/* * 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 #include #include #include #include #include "math.h" #include "vp8/common/common.h" #include "ratectrl.h" #include "vp8/common/entropymode.h" #include "vpx_mem/vpx_mem.h" #include "vp8/common/systemdependent.h" #include "encodemv.h" #define MIN_BPB_FACTOR 0.01 #define MAX_BPB_FACTOR 50 extern const MB_PREDICTION_MODE vp8_mode_order[MAX_MODES]; extern const MV_REFERENCE_FRAME vp8_ref_frame_order[MAX_MODES]; #ifdef MODE_STATS extern int y_modes[5]; extern int uv_modes[4]; extern int b_modes[10]; extern int inter_y_modes[10]; extern int inter_uv_modes[4]; extern int inter_b_modes[10]; #endif // Bits Per MB at different Q (Multiplied by 512) #define BPER_MB_NORMBITS 9 // Work in progress recalibration of baseline rate tables based on // the assumption that bits per mb is inversely proportional to the // quantizer value. const int vp8_bits_per_mb[2][QINDEX_RANGE] = { // Intra case 450000/Qintra { 1125000,900000, 750000, 642857, 562500, 500000, 450000, 450000, 409090, 375000, 346153, 321428, 300000, 281250, 264705, 264705, 250000, 236842, 225000, 225000, 214285, 214285, 204545, 204545, 195652, 195652, 187500, 180000, 180000, 173076, 166666, 160714, 155172, 150000, 145161, 140625, 136363, 132352, 128571, 125000, 121621, 121621, 118421, 115384, 112500, 109756, 107142, 104651, 102272, 100000, 97826, 97826, 95744, 93750, 91836, 90000, 88235, 86538, 84905, 83333, 81818, 80357, 78947, 77586, 76271, 75000, 73770, 72580, 71428, 70312, 69230, 68181, 67164, 66176, 65217, 64285, 63380, 62500, 61643, 60810, 60000, 59210, 59210, 58441, 57692, 56962, 56250, 55555, 54878, 54216, 53571, 52941, 52325, 51724, 51136, 50561, 49450, 48387, 47368, 46875, 45918, 45000, 44554, 44117, 43269, 42452, 41666, 40909, 40178, 39473, 38793, 38135, 36885, 36290, 35714, 35156, 34615, 34090, 33582, 33088, 32608, 32142, 31468, 31034, 30405, 29801, 29220, 28662, }, // Inter case 285000/Qinter { 712500, 570000, 475000, 407142, 356250, 316666, 285000, 259090, 237500, 219230, 203571, 190000, 178125, 167647, 158333, 150000, 142500, 135714, 129545, 123913, 118750, 114000, 109615, 105555, 101785, 98275, 95000, 91935, 89062, 86363, 83823, 81428, 79166, 77027, 75000, 73076, 71250, 69512, 67857, 66279, 64772, 63333, 61956, 60638, 59375, 58163, 57000, 55882, 54807, 53773, 52777, 51818, 50892, 50000, 49137, 47500, 45967, 44531, 43181, 41911, 40714, 39583, 38513, 37500, 36538, 35625, 34756, 33928, 33139, 32386, 31666, 30978, 30319, 29687, 29081, 28500, 27941, 27403, 26886, 26388, 25909, 25446, 25000, 24568, 23949, 23360, 22800, 22265, 21755, 21268, 20802, 20357, 19930, 19520, 19127, 18750, 18387, 18037, 17701, 17378, 17065, 16764, 16473, 16101, 15745, 15405, 15079, 14766, 14467, 14179, 13902, 13636, 13380, 13133, 12895, 12666, 12445, 12179, 11924, 11632, 11445, 11220, 11003, 10795, 10594, 10401, 10215, 10035, } }; static const int kf_boost_qadjustment[QINDEX_RANGE] = { 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 185, 186, 187, 188, 189, 190, 191, 192, 193, 194, 195, 196, 197, 198, 199, 200, 200, 201, 201, 202, 203, 203, 203, 204, 204, 205, 205, 206, 206, 207, 207, 208, 208, 209, 209, 210, 210, 211, 211, 212, 212, 213, 213, 214, 214, 215, 215, 216, 216, 217, 217, 218, 218, 219, 219, 220, 220, 220, 220, 220, 220, 220, 220, 220, 220, 220, 220, 220, 220, 220, 220, }; //#define GFQ_ADJUSTMENT (Q+100) #define GFQ_ADJUSTMENT vp8_gf_boost_qadjustment[Q] const int vp8_gf_boost_qadjustment[QINDEX_RANGE] = { 80, 82, 84, 86, 88, 90, 92, 94, 96, 97, 98, 99, 100, 101, 102, 103, 104, 105, 106, 107, 108, 109, 110, 111, 112, 113, 114, 115, 116, 117, 118, 119, 120, 121, 122, 123, 124, 125, 126, 127, 128, 129, 130, 131, 132, 133, 134, 135, 136, 137, 138, 139, 140, 141, 142, 143, 144, 145, 146, 147, 148, 149, 150, 151, 152, 153, 154, 155, 156, 157, 158, 159, 160, 161, 162, 163, 164, 165, 166, 167, 168, 169, 170, 171, 172, 173, 174, 175, 176, 177, 178, 179, 180, 181, 182, 183, 184, 184, 185, 185, 186, 186, 187, 187, 188, 188, 189, 189, 190, 190, 191, 191, 192, 192, 193, 193, 194, 194, 194, 194, 195, 195, 196, 196, 197, 197, 198, 198 }; /* const int vp8_gf_boost_qadjustment[QINDEX_RANGE] = { 100,101,102,103,104,105,105,106, 106,107,107,108,109,109,110,111, 112,113,114,115,116,117,118,119, 120,121,122,123,124,125,126,127, 128,129,130,131,132,133,134,135, 136,137,138,139,140,141,142,143, 144,145,146,147,148,149,150,151, 152,153,154,155,156,157,158,159, 160,161,162,163,164,165,166,167, 168,169,170,170,171,171,172,172, 173,173,173,174,174,174,175,175, 175,176,176,176,177,177,177,177, 178,178,179,179,180,180,181,181, 182,182,183,183,184,184,185,185, 186,186,187,187,188,188,189,189, 190,190,191,191,192,192,193,193, }; */ static const int kf_gf_boost_qlimits[QINDEX_RANGE] = { 150, 155, 160, 165, 170, 175, 180, 185, 190, 195, 200, 205, 210, 215, 220, 225, 230, 235, 240, 245, 250, 255, 260, 265, 270, 275, 280, 285, 290, 295, 300, 305, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 410, 420, 430, 440, 450, 460, 470, 480, 490, 500, 510, 520, 530, 540, 550, 560, 570, 580, 590, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, 600, }; // % adjustment to target kf size based on seperation from previous frame static const int kf_boost_seperation_adjustment[16] = { 30, 40, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100, 100, 100, 100, }; static const int gf_adjust_table[101] = { 100, 115, 130, 145, 160, 175, 190, 200, 210, 220, 230, 240, 260, 270, 280, 290, 300, 310, 320, 330, 340, 350, 360, 370, 380, 390, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, 400, }; static const int gf_intra_usage_adjustment[20] = { 125, 120, 115, 110, 105, 100, 95, 85, 80, 75, 70, 65, 60, 55, 50, 50, 50, 50, 50, 50, }; static const int gf_interval_table[101] = { 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 8, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 10, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, }; static const unsigned int prior_key_frame_weight[KEY_FRAME_CONTEXT] = { 1, 2, 3, 4, 5 }; void vp8_save_coding_context(VP8_COMP *cpi) { CODING_CONTEXT *const cc = & cpi->coding_context; // Stores a snapshot of key state variables which can subsequently be // restored with a call to vp8_restore_coding_context. These functions are // intended for use in a re-code loop in vp8_compress_frame where the // quantizer value is adjusted between loop iterations. cc->frames_since_key = cpi->frames_since_key; cc->filter_level = cpi->common.filter_level; cc->frames_till_gf_update_due = cpi->frames_till_gf_update_due; cc->frames_since_golden = cpi->common.frames_since_golden; vp8_copy(cc->mvc, cpi->common.fc.mvc); vp8_copy(cc->mvcosts, cpi->mb.mvcosts); vp8_copy(cc->kf_ymode_prob, cpi->common.kf_ymode_prob); vp8_copy(cc->ymode_prob, cpi->common.fc.ymode_prob); vp8_copy(cc->kf_uv_mode_prob, cpi->common.kf_uv_mode_prob); vp8_copy(cc->uv_mode_prob, cpi->common.fc.uv_mode_prob); vp8_copy(cc->ymode_count, cpi->ymode_count); vp8_copy(cc->uv_mode_count, cpi->uv_mode_count); // Stats #ifdef MODE_STATS vp8_copy(cc->y_modes, y_modes); vp8_copy(cc->uv_modes, uv_modes); vp8_copy(cc->b_modes, b_modes); vp8_copy(cc->inter_y_modes, inter_y_modes); vp8_copy(cc->inter_uv_modes, inter_uv_modes); vp8_copy(cc->inter_b_modes, inter_b_modes); #endif cc->this_frame_percent_intra = cpi->this_frame_percent_intra; } void vp8_restore_coding_context(VP8_COMP *cpi) { CODING_CONTEXT *const cc = & cpi->coding_context; // Restore key state variables to the snapshot state stored in the // previous call to vp8_save_coding_context. cpi->frames_since_key = cc->frames_since_key; cpi->common.filter_level = cc->filter_level; cpi->frames_till_gf_update_due = cc->frames_till_gf_update_due; cpi->common.frames_since_golden = cc->frames_since_golden; vp8_copy(cpi->common.fc.mvc, cc->mvc); vp8_copy(cpi->mb.mvcosts, cc->mvcosts); vp8_copy(cpi->common.kf_ymode_prob, cc->kf_ymode_prob); vp8_copy(cpi->common.fc.ymode_prob, cc->ymode_prob); vp8_copy(cpi->common.kf_uv_mode_prob, cc->kf_uv_mode_prob); vp8_copy(cpi->common.fc.uv_mode_prob, cc->uv_mode_prob); vp8_copy(cpi->ymode_count, cc->ymode_count); vp8_copy(cpi->uv_mode_count, cc->uv_mode_count); // Stats #ifdef MODE_STATS vp8_copy(y_modes, cc->y_modes); vp8_copy(uv_modes, cc->uv_modes); vp8_copy(b_modes, cc->b_modes); vp8_copy(inter_y_modes, cc->inter_y_modes); vp8_copy(inter_uv_modes, cc->inter_uv_modes); vp8_copy(inter_b_modes, cc->inter_b_modes); #endif cpi->this_frame_percent_intra = cc->this_frame_percent_intra; } void vp8_setup_key_frame(VP8_COMP *cpi) { // Setup for Key frame: vp8_default_coef_probs(& cpi->common); vp8_kf_default_bmode_probs(cpi->common.kf_bmode_prob); vpx_memcpy(cpi->common.fc.mvc, vp8_default_mv_context, sizeof(vp8_default_mv_context)); { int flag[2] = {1, 1}; vp8_build_component_cost_table(cpi->mb.mvcost, (const MV_CONTEXT *) cpi->common.fc.mvc, flag); } vpx_memset(cpi->common.fc.pre_mvc, 0, sizeof(cpi->common.fc.pre_mvc)); //initialize pre_mvc to all zero. //cpi->common.filter_level = 0; // Reset every key frame. cpi->common.filter_level = cpi->common.base_qindex * 3 / 8 ; // Provisional interval before next GF if (cpi->auto_gold) //cpi->frames_till_gf_update_due = DEFAULT_GF_INTERVAL; cpi->frames_till_gf_update_due = cpi->baseline_gf_interval; else cpi->frames_till_gf_update_due = cpi->goldfreq; cpi->common.refresh_golden_frame = TRUE; cpi->common.refresh_alt_ref_frame = TRUE; } static int estimate_bits_at_q(int frame_kind, int Q, int MBs, double correction_factor) { int Bpm = (int)(.5 + correction_factor * vp8_bits_per_mb[frame_kind][Q]); /* Attempt to retain reasonable accuracy without overflow. The cutoff is * chosen such that the maximum product of Bpm and MBs fits 31 bits. The * largest Bpm takes 20 bits. */ if (MBs > (1 << 11)) return (Bpm >> BPER_MB_NORMBITS) * MBs; else return (Bpm * MBs) >> BPER_MB_NORMBITS; } static void calc_iframe_target_size(VP8_COMP *cpi) { // boost defaults to half second int kf_boost; int target; // Clear down mmx registers to allow floating point in what follows vp8_clear_system_state(); //__asm emms; if (cpi->oxcf.fixed_q >= 0) { int Q = cpi->oxcf.key_q; target = estimate_bits_at_q(INTRA_FRAME, Q, cpi->common.MBs, cpi->key_frame_rate_correction_factor); } else if (cpi->pass == 2) { // New Two pass RC target = cpi->per_frame_bandwidth; } // First Frame is a special case else if (cpi->common.current_video_frame == 0) { /* 1 Pass there is no information on which to base size so use * bandwidth per second * fraction of the initial buffer * level */ target = cpi->oxcf.starting_buffer_level / 2; if(target > cpi->oxcf.target_bandwidth * 3 / 2) target = cpi->oxcf.target_bandwidth * 3 / 2; } else { // if this keyframe was forced, use a more recent Q estimate int Q = (cpi->common.frame_flags & FRAMEFLAGS_KEY) ? cpi->avg_frame_qindex : cpi->ni_av_qi; // Boost depends somewhat on frame rate kf_boost = (int)(2 * cpi->output_frame_rate - 16); // adjustment up based on q kf_boost = kf_boost * kf_boost_qadjustment[Q] / 100; // frame separation adjustment ( down) if (cpi->frames_since_key < cpi->output_frame_rate / 2) kf_boost = (int)(kf_boost * cpi->frames_since_key / (cpi->output_frame_rate / 2)); if (kf_boost < 16) kf_boost = 16; target = ((16 + kf_boost) * cpi->per_frame_bandwidth) >> 4; } if (cpi->oxcf.rc_max_intra_bitrate_pct) { unsigned int max_rate = cpi->per_frame_bandwidth * cpi->oxcf.rc_max_intra_bitrate_pct / 100; if (target > max_rate) target = max_rate; } cpi->this_frame_target = target; // TODO: if we separate rate targeting from Q targetting, move this. // Reset the active worst quality to the baseline value for key frames. if (cpi->pass != 2) cpi->active_worst_quality = cpi->worst_quality; #if 0 { FILE *f; f = fopen("kf_boost.stt", "a"); //fprintf(f, " %8d %10d %10d %10d %10d %10d %10d\n", // cpi->common.current_video_frame, cpi->target_bandwidth, cpi->frames_to_key, kf_boost_qadjustment[cpi->ni_av_qi], cpi->kf_boost, (cpi->this_frame_target *100 / cpi->per_frame_bandwidth), cpi->this_frame_target ); fprintf(f, " %8u %10d %10d %10d\n", cpi->common.current_video_frame, cpi->gfu_boost, cpi->baseline_gf_interval, cpi->source_alt_ref_pending); fclose(f); } #endif } // Do the best we can to define the parameters for the next GF based on what // information we have available. static void calc_gf_params(VP8_COMP *cpi) { int Q = (cpi->oxcf.fixed_q < 0) ? cpi->last_q[INTER_FRAME] : cpi->oxcf.fixed_q; int Boost = 0; int gf_frame_useage = 0; // Golden frame useage since last GF int tot_mbs = cpi->recent_ref_frame_usage[INTRA_FRAME] + cpi->recent_ref_frame_usage[LAST_FRAME] + cpi->recent_ref_frame_usage[GOLDEN_FRAME] + cpi->recent_ref_frame_usage[ALTREF_FRAME]; int pct_gf_active = (100 * cpi->gf_active_count) / (cpi->common.mb_rows * cpi->common.mb_cols); // Reset the last boost indicator //cpi->last_boost = 100; if (tot_mbs) gf_frame_useage = (cpi->recent_ref_frame_usage[GOLDEN_FRAME] + cpi->recent_ref_frame_usage[ALTREF_FRAME]) * 100 / tot_mbs; if (pct_gf_active > gf_frame_useage) gf_frame_useage = pct_gf_active; // Not two pass if (cpi->pass != 2) { // Single Pass lagged mode: TBD if (FALSE) { } // Single Pass compression: Has to use current and historical data else { #if 0 // Experimental code int index = cpi->one_pass_frame_index; int frames_to_scan = (cpi->max_gf_interval <= MAX_LAG_BUFFERS) ? cpi->max_gf_interval : MAX_LAG_BUFFERS; /* // *************** Experimental code - incomplete double decay_val = 1.0; double IIAccumulator = 0.0; double last_iiaccumulator = 0.0; double IIRatio; cpi->one_pass_frame_index = cpi->common.current_video_frame%MAX_LAG_BUFFERS; for ( i = 0; i < (frames_to_scan - 1); i++ ) { if ( index < 0 ) index = MAX_LAG_BUFFERS; index --; if ( cpi->one_pass_frame_stats[index].frame_coded_error > 0.0 ) { IIRatio = cpi->one_pass_frame_stats[index].frame_intra_error / cpi->one_pass_frame_stats[index].frame_coded_error; if ( IIRatio > 30.0 ) IIRatio = 30.0; } else IIRatio = 30.0; IIAccumulator += IIRatio * decay_val; decay_val = decay_val * cpi->one_pass_frame_stats[index].frame_pcnt_inter; if ( (i > MIN_GF_INTERVAL) && ((IIAccumulator - last_iiaccumulator) < 2.0) ) { break; } last_iiaccumulator = IIAccumulator; } Boost = IIAccumulator*100.0/16.0; cpi->baseline_gf_interval = i; */ #else /*************************************************************/ // OLD code // Adjust boost based upon ambient Q Boost = GFQ_ADJUSTMENT; // Adjust based upon most recently measure intra useage Boost = Boost * gf_intra_usage_adjustment[(cpi->this_frame_percent_intra < 15) ? cpi->this_frame_percent_intra : 14] / 100; // Adjust gf boost based upon GF usage since last GF Boost = Boost * gf_adjust_table[gf_frame_useage] / 100; #endif } // golden frame boost without recode loop often goes awry. be safe by keeping numbers down. if (!cpi->sf.recode_loop) { if (cpi->compressor_speed == 2) Boost = Boost / 2; } // Apply an upper limit based on Q for 1 pass encodes if (Boost > kf_gf_boost_qlimits[Q] && (cpi->pass == 0)) Boost = kf_gf_boost_qlimits[Q]; // Apply lower limits to boost. else if (Boost < 110) Boost = 110; // Note the boost used cpi->last_boost = Boost; } // Estimate next interval // This is updated once the real frame size/boost is known. if (cpi->oxcf.fixed_q == -1) { if (cpi->pass == 2) // 2 Pass { cpi->frames_till_gf_update_due = cpi->baseline_gf_interval; } else // 1 Pass { cpi->frames_till_gf_update_due = cpi->baseline_gf_interval; if (cpi->last_boost > 750) cpi->frames_till_gf_update_due++; if (cpi->last_boost > 1000) cpi->frames_till_gf_update_due++; if (cpi->last_boost > 1250) cpi->frames_till_gf_update_due++; if (cpi->last_boost >= 1500) cpi->frames_till_gf_update_due ++; if (gf_interval_table[gf_frame_useage] > cpi->frames_till_gf_update_due) cpi->frames_till_gf_update_due = gf_interval_table[gf_frame_useage]; if (cpi->frames_till_gf_update_due > cpi->max_gf_interval) cpi->frames_till_gf_update_due = cpi->max_gf_interval; } } else cpi->frames_till_gf_update_due = cpi->baseline_gf_interval; // ARF on or off if (cpi->pass != 2) { // For now Alt ref is not allowed except in 2 pass modes. cpi->source_alt_ref_pending = FALSE; /*if ( cpi->oxcf.fixed_q == -1) { if ( cpi->oxcf.play_alternate && (cpi->last_boost > (100 + (AF_THRESH*cpi->frames_till_gf_update_due)) ) ) cpi->source_alt_ref_pending = TRUE; else cpi->source_alt_ref_pending = FALSE; }*/ } } static void calc_pframe_target_size(VP8_COMP *cpi) { int min_frame_target; int Adjustment; int old_per_frame_bandwidth = cpi->per_frame_bandwidth; if ( cpi->current_layer > 0) cpi->per_frame_bandwidth = cpi->layer_context[cpi->current_layer].avg_frame_size_for_layer; min_frame_target = 0; if (cpi->pass == 2) { min_frame_target = cpi->min_frame_bandwidth; if (min_frame_target < (cpi->av_per_frame_bandwidth >> 5)) min_frame_target = cpi->av_per_frame_bandwidth >> 5; } else if (min_frame_target < cpi->per_frame_bandwidth / 4) min_frame_target = cpi->per_frame_bandwidth / 4; // Special alt reference frame case if((cpi->common.refresh_alt_ref_frame) && (cpi->oxcf.number_of_layers == 1)) { if (cpi->pass == 2) { cpi->per_frame_bandwidth = cpi->twopass.gf_bits; // Per frame bit target for the alt ref frame cpi->this_frame_target = cpi->per_frame_bandwidth; } /* One Pass ??? TBD */ /*else { int frames_in_section; int allocation_chunks; int Q = (cpi->oxcf.fixed_q < 0) ? cpi->last_q[INTER_FRAME] : cpi->oxcf.fixed_q; int alt_boost; int max_arf_rate; alt_boost = (cpi->gfu_boost * 3 * GFQ_ADJUSTMENT) / (2 * 100); alt_boost += (cpi->frames_till_gf_update_due * 50); // If alt ref is not currently active then we have a pottential double hit with GF and ARF so reduce the boost a bit. // A similar thing is done on GFs that preceed a arf update. if ( !cpi->source_alt_ref_active ) alt_boost = alt_boost * 3 / 4; frames_in_section = cpi->frames_till_gf_update_due+1; // Standard frames + GF allocation_chunks = (frames_in_section * 100) + alt_boost; // Normalize Altboost and allocations chunck down to prevent overflow while ( alt_boost > 1000 ) { alt_boost /= 2; allocation_chunks /= 2; } else { int bits_in_section; if ( cpi->kf_overspend_bits > 0 ) { Adjustment = (cpi->kf_bitrate_adjustment <= cpi->kf_overspend_bits) ? cpi->kf_bitrate_adjustment : cpi->kf_overspend_bits; if ( Adjustment > (cpi->per_frame_bandwidth - min_frame_target) ) Adjustment = (cpi->per_frame_bandwidth - min_frame_target); cpi->kf_overspend_bits -= Adjustment; // Calculate an inter frame bandwidth target for the next few frames designed to recover // any extra bits spent on the key frame. cpi->inter_frame_target = cpi->per_frame_bandwidth - Adjustment; if ( cpi->inter_frame_target < min_frame_target ) cpi->inter_frame_target = min_frame_target; } else cpi->inter_frame_target = cpi->per_frame_bandwidth; bits_in_section = cpi->inter_frame_target * frames_in_section; // Avoid loss of precision but avoid overflow if ( (bits_in_section>>7) > allocation_chunks ) cpi->this_frame_target = alt_boost * (bits_in_section / allocation_chunks); else cpi->this_frame_target = (alt_boost * bits_in_section) / allocation_chunks; } } */ } // Normal frames (gf,and inter) else { // 2 pass if (cpi->pass == 2) { cpi->this_frame_target = cpi->per_frame_bandwidth; } // 1 pass else { // Make rate adjustment to recover bits spent in key frame // Test to see if the key frame inter data rate correction should still be in force if (cpi->kf_overspend_bits > 0) { Adjustment = (cpi->kf_bitrate_adjustment <= cpi->kf_overspend_bits) ? cpi->kf_bitrate_adjustment : cpi->kf_overspend_bits; if (Adjustment > (cpi->per_frame_bandwidth - min_frame_target)) Adjustment = (cpi->per_frame_bandwidth - min_frame_target); cpi->kf_overspend_bits -= Adjustment; // Calculate an inter frame bandwidth target for the next few frames designed to recover // any extra bits spent on the key frame. cpi->this_frame_target = cpi->per_frame_bandwidth - Adjustment; if (cpi->this_frame_target < min_frame_target) cpi->this_frame_target = min_frame_target; } else cpi->this_frame_target = cpi->per_frame_bandwidth; // If appropriate make an adjustment to recover bits spent on a recent GF if ((cpi->gf_overspend_bits > 0) && (cpi->this_frame_target > min_frame_target)) { int Adjustment = (cpi->non_gf_bitrate_adjustment <= cpi->gf_overspend_bits) ? cpi->non_gf_bitrate_adjustment : cpi->gf_overspend_bits; if (Adjustment > (cpi->this_frame_target - min_frame_target)) Adjustment = (cpi->this_frame_target - min_frame_target); cpi->gf_overspend_bits -= Adjustment; cpi->this_frame_target -= Adjustment; } // Apply small + and - boosts for non gf frames if ((cpi->last_boost > 150) && (cpi->frames_till_gf_update_due > 0) && (cpi->current_gf_interval >= (MIN_GF_INTERVAL << 1))) { // % Adjustment limited to the range 1% to 10% Adjustment = (cpi->last_boost - 100) >> 5; if (Adjustment < 1) Adjustment = 1; else if (Adjustment > 10) Adjustment = 10; // Convert to bits Adjustment = (cpi->this_frame_target * Adjustment) / 100; if (Adjustment > (cpi->this_frame_target - min_frame_target)) Adjustment = (cpi->this_frame_target - min_frame_target); if (cpi->common.frames_since_golden == (cpi->current_gf_interval >> 1)) cpi->this_frame_target += ((cpi->current_gf_interval - 1) * Adjustment); else cpi->this_frame_target -= Adjustment; } } } // Sanity check that the total sum of adjustments is not above the maximum allowed // That is that having allowed for KF and GF penalties we have not pushed the // current interframe target to low. If the adjustment we apply here is not capable of recovering // all the extra bits we have spent in the KF or GF then the remainder will have to be recovered over // a longer time span via other buffer / rate control mechanisms. if (cpi->this_frame_target < min_frame_target) cpi->this_frame_target = min_frame_target; if (!cpi->common.refresh_alt_ref_frame) // Note the baseline target data rate for this inter frame. cpi->inter_frame_target = cpi->this_frame_target; // One Pass specific code if (cpi->pass == 0) { // Adapt target frame size with respect to any buffering constraints: if (cpi->buffered_mode) { int one_percent_bits = 1 + cpi->oxcf.optimal_buffer_level / 100; if ((cpi->buffer_level < cpi->oxcf.optimal_buffer_level) || (cpi->bits_off_target < cpi->oxcf.optimal_buffer_level)) { int percent_low = 0; // Decide whether or not we need to adjust the frame data rate target. // // If we are are below the optimal buffer fullness level and adherence // to buffering constraints is important to the end usage then adjust // the per frame target. if ((cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER) && (cpi->buffer_level < cpi->oxcf.optimal_buffer_level)) { percent_low = (cpi->oxcf.optimal_buffer_level - cpi->buffer_level) / one_percent_bits; } // Are we overshooting the long term clip data rate... else if (cpi->bits_off_target < 0) { // Adjust per frame data target downwards to compensate. percent_low = (int)(100 * -cpi->bits_off_target / (cpi->total_byte_count * 8)); } if (percent_low > cpi->oxcf.under_shoot_pct) percent_low = cpi->oxcf.under_shoot_pct; else if (percent_low < 0) percent_low = 0; // lower the target bandwidth for this frame. cpi->this_frame_target -= (cpi->this_frame_target * percent_low) / 200; // Are we using allowing control of active_worst_allowed_q // according to buffer level. if (cpi->auto_worst_q && cpi->ni_frames > 150) { int critical_buffer_level; // For streaming applications the most important factor is // cpi->buffer_level as this takes into account the // specified short term buffering constraints. However, // hitting the long term clip data rate target is also // important. if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER) { // Take the smaller of cpi->buffer_level and // cpi->bits_off_target critical_buffer_level = (cpi->buffer_level < cpi->bits_off_target) ? cpi->buffer_level : cpi->bits_off_target; } // For local file playback short term buffering constraints // are less of an issue else { // Consider only how we are doing for the clip as a // whole critical_buffer_level = cpi->bits_off_target; } // Set the active worst quality based upon the selected // buffer fullness number. if (critical_buffer_level < cpi->oxcf.optimal_buffer_level) { if ( critical_buffer_level > (cpi->oxcf.optimal_buffer_level >> 2) ) { int64_t qadjustment_range = cpi->worst_quality - cpi->ni_av_qi; int64_t above_base = (critical_buffer_level - (cpi->oxcf.optimal_buffer_level >> 2)); // Step active worst quality down from // cpi->ni_av_qi when (critical_buffer_level == // cpi->optimal_buffer_level) to // cpi->worst_quality when // (critical_buffer_level == // cpi->optimal_buffer_level >> 2) cpi->active_worst_quality = cpi->worst_quality - ((qadjustment_range * above_base) / (cpi->oxcf.optimal_buffer_level*3>>2)); } else { cpi->active_worst_quality = cpi->worst_quality; } } else { cpi->active_worst_quality = cpi->ni_av_qi; } } else { cpi->active_worst_quality = cpi->worst_quality; } } else { int percent_high = 0; if ((cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER) && (cpi->buffer_level > cpi->oxcf.optimal_buffer_level)) { percent_high = (cpi->buffer_level - cpi->oxcf.optimal_buffer_level) / one_percent_bits; } else if (cpi->bits_off_target > cpi->oxcf.optimal_buffer_level) { percent_high = (int)((100 * cpi->bits_off_target) / (cpi->total_byte_count * 8)); } if (percent_high > cpi->oxcf.over_shoot_pct) percent_high = cpi->oxcf.over_shoot_pct; else if (percent_high < 0) percent_high = 0; cpi->this_frame_target += (cpi->this_frame_target * percent_high) / 200; // Are we allowing control of active_worst_allowed_q according // to buffer level. if (cpi->auto_worst_q && cpi->ni_frames > 150) { // When using the relaxed buffer model stick to the user specified value cpi->active_worst_quality = cpi->ni_av_qi; } else { cpi->active_worst_quality = cpi->worst_quality; } } // Set active_best_quality to prevent quality rising too high cpi->active_best_quality = cpi->best_quality; // Worst quality obviously must not be better than best quality if (cpi->active_worst_quality <= cpi->active_best_quality) cpi->active_worst_quality = cpi->active_best_quality + 1; } // Unbuffered mode (eg. video conferencing) else { // Set the active worst quality cpi->active_worst_quality = cpi->worst_quality; } // Special trap for constrained quality mode // "active_worst_quality" may never drop below cq level // for any frame type. if ( cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY && cpi->active_worst_quality < cpi->cq_target_quality) { cpi->active_worst_quality = cpi->cq_target_quality; } } // Test to see if we have to drop a frame // The auto-drop frame code is only used in buffered mode. // In unbufferd mode (eg vide conferencing) the descision to // code or drop a frame is made outside the codec in response to real // world comms or buffer considerations. if (cpi->drop_frames_allowed && cpi->buffered_mode && (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER) && ((cpi->common.frame_type != KEY_FRAME))) //|| !cpi->oxcf.allow_spatial_resampling) ) { // Check for a buffer underun-crisis in which case we have to drop a frame if ((cpi->buffer_level < 0)) { #if 0 FILE *f = fopen("dec.stt", "a"); fprintf(f, "%10d %10d %10d %10d ***** BUFFER EMPTY\n", (int) cpi->common.current_video_frame, cpi->decimation_factor, cpi->common.horiz_scale, (cpi->buffer_level * 100) / cpi->oxcf.optimal_buffer_level); fclose(f); #endif //vpx_log("Decoder: Drop frame due to bandwidth: %d \n",cpi->buffer_level, cpi->av_per_frame_bandwidth); cpi->drop_frame = TRUE; } #if 0 // Check for other drop frame crtieria (Note 2 pass cbr uses decimation on whole KF sections) else if ((cpi->buffer_level < cpi->oxcf.drop_frames_water_mark * cpi->oxcf.optimal_buffer_level / 100) && (cpi->drop_count < cpi->max_drop_count) && (cpi->pass == 0)) { cpi->drop_frame = TRUE; } #endif if (cpi->drop_frame) { // Update the buffer level variable. cpi->bits_off_target += cpi->av_per_frame_bandwidth; if (cpi->bits_off_target > cpi->oxcf.maximum_buffer_size) cpi->bits_off_target = cpi->oxcf.maximum_buffer_size; cpi->buffer_level = cpi->bits_off_target; } else cpi->drop_count = 0; } // Adjust target frame size for Golden Frames: if (cpi->oxcf.error_resilient_mode == 0 && (cpi->frames_till_gf_update_due == 0) && !cpi->drop_frame) { //int Boost = 0; int Q = (cpi->oxcf.fixed_q < 0) ? cpi->last_q[INTER_FRAME] : cpi->oxcf.fixed_q; int gf_frame_useage = 0; // Golden frame useage since last GF int tot_mbs = cpi->recent_ref_frame_usage[INTRA_FRAME] + cpi->recent_ref_frame_usage[LAST_FRAME] + cpi->recent_ref_frame_usage[GOLDEN_FRAME] + cpi->recent_ref_frame_usage[ALTREF_FRAME]; int pct_gf_active = (100 * cpi->gf_active_count) / (cpi->common.mb_rows * cpi->common.mb_cols); // Reset the last boost indicator //cpi->last_boost = 100; if (tot_mbs) gf_frame_useage = (cpi->recent_ref_frame_usage[GOLDEN_FRAME] + cpi->recent_ref_frame_usage[ALTREF_FRAME]) * 100 / tot_mbs; if (pct_gf_active > gf_frame_useage) gf_frame_useage = pct_gf_active; // Is a fixed manual GF frequency being used if (cpi->auto_gold) { // For one pass throw a GF if recent frame intra useage is low or the GF useage is high if ((cpi->pass == 0) && (cpi->this_frame_percent_intra < 15 || gf_frame_useage >= 5)) cpi->common.refresh_golden_frame = TRUE; // Two pass GF descision else if (cpi->pass == 2) cpi->common.refresh_golden_frame = TRUE; } #if 0 // Debug stats if (0) { FILE *f; f = fopen("gf_useaget.stt", "a"); fprintf(f, " %8ld %10ld %10ld %10ld %10ld\n", cpi->common.current_video_frame, cpi->gfu_boost, GFQ_ADJUSTMENT, cpi->gfu_boost, gf_frame_useage); fclose(f); } #endif if (cpi->common.refresh_golden_frame == TRUE) { #if 0 if (0) // p_gw { FILE *f; f = fopen("GFexit.stt", "a"); fprintf(f, "%8ld GF coded\n", cpi->common.current_video_frame); fclose(f); } #endif if (cpi->auto_adjust_gold_quantizer) { calc_gf_params(cpi); } // If we are using alternate ref instead of gf then do not apply the boost // It will instead be applied to the altref update // Jims modified boost if (!cpi->source_alt_ref_active) { if (cpi->oxcf.fixed_q < 0) { if (cpi->pass == 2) { cpi->this_frame_target = cpi->per_frame_bandwidth; // The spend on the GF is defined in the two pass code for two pass encodes } else { int Boost = cpi->last_boost; int frames_in_section = cpi->frames_till_gf_update_due + 1; int allocation_chunks = (frames_in_section * 100) + (Boost - 100); int bits_in_section = cpi->inter_frame_target * frames_in_section; // Normalize Altboost and allocations chunck down to prevent overflow while (Boost > 1000) { Boost /= 2; allocation_chunks /= 2; } // Avoid loss of precision but avoid overflow if ((bits_in_section >> 7) > allocation_chunks) cpi->this_frame_target = Boost * (bits_in_section / allocation_chunks); else cpi->this_frame_target = (Boost * bits_in_section) / allocation_chunks; } } else cpi->this_frame_target = (estimate_bits_at_q(1, Q, cpi->common.MBs, 1.0) * cpi->last_boost) / 100; } // If there is an active ARF at this location use the minimum // bits on this frame even if it is a contructed arf. // The active maximum quantizer insures that an appropriate // number of bits will be spent if needed for contstructed ARFs. else { cpi->this_frame_target = 0; } cpi->current_gf_interval = cpi->frames_till_gf_update_due; } } cpi->per_frame_bandwidth = old_per_frame_bandwidth; } void vp8_update_rate_correction_factors(VP8_COMP *cpi, int damp_var) { int Q = cpi->common.base_qindex; int correction_factor = 100; double rate_correction_factor; double adjustment_limit; int projected_size_based_on_q = 0; // Clear down mmx registers to allow floating point in what follows vp8_clear_system_state(); //__asm emms; if (cpi->common.frame_type == KEY_FRAME) { rate_correction_factor = cpi->key_frame_rate_correction_factor; } else { if (cpi->common.refresh_alt_ref_frame || cpi->common.refresh_golden_frame) rate_correction_factor = cpi->gf_rate_correction_factor; else rate_correction_factor = cpi->rate_correction_factor; } // Work out how big we would have expected the frame to be at this Q given the current correction factor. // Stay in double to avoid int overflow when values are large //projected_size_based_on_q = ((int)(.5 + rate_correction_factor * vp8_bits_per_mb[cpi->common.frame_type][Q]) * cpi->common.MBs) >> BPER_MB_NORMBITS; projected_size_based_on_q = (int)(((.5 + rate_correction_factor * vp8_bits_per_mb[cpi->common.frame_type][Q]) * cpi->common.MBs) / (1 << BPER_MB_NORMBITS)); // Make some allowance for cpi->zbin_over_quant if (cpi->zbin_over_quant > 0) { int Z = cpi->zbin_over_quant; double Factor = 0.99; double factor_adjustment = 0.01 / 256.0; //(double)ZBIN_OQ_MAX; while (Z > 0) { Z --; projected_size_based_on_q = (int)(Factor * projected_size_based_on_q); Factor += factor_adjustment; if (Factor >= 0.999) Factor = 0.999; } } // Work out a size correction factor. //if ( cpi->this_frame_target > 0 ) // correction_factor = (100 * cpi->projected_frame_size) / cpi->this_frame_target; if (projected_size_based_on_q > 0) correction_factor = (100 * cpi->projected_frame_size) / projected_size_based_on_q; // More heavily damped adjustment used if we have been oscillating either side of target switch (damp_var) { case 0: adjustment_limit = 0.75; break; case 1: adjustment_limit = 0.375; break; case 2: default: adjustment_limit = 0.25; break; } //if ( (correction_factor > 102) && (Q < cpi->active_worst_quality) ) if (correction_factor > 102) { // We are not already at the worst allowable quality correction_factor = (int)(100.5 + ((correction_factor - 100) * adjustment_limit)); rate_correction_factor = ((rate_correction_factor * correction_factor) / 100); // Keep rate_correction_factor within limits if (rate_correction_factor > MAX_BPB_FACTOR) rate_correction_factor = MAX_BPB_FACTOR; } //else if ( (correction_factor < 99) && (Q > cpi->active_best_quality) ) else if (correction_factor < 99) { // We are not already at the best allowable quality correction_factor = (int)(100.5 - ((100 - correction_factor) * adjustment_limit)); rate_correction_factor = ((rate_correction_factor * correction_factor) / 100); // Keep rate_correction_factor within limits if (rate_correction_factor < MIN_BPB_FACTOR) rate_correction_factor = MIN_BPB_FACTOR; } if (cpi->common.frame_type == KEY_FRAME) cpi->key_frame_rate_correction_factor = rate_correction_factor; else { if (cpi->common.refresh_alt_ref_frame || cpi->common.refresh_golden_frame) cpi->gf_rate_correction_factor = rate_correction_factor; else cpi->rate_correction_factor = rate_correction_factor; } } int vp8_regulate_q(VP8_COMP *cpi, int target_bits_per_frame) { int Q = cpi->active_worst_quality; // Reset Zbin OQ value cpi->zbin_over_quant = 0; if (cpi->oxcf.fixed_q >= 0) { Q = cpi->oxcf.fixed_q; if (cpi->common.frame_type == KEY_FRAME) { Q = cpi->oxcf.key_q; } else if (cpi->common.refresh_alt_ref_frame) { Q = cpi->oxcf.alt_q; } else if (cpi->common.refresh_golden_frame) { Q = cpi->oxcf.gold_q; } } else { int i; int last_error = INT_MAX; int target_bits_per_mb; int bits_per_mb_at_this_q; double correction_factor; // Select the appropriate correction factor based upon type of frame. if (cpi->common.frame_type == KEY_FRAME) correction_factor = cpi->key_frame_rate_correction_factor; else { if (cpi->common.refresh_alt_ref_frame || cpi->common.refresh_golden_frame) correction_factor = cpi->gf_rate_correction_factor; else correction_factor = cpi->rate_correction_factor; } // Calculate required scaling factor based on target frame size and size of frame produced using previous Q if (target_bits_per_frame >= (INT_MAX >> BPER_MB_NORMBITS)) target_bits_per_mb = (target_bits_per_frame / cpi->common.MBs) << BPER_MB_NORMBITS; // Case where we would overflow int else target_bits_per_mb = (target_bits_per_frame << BPER_MB_NORMBITS) / cpi->common.MBs; i = cpi->active_best_quality; do { bits_per_mb_at_this_q = (int)(.5 + correction_factor * vp8_bits_per_mb[cpi->common.frame_type][i]); if (bits_per_mb_at_this_q <= target_bits_per_mb) { if ((target_bits_per_mb - bits_per_mb_at_this_q) <= last_error) Q = i; else Q = i - 1; break; } else last_error = bits_per_mb_at_this_q - target_bits_per_mb; } while (++i <= cpi->active_worst_quality); // If we are at MAXQ then enable Q over-run which seeks to claw back additional bits through things like // the RD multiplier and zero bin size. if (Q >= MAXQ) { int zbin_oqmax; double Factor = 0.99; double factor_adjustment = 0.01 / 256.0; //(double)ZBIN_OQ_MAX; if (cpi->common.frame_type == KEY_FRAME) zbin_oqmax = 0; //ZBIN_OQ_MAX/16 else if (cpi->common.refresh_alt_ref_frame || (cpi->common.refresh_golden_frame && !cpi->source_alt_ref_active)) zbin_oqmax = 16; else zbin_oqmax = ZBIN_OQ_MAX; /*{ double Factor = (double)target_bits_per_mb/(double)bits_per_mb_at_this_q; double Oq; Factor = Factor/1.2683; Oq = pow( Factor, (1.0/-0.165) ); if ( Oq > zbin_oqmax ) Oq = zbin_oqmax; cpi->zbin_over_quant = (int)Oq; }*/ // Each incrment in the zbin is assumed to have a fixed effect on bitrate. This is not of course true. // The effect will be highly clip dependent and may well have sudden steps. // The idea here is to acheive higher effective quantizers than the normal maximum by expanding the zero // bin and hence decreasing the number of low magnitude non zero coefficients. while (cpi->zbin_over_quant < zbin_oqmax) { cpi->zbin_over_quant ++; if (cpi->zbin_over_quant > zbin_oqmax) cpi->zbin_over_quant = zbin_oqmax; // Adjust bits_per_mb_at_this_q estimate bits_per_mb_at_this_q = (int)(Factor * bits_per_mb_at_this_q); Factor += factor_adjustment; if (Factor >= 0.999) Factor = 0.999; if (bits_per_mb_at_this_q <= target_bits_per_mb) // Break out if we get down to the target rate break; } } } return Q; } static int estimate_keyframe_frequency(VP8_COMP *cpi) { int i; // Average key frame frequency int av_key_frame_frequency = 0; /* First key frame at start of sequence is a special case. We have no * frequency data. */ if (cpi->key_frame_count == 1) { /* Assume a default of 1 kf every 2 seconds, or the max kf interval, * whichever is smaller. */ int key_freq = cpi->oxcf.key_freq>0 ? cpi->oxcf.key_freq : 1; av_key_frame_frequency = (int)cpi->output_frame_rate * 2; if (cpi->oxcf.auto_key && av_key_frame_frequency > key_freq) av_key_frame_frequency = cpi->oxcf.key_freq; cpi->prior_key_frame_distance[KEY_FRAME_CONTEXT - 1] = av_key_frame_frequency; } else { unsigned int total_weight = 0; int last_kf_interval = (cpi->frames_since_key > 0) ? cpi->frames_since_key : 1; /* reset keyframe context and calculate weighted average of last * KEY_FRAME_CONTEXT keyframes */ for (i = 0; i < KEY_FRAME_CONTEXT; i++) { if (i < KEY_FRAME_CONTEXT - 1) cpi->prior_key_frame_distance[i] = cpi->prior_key_frame_distance[i+1]; else cpi->prior_key_frame_distance[i] = last_kf_interval; av_key_frame_frequency += prior_key_frame_weight[i] * cpi->prior_key_frame_distance[i]; total_weight += prior_key_frame_weight[i]; } av_key_frame_frequency /= total_weight; } return av_key_frame_frequency; } void vp8_adjust_key_frame_context(VP8_COMP *cpi) { // Clear down mmx registers to allow floating point in what follows vp8_clear_system_state(); // Do we have any key frame overspend to recover? // Two-pass overspend handled elsewhere. if ((cpi->pass != 2) && (cpi->projected_frame_size > cpi->per_frame_bandwidth)) { int overspend; /* Update the count of key frame overspend to be recovered in * subsequent frames. A portion of the KF overspend is treated as gf * overspend (and hence recovered more quickly) as the kf is also a * gf. Otherwise the few frames following each kf tend to get more * bits allocated than those following other gfs. */ overspend = (cpi->projected_frame_size - cpi->per_frame_bandwidth); if (cpi->oxcf.number_of_layers > 1) cpi->kf_overspend_bits += overspend; else { cpi->kf_overspend_bits += overspend * 7 / 8; cpi->gf_overspend_bits += overspend * 1 / 8; } /* Work out how much to try and recover per frame. */ cpi->kf_bitrate_adjustment = cpi->kf_overspend_bits / estimate_keyframe_frequency(cpi); } cpi->frames_since_key = 0; cpi->key_frame_count++; } void vp8_compute_frame_size_bounds(VP8_COMP *cpi, int *frame_under_shoot_limit, int *frame_over_shoot_limit) { // Set-up bounds on acceptable frame size: if (cpi->oxcf.fixed_q >= 0) { // Fixed Q scenario: frame size never outranges target (there is no target!) *frame_under_shoot_limit = 0; *frame_over_shoot_limit = INT_MAX; } else { if (cpi->common.frame_type == KEY_FRAME) { *frame_over_shoot_limit = cpi->this_frame_target * 9 / 8; *frame_under_shoot_limit = cpi->this_frame_target * 7 / 8; } else { if (cpi->oxcf.number_of_layers > 1 || cpi->common.refresh_alt_ref_frame || cpi->common.refresh_golden_frame) { *frame_over_shoot_limit = cpi->this_frame_target * 9 / 8; *frame_under_shoot_limit = cpi->this_frame_target * 7 / 8; } else { // For CBR take buffer fullness into account if (cpi->oxcf.end_usage == USAGE_STREAM_FROM_SERVER) { if (cpi->buffer_level >= ((cpi->oxcf.optimal_buffer_level + cpi->oxcf.maximum_buffer_size) >> 1)) { // Buffer is too full so relax overshoot and tighten undershoot *frame_over_shoot_limit = cpi->this_frame_target * 12 / 8; *frame_under_shoot_limit = cpi->this_frame_target * 6 / 8; } else if (cpi->buffer_level <= (cpi->oxcf.optimal_buffer_level >> 1)) { // Buffer is too low so relax undershoot and tighten overshoot *frame_over_shoot_limit = cpi->this_frame_target * 10 / 8; *frame_under_shoot_limit = cpi->this_frame_target * 4 / 8; } else { *frame_over_shoot_limit = cpi->this_frame_target * 11 / 8; *frame_under_shoot_limit = cpi->this_frame_target * 5 / 8; } } // VBR and CQ mode // Note that tighter restrictions here can help quality but hurt encode speed else { // Stron overshoot limit for constrained quality if (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) { *frame_over_shoot_limit = cpi->this_frame_target * 11 / 8; *frame_under_shoot_limit = cpi->this_frame_target * 2 / 8; } else { *frame_over_shoot_limit = cpi->this_frame_target * 11 / 8; *frame_under_shoot_limit = cpi->this_frame_target * 5 / 8; } } } } } } // return of 0 means drop frame int vp8_pick_frame_size(VP8_COMP *cpi) { VP8_COMMON *cm = &cpi->common; if (cm->frame_type == KEY_FRAME) calc_iframe_target_size(cpi); else { calc_pframe_target_size(cpi); // Check if we're dropping the frame: if (cpi->drop_frame) { cpi->drop_frame = FALSE; cpi->drop_count++; return 0; } } return 1; }