The Tor Browser: media/libvpx/vp9/encoder/vp9_quantize.c@ac0c01689b40 (annotated)

media/libvpx/vp9/encoder/vp9_quantize.c@ac0c01689b40 (annotated)

media/libvpx/vp9/encoder/vp9_quantize.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 "vpx_mem/vpx_mem.h"
 #include "vp9/encoder/vp9_onyx_int.h"
 #include "vp9/encoder/vp9_rdopt.h"
 #include "vp9/encoder/vp9_quantize.h"
 #include "vp9/common/vp9_quant_common.h"
 #include "vp9/common/vp9_seg_common.h"
 #ifdef ENC_DEBUG
 extern int enc_debug;
 #endif
 void vp9_quantize_b_c(const int16_t *coeff_ptr, intptr_t count,
                       int skip_block,
                       const int16_t *zbin_ptr, const int16_t *round_ptr,
                       const int16_t *quant_ptr, const int16_t *quant_shift_ptr,
                       int16_t *qcoeff_ptr, int16_t *dqcoeff_ptr,
                       const int16_t *dequant_ptr,
                       int zbin_oq_value, uint16_t *eob_ptr,
                       const int16_t *scan, const int16_t *iscan) {
   int i, non_zero_count = count, eob = -1;
   const int zbins[2] = { zbin_ptr[0] + zbin_oq_value,
                          zbin_ptr[1] + zbin_oq_value };
   const int nzbins[2] = { zbins[0] * -1,
                           zbins[1] * -1 };
   vpx_memset(qcoeff_ptr, 0, count * sizeof(int16_t));
   vpx_memset(dqcoeff_ptr, 0, count * sizeof(int16_t));
   if (!skip_block) {
     // Pre-scan pass
     for (i = count - 1; i >= 0; i--) {
       const int rc = scan[i];
       const int coeff = coeff_ptr[rc];
       if (coeff < zbins[rc != 0] && coeff > nzbins[rc != 0])
         non_zero_count--;
       else
         break;
     }
     // Quantization pass: All coefficients with index >= zero_flag are
     // skippable. Note: zero_flag can be zero.
     for (i = 0; i < non_zero_count; i++) {
       const int rc = scan[i];
       const int coeff = coeff_ptr[rc];
       const int coeff_sign = (coeff >> 31);
       const int abs_coeff = (coeff ^ coeff_sign) - coeff_sign;
       if (abs_coeff >= zbins[rc != 0]) {
         int tmp = clamp(abs_coeff + round_ptr[rc != 0], INT16_MIN, INT16_MAX);
         tmp = ((((tmp * quant_ptr[rc != 0]) >> 16) + tmp) *
                   quant_shift_ptr[rc != 0]) >> 16;  // quantization
         qcoeff_ptr[rc]  = (tmp ^ coeff_sign) - coeff_sign;
         dqcoeff_ptr[rc] = qcoeff_ptr[rc] * dequant_ptr[rc != 0];
         if (tmp)
           eob = i;
       }
     }
   }
   *eob_ptr = eob + 1;
 }
 void vp9_quantize_b_32x32_c(const int16_t *coeff_ptr, intptr_t n_coeffs,
                             int skip_block,
                             const int16_t *zbin_ptr, const int16_t *round_ptr,
                             const int16_t *quant_ptr,
                             const int16_t *quant_shift_ptr,
                             int16_t *qcoeff_ptr, int16_t *dqcoeff_ptr,
                             const int16_t *dequant_ptr,
                             int zbin_oq_value, uint16_t *eob_ptr,
                             const int16_t *scan, const int16_t *iscan) {
   int i, rc, eob;
   int zbins[2], nzbins[2];
   int x, y, z, sz;
   int idx = 0;
   int idx_arr[1024];
   vpx_memset(qcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
   vpx_memset(dqcoeff_ptr, 0, n_coeffs*sizeof(int16_t));
   eob = -1;
   // Base ZBIN
   zbins[0] = ROUND_POWER_OF_TWO(zbin_ptr[0] + zbin_oq_value, 1);
   zbins[1] = ROUND_POWER_OF_TWO(zbin_ptr[1] + zbin_oq_value, 1);
   nzbins[0] = zbins[0] * -1;
   nzbins[1] = zbins[1] * -1;
   if (!skip_block) {
     // Pre-scan pass
     for (i = 0; i < n_coeffs; i++) {
       rc = scan[i];
       z = coeff_ptr[rc];
       // If the coefficient is out of the base ZBIN range, keep it for
       // quantization.
       if (z >= zbins[rc != 0] || z <= nzbins[rc != 0])
         idx_arr[idx++] = i;
     }
     // Quantization pass: only process the coefficients selected in
     // pre-scan pass. Note: idx can be zero.
     for (i = 0; i < idx; i++) {
       rc = scan[idx_arr[i]];
       z = coeff_ptr[rc];
       sz = (z >> 31);                               // sign of z
       x  = (z ^ sz) - sz;                           // x = abs(z)
       x += ROUND_POWER_OF_TWO(round_ptr[rc != 0], 1);
       x  = clamp(x, INT16_MIN, INT16_MAX);
       y  = ((((x * quant_ptr[rc != 0]) >> 16) + x) *
             quant_shift_ptr[rc != 0]) >> 15;      // quantize (x)
       x  = (y ^ sz) - sz;                         // get the sign back
       qcoeff_ptr[rc]  = x;                        // write to destination
       dqcoeff_ptr[rc] = x * dequant_ptr[rc != 0] / 2;  // dequantized value
       if (y)
         eob = idx_arr[i];                         // last nonzero coeffs
     }
   }
   *eob_ptr = eob + 1;
 }
 struct plane_block_idx {
   int plane;
   int block;
 };
 // TODO(jkoleszar): returning a struct so it can be used in a const context,
 // expect to refactor this further later.
 static INLINE struct plane_block_idx plane_block_idx(int y_blocks,
                                                      int b_idx) {
   const int v_offset = y_blocks * 5 / 4;
   struct plane_block_idx res;
   if (b_idx < y_blocks) {
     res.plane = 0;
     res.block = b_idx;
   } else if (b_idx < v_offset) {
     res.plane = 1;
     res.block = b_idx - y_blocks;
   } else {
     assert(b_idx < y_blocks * 3 / 2);
     res.plane = 2;
     res.block = b_idx - v_offset;
   }
   return res;
 }
 void vp9_regular_quantize_b_4x4(MACROBLOCK *x, int y_blocks, int b_idx,
                                 const int16_t *scan, const int16_t *iscan) {
   MACROBLOCKD *const xd = &x->e_mbd;
   const struct plane_block_idx pb_idx = plane_block_idx(y_blocks, b_idx);
   struct macroblock_plane* p = &x->plane[pb_idx.plane];
   struct macroblockd_plane* pd = &xd->plane[pb_idx.plane];
   vp9_quantize_b(BLOCK_OFFSET(p->coeff, pb_idx.block),
 , x->skip_block,
            p->zbin, p->round, p->quant, p->quant_shift,
            BLOCK_OFFSET(pd->qcoeff, pb_idx.block),
            BLOCK_OFFSET(pd->dqcoeff, pb_idx.block),
            pd->dequant, p->zbin_extra, &pd->eobs[pb_idx.block], scan, iscan);
 }
 static void invert_quant(int16_t *quant, int16_t *shift, int d) {
   unsigned t;
   int l;
   t = d;
   for (l = 0; t > 1; l++)
     t >>= 1;
   t = 1 + (1 << (16 + l)) / d;
   *quant = (int16_t)(t - (1 << 16));
   *shift = 1 << (16 - l);
 }
 void vp9_init_quantizer(VP9_COMP *cpi) {
   int i, q;
   VP9_COMMON *const cm = &cpi->common;
   for (q = 0; q < QINDEX_RANGE; q++) {
     const int qzbin_factor = q == 0 ? 64 : (vp9_dc_quant(q, 0) < 148 ? 84 : 80);
     const int qrounding_factor = q == 0 ? 64 : 48;
     // y
     for (i = 0; i < 2; ++i) {
       const int quant = i == 0 ? vp9_dc_quant(q, cm->y_dc_delta_q)
                                : vp9_ac_quant(q, 0);
       invert_quant(&cpi->y_quant[q][i], &cpi->y_quant_shift[q][i], quant);
       cpi->y_zbin[q][i] = ROUND_POWER_OF_TWO(qzbin_factor * quant, 7);
       cpi->y_round[q][i] = (qrounding_factor * quant) >> 7;
       cm->y_dequant[q][i] = quant;
     }
     // uv
     for (i = 0; i < 2; ++i) {
       const int quant = i == 0 ? vp9_dc_quant(q, cm->uv_dc_delta_q)
                                : vp9_ac_quant(q, cm->uv_ac_delta_q);
       invert_quant(&cpi->uv_quant[q][i], &cpi->uv_quant_shift[q][i], quant);
       cpi->uv_zbin[q][i] = ROUND_POWER_OF_TWO(qzbin_factor * quant, 7);
       cpi->uv_round[q][i] = (qrounding_factor * quant) >> 7;
       cm->uv_dequant[q][i] = quant;
     }
 #if CONFIG_ALPHA
     // alpha
     for (i = 0; i < 2; ++i) {
       const int quant = i == 0 ? vp9_dc_quant(q, cm->a_dc_delta_q)
                                : vp9_ac_quant(q, cm->a_ac_delta_q);
       invert_quant(&cpi->a_quant[q][i], &cpi->a_quant_shift[q][i], quant);
       cpi->a_zbin[q][i] = ROUND_POWER_OF_TWO(qzbin_factor * quant, 7);
       cpi->a_round[q][i] = (qrounding_factor * quant) >> 7;
       cm->a_dequant[q][i] = quant;
     }
 #endif
     for (i = 2; i < 8; i++) {
       cpi->y_quant[q][i] = cpi->y_quant[q][1];
       cpi->y_quant_shift[q][i] = cpi->y_quant_shift[q][1];
       cpi->y_zbin[q][i] = cpi->y_zbin[q][1];
       cpi->y_round[q][i] = cpi->y_round[q][1];
       cm->y_dequant[q][i] = cm->y_dequant[q][1];
       cpi->uv_quant[q][i] = cpi->uv_quant[q][1];
       cpi->uv_quant_shift[q][i] = cpi->uv_quant_shift[q][1];
       cpi->uv_zbin[q][i] = cpi->uv_zbin[q][1];
       cpi->uv_round[q][i] = cpi->uv_round[q][1];
       cm->uv_dequant[q][i] = cm->uv_dequant[q][1];
 #if CONFIG_ALPHA
       cpi->a_quant[q][i] = cpi->a_quant[q][1];
       cpi->a_quant_shift[q][i] = cpi->a_quant_shift[q][1];
       cpi->a_zbin[q][i] = cpi->a_zbin[q][1];
       cpi->a_round[q][i] = cpi->a_round[q][1];
       cm->a_dequant[q][i] = cm->a_dequant[q][1];
 #endif
     }
   }
 }
 void vp9_mb_init_quantizer(VP9_COMP *cpi, MACROBLOCK *x) {
   int i;
   VP9_COMMON *const cm = &cpi->common;
   MACROBLOCKD *xd = &x->e_mbd;
   int zbin_extra;
   int segment_id = xd->mi_8x8[0]->mbmi.segment_id;
   const int qindex = vp9_get_qindex(&cpi->common.seg, segment_id,
                                     cpi->common.base_qindex);
   int rdmult = vp9_compute_rd_mult(cpi, qindex + cm->y_dc_delta_q);
   // Y
   zbin_extra = (cpi->common.y_dequant[qindex][1] *
                  (cpi->zbin_mode_boost + x->act_zbin_adj)) >> 7;
   x->plane[0].quant = cpi->y_quant[qindex];
   x->plane[0].quant_shift = cpi->y_quant_shift[qindex];
   x->plane[0].zbin = cpi->y_zbin[qindex];
   x->plane[0].round = cpi->y_round[qindex];
   x->plane[0].zbin_extra = (int16_t)zbin_extra;
   x->e_mbd.plane[0].dequant = cpi->common.y_dequant[qindex];
   // UV
   zbin_extra = (cpi->common.uv_dequant[qindex][1] *
                 (cpi->zbin_mode_boost + x->act_zbin_adj)) >> 7;
   for (i = 1; i < 3; i++) {
     x->plane[i].quant = cpi->uv_quant[qindex];
     x->plane[i].quant_shift = cpi->uv_quant_shift[qindex];
     x->plane[i].zbin = cpi->uv_zbin[qindex];
     x->plane[i].round = cpi->uv_round[qindex];
     x->plane[i].zbin_extra = (int16_t)zbin_extra;
     x->e_mbd.plane[i].dequant = cpi->common.uv_dequant[qindex];
   }
 #if CONFIG_ALPHA
   x->plane[3].quant = cpi->a_quant[qindex];
   x->plane[3].quant_shift = cpi->a_quant_shift[qindex];
   x->plane[3].zbin = cpi->a_zbin[qindex];
   x->plane[3].round = cpi->a_round[qindex];
   x->plane[3].zbin_extra = (int16_t)zbin_extra;
   x->e_mbd.plane[3].dequant = cpi->common.a_dequant[qindex];
 #endif
   x->skip_block = vp9_segfeature_active(&cpi->common.seg, segment_id,
                                         SEG_LVL_SKIP);
   /* save this macroblock QIndex for vp9_update_zbin_extra() */
   x->q_index = qindex;
   /* R/D setup */
   cpi->mb.errorperbit = rdmult >> 6;
   cpi->mb.errorperbit += (cpi->mb.errorperbit == 0);
   vp9_initialize_me_consts(cpi, x->q_index);
 }
 void vp9_update_zbin_extra(VP9_COMP *cpi, MACROBLOCK *x) {
   const int qindex = x->q_index;
   const int y_zbin_extra = (cpi->common.y_dequant[qindex][1] *
                 (cpi->zbin_mode_boost + x->act_zbin_adj)) >> 7;
   const int uv_zbin_extra = (cpi->common.uv_dequant[qindex][1] *
                   (cpi->zbin_mode_boost + x->act_zbin_adj)) >> 7;
   x->plane[0].zbin_extra = (int16_t)y_zbin_extra;
   x->plane[1].zbin_extra = (int16_t)uv_zbin_extra;
   x->plane[2].zbin_extra = (int16_t)uv_zbin_extra;
 }
 void vp9_frame_init_quantizer(VP9_COMP *cpi) {
   // Clear Zbin mode boost for default case
   cpi->zbin_mode_boost = 0;
   // MB level quantizer setup
   vp9_mb_init_quantizer(cpi, &cpi->mb);
 }
 void vp9_set_quantizer(struct VP9_COMP *cpi, int q) {
   VP9_COMMON *cm = &cpi->common;
   cm->base_qindex = q;
   // if any of the delta_q values are changing update flag will
   // have to be set.
   cm->y_dc_delta_q = 0;
   cm->uv_dc_delta_q = 0;
   cm->uv_ac_delta_q = 0;
   // quantizer has to be reinitialized if any delta_q changes.
   // As there are not any here for now this is inactive code.
   // if(update)
   //    vp9_init_quantizer(cpi);
 }

The Tor Browser / annotate

media/libvpx/vp9/encoder/vp9_quantize.c@ac0c01689b40 (annotated)

media/libvpx/vp9/encoder/vp9_quantize.c