/* * Copyright (c) 2001-2016, Alliance for Open Media. All rights reserved * * This source code is subject to the terms of the BSD 2 Clause License and * the Alliance for Open Media Patent License 1.0. If the BSD 2 Clause License * was not distributed with this source code in the LICENSE file, you can * obtain it at www.aomedia.org/license/software. If the Alliance for Open * Media Patent License 1.0 was not distributed with this source code in the * PATENTS file, you can obtain it at www.aomedia.org/license/patent. */ /* clang-format off */ #ifdef HAVE_CONFIG_H # include "config.h" #endif #include #include #include #include "aom_dsp/entcode.h" #include "aom_dsp/entenc.h" #include "av1/common/blockd.h" #include "av1/common/odintrin.h" #include "av1/common/partition.h" #include "av1/common/pvq_state.h" #include "av1/encoder/encodemb.h" #include "av1/encoder/pvq_encoder.h" #include "aom_ports/system_state.h" /*Shift to ensure that the upper bound (i.e. for the max blocksize) of the dot-product of the 1st band of chroma with the luma ref doesn't overflow.*/ #define OD_CFL_FLIP_SHIFT (OD_LIMIT_BSIZE_MAX + 0) void aom_write_symbol_pvq(aom_writer *w, int symb, aom_cdf_prob *cdf, int nsymbs) { if (cdf[0] == 0) aom_cdf_init_q15_1D(cdf, nsymbs, CDF_SIZE(nsymbs)); aom_write_symbol(w, symb, cdf, nsymbs); } static void aom_encode_pvq_codeword(aom_writer *w, od_pvq_codeword_ctx *adapt, const od_coeff *in, int n, int k) { int i; aom_encode_band_pvq_splits(w, adapt, in, n, k, 0); for (i = 0; i < n; i++) if (in[i]) aom_write_bit(w, in[i] < 0); } /* Computes 1/sqrt(i) using a table for small values. */ static double od_rsqrt_table(int i) { static double table[16] = { 1.000000, 0.707107, 0.577350, 0.500000, 0.447214, 0.408248, 0.377964, 0.353553, 0.333333, 0.316228, 0.301511, 0.288675, 0.277350, 0.267261, 0.258199, 0.250000}; if (i <= 16) return table[i-1]; else return 1./sqrt(i); } /*Computes 1/sqrt(start+2*i+1) using a lookup table containing the results where 0 <= i < table_size.*/ static double od_custom_rsqrt_dynamic_table(const double* table, const int table_size, const double start, const int i) { if (i < table_size) return table[i]; else return od_rsqrt_table((int)(start + 2*i + 1)); } /*Fills tables used in od_custom_rsqrt_dynamic_table for a given start.*/ static void od_fill_dynamic_rsqrt_table(double *table, const int table_size, const double start) { int i; for (i = 0; i < table_size; i++) table[i] = od_rsqrt_table((int)(start + 2*i + 1)); } /** Find the codepoint on the given PSphere closest to the desired * vector. Double-precision PVQ search just to make sure our tests * aren't limited by numerical accuracy. * * @param [in] xcoeff input vector to quantize (x in the math doc) * @param [in] n number of dimensions * @param [in] k number of pulses * @param [out] ypulse optimal codevector found (y in the math doc) * @param [out] g2 multiplier for the distortion (typically squared * gain units) * @param [in] pvq_norm_lambda enc->pvq_norm_lambda for quantized RDO * @param [in] prev_k number of pulses already in ypulse that we should * reuse for the search (or 0 for a new search) * @return cosine distance between x and y (between 0 and 1) */ double pvq_search_rdo_double_c(const od_val16 *xcoeff, int n, int k, od_coeff *ypulse, double g2, double pvq_norm_lambda, int prev_k) { int i, j; double xy; double yy; /* TODO - This blows our 8kB stack space budget and should be fixed when converting PVQ to fixed point. */ double x[MAXN]; double xx; double lambda; double norm_1; int rdo_pulses; double delta_rate; xx = xy = yy = 0; for (j = 0; j < n; j++) { x[j] = fabs((float)xcoeff[j]); xx += x[j]*x[j]; } norm_1 = 1./sqrt(1e-30 + xx); lambda = pvq_norm_lambda/(1e-30 + g2); i = 0; if (prev_k > 0 && prev_k <= k) { /* We reuse pulses from a previous search so we don't have to search them again. */ for (j = 0; j < n; j++) { ypulse[j] = abs(ypulse[j]); xy += x[j]*ypulse[j]; yy += ypulse[j]*ypulse[j]; i += ypulse[j]; } } else if (k > 2) { double l1_norm; double l1_inv; l1_norm = 0; for (j = 0; j < n; j++) l1_norm += x[j]; l1_inv = 1./OD_MAXF(l1_norm, 1e-100); for (j = 0; j < n; j++) { double tmp; tmp = k*x[j]*l1_inv; ypulse[j] = OD_MAXI(0, (int)floor(tmp)); xy += x[j]*ypulse[j]; yy += ypulse[j]*ypulse[j]; i += ypulse[j]; } } else OD_CLEAR(ypulse, n); /* Only use RDO on the last few pulses. This not only saves CPU, but using RDO on all pulses actually makes the results worse for reasons I don't fully understand. */ rdo_pulses = 1 + k/4; /* Rough assumption for now, the last position costs about 3 bits more than the first. */ delta_rate = 3./n; /* Search one pulse at a time */ for (; i < k - rdo_pulses; i++) { int pos; double best_xy; double best_yy; pos = 0; best_xy = -10; best_yy = 1; for (j = 0; j < n; j++) { double tmp_xy; double tmp_yy; tmp_xy = xy + x[j]; tmp_yy = yy + 2*ypulse[j] + 1; tmp_xy *= tmp_xy; if (j == 0 || tmp_xy*best_yy > best_xy*tmp_yy) { best_xy = tmp_xy; best_yy = tmp_yy; pos = j; } } xy = xy + x[pos]; yy = yy + 2*ypulse[pos] + 1; ypulse[pos]++; } /* Search last pulses with RDO. Distortion is D = (x-y)^2 = x^2 - 2*x*y + y^2 and since x^2 and y^2 are constant, we just maximize x*y, plus a lambda*rate term. Note that since x and y aren't normalized here, we need to divide by sqrt(x^2)*sqrt(y^2). */ for (; i < k; i++) { double rsqrt_table[4]; int rsqrt_table_size = 4; int pos; double best_cost; pos = 0; best_cost = -1e5; /*Fill the small rsqrt lookup table with inputs relative to yy. Specifically, the table of n values is filled with rsqrt(yy + 1), rsqrt(yy + 2 + 1) .. rsqrt(yy + 2*(n-1) + 1).*/ od_fill_dynamic_rsqrt_table(rsqrt_table, rsqrt_table_size, yy); for (j = 0; j < n; j++) { double tmp_xy; double tmp_yy; tmp_xy = xy + x[j]; /*Calculate rsqrt(yy + 2*ypulse[j] + 1) using an optimized method.*/ tmp_yy = od_custom_rsqrt_dynamic_table(rsqrt_table, rsqrt_table_size, yy, ypulse[j]); tmp_xy = 2*tmp_xy*norm_1*tmp_yy - lambda*j*delta_rate; if (j == 0 || tmp_xy > best_cost) { best_cost = tmp_xy; pos = j; } } xy = xy + x[pos]; yy = yy + 2*ypulse[pos] + 1; ypulse[pos]++; } for (i = 0; i < n; i++) { if (xcoeff[i] < 0) ypulse[i] = -ypulse[i]; } return xy/(1e-100 + sqrt(xx*yy)); } /** Encodes the gain so that the return value increases with the * distance |x-ref|, so that we can encode a zero when x=ref. The * value x=0 is not covered because it is only allowed in the noref * case. * * @param [in] x quantized gain to encode * @param [in] ref quantized gain of the reference * @return interleave-encoded quantized gain value */ static int neg_interleave(int x, int ref) { if (x < ref) return -2*(x - ref) - 1; else if (x < 2*ref) return 2*(x - ref); else return x-1; } int od_vector_is_null(const od_coeff *x, int len) { int i; for (i = 0; i < len; i++) if (x[i]) return 0; return 1; } static double od_pvq_rate(int qg, int icgr, int theta, int ts, const od_adapt_ctx *adapt, const od_coeff *y0, int k, int n, int speed) { double rate; if (k == 0) rate = 0; else if (speed > 0) { int i; int sum; double f; /* Compute "center of mass" of the pulse vector. */ sum = 0; for (i = 0; i < n - (theta != -1); i++) sum += i*abs(y0[i]); f = sum/(double)(k*n); /* Estimates the number of bits it will cost to encode K pulses in N dimensions based on hand-tuned fit for bitrate vs K, N and "center of mass". */ rate = (1 + .4*f)*n*OD_LOG2(1 + OD_MAXF(0, log(n*2*(1*f + .025))*k/n)) + 3; } else { aom_writer w; od_pvq_codeword_ctx cd; int tell; #if !CONFIG_ANS od_ec_enc_init(&w.ec, 1000); #else # error "CONFIG_PVQ currently requires !CONFIG_ANS." #endif OD_COPY(&cd, &adapt->pvq.pvq_codeword_ctx, 1); #if !CONFIG_ANS tell = od_ec_enc_tell_frac(&w.ec); #else # error "CONFIG_PVQ currently requires !CONFIG_ANS." #endif aom_encode_pvq_codeword(&w, &cd, y0, n - (theta != -1), k); #if !CONFIG_ANS rate = (od_ec_enc_tell_frac(&w.ec)-tell)/8.; od_ec_enc_clear(&w.ec); #else # error "CONFIG_PVQ currently requires !CONFIG_ANS." #endif } if (qg > 0 && theta >= 0) { /* Approximate cost of entropy-coding theta */ rate += .9*OD_LOG2(ts); if (qg == icgr) rate -= .5; } return rate; } #define MAX_PVQ_ITEMS (20) /* This stores the information about a PVQ search candidate, so we can sort based on K. */ typedef struct { int gain; int k; od_val32 qtheta; int theta; int ts; od_val32 qcg; } pvq_search_item; int items_compare(pvq_search_item *a, pvq_search_item *b) { /* Break ties in K with gain to ensure a stable sort. Otherwise, the order depends on qsort implementation. */ return a->k == b->k ? a->gain - b->gain : a->k - b->k; } /** Perform PVQ quantization with prediction, trying several * possible gains and angles. See draft-valin-videocodec-pvq and * http://jmvalin.ca/slides/pvq.pdf for more details. * * @param [out] out coefficients after quantization * @param [in] x0 coefficients before quantization * @param [in] r0 reference, aka predicted coefficients * @param [in] n number of dimensions * @param [in] q0 quantization step size * @param [out] y pulse vector (i.e. selected PVQ codevector) * @param [out] itheta angle between input and reference (-1 if noref) * @param [out] vk total number of pulses * @param [in] beta per-band activity masking beta param * @param [out] skip_diff distortion cost of skipping this block * (accumulated) * @param [in] is_keyframe whether we're encoding a keyframe * @param [in] pli plane index * @param [in] adapt probability adaptation context * @param [in] qm QM with magnitude compensation * @param [in] qm_inv Inverse of QM with magnitude compensation * @param [in] pvq_norm_lambda enc->pvq_norm_lambda for quantized RDO * @param [in] speed Make search faster by making approximations * @return gain index of the quatized gain */ static int pvq_theta(od_coeff *out, const od_coeff *x0, const od_coeff *r0, int n, int q0, od_coeff *y, int *itheta, int *vk, od_val16 beta, double *skip_diff, int is_keyframe, int pli, const od_adapt_ctx *adapt, const int16_t *qm, const int16_t *qm_inv, double pvq_norm_lambda, int speed) { od_val32 g; od_val32 gr; od_coeff y_tmp[MAXN + 3]; int i; /* Number of pulses. */ int k; /* Companded gain of x and reference, normalized to q. */ od_val32 cg; od_val32 cgr; int icgr; int qg; /* Best RDO cost (D + lamdba*R) so far. */ double best_cost; double dist0; /* Distortion (D) that corresponds to the best RDO cost. */ double best_dist; double dist; /* Sign of Householder reflection. */ int s; /* Dimension on which Householder reflects. */ int m; od_val32 theta; double corr; int best_k; od_val32 best_qtheta; od_val32 gain_offset; int noref; double skip_dist; int cfl_enabled; int skip; double gain_weight; od_val16 x16[MAXN]; od_val16 r16[MAXN]; int xshift; int rshift; /* Give more weight to gain error when calculating the total distortion. */ gain_weight = 1.0; OD_ASSERT(n > 1); corr = 0; #if !defined(OD_FLOAT_PVQ) /* Shift needed to make x fit in 16 bits even after rotation. This shift value is not normative (it can be changed without breaking the bitstream) */ xshift = OD_MAXI(0, od_vector_log_mag(x0, n) - 15); /* Shift needed to make the reference fit in 15 bits, so that the Householder vector can fit in 16 bits. This shift value *is* normative, and has to match the decoder. */ rshift = OD_MAXI(0, od_vector_log_mag(r0, n) - 14); #else xshift = 0; rshift = 0; #endif for (i = 0; i < n; i++) { #if defined(OD_FLOAT_PVQ) /*This is slightly different from the original float PVQ code, where the qm was applied in the accumulation in od_pvq_compute_gain and the vectors were od_coeffs, not od_val16 (i.e. double).*/ x16[i] = x0[i]*(double)qm[i]*OD_QM_SCALE_1; r16[i] = r0[i]*(double)qm[i]*OD_QM_SCALE_1; #else x16[i] = OD_SHR_ROUND(x0[i]*qm[i], OD_QM_SHIFT + xshift); r16[i] = OD_SHR_ROUND(r0[i]*qm[i], OD_QM_SHIFT + rshift); #endif corr += OD_MULT16_16(x16[i], r16[i]); } cfl_enabled = is_keyframe && pli != 0 && !OD_DISABLE_CFL; cg = od_pvq_compute_gain(x16, n, q0, &g, beta, xshift); cgr = od_pvq_compute_gain(r16, n, q0, &gr, beta, rshift); if (cfl_enabled) cgr = OD_CGAIN_SCALE; /* gain_offset is meant to make sure one of the quantized gains has exactly the same gain as the reference. */ #if defined(OD_FLOAT_PVQ) icgr = (int)floor(.5 + cgr); #else icgr = OD_SHR_ROUND(cgr, OD_CGAIN_SHIFT); #endif gain_offset = cgr - OD_SHL(icgr, OD_CGAIN_SHIFT); /* Start search with null case: gain=0, no pulse. */ qg = 0; dist = gain_weight*cg*cg*OD_CGAIN_SCALE_2; best_dist = dist; best_cost = dist + pvq_norm_lambda*od_pvq_rate(0, 0, -1, 0, adapt, NULL, 0, n, speed); noref = 1; best_k = 0; *itheta = -1; OD_CLEAR(y, n); best_qtheta = 0; m = 0; s = 1; corr = corr/(1e-100 + g*(double)gr/OD_SHL(1, xshift + rshift)); corr = OD_MAXF(OD_MINF(corr, 1.), -1.); if (is_keyframe) skip_dist = gain_weight*cg*cg*OD_CGAIN_SCALE_2; else { skip_dist = gain_weight*(cg - cgr)*(cg - cgr) + cgr*(double)cg*(2 - 2*corr); skip_dist *= OD_CGAIN_SCALE_2; } if (!is_keyframe) { /* noref, gain=0 isn't allowed, but skip is allowed. */ od_val32 scgr; scgr = OD_MAXF(0,gain_offset); if (icgr == 0) { best_dist = gain_weight*(cg - scgr)*(cg - scgr) + scgr*(double)cg*(2 - 2*corr); best_dist *= OD_CGAIN_SCALE_2; } best_cost = best_dist + pvq_norm_lambda*od_pvq_rate(0, icgr, 0, 0, adapt, NULL, 0, n, speed); best_qtheta = 0; *itheta = 0; noref = 0; } dist0 = best_dist; if (n <= OD_MAX_PVQ_SIZE && !od_vector_is_null(r0, n) && corr > 0) { od_val16 xr[MAXN]; int gain_bound; int prev_k; pvq_search_item items[MAX_PVQ_ITEMS]; int idx; int nitems; double cos_dist; idx = 0; gain_bound = OD_SHR(cg - gain_offset, OD_CGAIN_SHIFT); /* Perform theta search only if prediction is useful. */ theta = OD_ROUND32(OD_THETA_SCALE*acos(corr)); m = od_compute_householder(r16, n, gr, &s, rshift); od_apply_householder(xr, x16, r16, n); prev_k = 0; for (i = m; i < n - 1; i++) xr[i] = xr[i + 1]; /* Compute all candidate PVQ searches within a reasonable range of gain and theta. */ for (i = OD_MAXI(1, gain_bound - 1); i <= gain_bound + 1; i++) { int j; od_val32 qcg; int ts; int theta_lower; int theta_upper; /* Quantized companded gain */ qcg = OD_SHL(i, OD_CGAIN_SHIFT) + gain_offset; /* Set angular resolution (in ra) to match the encoded gain */ ts = od_pvq_compute_max_theta(qcg, beta); theta_lower = OD_MAXI(0, (int)floor(.5 + theta*OD_THETA_SCALE_1*2/M_PI*ts) - 2); theta_upper = OD_MINI(ts - 1, (int)ceil(theta*OD_THETA_SCALE_1*2/M_PI*ts)); /* Include the angles within a reasonable range. */ for (j = theta_lower; j <= theta_upper; j++) { od_val32 qtheta; qtheta = od_pvq_compute_theta(j, ts); k = od_pvq_compute_k(qcg, j, 0, n, beta); items[idx].gain = i; items[idx].theta = j; items[idx].k = k; items[idx].qcg = qcg; items[idx].qtheta = qtheta; items[idx].ts = ts; idx++; OD_ASSERT(idx < MAX_PVQ_ITEMS); } } nitems = idx; cos_dist = 0; /* Sort PVQ search candidates in ascending order of pulses K so that we can reuse all the previously searched pulses across searches. */ qsort(items, nitems, sizeof(items[0]), (int (*)(const void *, const void *))items_compare); /* Search for the best gain/theta in order. */ for (idx = 0; idx < nitems; idx++) { int j; od_val32 qcg; int ts; double cost; double dist_theta; double sin_prod; od_val32 qtheta; /* Quantized companded gain */ qcg = items[idx].qcg; i = items[idx].gain; j = items[idx].theta; /* Set angular resolution (in ra) to match the encoded gain */ ts = items[idx].ts; /* Search for the best angle within a reasonable range. */ qtheta = items[idx].qtheta; k = items[idx].k; /* Compute the minimal possible distortion by not taking the PVQ cos_dist into account. */ dist_theta = 2 - 2.*od_pvq_cos(theta - qtheta)*OD_TRIG_SCALE_1; dist = gain_weight*(qcg - cg)*(qcg - cg) + qcg*(double)cg*dist_theta; dist *= OD_CGAIN_SCALE_2; /* If we have no hope of beating skip (including a 1-bit worst-case penalty), stop now. */ if (dist > dist0 + 1.0*pvq_norm_lambda && k != 0) continue; sin_prod = od_pvq_sin(theta)*OD_TRIG_SCALE_1*od_pvq_sin(qtheta)* OD_TRIG_SCALE_1; /* PVQ search, using a gain of qcg*cg*sin(theta)*sin(qtheta) since that's the factor by which cos_dist is multiplied to get the distortion metric. */ if (k == 0) { cos_dist = 0; OD_CLEAR(y_tmp, n-1); } else if (k != prev_k) { cos_dist = pvq_search_rdo_double(xr, n - 1, k, y_tmp, qcg*(double)cg*sin_prod*OD_CGAIN_SCALE_2, pvq_norm_lambda, prev_k); } prev_k = k; /* See Jmspeex' Journal of Dubious Theoretical Results. */ dist_theta = 2 - 2.*od_pvq_cos(theta - qtheta)*OD_TRIG_SCALE_1 + sin_prod*(2 - 2*cos_dist); dist = gain_weight*(qcg - cg)*(qcg - cg) + qcg*(double)cg*dist_theta; dist *= OD_CGAIN_SCALE_2; /* Do approximate RDO. */ cost = dist + pvq_norm_lambda*od_pvq_rate(i, icgr, j, ts, adapt, y_tmp, k, n, speed); if (cost < best_cost) { best_cost = cost; best_dist = dist; qg = i; best_k = k; best_qtheta = qtheta; *itheta = j; noref = 0; OD_COPY(y, y_tmp, n - 1); } } } /* Don't bother with no-reference version if there's a reasonable correlation. */ if (n <= OD_MAX_PVQ_SIZE && (corr < .5 || cg < (od_val32)(OD_SHL(2, OD_CGAIN_SHIFT)))) { int gain_bound; int prev_k; gain_bound = OD_SHR(cg, OD_CGAIN_SHIFT); prev_k = 0; /* Search for the best gain (haven't determined reasonable range yet). */ for (i = OD_MAXI(1, gain_bound); i <= gain_bound + 1; i++) { double cos_dist; double cost; od_val32 qcg; qcg = OD_SHL(i, OD_CGAIN_SHIFT); k = od_pvq_compute_k(qcg, -1, 1, n, beta); /* Compute the minimal possible distortion by not taking the PVQ cos_dist into account. */ dist = gain_weight*(qcg - cg)*(qcg - cg); dist *= OD_CGAIN_SCALE_2; if (dist > dist0 && k != 0) continue; cos_dist = pvq_search_rdo_double(x16, n, k, y_tmp, qcg*(double)cg*OD_CGAIN_SCALE_2, pvq_norm_lambda, prev_k); prev_k = k; /* See Jmspeex' Journal of Dubious Theoretical Results. */ dist = gain_weight*(qcg - cg)*(qcg - cg) + qcg*(double)cg*(2 - 2*cos_dist); dist *= OD_CGAIN_SCALE_2; /* Do approximate RDO. */ cost = dist + pvq_norm_lambda*od_pvq_rate(i, 0, -1, 0, adapt, y_tmp, k, n, speed); if (cost <= best_cost) { best_cost = cost; best_dist = dist; qg = i; noref = 1; best_k = k; *itheta = -1; OD_COPY(y, y_tmp, n); } } } k = best_k; theta = best_qtheta; skip = 0; if (noref) { if (qg == 0) skip = OD_PVQ_SKIP_ZERO; } else { if (!is_keyframe && qg == 0) { skip = (icgr ? OD_PVQ_SKIP_ZERO : OD_PVQ_SKIP_COPY); } if (qg == icgr && *itheta == 0 && !cfl_enabled) skip = OD_PVQ_SKIP_COPY; } /* Synthesize like the decoder would. */ if (skip) { if (skip == OD_PVQ_SKIP_COPY) OD_COPY(out, r0, n); else OD_CLEAR(out, n); } else { if (noref) gain_offset = 0; g = od_gain_expand(OD_SHL(qg, OD_CGAIN_SHIFT) + gain_offset, q0, beta); od_pvq_synthesis_partial(out, y, r16, n, noref, g, theta, m, s, qm_inv); } *vk = k; *skip_diff += skip_dist - best_dist; /* Encode gain differently depending on whether we use prediction or not. Special encoding on inter frames where qg=0 is allowed for noref=0 but not noref=1.*/ if (is_keyframe) return noref ? qg : neg_interleave(qg, icgr); else return noref ? qg - 1 : neg_interleave(qg + 1, icgr + 1); } /** Encodes a single vector of integers (eg, a partition within a * coefficient block) using PVQ * * @param [in,out] w multi-symbol entropy encoder * @param [in] qg quantized gain * @param [in] theta quantized post-prediction theta * @param [in] in coefficient vector to code * @param [in] n number of coefficients in partition * @param [in] k number of pulses in partition * @param [in,out] model entropy encoder state * @param [in,out] adapt adaptation context * @param [in,out] exg ExQ16 expectation of gain value * @param [in,out] ext ExQ16 expectation of theta value * @param [in] cdf_ctx selects which cdf context to use * @param [in] is_keyframe whether we're encoding a keyframe * @param [in] code_skip whether the "skip rest" flag is allowed * @param [in] skip_rest when set, we skip all higher bands * @param [in] encode_flip whether we need to encode the CfL flip flag now * @param [in] flip value of the CfL flip flag */ void pvq_encode_partition(aom_writer *w, int qg, int theta, const od_coeff *in, int n, int k, generic_encoder model[3], od_adapt_ctx *adapt, int *exg, int *ext, int cdf_ctx, int is_keyframe, int code_skip, int skip_rest, int encode_flip, int flip) { int noref; int id; noref = (theta == -1); id = (qg > 0) + 2*OD_MINI(theta + 1,3) + 8*code_skip*skip_rest; if (is_keyframe) { OD_ASSERT(id != 8); if (id >= 8) id--; } else { OD_ASSERT(id != 10); if (id >= 10) id--; } /* Jointly code gain, theta and noref for small values. Then we handle larger gain and theta values. For noref, theta = -1. */ aom_write_symbol_pvq(w, id, &adapt->pvq.pvq_gaintheta_cdf[cdf_ctx][0], 8 + 7*code_skip); if (encode_flip) { /* We could eventually do some smarter entropy coding here, but it would have to be good enough to overcome the overhead of the entropy coder. An early attempt using a "toogle" flag with simple adaptation wasn't worth the trouble. */ aom_write_bit(w, flip); } if (qg > 0) { int tmp; tmp = *exg; generic_encode(w, &model[!noref], qg - 1, &tmp, 2); OD_IIR_DIADIC(*exg, qg << 16, 2); } if (theta > 1) { int tmp; tmp = *ext; generic_encode(w, &model[2], theta - 2, &tmp, 2); OD_IIR_DIADIC(*ext, theta << 16, 2); } aom_encode_pvq_codeword(w, &adapt->pvq.pvq_codeword_ctx, in, n - (theta != -1), k); } /** Quantizes a scalar with rate-distortion optimization (RDO) * @param [in] x unquantized value * @param [in] q quantization step size * @param [in] delta0 rate increase for encoding a 1 instead of a 0 * @param [in] pvq_norm_lambda enc->pvq_norm_lambda for quantized RDO * @retval quantized value */ int od_rdo_quant(od_coeff x, int q, double delta0, double pvq_norm_lambda) { int n; /* Optimal quantization threshold is 1/2 + lambda*delta_rate/2. See Jmspeex' Journal of Dubious Theoretical Results for details. */ n = OD_DIV_R0(abs(x), q); if ((double)abs(x)/q < (double)n/2 + pvq_norm_lambda*delta0/(2*n)) { return 0; } else { return OD_DIV_R0(x, q); } } /** Encode a coefficient block (excepting DC) using PVQ * * @param [in,out] enc daala encoder context * @param [in] ref 'reference' (prediction) vector * @param [in] in coefficient block to quantize and encode * @param [out] out quantized coefficient block * @param [in] q0 scale/quantizer * @param [in] pli plane index * @param [in] bs log of the block size minus two * @param [in] beta per-band activity masking beta param * @param [in] is_keyframe whether we're encoding a keyframe * @param [in] qm QM with magnitude compensation * @param [in] qm_inv Inverse of QM with magnitude compensation * @param [in] speed Make search faster by making approximations * @param [in] pvq_info If null, conisdered as RDO search mode * @return Returns block skip info indicating whether DC/AC are coded. * bit0: DC is coded, bit1: AC is coded (1 means coded) * */ PVQ_SKIP_TYPE od_pvq_encode(daala_enc_ctx *enc, od_coeff *ref, const od_coeff *in, od_coeff *out, int q_dc, int q_ac, int pli, int bs, const od_val16 *beta, int is_keyframe, const int16_t *qm, const int16_t *qm_inv, int speed, PVQ_INFO *pvq_info){ int theta[PVQ_MAX_PARTITIONS]; int qg[PVQ_MAX_PARTITIONS]; int k[PVQ_MAX_PARTITIONS]; od_coeff y[OD_TXSIZE_MAX*OD_TXSIZE_MAX]; int *exg; int *ext; int nb_bands; int i; const int *off; int size[PVQ_MAX_PARTITIONS]; generic_encoder *model; double skip_diff; int tell; uint16_t *skip_cdf; od_rollback_buffer buf; int dc_quant; int flip; int cfl_encoded; int skip_rest; int skip_dir; int skip_theta_value; const unsigned char *pvq_qm; double dc_rate; int use_masking; PVQ_SKIP_TYPE ac_dc_coded; aom_clear_system_state(); use_masking = enc->use_activity_masking; if (use_masking) pvq_qm = &enc->state.pvq_qm_q4[pli][0]; else pvq_qm = 0; exg = &enc->state.adapt->pvq.pvq_exg[pli][bs][0]; ext = enc->state.adapt->pvq.pvq_ext + bs*PVQ_MAX_PARTITIONS; skip_cdf = enc->state.adapt->skip_cdf[2*bs + (pli != 0)]; model = enc->state.adapt->pvq.pvq_param_model; nb_bands = OD_BAND_OFFSETS[bs][0]; off = &OD_BAND_OFFSETS[bs][1]; if (use_masking) dc_quant = OD_MAXI(1, q_dc * pvq_qm[od_qm_get_index(bs, 0)] >> 4); else dc_quant = OD_MAXI(1, q_dc); tell = 0; for (i = 0; i < nb_bands; i++) size[i] = off[i+1] - off[i]; skip_diff = 0; flip = 0; /*If we are coding a chroma block of a keyframe, we are doing CfL.*/ if (pli != 0 && is_keyframe) { od_val32 xy; xy = 0; /*Compute the dot-product of the first band of chroma with the luma ref.*/ for (i = off[0]; i < off[1]; i++) { #if defined(OD_FLOAT_PVQ) xy += ref[i]*(double)qm[i]*OD_QM_SCALE_1* (double)in[i]*(double)qm[i]*OD_QM_SCALE_1; #else od_val32 rq; od_val32 inq; rq = ref[i]*qm[i]; inq = in[i]*qm[i]; xy += OD_SHR(rq*(int64_t)inq, OD_SHL(OD_QM_SHIFT + OD_CFL_FLIP_SHIFT, 1)); #endif } /*If cos(theta) < 0, then |theta| > pi/2 and we should negate the ref.*/ if (xy < 0) { flip = 1; for(i = off[0]; i < off[nb_bands]; i++) ref[i] = -ref[i]; } } for (i = 0; i < nb_bands; i++) { int q; if (use_masking) q = OD_MAXI(1, q_ac * pvq_qm[od_qm_get_index(bs, i + 1)] >> 4); else q = OD_MAXI(1, q_ac); qg[i] = pvq_theta(out + off[i], in + off[i], ref + off[i], size[i], q, y + off[i], &theta[i], &k[i], beta[i], &skip_diff, is_keyframe, pli, enc->state.adapt, qm + off[i], qm_inv + off[i], enc->pvq_norm_lambda, speed); } od_encode_checkpoint(enc, &buf); if (is_keyframe) out[0] = 0; else { int n; n = OD_DIV_R0(abs(in[0] - ref[0]), dc_quant); if (n == 0) { out[0] = 0; } else { int tell2; od_rollback_buffer dc_buf; dc_rate = -OD_LOG2((double)(OD_ICDF(skip_cdf[3]) - OD_ICDF(skip_cdf[2]))/ (double)(OD_ICDF(skip_cdf[2]) - OD_ICDF(skip_cdf[1]))); dc_rate += 1; #if !CONFIG_ANS tell2 = od_ec_enc_tell_frac(&enc->w.ec); #else #error "CONFIG_PVQ currently requires !CONFIG_ANS." #endif od_encode_checkpoint(enc, &dc_buf); generic_encode(&enc->w, &enc->state.adapt->model_dc[pli], n - 1, &enc->state.adapt->ex_dc[pli][bs][0], 2); #if !CONFIG_ANS tell2 = od_ec_enc_tell_frac(&enc->w.ec) - tell2; #else #error "CONFIG_PVQ currently requires !CONFIG_ANS." #endif dc_rate += tell2/8.0; od_encode_rollback(enc, &dc_buf); out[0] = od_rdo_quant(in[0] - ref[0], dc_quant, dc_rate, enc->pvq_norm_lambda); } } #if !CONFIG_ANS tell = od_ec_enc_tell_frac(&enc->w.ec); #else #error "CONFIG_PVQ currently requires !CONFIG_ANS." #endif /* Code as if we're not skipping. */ aom_write_symbol(&enc->w, 2 + (out[0] != 0), skip_cdf, 4); ac_dc_coded = AC_CODED + (out[0] != 0); cfl_encoded = 0; skip_rest = 1; skip_theta_value = is_keyframe ? -1 : 0; for (i = 1; i < nb_bands; i++) { if (theta[i] != skip_theta_value || qg[i]) skip_rest = 0; } skip_dir = 0; if (nb_bands > 1) { for (i = 0; i < 3; i++) { int j; int tmp; tmp = 1; // ToDo(yaowu): figure out better stop condition without gcc warning. for (j = i + 1; j < nb_bands && j < PVQ_MAX_PARTITIONS; j += 3) { if (theta[j] != skip_theta_value || qg[j]) tmp = 0; } skip_dir |= tmp << i; } } if (theta[0] == skip_theta_value && qg[0] == 0 && skip_rest) nb_bands = 0; /* NOTE: There was no other better place to put this function. */ if (pvq_info) av1_store_pvq_enc_info(pvq_info, qg, theta, k, y, nb_bands, off, size, skip_rest, skip_dir, bs); for (i = 0; i < nb_bands; i++) { int encode_flip; /* Encode CFL flip bit just after the first time it's used. */ encode_flip = pli != 0 && is_keyframe && theta[i] != -1 && !cfl_encoded; if (i == 0 || (!skip_rest && !(skip_dir & (1 << ((i - 1)%3))))) { pvq_encode_partition(&enc->w, qg[i], theta[i], y + off[i], size[i], k[i], model, enc->state.adapt, exg + i, ext + i, (pli != 0)*OD_TXSIZES*PVQ_MAX_PARTITIONS + bs*PVQ_MAX_PARTITIONS + i, is_keyframe, i == 0 && (i < nb_bands - 1), skip_rest, encode_flip, flip); } if (i == 0 && !skip_rest && bs > 0) { aom_write_symbol(&enc->w, skip_dir, &enc->state.adapt->pvq.pvq_skip_dir_cdf[(pli != 0) + 2*(bs - 1)][0], 7); } if (encode_flip) cfl_encoded = 1; } #if !CONFIG_ANS tell = od_ec_enc_tell_frac(&enc->w.ec) - tell; #else #error "CONFIG_PVQ currently requires !CONFIG_ANS." #endif /* Account for the rate of skipping the AC, based on the same DC decision we made when trying to not skip AC. */ { double skip_rate; if (out[0] != 0) { skip_rate = -OD_LOG2((OD_ICDF(skip_cdf[1]) - OD_ICDF(skip_cdf[0]))/ (double)OD_ICDF(skip_cdf[3])); } else { skip_rate = -OD_LOG2(OD_ICDF(skip_cdf[0])/ (double)OD_ICDF(skip_cdf[3])); } tell -= (int)floor(.5+8*skip_rate); } if (nb_bands == 0 || skip_diff <= enc->pvq_norm_lambda/8*tell) { if (is_keyframe) out[0] = 0; else { int n; n = OD_DIV_R0(abs(in[0] - ref[0]), dc_quant); if (n == 0) { out[0] = 0; } else { int tell2; od_rollback_buffer dc_buf; dc_rate = -OD_LOG2((double)(OD_ICDF(skip_cdf[1]) - OD_ICDF(skip_cdf[0]))/ (double)OD_ICDF(skip_cdf[0])); dc_rate += 1; #if !CONFIG_ANS tell2 = od_ec_enc_tell_frac(&enc->w.ec); #else #error "CONFIG_PVQ currently requires !CONFIG_ANS." #endif od_encode_checkpoint(enc, &dc_buf); generic_encode(&enc->w, &enc->state.adapt->model_dc[pli], n - 1, &enc->state.adapt->ex_dc[pli][bs][0], 2); #if !CONFIG_ANS tell2 = od_ec_enc_tell_frac(&enc->w.ec) - tell2; #else #error "CONFIG_PVQ currently requires !CONFIG_ANS." #endif dc_rate += tell2/8.0; od_encode_rollback(enc, &dc_buf); out[0] = od_rdo_quant(in[0] - ref[0], dc_quant, dc_rate, enc->pvq_norm_lambda); } } /* We decide to skip, roll back everything as it was before. */ od_encode_rollback(enc, &buf); aom_write_symbol(&enc->w, out[0] != 0, skip_cdf, 4); ac_dc_coded = (out[0] != 0); if (is_keyframe) for (i = 1; i < 1 << (2*bs + 4); i++) out[i] = 0; else for (i = 1; i < 1 << (2*bs + 4); i++) out[i] = ref[i]; } if (pvq_info) pvq_info->ac_dc_coded = ac_dc_coded; return ac_dc_coded; }