated)

media/libvpx/vp9/encoder/vp9_encodemv.c