X-Git-Url: https://git.sesse.net/?a=blobdiff_plain;f=qdc.cpp;h=a0fe2e7b1a71a36f8f9fe0682cf710218669ca85;hb=755cd83d9f558a3a08d1c63d9944738f41a852c7;hp=43fcba0de2dc343fbdee87d762992fa00c9ff95b;hpb=8ec2525e753942bb77820927364f6f02c24313f9;p=narabu diff --git a/qdc.cpp b/qdc.cpp index 43fcba0..a0fe2e7 100644 --- a/qdc.cpp +++ b/qdc.cpp @@ -1,6 +1,7 @@ #include #include #include +#include #include #include @@ -9,6 +10,7 @@ #include "ryg_rans/renormalize.h" #include +#include #define WIDTH 1280 #define HEIGHT 720 @@ -67,7 +69,6 @@ struct SymbolStats uint32_t cum_freqs[NUM_SYMS + 1]; void clear(); - void count_freqs(uint8_t const* in, size_t nbytes); void calc_cum_freqs(); void normalize_freqs(uint32_t target_total); }; @@ -78,14 +79,6 @@ void SymbolStats::clear() freqs[i] = 0; } -void SymbolStats::count_freqs(uint8_t const* in, size_t nbytes) -{ - clear(); - - for (size_t i=0; i < nbytes; i++) - freqs[in[i]]++; -} - void SymbolStats::calc_cum_freqs() { cum_freqs[0] = 0; @@ -93,119 +86,6 @@ void SymbolStats::calc_cum_freqs() cum_freqs[i+1] = cum_freqs[i] + freqs[i]; } -static double cache[NUM_SYMS + 1][prob_scale + 1]; -static double log2cache[prob_scale + 1]; -static int64_t cachefill = 0; - -double find_optimal_cost(const uint32_t *cum_freqs, int sym_to, int available_slots) -{ - assert(sym_to >= 0); - - while (sym_to > 0 && cum_freqs[sym_to] == cum_freqs[sym_to - 1]) { --sym_to; } - if (cache[sym_to][available_slots] >= 0.0) { - //printf("CACHE: %d,%d\n", sym_to, available_slots); - return cache[sym_to][available_slots]; - } - if (sym_to == 0) { - return 0.0; - } - if (sym_to == 1) { - return cum_freqs[0] * log2cache[available_slots]; - } - if (available_slots == 1) { - return cum_freqs[0] * log2cache[1] + find_optimal_cost(cum_freqs, sym_to - 1, 0); - } - -// printf("UNCACHE: %d,%d\n", sym_to, available_slots); -#if 0 - // ok, test all possible options for the last symbol (TODO: save the choice) - double best_so_far = HUGE_VAL; - //for (int i = num_syms - 1; i < available_slots; ++i) { - double f = freqs[sym_to - 1]; - for (int i = available_slots; i --> 0; ) { - double cost1 = f * log2cache[available_slots - i]; - double cost2 = find_optimal_cost(freqs, sym_to - 1, i); - - if (sym_to == 3 && available_slots == 838) { - printf("%d %f\n", i, cost1 + cost2); - } else - if (cost1 + cost2 > best_so_far) { - break; - } - best_so_far = cost1 + cost2; - } -#elif 1 - // Minimize the number of total bits spent as a function of how many slots - // we assign to this symbol. - // - // The cost function is convex (I don't know how to prove it, but it makes - // intuitively a lot of sense). Find a reasonable guess and see what way - // we should search, then iterate until we either hit the end or we start - // increasing again. - double f = cum_freqs[sym_to - 1] - cum_freqs[sym_to - 2]; - double start = lrint(available_slots * f / cum_freqs[sym_to - 1]); - - int x1 = std::max(floor(start), 1); - int x2 = x1 + 1; - - double f1 = f * log2cache[x1] + find_optimal_cost(cum_freqs, sym_to - 1, available_slots - x1); - double f2 = f * log2cache[x2] + find_optimal_cost(cum_freqs, sym_to - 1, available_slots - x2); - - int x, direction; // -1 or +1 - double best_so_far = std::min(f1, f2); - if (isinf(f1) && isinf(f2)) { - // The cost isn't infinite due to the first term, so we need to go downwards - // to give the second term more room to breathe. - x = x1; - direction = -1; - } else if (f1 < f2) { - x = x1; - direction = -1; - } else { - x = x2; - direction = 1; - } - - //printf("[%d,%d] freq=%ld cumfreq=%d From %d and %d, chose %d [%f] and direction=%d\n", - // sym_to, available_slots, freqs[sym_to - 1], cum_freqs[sym_to - 1], x1, x2, x, best_so_far, direction); - - while ((x + direction) > 0 && (x + direction) <= available_slots) { - x += direction; - double fn = f * log2cache[x] + find_optimal_cost(cum_freqs, sym_to - 1, available_slots - x); - // printf("[%d,%d] %d is %f\n", sym_to, available_slots, x, fn); - if (fn > best_so_far) { - break; - } - best_so_far = fn; - } -#endif - if (++cachefill % 131072 == 0) { - // printf("%d,%d = %f (cachefill = %.2f%%)\n", sym_to, available_slots, best_so_far, - // 100.0 * (cachefill / double((NUM_SYMS + 1) * (prob_scale + 1)))); - } - assert(best_so_far >= 0.0); - assert(cache[sym_to][available_slots] < 0.0); - cache[sym_to][available_slots] = best_so_far; - return best_so_far; -} - -double find_optimal_cost(const uint32_t *cum_freqs, const uint64_t *freqs) -{ - for (int j = 0; j <= NUM_SYMS; ++j) { - for (unsigned k = 0; k <= prob_scale; ++k) { - cache[j][k] = -1.0; - } - } - for (unsigned k = 0; k <= prob_scale; ++k) { - log2cache[k] = -log2(k * (1.0 / prob_scale)); - //printf("log2cache[%d] = %f\n", k, log2cache[k]); - } - cachefill = 0; - double ret = find_optimal_cost(cum_freqs, NUM_SYMS, prob_scale); - printf("Used %ld function invocations\n", cachefill); - return ret; -} - void SymbolStats::normalize_freqs(uint32_t target_total) { uint64_t real_freq[NUM_SYMS + 1]; // hack @@ -227,47 +107,6 @@ void SymbolStats::normalize_freqs(uint32_t target_total) OptimalRenormalize(cum_freqs, NUM_SYMS, prob_scale); -#if 0 - double optimal_cost = find_optimal_cost(cum_freqs + 1, real_freq + 1); - - // resample distribution based on cumulative freqs - for (int i = 1; i <= NUM_SYMS; i++) - //cum_freqs[i] = ((uint64_t)target_total * cum_freqs[i])/cur_total; - cum_freqs[i] = lrint(cum_freqs[i] * double(target_total) / cur_total); - - // if we nuked any non-0 frequency symbol to 0, we need to steal - // the range to make the frequency nonzero from elsewhere. - // - // this is not at all optimal, i'm just doing the first thing that comes to mind. - for (int i=0; i < NUM_SYMS; i++) { - if (freqs[i] && cum_freqs[i+1] == cum_freqs[i]) { - // symbol i was set to zero freq - - // find best symbol to steal frequency from (try to steal from low-freq ones) - uint32_t best_freq = ~0u; - int best_steal = -1; - for (int j=0; j < NUM_SYMS; j++) { - uint32_t freq = cum_freqs[j+1] - cum_freqs[j]; - if (freq > 1 && freq < best_freq) { - best_freq = freq; - best_steal = j; - } - } - assert(best_steal != -1); - - // and steal from it! - if (best_steal < i) { - for (int j = best_steal + 1; j <= i; j++) - cum_freqs[j]--; - } else { - assert(best_steal > i); - for (int j = i + 1; j <= best_steal; j++) - cum_freqs[j]++; - } - } - } -#endif - // calculate updated freqs and make sure we didn't screw anything up assert(cum_freqs[0] == 0 && cum_freqs[NUM_SYMS] == target_total); for (int i=0; i < NUM_SYMS; i++) { @@ -302,6 +141,7 @@ SymbolStats stats[64]; int pick_stats_for(int y, int x) { + //return 0; //return std::min(hypot(x, y), 7); return std::min(x + y, 7); //if (x + y >= 7) return 7; @@ -331,26 +171,23 @@ public: RansEncoder() { out_buf.reset(new uint8_t[out_max_size]); - sign_buf.reset(new uint8_t[max_num_sign]); clear(); } - void init_prob(const SymbolStats &s) + void init_prob(SymbolStats &s) { for (int i = 0; i < NUM_SYMS; i++) { - printf("%d: cumfreqs=%d freqs=%d prob_bits=%d\n", i, s.cum_freqs[i], s.freqs[i], prob_bits); - RansEncSymbolInit(&esyms[i], s.cum_freqs[i], s.freqs[i], prob_bits); + printf("%d: cumfreqs=%d freqs=%d prob_bits=%d\n", i, s.cum_freqs[i], s.freqs[i], prob_bits + 1); + RansEncSymbolInit(&esyms[i], s.cum_freqs[i], s.freqs[i], prob_bits + 1); } + sign_bias = s.cum_freqs[256]; } void clear() { out_end = out_buf.get() + out_max_size; - sign_end = sign_buf.get() + max_num_sign; ptr = out_end; // *end* of output buffer - sign_ptr = sign_end; // *end* of output buffer RansEncInit(&rans); - free_sign_bits = 0; } uint32_t save_block(FILE *codedfp) // Returns number of bytes. @@ -359,33 +196,41 @@ public: //printf("post-flush = %08x\n", rans); uint32_t num_rans_bytes = out_end - ptr; +#if 0 + if (num_rans_bytes == 4) { + uint32_t block; + memcpy(&block, ptr, 4); + + if (block == last_block) { + write_varint(0, codedfp); + clear(); + return 1; + } + + last_block = block; + } else { + last_block = 0; + } +#endif + write_varint(num_rans_bytes, codedfp); //fwrite(&num_rans_bytes, 1, 4, codedfp); fwrite(ptr, 1, num_rans_bytes, codedfp); //printf("first rANS bytes: %02x %02x %02x %02x %02x %02x %02x %02x\n", ptr[0], ptr[1], ptr[2], ptr[3], ptr[4], ptr[5], ptr[6], ptr[7]); - if (free_sign_bits > 0) { - *sign_ptr <<= free_sign_bits; - } - -#if 1 - uint32_t num_sign_bytes = sign_end - sign_ptr; - write_varint((num_sign_bytes << 3) | free_sign_bits, codedfp); - fwrite(sign_ptr, 1, num_sign_bytes, codedfp); -#endif clear(); - printf("Saving block: %d rANS bytes, %d sign bytes\n", num_rans_bytes, num_sign_bytes); - return num_rans_bytes + num_sign_bytes; + printf("Saving block: %d rANS bytes\n", num_rans_bytes); + return num_rans_bytes; //return num_rans_bytes; } void encode_coeff(short signed_k) { - printf("encoding coeff %d\n", signed_k); - short k = abs(signed_k); + //printf("encoding coeff %d (sym %d), rans before encoding = %08x\n", signed_k, ((abs(signed_k) - 1) & 255), rans); + unsigned short k = abs(signed_k); if (k >= ESCAPE_LIMIT) { // Put the coefficient as a 1/(2^12) symbol _before_ // the 255 coefficient, since the decoder will read the @@ -393,33 +238,24 @@ public: RansEncPut(&rans, &ptr, k, 1, prob_bits); k = ESCAPE_LIMIT; } - if (k != 0) { -#if 1 - if (free_sign_bits == 0) { - --sign_ptr; - *sign_ptr = 0; - free_sign_bits = 8; - } - *sign_ptr <<= 1; - *sign_ptr |= (signed_k < 0); - --free_sign_bits; -#else - RansEncPut(&rans, &ptr, (k < 0) ? prob_scale / 2 : 0, prob_scale / 2, prob_bits); -#endif + RansEncPutSymbol(&rans, &ptr, &esyms[(k - 1) & 255]); + if (signed_k < 0) { + rans += sign_bias; } - RansEncPutSymbol(&rans, &ptr, &esyms[k]); } private: static constexpr size_t out_max_size = 32 << 20; // 32 MB. static constexpr size_t max_num_sign = 1048576; // Way too big. And actually bytes. - unique_ptr out_buf, sign_buf; - uint8_t *out_end, *sign_end; - uint8_t *ptr, *sign_ptr; + unique_ptr out_buf; + uint8_t *out_end; + uint8_t *ptr; RansState rans; - size_t free_sign_bits; RansEncSymbol esyms[NUM_SYMS]; + uint32_t sign_bias; + + uint32_t last_block = 0; // Not a valid 4-byte rANS block (?) }; static constexpr int dc_scalefac = 8; // Matches the FDCT's gain. @@ -778,7 +614,7 @@ int main(int argc, char **argv) fclose(fp); // For each coefficient, make some tables. - size_t extra_bits = 0, sign_bits = 0; + size_t extra_bits = 0; for (unsigned i = 0; i < 64; ++i) { stats[i].clear(); } @@ -791,20 +627,19 @@ int main(int argc, char **argv) // Luma for (unsigned yb = 0; yb < HEIGHT; yb += 8) { for (unsigned xb = 0; xb < WIDTH; xb += 8) { - short k = abs(coeff_y[(yb + y) * WIDTH + (xb + x)]); + unsigned short k = abs(coeff_y[(yb + y) * WIDTH + (xb + x)]); if (k >= ESCAPE_LIMIT) { k = ESCAPE_LIMIT; extra_bits += 12; // escape this one } - if (k != 0) ++sign_bits; - ++s_luma.freqs[k]; + ++s_luma.freqs[(k - 1) & 255]; } } // Chroma for (unsigned yb = 0; yb < HEIGHT; yb += 8) { for (unsigned xb = 0; xb < WIDTH/2; xb += 8) { - short k_cb = abs(coeff_cb[(yb + y) * WIDTH/2 + (xb + x)]); - short k_cr = abs(coeff_cr[(yb + y) * WIDTH/2 + (xb + x)]); + unsigned short k_cb = abs(coeff_cb[(yb + y) * WIDTH/2 + (xb + x)]); + unsigned short k_cr = abs(coeff_cr[(yb + y) * WIDTH/2 + (xb + x)]); if (k_cb >= ESCAPE_LIMIT) { k_cb = ESCAPE_LIMIT; extra_bits += 12; // escape this one @@ -813,16 +648,17 @@ int main(int argc, char **argv) k_cr = ESCAPE_LIMIT; extra_bits += 12; // escape this one } - if (k_cb != 0) ++sign_bits; - if (k_cr != 0) ++sign_bits; - ++s_chroma.freqs[k_cb]; - ++s_chroma.freqs[k_cr]; + ++s_chroma.freqs[(k_cb - 1) & 255]; + ++s_chroma.freqs[(k_cr - 1) & 255]; } } } } for (unsigned i = 0; i < 64; ++i) { + stats[i].freqs[255] /= 2; // zero, has no sign bits (yes, this is trickery) stats[i].normalize_freqs(prob_scale); + stats[i].cum_freqs[256] += stats[i].freqs[255]; + stats[i].freqs[255] *= 2; } FILE *codedfp = fopen("coded.dat", "wb"); @@ -853,6 +689,7 @@ int main(int argc, char **argv) rans_encoder.init_prob(s_luma); // Luma + std::vector lens; // need to reverse later rans_encoder.clear(); @@ -864,7 +701,9 @@ int main(int argc, char **argv) rans_encoder.encode_coeff(k); } if (yb % 16 == 8) { - num_bytes += rans_encoder.save_block(codedfp); + int l = rans_encoder.save_block(codedfp); + num_bytes += l; + lens.push_back(l); } } if (HEIGHT % 16 != 0) { @@ -872,6 +711,19 @@ int main(int argc, char **argv) } tot_bytes += num_bytes; printf("coeff %d Y': %ld bytes\n", y * 8 + x, num_bytes); + + double sum_l = 0.0; + for (int l : lens) { + sum_l += l; + } + double avg_l = sum_l / lens.size(); + + double sum_sql = 0.0; + for (int l : lens) { + sum_sql += (l - avg_l) * (l - avg_l); + } + double stddev_l = sqrt(sum_sql / (lens.size() - 1)); + printf("coeff %d: avg=%.2f bytes, stddev=%.2f bytes\n", y*8+x, avg_l, stddev_l); } } @@ -927,10 +779,8 @@ int main(int argc, char **argv) } } - printf("%ld bytes + %ld sign bits (%ld) + %ld escape bits (%ld) = %ld total bytes\n", - tot_bytes - sign_bits / 8 - extra_bits / 8, - sign_bits, - sign_bits / 8, + printf("%ld bytes + %ld escape bits (%ld) = %ld total bytes\n", + tot_bytes - extra_bits / 8, extra_bits, extra_bits / 8, tot_bytes);