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c2876cf0fd
vpx/vp9/encoder/vp9_firstpass.c
Adrian Grange c2876cf0fd Initial addition of multiple ARF frames 
This is work-in-progress, it implements multiple ARF
encoding behind an experimental flag.

It adds the ability to insert multiple ARF frames into a
single ARF group. This patch implements the reordering
of the coded frames, and implements a fixed-length coding
pattern. It applies a fixed quantizer strategy based on
where the frame is in the coding sequence.

Further work to modify the rate control strategy is
ongoing and will be submitted via a set of future patches.

In this first step, each ARF group is recursively
bisected and an ARF frame added at that position in the
sequence. The recursion continues until ARF frames are
within MIN_GF_INTERVAL frames.

The code sits behind the "multiple-arf" experimental
flag ("CONFIG_MULTIPLE_ARF"). The experimental flag
"oneshotq" ("CONFIG_ONESHOTQ") also needs to be enabled
for this patch to work correctly.

Change-Id: Ie473b05ebb43ac473c0cfb659b2b8042823085e2
2013-04-15 09:11:39 -07:00

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/*
* 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 "limits.h"
#include "vp9/encoder/vp9_block.h"
#include "vp9/encoder/vp9_onyx_int.h"
#include "vp9/encoder/vp9_variance.h"
#include "vp9/encoder/vp9_encodeintra.h"
#include "vp9/common/vp9_setupintrarecon.h"
#include "vp9/encoder/vp9_mcomp.h"
#include "vp9/encoder/vp9_firstpass.h"
#include "vpx_scale/vpx_scale.h"
#include "vp9/encoder/vp9_encodeframe.h"
#include "vp9/encoder/vp9_encodemb.h"
#include "vp9/common/vp9_extend.h"
#include "vp9/common/vp9_systemdependent.h"
#include "vpx_mem/vpx_mem.h"
#include "vp9/common/vp9_swapyv12buffer.h"
#include <stdio.h>
#include "vp9/encoder/vp9_quantize.h"
#include "vp9/encoder/vp9_rdopt.h"
#include "vp9/encoder/vp9_ratectrl.h"
#include "vp9/common/vp9_quant_common.h"
#include "vp9/common/vp9_entropymv.h"
#include "vp9/encoder/vp9_encodemv.h"
#include "./vpx_scale_rtcd.h"
#define OUTPUT_FPF 0
#define IIFACTOR 12.5
#define IIKFACTOR1 12.5
#define IIKFACTOR2 15.0
#define RMAX 128.0
#define GF_RMAX 96.0
#define ERR_DIVISOR 150.0
#define MIN_DECAY_FACTOR 0.1
#define KF_MB_INTRA_MIN 150
#define GF_MB_INTRA_MIN 100
#define DOUBLE_DIVIDE_CHECK(X) ((X)<0?(X)-.000001:(X)+.000001)
#define POW1 (double)cpi->oxcf.two_pass_vbrbias/100.0
#define POW2 (double)cpi->oxcf.two_pass_vbrbias/100.0
static void find_next_key_frame(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame);
static int select_cq_level(int qindex) {
int ret_val = QINDEX_RANGE - 1;
int i;
double target_q = (vp9_convert_qindex_to_q(qindex) * 0.5847) + 1.0;
for (i = 0; i < QINDEX_RANGE; i++) {
if (target_q <= vp9_convert_qindex_to_q(i)) {
ret_val = i;
break;
}
}
return ret_val;
}
// Resets the first pass file to the given position using a relative seek from the current position
static void reset_fpf_position(VP9_COMP *cpi, FIRSTPASS_STATS *Position) {
cpi->twopass.stats_in = Position;
}
static int lookup_next_frame_stats(VP9_COMP *cpi, FIRSTPASS_STATS *next_frame) {
if (cpi->twopass.stats_in >= cpi->twopass.stats_in_end)
return EOF;
*next_frame = *cpi->twopass.stats_in;
return 1;
}
// Read frame stats at an offset from the current position
static int read_frame_stats(VP9_COMP *cpi,
FIRSTPASS_STATS *frame_stats,
int offset) {
FIRSTPASS_STATS *fps_ptr = cpi->twopass.stats_in;
// Check legality of offset
if (offset >= 0) {
if (&fps_ptr[offset] >= cpi->twopass.stats_in_end)
return EOF;
} else if (offset < 0) {
if (&fps_ptr[offset] < cpi->twopass.stats_in_start)
return EOF;
}
*frame_stats = fps_ptr[offset];
return 1;
}
static int input_stats(VP9_COMP *cpi, FIRSTPASS_STATS *fps) {
if (cpi->twopass.stats_in >= cpi->twopass.stats_in_end)
return EOF;
*fps = *cpi->twopass.stats_in;
cpi->twopass.stats_in =
(void *)((char *)cpi->twopass.stats_in + sizeof(FIRSTPASS_STATS));
return 1;
}
static void output_stats(const VP9_COMP *cpi,
struct vpx_codec_pkt_list *pktlist,
FIRSTPASS_STATS *stats) {
struct vpx_codec_cx_pkt pkt;
pkt.kind = VPX_CODEC_STATS_PKT;
pkt.data.twopass_stats.buf = stats;
pkt.data.twopass_stats.sz = sizeof(FIRSTPASS_STATS);
vpx_codec_pkt_list_add(pktlist, &pkt);
// TEMP debug code
#if OUTPUT_FPF
{
FILE *fpfile;
fpfile = fopen("firstpass.stt", "a");
fprintf(fpfile, "%12.0f %12.0f %12.0f %12.0f %12.0f %12.4f %12.4f"
"%12.4f %12.4f %12.4f %12.4f %12.4f %12.4f %12.4f"
"%12.0f %12.0f %12.4f %12.0f %12.0f %12.4f\n",
stats->frame,
stats->intra_error,
stats->coded_error,
stats->sr_coded_error,
stats->ssim_weighted_pred_err,
stats->pcnt_inter,
stats->pcnt_motion,
stats->pcnt_second_ref,
stats->pcnt_neutral,
stats->MVr,
stats->mvr_abs,
stats->MVc,
stats->mvc_abs,
stats->MVrv,
stats->MVcv,
stats->mv_in_out_count,
stats->new_mv_count,
stats->count,
stats->duration);
fclose(fpfile);
}
#endif
}
static void zero_stats(FIRSTPASS_STATS *section) {
section->frame = 0.0;
section->intra_error = 0.0;
section->coded_error = 0.0;
section->sr_coded_error = 0.0;
section->ssim_weighted_pred_err = 0.0;
section->pcnt_inter = 0.0;
section->pcnt_motion = 0.0;
section->pcnt_second_ref = 0.0;
section->pcnt_neutral = 0.0;
section->MVr = 0.0;
section->mvr_abs = 0.0;
section->MVc = 0.0;
section->mvc_abs = 0.0;
section->MVrv = 0.0;
section->MVcv = 0.0;
section->mv_in_out_count = 0.0;
section->new_mv_count = 0.0;
section->count = 0.0;
section->duration = 1.0;
}
static void accumulate_stats(FIRSTPASS_STATS *section, FIRSTPASS_STATS *frame) {
section->frame += frame->frame;
section->intra_error += frame->intra_error;
section->coded_error += frame->coded_error;
section->sr_coded_error += frame->sr_coded_error;
section->ssim_weighted_pred_err += frame->ssim_weighted_pred_err;
section->pcnt_inter += frame->pcnt_inter;
section->pcnt_motion += frame->pcnt_motion;
section->pcnt_second_ref += frame->pcnt_second_ref;
section->pcnt_neutral += frame->pcnt_neutral;
section->MVr += frame->MVr;
section->mvr_abs += frame->mvr_abs;
section->MVc += frame->MVc;
section->mvc_abs += frame->mvc_abs;
section->MVrv += frame->MVrv;
section->MVcv += frame->MVcv;
section->mv_in_out_count += frame->mv_in_out_count;
section->new_mv_count += frame->new_mv_count;
section->count += frame->count;
section->duration += frame->duration;
}
static void subtract_stats(FIRSTPASS_STATS *section, FIRSTPASS_STATS *frame) {
section->frame -= frame->frame;
section->intra_error -= frame->intra_error;
section->coded_error -= frame->coded_error;
section->sr_coded_error -= frame->sr_coded_error;
section->ssim_weighted_pred_err -= frame->ssim_weighted_pred_err;
section->pcnt_inter -= frame->pcnt_inter;
section->pcnt_motion -= frame->pcnt_motion;
section->pcnt_second_ref -= frame->pcnt_second_ref;
section->pcnt_neutral -= frame->pcnt_neutral;
section->MVr -= frame->MVr;
section->mvr_abs -= frame->mvr_abs;
section->MVc -= frame->MVc;
section->mvc_abs -= frame->mvc_abs;
section->MVrv -= frame->MVrv;
section->MVcv -= frame->MVcv;
section->mv_in_out_count -= frame->mv_in_out_count;
section->new_mv_count -= frame->new_mv_count;
section->count -= frame->count;
section->duration -= frame->duration;
}
static void avg_stats(FIRSTPASS_STATS *section) {
if (section->count < 1.0)
return;
section->intra_error /= section->count;
section->coded_error /= section->count;
section->sr_coded_error /= section->count;
section->ssim_weighted_pred_err /= section->count;
section->pcnt_inter /= section->count;
section->pcnt_second_ref /= section->count;
section->pcnt_neutral /= section->count;
section->pcnt_motion /= section->count;
section->MVr /= section->count;
section->mvr_abs /= section->count;
section->MVc /= section->count;
section->mvc_abs /= section->count;
section->MVrv /= section->count;
section->MVcv /= section->count;
section->mv_in_out_count /= section->count;
section->duration /= section->count;
}
// Calculate a modified Error used in distributing bits between easier and harder frames
static double calculate_modified_err(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
double av_err = (cpi->twopass.total_stats->ssim_weighted_pred_err /
cpi->twopass.total_stats->count);
double this_err = this_frame->ssim_weighted_pred_err;
double modified_err;
if (this_err > av_err)
modified_err = av_err * pow((this_err / DOUBLE_DIVIDE_CHECK(av_err)), POW1);
else
modified_err = av_err * pow((this_err / DOUBLE_DIVIDE_CHECK(av_err)), POW2);
return modified_err;
}
static const double weight_table[256] = {
0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000, 0.020000,
0.020000, 0.031250, 0.062500, 0.093750, 0.125000, 0.156250, 0.187500, 0.218750,
0.250000, 0.281250, 0.312500, 0.343750, 0.375000, 0.406250, 0.437500, 0.468750,
0.500000, 0.531250, 0.562500, 0.593750, 0.625000, 0.656250, 0.687500, 0.718750,
0.750000, 0.781250, 0.812500, 0.843750, 0.875000, 0.906250, 0.937500, 0.968750,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000,
1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000, 1.000000
};
static double simple_weight(YV12_BUFFER_CONFIG *source) {
int i, j;
uint8_t *src = source->y_buffer;
double sum_weights = 0.0;
// Loop throught the Y plane raw examining levels and creating a weight for the image
i = source->y_height;
do {
j = source->y_width;
do {
sum_weights += weight_table[ *src];
src++;
} while (--j);
src -= source->y_width;
src += source->y_stride;
} while (--i);
sum_weights /= (source->y_height * source->y_width);
return sum_weights;
}
// This function returns the current per frame maximum bitrate target.
static int frame_max_bits(VP9_COMP *cpi) {
// Max allocation for a single frame based on the max section guidelines
// passed in and how many bits are left.
int max_bits;
// For VBR base this on the bits and frames left plus the
// two_pass_vbrmax_section rate passed in by the user.
max_bits = (int) (((double) cpi->twopass.bits_left
/ (cpi->twopass.total_stats->count - (double) cpi->common
.current_video_frame))
* ((double) cpi->oxcf.two_pass_vbrmax_section / 100.0));
// Trap case where we are out of bits.
if (max_bits < 0)
max_bits = 0;
return max_bits;
}
void vp9_init_first_pass(VP9_COMP *cpi) {
zero_stats(cpi->twopass.total_stats);
}
void vp9_end_first_pass(VP9_COMP *cpi) {
output_stats(cpi, cpi->output_pkt_list, cpi->twopass.total_stats);
}
static void zz_motion_search(VP9_COMP *cpi, MACROBLOCK *x, YV12_BUFFER_CONFIG *recon_buffer, int *best_motion_err, int recon_yoffset) {
MACROBLOCKD *const xd = &x->e_mbd;
BLOCK *b = &x->block[0];
BLOCKD *d = &x->e_mbd.block[0];
uint8_t *src_ptr = (*(b->base_src) + b->src);
int src_stride = b->src_stride;
uint8_t *ref_ptr;
int ref_stride = d->pre_stride;
// Set up pointers for this macro block recon buffer
xd->pre.y_buffer = recon_buffer->y_buffer + recon_yoffset;
ref_ptr = (uint8_t *)(*(d->base_pre) + d->pre);
vp9_mse16x16(src_ptr, src_stride, ref_ptr, ref_stride,
(unsigned int *)(best_motion_err));
}
static void first_pass_motion_search(VP9_COMP *cpi, MACROBLOCK *x,
int_mv *ref_mv, MV *best_mv,
YV12_BUFFER_CONFIG *recon_buffer,
int *best_motion_err, int recon_yoffset) {
MACROBLOCKD *const xd = &x->e_mbd;
BLOCK *b = &x->block[0];
BLOCKD *d = &x->e_mbd.block[0];
int num00;
int_mv tmp_mv;
int_mv ref_mv_full;
int tmp_err;
int step_param = 3;
int further_steps = (MAX_MVSEARCH_STEPS - 1) - step_param;
int n;
vp9_variance_fn_ptr_t v_fn_ptr = cpi->fn_ptr[BLOCK_16X16];
int new_mv_mode_penalty = 256;
int sr = 0;
int quart_frm = MIN(cpi->common.width, cpi->common.height);
// refine the motion search range accroding to the frame dimension
// for first pass test
while ((quart_frm << sr) < MAX_FULL_PEL_VAL)
sr++;
if (sr)
sr--;
step_param += sr;
further_steps -= sr;
// override the default variance function to use MSE
v_fn_ptr.vf = vp9_mse16x16;
// Set up pointers for this macro block recon buffer
xd->pre.y_buffer = recon_buffer->y_buffer + recon_yoffset;
// Initial step/diamond search centred on best mv
tmp_mv.as_int = 0;
ref_mv_full.as_mv.col = ref_mv->as_mv.col >> 3;
ref_mv_full.as_mv.row = ref_mv->as_mv.row >> 3;
tmp_err = cpi->diamond_search_sad(x, b, d, &ref_mv_full, &tmp_mv, step_param,
x->sadperbit16, &num00, &v_fn_ptr,
x->nmvjointcost,
x->mvcost, ref_mv);
if (tmp_err < INT_MAX - new_mv_mode_penalty)
tmp_err += new_mv_mode_penalty;
if (tmp_err < *best_motion_err) {
*best_motion_err = tmp_err;
best_mv->row = tmp_mv.as_mv.row;
best_mv->col = tmp_mv.as_mv.col;
}
// Further step/diamond searches as necessary
n = num00;
num00 = 0;
while (n < further_steps) {
n++;
if (num00)
num00--;
else {
tmp_err = cpi->diamond_search_sad(x, b, d, &ref_mv_full, &tmp_mv,
step_param + n, x->sadperbit16,
&num00, &v_fn_ptr,
x->nmvjointcost,
x->mvcost, ref_mv);
if (tmp_err < INT_MAX - new_mv_mode_penalty)
tmp_err += new_mv_mode_penalty;
if (tmp_err < *best_motion_err) {
*best_motion_err = tmp_err;
best_mv->row = tmp_mv.as_mv.row;
best_mv->col = tmp_mv.as_mv.col;
}
}
}
}
void vp9_first_pass(VP9_COMP *cpi) {
int mb_row, mb_col;
MACROBLOCK *const x = &cpi->mb;
VP9_COMMON *const cm = &cpi->common;
MACROBLOCKD *const xd = &x->e_mbd;
int recon_yoffset, recon_uvoffset;
YV12_BUFFER_CONFIG *lst_yv12 =
&cm->yv12_fb[cm->ref_frame_map[cpi->lst_fb_idx]];
YV12_BUFFER_CONFIG *new_yv12 = &cm->yv12_fb[cm->new_fb_idx];
YV12_BUFFER_CONFIG *gld_yv12 =
&cm->yv12_fb[cm->ref_frame_map[cpi->gld_fb_idx]];
int recon_y_stride = lst_yv12->y_stride;
int recon_uv_stride = lst_yv12->uv_stride;
int64_t intra_error = 0;
int64_t coded_error = 0;
int64_t sr_coded_error = 0;
int sum_mvr = 0, sum_mvc = 0;
int sum_mvr_abs = 0, sum_mvc_abs = 0;
int sum_mvrs = 0, sum_mvcs = 0;
int mvcount = 0;
int intercount = 0;
int second_ref_count = 0;
int intrapenalty = 256;
int neutral_count = 0;
int new_mv_count = 0;
int sum_in_vectors = 0;
uint32_t lastmv_as_int = 0;
int_mv zero_ref_mv;
zero_ref_mv.as_int = 0;
vp9_clear_system_state(); // __asm emms;
x->src = * cpi->Source;
xd->pre = *lst_yv12;
xd->dst = *new_yv12;
x->partition_info = x->pi;
xd->mode_info_context = cm->mi;
vp9_build_block_offsets(x);
vp9_setup_block_dptrs(&x->e_mbd);
vp9_setup_block_ptrs(x);
// set up frame new frame for intra coded blocks
vp9_setup_intra_recon(new_yv12);
vp9_frame_init_quantizer(cpi);
// Initialise the MV cost table to the defaults
// if( cm->current_video_frame == 0)
// if ( 0 )
{
vp9_init_mv_probs(cm);
vp9_initialize_rd_consts(cpi, cm->base_qindex + cm->y1dc_delta_q);
}
// for each macroblock row in image
for (mb_row = 0; mb_row < cm->mb_rows; mb_row++) {
int_mv best_ref_mv;
best_ref_mv.as_int = 0;
// reset above block coeffs
xd->up_available = (mb_row != 0);
recon_yoffset = (mb_row * recon_y_stride * 16);
recon_uvoffset = (mb_row * recon_uv_stride * 8);
// Set up limit values for motion vectors to prevent them extending outside the UMV borders
x->mv_row_min = -((mb_row * 16) + (VP9BORDERINPIXELS - 16));
x->mv_row_max = ((cm->mb_rows - 1 - mb_row) * 16)
+ (VP9BORDERINPIXELS - 16);
// for each macroblock col in image
for (mb_col = 0; mb_col < cm->mb_cols; mb_col++) {
int this_error;
int gf_motion_error = INT_MAX;
int use_dc_pred = (mb_col || mb_row) && (!mb_col || !mb_row);
xd->dst.y_buffer = new_yv12->y_buffer + recon_yoffset;
xd->dst.u_buffer = new_yv12->u_buffer + recon_uvoffset;
xd->dst.v_buffer = new_yv12->v_buffer + recon_uvoffset;
xd->left_available = (mb_col != 0);
// do intra 16x16 prediction
this_error = vp9_encode_intra(cpi, x, use_dc_pred);
// "intrapenalty" below deals with situations where the intra and inter error scores are very low (eg a plain black frame)
// We do not have special cases in first pass for 0,0 and nearest etc so all inter modes carry an overhead cost estimate fot the mv.
// When the error score is very low this causes us to pick all or lots of INTRA modes and throw lots of key frames.
// This penalty adds a cost matching that of a 0,0 mv to the intra case.
this_error += intrapenalty;
// Cumulative intra error total
intra_error += (int64_t)this_error;
// Set up limit values for motion vectors to prevent them extending outside the UMV borders
x->mv_col_min = -((mb_col * 16) + (VP9BORDERINPIXELS - 16));
x->mv_col_max = ((cm->mb_cols - 1 - mb_col) * 16)
+ (VP9BORDERINPIXELS - 16);
// Other than for the first frame do a motion search
if (cm->current_video_frame > 0) {
int tmp_err;
int motion_error = INT_MAX;
int_mv mv, tmp_mv;
// Simple 0,0 motion with no mv overhead
zz_motion_search(cpi, x, lst_yv12, &motion_error, recon_yoffset);
mv.as_int = tmp_mv.as_int = 0;
// Test last reference frame using the previous best mv as the
// starting point (best reference) for the search
first_pass_motion_search(cpi, x, &best_ref_mv,
&mv.as_mv, lst_yv12,
&motion_error, recon_yoffset);
// If the current best reference mv is not centred on 0,0 then do a 0,0 based search as well
if (best_ref_mv.as_int) {
tmp_err = INT_MAX;
first_pass_motion_search(cpi, x, &zero_ref_mv, &tmp_mv.as_mv,
lst_yv12, &tmp_err, recon_yoffset);
if (tmp_err < motion_error) {
motion_error = tmp_err;
mv.as_int = tmp_mv.as_int;
}
}
// Experimental search in an older reference frame
if (cm->current_video_frame > 1) {
// Simple 0,0 motion with no mv overhead
zz_motion_search(cpi, x, gld_yv12,
&gf_motion_error, recon_yoffset);
first_pass_motion_search(cpi, x, &zero_ref_mv,
&tmp_mv.as_mv, gld_yv12,
&gf_motion_error, recon_yoffset);
if ((gf_motion_error < motion_error) &&
(gf_motion_error < this_error)) {
second_ref_count++;
}
// Reset to last frame as reference buffer
xd->pre.y_buffer = lst_yv12->y_buffer + recon_yoffset;
xd->pre.u_buffer = lst_yv12->u_buffer + recon_uvoffset;
xd->pre.v_buffer = lst_yv12->v_buffer + recon_uvoffset;
// In accumulating a score for the older reference frame
// take the best of the motion predicted score and
// the intra coded error (just as will be done for)
// accumulation of "coded_error" for the last frame.
if (gf_motion_error < this_error)
sr_coded_error += gf_motion_error;
else
sr_coded_error += this_error;
} else
sr_coded_error += motion_error;
/* Intra assumed best */
best_ref_mv.as_int = 0;
if (motion_error <= this_error) {
// Keep a count of cases where the inter and intra were
// very close and very low. This helps with scene cut
// detection for example in cropped clips with black bars
// at the sides or top and bottom.
if ((((this_error - intrapenalty) * 9) <=
(motion_error * 10)) &&
(this_error < (2 * intrapenalty))) {
neutral_count++;
}
mv.as_mv.row <<= 3;
mv.as_mv.col <<= 3;
this_error = motion_error;
vp9_set_mbmode_and_mvs(x, NEWMV, &mv);
xd->mode_info_context->mbmi.txfm_size = TX_4X4;
vp9_encode_inter16x16y(x, mb_row, mb_col);
sum_mvr += mv.as_mv.row;
sum_mvr_abs += abs(mv.as_mv.row);
sum_mvc += mv.as_mv.col;
sum_mvc_abs += abs(mv.as_mv.col);
sum_mvrs += mv.as_mv.row * mv.as_mv.row;
sum_mvcs += mv.as_mv.col * mv.as_mv.col;
intercount++;
best_ref_mv.as_int = mv.as_int;
// Was the vector non-zero
if (mv.as_int) {
mvcount++;
// Was it different from the last non zero vector
if (mv.as_int != lastmv_as_int)
new_mv_count++;
lastmv_as_int = mv.as_int;
// Does the Row vector point inwards or outwards
if (mb_row < cm->mb_rows / 2) {
if (mv.as_mv.row > 0)
sum_in_vectors--;
else if (mv.as_mv.row < 0)
sum_in_vectors++;
} else if (mb_row > cm->mb_rows / 2) {
if (mv.as_mv.row > 0)
sum_in_vectors++;
else if (mv.as_mv.row < 0)
sum_in_vectors--;
}
// Does the Row vector point inwards or outwards
if (mb_col < cm->mb_cols / 2) {
if (mv.as_mv.col > 0)
sum_in_vectors--;
else if (mv.as_mv.col < 0)
sum_in_vectors++;
} else if (mb_col > cm->mb_cols / 2) {
if (mv.as_mv.col > 0)
sum_in_vectors++;
else if (mv.as_mv.col < 0)
sum_in_vectors--;
}
}
}
} else
sr_coded_error += (int64_t)this_error;
coded_error += (int64_t)this_error;
// adjust to the next column of macroblocks
x->src.y_buffer += 16;
x->src.u_buffer += 8;
x->src.v_buffer += 8;
recon_yoffset += 16;
recon_uvoffset += 8;
}
// adjust to the next row of mbs
x->src.y_buffer += 16 * x->src.y_stride - 16 * cm->mb_cols;
x->src.u_buffer += 8 * x->src.uv_stride - 8 * cm->mb_cols;
x->src.v_buffer += 8 * x->src.uv_stride - 8 * cm->mb_cols;
// extend the recon for intra prediction
vp9_extend_mb_row(new_yv12, xd->dst.y_buffer + 16,
xd->dst.u_buffer + 8, xd->dst.v_buffer + 8);
vp9_clear_system_state(); // __asm emms;
}
vp9_clear_system_state(); // __asm emms;
{
double weight = 0.0;
FIRSTPASS_STATS fps;
fps.frame = cm->current_video_frame;
fps.intra_error = (double)(intra_error >> 8);
fps.coded_error = (double)(coded_error >> 8);
fps.sr_coded_error = (double)(sr_coded_error >> 8);
weight = simple_weight(cpi->Source);
if (weight < 0.1)
weight = 0.1;
fps.ssim_weighted_pred_err = fps.coded_error * weight;
fps.pcnt_inter = 0.0;
fps.pcnt_motion = 0.0;
fps.MVr = 0.0;
fps.mvr_abs = 0.0;
fps.MVc = 0.0;
fps.mvc_abs = 0.0;
fps.MVrv = 0.0;
fps.MVcv = 0.0;
fps.mv_in_out_count = 0.0;
fps.new_mv_count = 0.0;
fps.count = 1.0;
fps.pcnt_inter = 1.0 * (double)intercount / cm->MBs;
fps.pcnt_second_ref = 1.0 * (double)second_ref_count / cm->MBs;
fps.pcnt_neutral = 1.0 * (double)neutral_count / cm->MBs;
if (mvcount > 0) {
fps.MVr = (double)sum_mvr / (double)mvcount;
fps.mvr_abs = (double)sum_mvr_abs / (double)mvcount;
fps.MVc = (double)sum_mvc / (double)mvcount;
fps.mvc_abs = (double)sum_mvc_abs / (double)mvcount;
fps.MVrv = ((double)sum_mvrs - (fps.MVr * fps.MVr / (double)mvcount)) / (double)mvcount;
fps.MVcv = ((double)sum_mvcs - (fps.MVc * fps.MVc / (double)mvcount)) / (double)mvcount;
fps.mv_in_out_count = (double)sum_in_vectors / (double)(mvcount * 2);
fps.new_mv_count = new_mv_count;
fps.pcnt_motion = 1.0 * (double)mvcount / cpi->common.MBs;
}
// TODO: handle the case when duration is set to 0, or something less
// than the full time between subsequent values of cpi->source_time_stamp.
fps.duration = (double)(cpi->source->ts_end
- cpi->source->ts_start);
// don't want to do output stats with a stack variable!
memcpy(cpi->twopass.this_frame_stats,
&fps,
sizeof(FIRSTPASS_STATS));
output_stats(cpi, cpi->output_pkt_list, cpi->twopass.this_frame_stats);
accumulate_stats(cpi->twopass.total_stats, &fps);
}
// Copy the previous Last Frame back into gf and and arf buffers if
// the prediction is good enough... but also dont allow it to lag too far
if ((cpi->twopass.sr_update_lag > 3) ||
((cm->current_video_frame > 0) &&
(cpi->twopass.this_frame_stats->pcnt_inter > 0.20) &&
((cpi->twopass.this_frame_stats->intra_error /
DOUBLE_DIVIDE_CHECK(cpi->twopass.this_frame_stats->coded_error)) >
2.0))) {
vp8_yv12_copy_frame(lst_yv12, gld_yv12);
cpi->twopass.sr_update_lag = 1;
} else
cpi->twopass.sr_update_lag++;
// swap frame pointers so last frame refers to the frame we just compressed
vp9_swap_yv12_buffer(lst_yv12, new_yv12);
vp8_yv12_extend_frame_borders(lst_yv12);
// Special case for the first frame. Copy into the GF buffer as a second reference.
if (cm->current_video_frame == 0) {
vp8_yv12_copy_frame(lst_yv12, gld_yv12);
}
// use this to see what the first pass reconstruction looks like
if (0) {
char filename[512];
FILE *recon_file;
sprintf(filename, "enc%04d.yuv", (int) cm->current_video_frame);
if (cm->current_video_frame == 0)
recon_file = fopen(filename, "wb");
else
recon_file = fopen(filename, "ab");
(void)fwrite(lst_yv12->buffer_alloc, lst_yv12->frame_size, 1, recon_file);
fclose(recon_file);
}
cm->current_video_frame++;
}
// Estimate a cost per mb attributable to overheads such as the coding of
// modes and motion vectors.
// Currently simplistic in its assumptions for testing.
//
static double bitcost(double prob) {
return -(log(prob) / log(2.0));
}
static int64_t estimate_modemvcost(VP9_COMP *cpi,
FIRSTPASS_STATS *fpstats) {
#if 0
int mv_cost;
int mode_cost;
double av_pct_inter = fpstats->pcnt_inter / fpstats->count;
double av_pct_motion = fpstats->pcnt_motion / fpstats->count;
double av_intra = (1.0 - av_pct_inter);
double zz_cost;
double motion_cost;
double intra_cost;
zz_cost = bitcost(av_pct_inter - av_pct_motion);
motion_cost = bitcost(av_pct_motion);
intra_cost = bitcost(av_intra);
// Estimate of extra bits per mv overhead for mbs
// << 9 is the normalization to the (bits * 512) used in vp9_bits_per_mb
mv_cost = ((int)(fpstats->new_mv_count / fpstats->count) * 8) << 9;
// Crude estimate of overhead cost from modes
// << 9 is the normalization to (bits * 512) used in vp9_bits_per_mb
mode_cost =
(int)((((av_pct_inter - av_pct_motion) * zz_cost) +
(av_pct_motion * motion_cost) +
(av_intra * intra_cost)) * cpi->common.MBs) << 9;
// return mv_cost + mode_cost;
// TODO PGW Fix overhead costs for extended Q range
#endif
return 0;
}
static double calc_correction_factor(double err_per_mb,
double err_divisor,
double pt_low,
double pt_high,
int Q) {
double power_term;
double error_term = err_per_mb / err_divisor;
double correction_factor;
// Adjustment based on actual quantizer to power term.
power_term = (vp9_convert_qindex_to_q(Q) * 0.01) + pt_low;
power_term = (power_term > pt_high) ? pt_high : power_term;
// Calculate correction factor
if (power_term < 1.0)
assert(error_term >= 0.0);
correction_factor = pow(error_term, power_term);
// Clip range
correction_factor =
(correction_factor < 0.05)
? 0.05 : (correction_factor > 5.0) ? 5.0 : correction_factor;
return correction_factor;
}
// Given a current maxQ value sets a range for future values.
// PGW TODO..
// This code removes direct dependency on QIndex to determine the range
// (now uses the actual quantizer) but has not been tuned.
static void adjust_maxq_qrange(VP9_COMP *cpi) {
int i;
double q;
// Set the max corresponding to cpi->avg_q * 2.0
q = cpi->avg_q * 2.0;
cpi->twopass.maxq_max_limit = cpi->worst_quality;
for (i = cpi->best_quality; i <= cpi->worst_quality; i++) {
cpi->twopass.maxq_max_limit = i;
if (vp9_convert_qindex_to_q(i) >= q)
break;
}
// Set the min corresponding to cpi->avg_q * 0.5
q = cpi->avg_q * 0.5;
cpi->twopass.maxq_min_limit = cpi->best_quality;
for (i = cpi->worst_quality; i >= cpi->best_quality; i--) {
cpi->twopass.maxq_min_limit = i;
if (vp9_convert_qindex_to_q(i) <= q)
break;
}
}
static int estimate_max_q(VP9_COMP *cpi,
FIRSTPASS_STATS *fpstats,
int section_target_bandwitdh) {
int Q;
int num_mbs = cpi->common.MBs;
int target_norm_bits_per_mb;
double section_err = (fpstats->coded_error / fpstats->count);
double sr_err_diff;
double sr_correction;
double err_per_mb = section_err / num_mbs;
double err_correction_factor;
double speed_correction = 1.0;
if (section_target_bandwitdh <= 0)
return cpi->twopass.maxq_max_limit; // Highest value allowed
target_norm_bits_per_mb =
(section_target_bandwitdh < (1 << 20))
? (512 * section_target_bandwitdh) / num_mbs
: 512 * (section_target_bandwitdh / num_mbs);
// Look at the drop in prediction quality between the last frame
// and the GF buffer (which contained an older frame).
if (fpstats->sr_coded_error > fpstats->coded_error) {
sr_err_diff =
(fpstats->sr_coded_error - fpstats->coded_error) /
(fpstats->count * cpi->common.MBs);
sr_correction = (sr_err_diff / 32.0);
sr_correction = pow(sr_correction, 0.25);
if (sr_correction < 0.75)
sr_correction = 0.75;
else if (sr_correction > 1.25)
sr_correction = 1.25;
} else {
sr_correction = 0.75;
}
// Calculate a corrective factor based on a rolling ratio of bits spent
// vs target bits
if ((cpi->rolling_target_bits > 0) &&
(cpi->active_worst_quality < cpi->worst_quality)) {
double rolling_ratio;
rolling_ratio = (double)cpi->rolling_actual_bits /
(double)cpi->rolling_target_bits;
if (rolling_ratio < 0.95)
cpi->twopass.est_max_qcorrection_factor -= 0.005;
else if (rolling_ratio > 1.05)
cpi->twopass.est_max_qcorrection_factor += 0.005;
cpi->twopass.est_max_qcorrection_factor =
(cpi->twopass.est_max_qcorrection_factor < 0.1)
? 0.1
: (cpi->twopass.est_max_qcorrection_factor > 10.0)
? 10.0 : cpi->twopass.est_max_qcorrection_factor;
}
// Corrections for higher compression speed settings
// (reduced compression expected)
if (cpi->compressor_speed == 1) {
if (cpi->oxcf.cpu_used <= 5)
speed_correction = 1.04 + (cpi->oxcf.cpu_used * 0.04);
else
speed_correction = 1.25;
}
// Try and pick a max Q that will be high enough to encode the
// content at the given rate.
for (Q = cpi->twopass.maxq_min_limit; Q < cpi->twopass.maxq_max_limit; Q++) {
int bits_per_mb_at_this_q;
err_correction_factor =
calc_correction_factor(err_per_mb, ERR_DIVISOR, 0.4, 0.90, Q) *
sr_correction * speed_correction *
cpi->twopass.est_max_qcorrection_factor;
bits_per_mb_at_this_q =
vp9_bits_per_mb(INTER_FRAME, Q, err_correction_factor);
if (bits_per_mb_at_this_q <= target_norm_bits_per_mb)
break;
}
// Restriction on active max q for constrained quality mode.
if ((cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) &&
(Q < cpi->cq_target_quality)) {
Q = cpi->cq_target_quality;
}
// Adjust maxq_min_limit and maxq_max_limit limits based on
// average q observed in clip for non kf/gf/arf frames
// Give average a chance to settle though.
// PGW TODO.. This code is broken for the extended Q range
if ((cpi->ni_frames >
((int)cpi->twopass.total_stats->count >> 8)) &&
(cpi->ni_frames > 25)) {
adjust_maxq_qrange(cpi);
}
return Q;
}
// For cq mode estimate a cq level that matches the observed
// complexity and data rate.
static int estimate_cq(VP9_COMP *cpi,
FIRSTPASS_STATS *fpstats,
int section_target_bandwitdh) {
int Q;
int num_mbs = cpi->common.MBs;
int target_norm_bits_per_mb;
double section_err = (fpstats->coded_error / fpstats->count);
double err_per_mb = section_err / num_mbs;
double err_correction_factor;
double sr_err_diff;
double sr_correction;
double speed_correction = 1.0;
double clip_iiratio;
double clip_iifactor;
target_norm_bits_per_mb = (section_target_bandwitdh < (1 << 20))
? (512 * section_target_bandwitdh) / num_mbs
: 512 * (section_target_bandwitdh / num_mbs);
// Corrections for higher compression speed settings
// (reduced compression expected)
if (cpi->compressor_speed == 1) {
if (cpi->oxcf.cpu_used <= 5)
speed_correction = 1.04 + (cpi->oxcf.cpu_used * 0.04);
else
speed_correction = 1.25;
}
// Look at the drop in prediction quality between the last frame
// and the GF buffer (which contained an older frame).
if (fpstats->sr_coded_error > fpstats->coded_error) {
sr_err_diff =
(fpstats->sr_coded_error - fpstats->coded_error) /
(fpstats->count * cpi->common.MBs);
sr_correction = (sr_err_diff / 32.0);
sr_correction = pow(sr_correction, 0.25);
if (sr_correction < 0.75)
sr_correction = 0.75;
else if (sr_correction > 1.25)
sr_correction = 1.25;
} else {
sr_correction = 0.75;
}
// II ratio correction factor for clip as a whole
clip_iiratio = cpi->twopass.total_stats->intra_error /
DOUBLE_DIVIDE_CHECK(cpi->twopass.total_stats->coded_error);
clip_iifactor = 1.0 - ((clip_iiratio - 10.0) * 0.025);
if (clip_iifactor < 0.80)
clip_iifactor = 0.80;
// Try and pick a Q that can encode the content at the given rate.
for (Q = 0; Q < MAXQ; Q++) {
int bits_per_mb_at_this_q;
// Error per MB based correction factor
err_correction_factor =
calc_correction_factor(err_per_mb, 100.0, 0.4, 0.90, Q) *
sr_correction * speed_correction * clip_iifactor;
bits_per_mb_at_this_q =
vp9_bits_per_mb(INTER_FRAME, Q, err_correction_factor);
if (bits_per_mb_at_this_q <= target_norm_bits_per_mb)
break;
}
// Clip value to range "best allowed to (worst allowed - 1)"
Q = select_cq_level(Q);
if (Q >= cpi->worst_quality)
Q = cpi->worst_quality - 1;
if (Q < cpi->best_quality)
Q = cpi->best_quality;
return Q;
}
extern void vp9_new_frame_rate(VP9_COMP *cpi, double framerate);
void vp9_init_second_pass(VP9_COMP *cpi) {
FIRSTPASS_STATS this_frame;
FIRSTPASS_STATS *start_pos;
double lower_bounds_min_rate = FRAME_OVERHEAD_BITS * cpi->oxcf.frame_rate;
double two_pass_min_rate = (double)(cpi->oxcf.target_bandwidth
* cpi->oxcf.two_pass_vbrmin_section / 100);
if (two_pass_min_rate < lower_bounds_min_rate)
two_pass_min_rate = lower_bounds_min_rate;
zero_stats(cpi->twopass.total_stats);
zero_stats(cpi->twopass.total_left_stats);
if (!cpi->twopass.stats_in_end)
return;
*cpi->twopass.total_stats = *cpi->twopass.stats_in_end;
*cpi->twopass.total_left_stats = *cpi->twopass.total_stats;
// each frame can have a different duration, as the frame rate in the source
// isn't guaranteed to be constant. The frame rate prior to the first frame
// encoded in the second pass is a guess. However the sum duration is not.
// Its calculated based on the actual durations of all frames from the first
// pass.
vp9_new_frame_rate(cpi,
10000000.0 * cpi->twopass.total_stats->count /
cpi->twopass.total_stats->duration);
cpi->output_frame_rate = cpi->oxcf.frame_rate;
cpi->twopass.bits_left = (int64_t)(cpi->twopass.total_stats->duration *
cpi->oxcf.target_bandwidth / 10000000.0);
cpi->twopass.bits_left -= (int64_t)(cpi->twopass.total_stats->duration *
two_pass_min_rate / 10000000.0);
// Calculate a minimum intra value to be used in determining the IIratio
// scores used in the second pass. We have this minimum to make sure
// that clips that are static but "low complexity" in the intra domain
// are still boosted appropriately for KF/GF/ARF
cpi->twopass.kf_intra_err_min = KF_MB_INTRA_MIN * cpi->common.MBs;
cpi->twopass.gf_intra_err_min = GF_MB_INTRA_MIN * cpi->common.MBs;
// This variable monitors how far behind the second ref update is lagging
cpi->twopass.sr_update_lag = 1;
// Scan the first pass file and calculate an average Intra / Inter error score ratio for the sequence
{
double sum_iiratio = 0.0;
double IIRatio;
start_pos = cpi->twopass.stats_in; // Note starting "file" position
while (input_stats(cpi, &this_frame) != EOF) {
IIRatio = this_frame.intra_error / DOUBLE_DIVIDE_CHECK(this_frame.coded_error);
IIRatio = (IIRatio < 1.0) ? 1.0 : (IIRatio > 20.0) ? 20.0 : IIRatio;
sum_iiratio += IIRatio;
}
cpi->twopass.avg_iiratio = sum_iiratio / DOUBLE_DIVIDE_CHECK((double)cpi->twopass.total_stats->count);
// Reset file position
reset_fpf_position(cpi, start_pos);
}
// Scan the first pass file and calculate a modified total error based upon the bias/power function
// used to allocate bits
{
start_pos = cpi->twopass.stats_in; // Note starting "file" position
cpi->twopass.modified_error_total = 0.0;
cpi->twopass.modified_error_used = 0.0;
while (input_stats(cpi, &this_frame) != EOF) {
cpi->twopass.modified_error_total += calculate_modified_err(cpi, &this_frame);
}
cpi->twopass.modified_error_left = cpi->twopass.modified_error_total;
reset_fpf_position(cpi, start_pos); // Reset file position
}
}
void vp9_end_second_pass(VP9_COMP *cpi) {
}
// This function gives and estimate of how badly we believe
// the prediction quality is decaying from frame to frame.
static double get_prediction_decay_rate(VP9_COMP *cpi,
FIRSTPASS_STATS *next_frame) {
double prediction_decay_rate;
double second_ref_decay;
double mb_sr_err_diff;
// Initial basis is the % mbs inter coded
prediction_decay_rate = next_frame->pcnt_inter;
// Look at the observed drop in prediction quality between the last frame
// and the GF buffer (which contains an older frame).
mb_sr_err_diff =
(next_frame->sr_coded_error - next_frame->coded_error) /
(cpi->common.MBs);
if (mb_sr_err_diff <= 512.0) {
second_ref_decay = 1.0 - (mb_sr_err_diff / 512.0);
second_ref_decay = pow(second_ref_decay, 0.5);
if (second_ref_decay < 0.85)
second_ref_decay = 0.85;
else if (second_ref_decay > 1.0)
second_ref_decay = 1.0;
} else {
second_ref_decay = 0.85;
}
if (second_ref_decay < prediction_decay_rate)
prediction_decay_rate = second_ref_decay;
return prediction_decay_rate;
}
// Function to test for a condition where a complex transition is followed
// by a static section. For example in slide shows where there is a fade
// between slides. This is to help with more optimal kf and gf positioning.
static int detect_transition_to_still(
VP9_COMP *cpi,
int frame_interval,
int still_interval,
double loop_decay_rate,
double last_decay_rate) {
int trans_to_still = FALSE;
// Break clause to detect very still sections after motion
// For example a static image after a fade or other transition
// instead of a clean scene cut.
if ((frame_interval > MIN_GF_INTERVAL) &&
(loop_decay_rate >= 0.999) &&
(last_decay_rate < 0.9)) {
int j;
FIRSTPASS_STATS *position = cpi->twopass.stats_in;
FIRSTPASS_STATS tmp_next_frame;
double zz_inter;
// Look ahead a few frames to see if static condition
// persists...
for (j = 0; j < still_interval; j++) {
if (EOF == input_stats(cpi, &tmp_next_frame))
break;
zz_inter =
(tmp_next_frame.pcnt_inter - tmp_next_frame.pcnt_motion);
if (zz_inter < 0.999)
break;
}
// Reset file position
reset_fpf_position(cpi, position);
// Only if it does do we signal a transition to still
if (j == still_interval)
trans_to_still = TRUE;
}
return trans_to_still;
}
// This function detects a flash through the high relative pcnt_second_ref
// score in the frame following a flash frame. The offset passed in should
// reflect this
static int detect_flash(VP9_COMP *cpi, int offset) {
FIRSTPASS_STATS next_frame;
int flash_detected = FALSE;
// Read the frame data.
// The return is FALSE (no flash detected) if not a valid frame
if (read_frame_stats(cpi, &next_frame, offset) != EOF) {
// What we are looking for here is a situation where there is a
// brief break in prediction (such as a flash) but subsequent frames
// are reasonably well predicted by an earlier (pre flash) frame.
// The recovery after a flash is indicated by a high pcnt_second_ref
// comapred to pcnt_inter.
if ((next_frame.pcnt_second_ref > next_frame.pcnt_inter) &&
(next_frame.pcnt_second_ref >= 0.5)) {
flash_detected = TRUE;
}
}
return flash_detected;
}
// Update the motion related elements to the GF arf boost calculation
static void accumulate_frame_motion_stats(
VP9_COMP *cpi,
FIRSTPASS_STATS *this_frame,
double *this_frame_mv_in_out,
double *mv_in_out_accumulator,
double *abs_mv_in_out_accumulator,
double *mv_ratio_accumulator) {
// double this_frame_mv_in_out;
double this_frame_mvr_ratio;
double this_frame_mvc_ratio;
double motion_pct;
// Accumulate motion stats.
motion_pct = this_frame->pcnt_motion;
// Accumulate Motion In/Out of frame stats
*this_frame_mv_in_out = this_frame->mv_in_out_count * motion_pct;
*mv_in_out_accumulator += this_frame->mv_in_out_count * motion_pct;
*abs_mv_in_out_accumulator +=
fabs(this_frame->mv_in_out_count * motion_pct);
// Accumulate a measure of how uniform (or conversely how random)
// the motion field is. (A ratio of absmv / mv)
if (motion_pct > 0.05) {
this_frame_mvr_ratio = fabs(this_frame->mvr_abs) /
DOUBLE_DIVIDE_CHECK(fabs(this_frame->MVr));
this_frame_mvc_ratio = fabs(this_frame->mvc_abs) /
DOUBLE_DIVIDE_CHECK(fabs(this_frame->MVc));
*mv_ratio_accumulator +=
(this_frame_mvr_ratio < this_frame->mvr_abs)
? (this_frame_mvr_ratio * motion_pct)
: this_frame->mvr_abs * motion_pct;
*mv_ratio_accumulator +=
(this_frame_mvc_ratio < this_frame->mvc_abs)
? (this_frame_mvc_ratio * motion_pct)
: this_frame->mvc_abs * motion_pct;
}
}
// Calculate a baseline boost number for the current frame.
static double calc_frame_boost(
VP9_COMP *cpi,
FIRSTPASS_STATS *this_frame,
double this_frame_mv_in_out) {
double frame_boost;
// Underlying boost factor is based on inter intra error ratio
if (this_frame->intra_error > cpi->twopass.gf_intra_err_min)
frame_boost = (IIFACTOR * this_frame->intra_error /
DOUBLE_DIVIDE_CHECK(this_frame->coded_error));
else
frame_boost = (IIFACTOR * cpi->twopass.gf_intra_err_min /
DOUBLE_DIVIDE_CHECK(this_frame->coded_error));
// Increase boost for frames where new data coming into frame
// (eg zoom out). Slightly reduce boost if there is a net balance
// of motion out of the frame (zoom in).
// The range for this_frame_mv_in_out is -1.0 to +1.0
if (this_frame_mv_in_out > 0.0)
frame_boost += frame_boost * (this_frame_mv_in_out * 2.0);
// In extreme case boost is halved
else
frame_boost += frame_boost * (this_frame_mv_in_out / 2.0);
// Clip to maximum
if (frame_boost > GF_RMAX)
frame_boost = GF_RMAX;
return frame_boost;
}
static int calc_arf_boost(
VP9_COMP *cpi,
int offset,
int f_frames,
int b_frames,
int *f_boost,
int *b_boost) {
FIRSTPASS_STATS this_frame;
int i;
double boost_score = 0.0;
double mv_ratio_accumulator = 0.0;
double decay_accumulator = 1.0;
double this_frame_mv_in_out = 0.0;
double mv_in_out_accumulator = 0.0;
double abs_mv_in_out_accumulator = 0.0;
int arf_boost;
int flash_detected = FALSE;
// Search forward from the proposed arf/next gf position
for (i = 0; i < f_frames; i++) {
if (read_frame_stats(cpi, &this_frame, (i + offset)) == EOF)
break;
// Update the motion related elements to the boost calculation
accumulate_frame_motion_stats(cpi, &this_frame,
&this_frame_mv_in_out, &mv_in_out_accumulator,
&abs_mv_in_out_accumulator, &mv_ratio_accumulator);
// We want to discount the flash frame itself and the recovery
// frame that follows as both will have poor scores.
flash_detected = detect_flash(cpi, (i + offset)) ||
detect_flash(cpi, (i + offset + 1));
// Cumulative effect of prediction quality decay
if (!flash_detected) {
decay_accumulator =
decay_accumulator * get_prediction_decay_rate(cpi, &this_frame);
decay_accumulator = decay_accumulator < MIN_DECAY_FACTOR
? MIN_DECAY_FACTOR : decay_accumulator;
}
boost_score += (decay_accumulator *
calc_frame_boost(cpi, &this_frame, this_frame_mv_in_out));
}
*f_boost = (int)boost_score;
// Reset for backward looking loop
boost_score = 0.0;
mv_ratio_accumulator = 0.0;
decay_accumulator = 1.0;
this_frame_mv_in_out = 0.0;
mv_in_out_accumulator = 0.0;
abs_mv_in_out_accumulator = 0.0;
// Search backward towards last gf position
for (i = -1; i >= -b_frames; i--) {
if (read_frame_stats(cpi, &this_frame, (i + offset)) == EOF)
break;
// Update the motion related elements to the boost calculation
accumulate_frame_motion_stats(cpi, &this_frame,
&this_frame_mv_in_out, &mv_in_out_accumulator,
&abs_mv_in_out_accumulator, &mv_ratio_accumulator);
// We want to discount the the flash frame itself and the recovery
// frame that follows as both will have poor scores.
flash_detected = detect_flash(cpi, (i + offset)) ||
detect_flash(cpi, (i + offset + 1));
// Cumulative effect of prediction quality decay
if (!flash_detected) {
decay_accumulator =
decay_accumulator * get_prediction_decay_rate(cpi, &this_frame);
decay_accumulator = decay_accumulator < MIN_DECAY_FACTOR
? MIN_DECAY_FACTOR : decay_accumulator;
}
boost_score += (decay_accumulator *
calc_frame_boost(cpi, &this_frame, this_frame_mv_in_out));
}
*b_boost = (int)boost_score;
arf_boost = (*f_boost + *b_boost);
if (arf_boost < ((b_frames + f_frames) * 20))
arf_boost = ((b_frames + f_frames) * 20);
return arf_boost;
}
void configure_arnr_filter(VP9_COMP *cpi, const unsigned int this_frame,
int group_boost) {
int half_gf_int;
int frames_after_arf;
int frames_bwd = cpi->oxcf.arnr_max_frames - 1;
int frames_fwd = cpi->oxcf.arnr_max_frames - 1;
int q;
// Define the arnr filter width for this group of frames:
// We only filter frames that lie within a distance of half
// the GF interval from the ARF frame. We also have to trap
// cases where the filter extends beyond the end of clip.
// Note: this_frame->frame has been updated in the loop
// so it now points at the ARF frame.
half_gf_int = cpi->baseline_gf_interval >> 1;
frames_after_arf = (int)(cpi->twopass.total_stats->count - this_frame - 1);
switch (cpi->oxcf.arnr_type) {
case 1: // Backward filter
frames_fwd = 0;
if (frames_bwd > half_gf_int)
frames_bwd = half_gf_int;
break;
case 2: // Forward filter
if (frames_fwd > half_gf_int)
frames_fwd = half_gf_int;
if (frames_fwd > frames_after_arf)
frames_fwd = frames_after_arf;
frames_bwd = 0;
break;
case 3: // Centered filter
default:
frames_fwd >>= 1;
if (frames_fwd > frames_after_arf)
frames_fwd = frames_after_arf;
if (frames_fwd > half_gf_int)
frames_fwd = half_gf_int;
frames_bwd = frames_fwd;
// For even length filter there is one more frame backward
// than forward: e.g. len=6 ==> bbbAff, len=7 ==> bbbAfff.
if (frames_bwd < half_gf_int)
frames_bwd += (cpi->oxcf.arnr_max_frames + 1) & 0x1;
break;
}
cpi->active_arnr_frames = frames_bwd + 1 + frames_fwd;
// Adjust the strength based on active max q
q = ((int)vp9_convert_qindex_to_q(cpi->active_worst_quality) >> 1);
if (q > 8) {
cpi->active_arnr_strength = cpi->oxcf.arnr_strength;
} else {
cpi->active_arnr_strength = cpi->oxcf.arnr_strength - (8 - q);
if (cpi->active_arnr_strength < 0)
cpi->active_arnr_strength = 0;
}
// Adjust number of frames in filter and strength based on gf boost level.
if (cpi->active_arnr_frames > (group_boost / 150)) {
cpi->active_arnr_frames = (group_boost / 150);
cpi->active_arnr_frames += !(cpi->active_arnr_frames & 1);
}
if (cpi->active_arnr_strength > (group_boost / 300)) {
cpi->active_arnr_strength = (group_boost / 300);
}
}
#if CONFIG_MULTIPLE_ARF
// Work out the frame coding order for a GF or an ARF group.
// The current implementation codes frames in their natural order for a
// GF group, and inserts additional ARFs into an ARF group using a
// binary split approach.
// NOTE: this function is currently implemented recursively.
static void schedule_frames(VP9_COMP *cpi, const int start, const int end,
const int arf_idx, const int gf_or_arf_group,
const int level) {
int i, abs_end, half_range;
int *cfo = cpi->frame_coding_order;
int idx = cpi->new_frame_coding_order_period;
// If (end < 0) an ARF should be coded at position (-end).
assert(start >= 0);
// printf("start:%d end:%d\n", start, end);
// GF Group: code frames in logical order.
if (gf_or_arf_group == 0) {
assert(end >= start);
for (i = start; i <= end; ++i) {
cfo[idx] = i;
cpi->arf_buffer_idx[idx] = arf_idx;
cpi->arf_weight[idx] = -1;
++idx;
}
cpi->new_frame_coding_order_period = idx;
return;
}
// ARF Group: work out the ARF schedule.
// Mark ARF frames as negative.
if (end < 0) {
// printf("start:%d end:%d\n", -end, -end);
// ARF frame is at the end of the range.
cfo[idx] = end;
// What ARF buffer does this ARF use as predictor.
cpi->arf_buffer_idx[idx] = (arf_idx > 2) ? (arf_idx - 1) : 2;
cpi->arf_weight[idx] = level;
++idx;
abs_end = -end;
} else {
abs_end = end;
}
half_range = (abs_end - start) >> 1;
// ARFs may not be adjacent, they must be separated by at least
// MIN_GF_INTERVAL non-ARF frames.
if ((start + MIN_GF_INTERVAL) >= (abs_end - MIN_GF_INTERVAL)) {
// printf("start:%d end:%d\n", start, abs_end);
// Update the coding order and active ARF.
for (i = start; i <= abs_end; ++i) {
cfo[idx] = i;
cpi->arf_buffer_idx[idx] = arf_idx;
cpi->arf_weight[idx] = -1;
++idx;
}
cpi->new_frame_coding_order_period = idx;
} else {
// Place a new ARF at the mid-point of the range.
cpi->new_frame_coding_order_period = idx;
schedule_frames(cpi, start, -(start + half_range), arf_idx + 1,
gf_or_arf_group, level + 1);
schedule_frames(cpi, start + half_range + 1, abs_end, arf_idx,
gf_or_arf_group, level + 1);
}
}
#define FIXED_ARF_GROUP_SIZE 16
void define_fixed_arf_period(VP9_COMP *cpi) {
int i;
int max_level = INT_MIN;
assert(cpi->multi_arf_enabled);
assert(cpi->oxcf.lag_in_frames >= FIXED_ARF_GROUP_SIZE);
// Save the weight of the last frame in the sequence before next
// sequence pattern overwrites it.
cpi->this_frame_weight = cpi->arf_weight[cpi->sequence_number];
assert(cpi->this_frame_weight >= 0);
// Initialize frame coding order variables.
cpi->new_frame_coding_order_period = 0;
cpi->next_frame_in_order = 0;
cpi->arf_buffered = 0;
vp9_zero(cpi->frame_coding_order);
vp9_zero(cpi->arf_buffer_idx);
vpx_memset(cpi->arf_weight, -1, sizeof(cpi->arf_weight));
if (cpi->twopass.frames_to_key <= (FIXED_ARF_GROUP_SIZE + 8)) {
// Setup a GF group close to the keyframe.
cpi->source_alt_ref_pending = FALSE;
cpi->baseline_gf_interval = cpi->twopass.frames_to_key;
schedule_frames(cpi, 0, (cpi->baseline_gf_interval - 1), 2, 0, 0);
} else {
// Setup a fixed period ARF group.
cpi->source_alt_ref_pending = TRUE;
cpi->baseline_gf_interval = FIXED_ARF_GROUP_SIZE;
schedule_frames(cpi, 0, -(cpi->baseline_gf_interval - 1), 2, 1, 0);
}
// Replace level indicator of -1 with correct level.
for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
if (cpi->arf_weight[i] > max_level) {
max_level = cpi->arf_weight[i];
}
}
++max_level;
for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
if (cpi->arf_weight[i] == -1) {
cpi->arf_weight[i] = max_level;
}
}
cpi->max_arf_level = max_level;
#if 0
printf("\nSchedule: ");
for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
printf("%4d ", cpi->frame_coding_order[i]);
}
printf("\n");
printf("ARFref: ");
for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
printf("%4d ", cpi->arf_buffer_idx[i]);
}
printf("\n");
printf("Weight: ");
for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
printf("%4d ", cpi->arf_weight[i]);
}
printf("\n");
#endif
}
#endif
// Analyse and define a gf/arf group.
static void define_gf_group(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
FIRSTPASS_STATS next_frame;
FIRSTPASS_STATS *start_pos;
int i;
double boost_score = 0.0;
double old_boost_score = 0.0;
double gf_group_err = 0.0;
double gf_first_frame_err = 0.0;
double mod_frame_err = 0.0;
double mv_ratio_accumulator = 0.0;
double decay_accumulator = 1.0;
double zero_motion_accumulator = 1.0;
double loop_decay_rate = 1.00; // Starting decay rate
double last_loop_decay_rate = 1.00;
double this_frame_mv_in_out = 0.0;
double mv_in_out_accumulator = 0.0;
double abs_mv_in_out_accumulator = 0.0;
double mv_ratio_accumulator_thresh;
int max_bits = frame_max_bits(cpi); // Max for a single frame
unsigned int allow_alt_ref =
cpi->oxcf.play_alternate && cpi->oxcf.lag_in_frames;
int f_boost = 0;
int b_boost = 0;
int flash_detected;
int active_max_gf_interval;
cpi->twopass.gf_group_bits = 0;
vp9_clear_system_state(); // __asm emms;
start_pos = cpi->twopass.stats_in;
vpx_memset(&next_frame, 0, sizeof(next_frame)); // assure clean
// Load stats for the current frame.
mod_frame_err = calculate_modified_err(cpi, this_frame);
// Note the error of the frame at the start of the group (this will be
// the GF frame error if we code a normal gf
gf_first_frame_err = mod_frame_err;
// Special treatment if the current frame is a key frame (which is also
// a gf). If it is then its error score (and hence bit allocation) need
// to be subtracted out from the calculation for the GF group
if (cpi->common.frame_type == KEY_FRAME)
gf_group_err -= gf_first_frame_err;
// Motion breakout threshold for loop below depends on image size.
mv_ratio_accumulator_thresh = (cpi->common.width + cpi->common.height) / 10.0;
// Work out a maximum interval for the GF.
// If the image appears completely static we can extend beyond this.
// The value chosen depends on the active Q range. At low Q we have
// bits to spare and are better with a smaller interval and smaller boost.
// At high Q when there are few bits to spare we are better with a longer
// interval to spread the cost of the GF.
active_max_gf_interval =
12 + ((int)vp9_convert_qindex_to_q(cpi->active_worst_quality) >> 5);
if (active_max_gf_interval > cpi->max_gf_interval)
active_max_gf_interval = cpi->max_gf_interval;
i = 0;
while (((i < cpi->twopass.static_scene_max_gf_interval) ||
((cpi->twopass.frames_to_key - i) < MIN_GF_INTERVAL)) &&
(i < cpi->twopass.frames_to_key)) {
i++; // Increment the loop counter
// Accumulate error score of frames in this gf group
mod_frame_err = calculate_modified_err(cpi, this_frame);
gf_group_err += mod_frame_err;
if (EOF == input_stats(cpi, &next_frame))
break;
// Test for the case where there is a brief flash but the prediction
// quality back to an earlier frame is then restored.
flash_detected = detect_flash(cpi, 0);
// Update the motion related elements to the boost calculation
accumulate_frame_motion_stats(cpi, &next_frame,
&this_frame_mv_in_out, &mv_in_out_accumulator,
&abs_mv_in_out_accumulator, &mv_ratio_accumulator);
// Cumulative effect of prediction quality decay
if (!flash_detected) {
last_loop_decay_rate = loop_decay_rate;
loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
decay_accumulator = decay_accumulator * loop_decay_rate;
// Monitor for static sections.
if ((next_frame.pcnt_inter - next_frame.pcnt_motion) <
zero_motion_accumulator) {
zero_motion_accumulator =
(next_frame.pcnt_inter - next_frame.pcnt_motion);
}
// Break clause to detect very still sections after motion
// (for example a static image after a fade or other transition).
if (detect_transition_to_still(cpi, i, 5, loop_decay_rate,
last_loop_decay_rate)) {
allow_alt_ref = FALSE;
break;
}
}
// Calculate a boost number for this frame
boost_score +=
(decay_accumulator *
calc_frame_boost(cpi, &next_frame, this_frame_mv_in_out));
// Break out conditions.
if (
// Break at cpi->max_gf_interval unless almost totally static
(i >= active_max_gf_interval && (zero_motion_accumulator < 0.995)) ||
(
// Don't break out with a very short interval
(i > MIN_GF_INTERVAL) &&
// Don't break out very close to a key frame
((cpi->twopass.frames_to_key - i) >= MIN_GF_INTERVAL) &&
((boost_score > 125.0) || (next_frame.pcnt_inter < 0.75)) &&
(!flash_detected) &&
((mv_ratio_accumulator > mv_ratio_accumulator_thresh) ||
(abs_mv_in_out_accumulator > 3.0) ||
(mv_in_out_accumulator < -2.0) ||
((boost_score - old_boost_score) < IIFACTOR))
)) {
boost_score = old_boost_score;
break;
}
vpx_memcpy(this_frame, &next_frame, sizeof(*this_frame));
old_boost_score = boost_score;
}
// Don't allow a gf too near the next kf
if ((cpi->twopass.frames_to_key - i) < MIN_GF_INTERVAL) {
while (i < cpi->twopass.frames_to_key) {
i++;
if (EOF == input_stats(cpi, this_frame))
break;
if (i < cpi->twopass.frames_to_key) {
mod_frame_err = calculate_modified_err(cpi, this_frame);
gf_group_err += mod_frame_err;
}
}
}
// Set the interval until the next gf or arf.
cpi->baseline_gf_interval = i;
#if CONFIG_MULTIPLE_ARF
if (cpi->multi_arf_enabled) {
// Initialize frame coding order variables.
cpi->new_frame_coding_order_period = 0;
cpi->next_frame_in_order = 0;
cpi->arf_buffered = 0;
vp9_zero(cpi->frame_coding_order);
vp9_zero(cpi->arf_buffer_idx);
vpx_memset(cpi->arf_weight, -1, sizeof(cpi->arf_weight));
}
#endif
// Should we use the alternate reference frame
if (allow_alt_ref &&
(i < cpi->oxcf.lag_in_frames) &&
(i >= MIN_GF_INTERVAL) &&
// dont use ARF very near next kf
(i <= (cpi->twopass.frames_to_key - MIN_GF_INTERVAL)) &&
((next_frame.pcnt_inter > 0.75) ||
(next_frame.pcnt_second_ref > 0.5)) &&
((mv_in_out_accumulator / (double)i > -0.2) ||
(mv_in_out_accumulator > -2.0)) &&
(boost_score > 100)) {
// Alternative boost calculation for alt ref
cpi->gfu_boost = calc_arf_boost(cpi, 0, (i - 1), (i - 1), &f_boost, &b_boost);
cpi->source_alt_ref_pending = TRUE;
#if CONFIG_MULTIPLE_ARF
// Set the ARF schedule.
if (cpi->multi_arf_enabled) {
schedule_frames(cpi, 0, -(cpi->baseline_gf_interval - 1), 2, 1, 0);
}
#endif
} else {
cpi->gfu_boost = (int)boost_score;
cpi->source_alt_ref_pending = FALSE;
#if CONFIG_MULTIPLE_ARF
// Set the GF schedule.
if (cpi->multi_arf_enabled) {
schedule_frames(cpi, 0, cpi->baseline_gf_interval - 1, 2, 0, 0);
assert(cpi->new_frame_coding_order_period == cpi->baseline_gf_interval);
}
#endif
}
#if CONFIG_MULTIPLE_ARF
if (cpi->multi_arf_enabled && (cpi->common.frame_type != KEY_FRAME)) {
int max_level = INT_MIN;
// Replace level indicator of -1 with correct level.
for (i = 0; i < cpi->frame_coding_order_period; ++i) {
if (cpi->arf_weight[i] > max_level) {
max_level = cpi->arf_weight[i];
}
}
++max_level;
for (i = 0; i < cpi->frame_coding_order_period; ++i) {
if (cpi->arf_weight[i] == -1) {
cpi->arf_weight[i] = max_level;
}
}
cpi->max_arf_level = max_level;
}
#if 0
if (cpi->multi_arf_enabled) {
printf("\nSchedule: ");
for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
printf("%4d ", cpi->frame_coding_order[i]);
}
printf("\n");
printf("ARFref: ");
for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
printf("%4d ", cpi->arf_buffer_idx[i]);
}
printf("\n");
printf("Weight: ");
for (i = 0; i < cpi->new_frame_coding_order_period; ++i) {
printf("%4d ", cpi->arf_weight[i]);
}
printf("\n");
}
#endif
#endif
// Now decide how many bits should be allocated to the GF group as a
// proportion of those remaining in the kf group.
// The final key frame group in the clip is treated as a special case
// where cpi->twopass.kf_group_bits is tied to cpi->twopass.bits_left.
// This is also important for short clips where there may only be one
// key frame.
if (cpi->twopass.frames_to_key >= (int)(cpi->twopass.total_stats->count -
cpi->common.current_video_frame)) {
cpi->twopass.kf_group_bits =
(cpi->twopass.bits_left > 0) ? cpi->twopass.bits_left : 0;
}
// Calculate the bits to be allocated to the group as a whole
if ((cpi->twopass.kf_group_bits > 0) &&
(cpi->twopass.kf_group_error_left > 0)) {
cpi->twopass.gf_group_bits =
(int64_t)(cpi->twopass.kf_group_bits *
(gf_group_err / cpi->twopass.kf_group_error_left));
} else
cpi->twopass.gf_group_bits = 0;
cpi->twopass.gf_group_bits =
(cpi->twopass.gf_group_bits < 0)
? 0
: (cpi->twopass.gf_group_bits > cpi->twopass.kf_group_bits)
? cpi->twopass.kf_group_bits : cpi->twopass.gf_group_bits;
// Clip cpi->twopass.gf_group_bits based on user supplied data rate
// variability limit (cpi->oxcf.two_pass_vbrmax_section)
if (cpi->twopass.gf_group_bits >
(int64_t)max_bits * cpi->baseline_gf_interval)
cpi->twopass.gf_group_bits = (int64_t)max_bits * cpi->baseline_gf_interval;
// Reset the file position
reset_fpf_position(cpi, start_pos);
// Update the record of error used so far (only done once per gf group)
cpi->twopass.modified_error_used += gf_group_err;
// Assign bits to the arf or gf.
for (i = 0;
i <= (cpi->source_alt_ref_pending && cpi->common.frame_type != KEY_FRAME);
++i) {
int boost;
int allocation_chunks;
int Q =
(cpi->oxcf.fixed_q < 0) ? cpi->last_q[INTER_FRAME] : cpi->oxcf.fixed_q;
int gf_bits;
boost = (cpi->gfu_boost * vp9_gfboost_qadjust(Q)) / 100;
// Set max and minimum boost and hence minimum allocation
if (boost > ((cpi->baseline_gf_interval + 1) * 200))
boost = ((cpi->baseline_gf_interval + 1) * 200);
else if (boost < 125)
boost = 125;
if (cpi->source_alt_ref_pending && i == 0)
allocation_chunks =
((cpi->baseline_gf_interval + 1) * 100) + boost;
else
allocation_chunks =
(cpi->baseline_gf_interval * 100) + (boost - 100);
// Prevent overflow
if (boost > 1028) { // TODO(agrange) Should this be 1024?
int divisor = boost >> 10;
boost /= divisor;
allocation_chunks /= divisor;
}
// Calculate the number of bits to be spent on the gf or arf based on
// the boost number
gf_bits = (int)((double)boost *
(cpi->twopass.gf_group_bits /
(double)allocation_chunks));
// If the frame that is to be boosted is simpler than the average for
// the gf/arf group then use an alternative calculation
// based on the error score of the frame itself
if (mod_frame_err < gf_group_err / (double)cpi->baseline_gf_interval) {
double alt_gf_grp_bits;
int alt_gf_bits;
alt_gf_grp_bits =
(double)cpi->twopass.kf_group_bits *
(mod_frame_err * (double)cpi->baseline_gf_interval) /
DOUBLE_DIVIDE_CHECK(cpi->twopass.kf_group_error_left);
alt_gf_bits = (int)((double)boost * (alt_gf_grp_bits /
(double)allocation_chunks));
if (gf_bits > alt_gf_bits) {
gf_bits = alt_gf_bits;
}
}
// Else if it is harder than other frames in the group make sure it at
// least receives an allocation in keeping with its relative error
// score, otherwise it may be worse off than an "un-boosted" frame
else {
int alt_gf_bits =
(int)((double)cpi->twopass.kf_group_bits *
mod_frame_err /
DOUBLE_DIVIDE_CHECK(cpi->twopass.kf_group_error_left));
if (alt_gf_bits > gf_bits) {
gf_bits = alt_gf_bits;
}
}
// Dont allow a negative value for gf_bits
if (gf_bits < 0)
gf_bits = 0;
// Add in minimum for a frame
gf_bits += cpi->min_frame_bandwidth;
if (i == 0) {
cpi->twopass.gf_bits = gf_bits;
}
if (i == 1 || (!cpi->source_alt_ref_pending
&& (cpi->common.frame_type != KEY_FRAME))) {
// Per frame bit target for this frame
cpi->per_frame_bandwidth = gf_bits;
}
}
{
// Adjust KF group bits and error remaining
cpi->twopass.kf_group_error_left -= (int64_t)gf_group_err;
cpi->twopass.kf_group_bits -= cpi->twopass.gf_group_bits;
if (cpi->twopass.kf_group_bits < 0)
cpi->twopass.kf_group_bits = 0;
// Note the error score left in the remaining frames of the group.
// For normal GFs we want to remove the error score for the first frame
// of the group (except in Key frame case where this has already
// happened)
if (!cpi->source_alt_ref_pending && cpi->common.frame_type != KEY_FRAME)
cpi->twopass.gf_group_error_left = (int64_t)(gf_group_err
- gf_first_frame_err);
else
cpi->twopass.gf_group_error_left = (int64_t)gf_group_err;
cpi->twopass.gf_group_bits -= cpi->twopass.gf_bits
- cpi->min_frame_bandwidth;
if (cpi->twopass.gf_group_bits < 0)
cpi->twopass.gf_group_bits = 0;
// This condition could fail if there are two kfs very close together
// despite (MIN_GF_INTERVAL) and would cause a divide by 0 in the
// calculation of cpi->twopass.alt_extra_bits.
if (cpi->baseline_gf_interval >= 3) {
int boost = (cpi->source_alt_ref_pending)
? b_boost : cpi->gfu_boost;
if (boost >= 150) {
int pct_extra;
pct_extra = (boost - 100) / 50;
pct_extra = (pct_extra > 20) ? 20 : pct_extra;
// TODO(agrange) Remove cpi->twopass.alt_extra_bits.
cpi->twopass.alt_extra_bits = (int)
((cpi->twopass.gf_group_bits * pct_extra) / 100);
cpi->twopass.gf_group_bits -= cpi->twopass.alt_extra_bits;
cpi->twopass.alt_extra_bits /=
((cpi->baseline_gf_interval - 1) >> 1);
} else
cpi->twopass.alt_extra_bits = 0;
} else
cpi->twopass.alt_extra_bits = 0;
}
if (cpi->common.frame_type != KEY_FRAME) {
FIRSTPASS_STATS sectionstats;
zero_stats(&sectionstats);
reset_fpf_position(cpi, start_pos);
for (i = 0; i < cpi->baseline_gf_interval; i++) {
input_stats(cpi, &next_frame);
accumulate_stats(&sectionstats, &next_frame);
}
avg_stats(&sectionstats);
cpi->twopass.section_intra_rating = (int)
(sectionstats.intra_error /
DOUBLE_DIVIDE_CHECK(sectionstats.coded_error));
reset_fpf_position(cpi, start_pos);
}
}
// Allocate bits to a normal frame that is neither a gf an arf or a key frame.
static void assign_std_frame_bits(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
int target_frame_size;
double modified_err;
double err_fraction;
// Max for a single frame.
int max_bits = frame_max_bits(cpi);
// Calculate modified prediction error used in bit allocation.
modified_err = calculate_modified_err(cpi, this_frame);
if (cpi->twopass.gf_group_error_left > 0)
// What portion of the remaining GF group error is used by this frame.
err_fraction = modified_err / cpi->twopass.gf_group_error_left;
else
err_fraction = 0.0;
// How many of those bits available for allocation should we give it?
target_frame_size = (int)((double)cpi->twopass.gf_group_bits * err_fraction);
// Clip target size to 0 - max_bits (or cpi->twopass.gf_group_bits) at
// the top end.
if (target_frame_size < 0)
target_frame_size = 0;
else {
if (target_frame_size > max_bits)
target_frame_size = max_bits;
if (target_frame_size > cpi->twopass.gf_group_bits)
target_frame_size = (int)cpi->twopass.gf_group_bits;
}
// Adjust error and bits remaining.
cpi->twopass.gf_group_error_left -= (int64_t)modified_err;
cpi->twopass.gf_group_bits -= target_frame_size;
if (cpi->twopass.gf_group_bits < 0)
cpi->twopass.gf_group_bits = 0;
// Add in the minimum number of bits that is set aside for every frame.
target_frame_size += cpi->min_frame_bandwidth;
// Per frame bit target for this frame.
cpi->per_frame_bandwidth = target_frame_size;
}
// Make a damped adjustment to the active max q.
static int adjust_active_maxq(int old_maxqi, int new_maxqi) {
int i;
int ret_val = new_maxqi;
double old_q;
double new_q;
double target_q;
old_q = vp9_convert_qindex_to_q(old_maxqi);
new_q = vp9_convert_qindex_to_q(new_maxqi);
target_q = ((old_q * 7.0) + new_q) / 8.0;
if (target_q > old_q) {
for (i = old_maxqi; i <= new_maxqi; i++) {
if (vp9_convert_qindex_to_q(i) >= target_q) {
ret_val = i;
break;
}
}
} else {
for (i = old_maxqi; i >= new_maxqi; i--) {
if (vp9_convert_qindex_to_q(i) <= target_q) {
ret_val = i;
break;
}
}
}
return ret_val;
}
void vp9_second_pass(VP9_COMP *cpi) {
int tmp_q;
int frames_left = (int)(cpi->twopass.total_stats->count -
cpi->common.current_video_frame);
FIRSTPASS_STATS this_frame;
FIRSTPASS_STATS this_frame_copy;
double this_frame_intra_error;
double this_frame_coded_error;
if (!cpi->twopass.stats_in) {
return;
}
vp9_clear_system_state();
// Special case code for first frame.
if (cpi->common.current_video_frame == 0) {
cpi->twopass.est_max_qcorrection_factor = 1.0;
// Set a cq_level in constrained quality mode.
if (cpi->oxcf.end_usage == USAGE_CONSTRAINED_QUALITY) {
int est_cq;
est_cq =
estimate_cq(cpi,
cpi->twopass.total_left_stats,
(int)(cpi->twopass.bits_left / frames_left));
cpi->cq_target_quality = cpi->oxcf.cq_level;
if (est_cq > cpi->cq_target_quality)
cpi->cq_target_quality = est_cq;
}
// guess at maxq needed in 2nd pass
cpi->twopass.maxq_max_limit = cpi->worst_quality;
cpi->twopass.maxq_min_limit = cpi->best_quality;
tmp_q = estimate_max_q(
cpi,
cpi->twopass.total_left_stats,
(int)(cpi->twopass.bits_left / frames_left));
cpi->active_worst_quality = tmp_q;
cpi->ni_av_qi = tmp_q;
cpi->avg_q = vp9_convert_qindex_to_q(tmp_q);
#ifndef ONE_SHOT_Q_ESTIMATE
// Limit the maxq value returned subsequently.
// This increases the risk of overspend or underspend if the initial
// estimate for the clip is bad, but helps prevent excessive
// variation in Q, especially near the end of a clip
// where for example a small overspend may cause Q to crash
adjust_maxq_qrange(cpi);
#endif
}
#ifndef ONE_SHOT_Q_ESTIMATE
// The last few frames of a clip almost always have to few or too many
// bits and for the sake of over exact rate control we dont want to make
// radical adjustments to the allowed quantizer range just to use up a
// few surplus bits or get beneath the target rate.
else if ((cpi->common.current_video_frame <
(((unsigned int)cpi->twopass.total_stats->count * 255) >> 8)) &&
((cpi->common.current_video_frame + cpi->baseline_gf_interval) <
(unsigned int)cpi->twopass.total_stats->count)) {
if (frames_left < 1)
frames_left = 1;
tmp_q = estimate_max_q(
cpi,
cpi->twopass.total_left_stats,
(int)(cpi->twopass.bits_left / frames_left));
// Make a damped adjustment to active max Q
cpi->active_worst_quality =
adjust_active_maxq(cpi->active_worst_quality, tmp_q);
}
#endif
vpx_memset(&this_frame, 0, sizeof(FIRSTPASS_STATS));
if (EOF == input_stats(cpi, &this_frame))
return;
this_frame_intra_error = this_frame.intra_error;
this_frame_coded_error = this_frame.coded_error;
// keyframe and section processing !
if (cpi->twopass.frames_to_key == 0) {
// Define next KF group and assign bits to it
vpx_memcpy(&this_frame_copy, &this_frame, sizeof(this_frame));
find_next_key_frame(cpi, &this_frame_copy);
}
// Is this a GF / ARF (Note that a KF is always also a GF)
if (cpi->frames_till_gf_update_due == 0) {
// Define next gf group and assign bits to it
vpx_memcpy(&this_frame_copy, &this_frame, sizeof(this_frame));
#if CONFIG_MULTIPLE_ARF
if (cpi->multi_arf_enabled) {
define_fixed_arf_period(cpi);
} else {
#endif
define_gf_group(cpi, &this_frame_copy);
#if CONFIG_MULTIPLE_ARF
}
#endif
// If we are going to code an altref frame at the end of the group
// and the current frame is not a key frame....
// If the previous group used an arf this frame has already benefited
// from that arf boost and it should not be given extra bits
// If the previous group was NOT coded using arf we may want to apply
// some boost to this GF as well
if (cpi->source_alt_ref_pending && (cpi->common.frame_type != KEY_FRAME)) {
// Assign a standard frames worth of bits from those allocated
// to the GF group
int bak = cpi->per_frame_bandwidth;
vpx_memcpy(&this_frame_copy, &this_frame, sizeof(this_frame));
assign_std_frame_bits(cpi, &this_frame_copy);
cpi->per_frame_bandwidth = bak;
}
} else {
// Otherwise this is an ordinary frame
// Assign bits from those allocated to the GF group
vpx_memcpy(&this_frame_copy, &this_frame, sizeof(this_frame));
assign_std_frame_bits(cpi, &this_frame_copy);
}
// Keep a globally available copy of this and the next frame's iiratio.
cpi->twopass.this_iiratio = (int)(this_frame_intra_error /
DOUBLE_DIVIDE_CHECK(this_frame_coded_error));
{
FIRSTPASS_STATS next_frame;
if (lookup_next_frame_stats(cpi, &next_frame) != EOF) {
cpi->twopass.next_iiratio = (int)(next_frame.intra_error /
DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
}
}
// Set nominal per second bandwidth for this frame
cpi->target_bandwidth = (int)(cpi->per_frame_bandwidth
* cpi->output_frame_rate);
if (cpi->target_bandwidth < 0)
cpi->target_bandwidth = 0;
cpi->twopass.frames_to_key--;
// Update the total stats remaining structure
subtract_stats(cpi->twopass.total_left_stats, &this_frame);
}
static int test_candidate_kf(VP9_COMP *cpi,
FIRSTPASS_STATS *last_frame,
FIRSTPASS_STATS *this_frame,
FIRSTPASS_STATS *next_frame) {
int is_viable_kf = FALSE;
// Does the frame satisfy the primary criteria of a key frame
// If so, then examine how well it predicts subsequent frames
if ((this_frame->pcnt_second_ref < 0.10) &&
(next_frame->pcnt_second_ref < 0.10) &&
((this_frame->pcnt_inter < 0.05) ||
(
((this_frame->pcnt_inter - this_frame->pcnt_neutral) < .35) &&
((this_frame->intra_error / DOUBLE_DIVIDE_CHECK(this_frame->coded_error)) < 2.5) &&
((fabs(last_frame->coded_error - this_frame->coded_error) / DOUBLE_DIVIDE_CHECK(this_frame->coded_error) > .40) ||
(fabs(last_frame->intra_error - this_frame->intra_error) / DOUBLE_DIVIDE_CHECK(this_frame->intra_error) > .40) ||
((next_frame->intra_error / DOUBLE_DIVIDE_CHECK(next_frame->coded_error)) > 3.5)
)
)
)
) {
int i;
FIRSTPASS_STATS *start_pos;
FIRSTPASS_STATS local_next_frame;
double boost_score = 0.0;
double old_boost_score = 0.0;
double decay_accumulator = 1.0;
double next_iiratio;
vpx_memcpy(&local_next_frame, next_frame, sizeof(*next_frame));
// Note the starting file position so we can reset to it
start_pos = cpi->twopass.stats_in;
// Examine how well the key frame predicts subsequent frames
for (i = 0; i < 16; i++) {
next_iiratio = (IIKFACTOR1 * local_next_frame.intra_error / DOUBLE_DIVIDE_CHECK(local_next_frame.coded_error));
if (next_iiratio > RMAX)
next_iiratio = RMAX;
// Cumulative effect of decay in prediction quality
if (local_next_frame.pcnt_inter > 0.85)
decay_accumulator = decay_accumulator * local_next_frame.pcnt_inter;
else
decay_accumulator = decay_accumulator * ((0.85 + local_next_frame.pcnt_inter) / 2.0);
// decay_accumulator = decay_accumulator * local_next_frame.pcnt_inter;
// Keep a running total
boost_score += (decay_accumulator * next_iiratio);
// Test various breakout clauses
if ((local_next_frame.pcnt_inter < 0.05) ||
(next_iiratio < 1.5) ||
(((local_next_frame.pcnt_inter -
local_next_frame.pcnt_neutral) < 0.20) &&
(next_iiratio < 3.0)) ||
((boost_score - old_boost_score) < 3.0) ||
(local_next_frame.intra_error < 200)
) {
break;
}
old_boost_score = boost_score;
// Get the next frame details
if (EOF == input_stats(cpi, &local_next_frame))
break;
}
// If there is tolerable prediction for at least the next 3 frames then
// break out else discard this potential key frame and move on
if (boost_score > 30.0 && (i > 3))
is_viable_kf = TRUE;
else {
// Reset the file position
reset_fpf_position(cpi, start_pos);
is_viable_kf = FALSE;
}
}
return is_viable_kf;
}
static void find_next_key_frame(VP9_COMP *cpi, FIRSTPASS_STATS *this_frame) {
int i, j;
FIRSTPASS_STATS last_frame;
FIRSTPASS_STATS first_frame;
FIRSTPASS_STATS next_frame;
FIRSTPASS_STATS *start_position;
double decay_accumulator = 1.0;
double zero_motion_accumulator = 1.0;
double boost_score = 0;
double old_boost_score = 0.0;
double loop_decay_rate;
double kf_mod_err = 0.0;
double kf_group_err = 0.0;
double kf_group_intra_err = 0.0;
double kf_group_coded_err = 0.0;
double recent_loop_decay[8] = {1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0, 1.0};
vpx_memset(&next_frame, 0, sizeof(next_frame)); // assure clean
vp9_clear_system_state(); // __asm emms;
start_position = cpi->twopass.stats_in;
cpi->common.frame_type = KEY_FRAME;
// is this a forced key frame by interval
cpi->this_key_frame_forced = cpi->next_key_frame_forced;
// Clear the alt ref active flag as this can never be active on a key frame
cpi->source_alt_ref_active = FALSE;
// Kf is always a gf so clear frames till next gf counter
cpi->frames_till_gf_update_due = 0;
cpi->twopass.frames_to_key = 1;
// Take a copy of the initial frame details
vpx_memcpy(&first_frame, this_frame, sizeof(*this_frame));
cpi->twopass.kf_group_bits = 0; // Total bits available to kf group
cpi->twopass.kf_group_error_left = 0; // Group modified error score.
kf_mod_err = calculate_modified_err(cpi, this_frame);
// find the next keyframe
i = 0;
while (cpi->twopass.stats_in < cpi->twopass.stats_in_end) {
// Accumulate kf group error
kf_group_err += calculate_modified_err(cpi, this_frame);
// These figures keep intra and coded error counts for all frames including key frames in the group.
// The effect of the key frame itself can be subtracted out using the first_frame data collected above
kf_group_intra_err += this_frame->intra_error;
kf_group_coded_err += this_frame->coded_error;
// load a the next frame's stats
vpx_memcpy(&last_frame, this_frame, sizeof(*this_frame));
input_stats(cpi, this_frame);
// Provided that we are not at the end of the file...
if (cpi->oxcf.auto_key
&& lookup_next_frame_stats(cpi, &next_frame) != EOF) {
// Normal scene cut check
if (test_candidate_kf(cpi, &last_frame, this_frame, &next_frame)) {
break;
}
// How fast is prediction quality decaying
loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
// We want to know something about the recent past... rather than
// as used elsewhere where we are concened with decay in prediction
// quality since the last GF or KF.
recent_loop_decay[i % 8] = loop_decay_rate;
decay_accumulator = 1.0;
for (j = 0; j < 8; j++) {
decay_accumulator = decay_accumulator * recent_loop_decay[j];
}
// Special check for transition or high motion followed by a
// to a static scene.
if (detect_transition_to_still(cpi, i,
(cpi->key_frame_frequency - i),
loop_decay_rate,
decay_accumulator)) {
break;
}
// Step on to the next frame
cpi->twopass.frames_to_key++;
// If we don't have a real key frame within the next two
// forcekeyframeevery intervals then break out of the loop.
if (cpi->twopass.frames_to_key >= 2 * (int)cpi->key_frame_frequency)
break;
} else
cpi->twopass.frames_to_key++;
i++;
}
// If there is a max kf interval set by the user we must obey it.
// We already breakout of the loop above at 2x max.
// This code centers the extra kf if the actual natural
// interval is between 1x and 2x
if (cpi->oxcf.auto_key
&& cpi->twopass.frames_to_key > (int)cpi->key_frame_frequency) {
FIRSTPASS_STATS *current_pos = cpi->twopass.stats_in;
FIRSTPASS_STATS tmp_frame;
cpi->twopass.frames_to_key /= 2;
// Copy first frame details
vpx_memcpy(&tmp_frame, &first_frame, sizeof(first_frame));
// Reset to the start of the group
reset_fpf_position(cpi, start_position);
kf_group_err = 0;
kf_group_intra_err = 0;
kf_group_coded_err = 0;
// Rescan to get the correct error data for the forced kf group
for (i = 0; i < cpi->twopass.frames_to_key; i++) {
// Accumulate kf group errors
kf_group_err += calculate_modified_err(cpi, &tmp_frame);
kf_group_intra_err += tmp_frame.intra_error;
kf_group_coded_err += tmp_frame.coded_error;
// Load a the next frame's stats
input_stats(cpi, &tmp_frame);
}
// Reset to the start of the group
reset_fpf_position(cpi, current_pos);
cpi->next_key_frame_forced = TRUE;
} else
cpi->next_key_frame_forced = FALSE;
// Special case for the last frame of the file
if (cpi->twopass.stats_in >= cpi->twopass.stats_in_end) {
// Accumulate kf group error
kf_group_err += calculate_modified_err(cpi, this_frame);
// These figures keep intra and coded error counts for all frames including key frames in the group.
// The effect of the key frame itself can be subtracted out using the first_frame data collected above
kf_group_intra_err += this_frame->intra_error;
kf_group_coded_err += this_frame->coded_error;
}
// Calculate the number of bits that should be assigned to the kf group.
if ((cpi->twopass.bits_left > 0) && (cpi->twopass.modified_error_left > 0.0)) {
// Max for a single normal frame (not key frame)
int max_bits = frame_max_bits(cpi);
// Maximum bits for the kf group
int64_t max_grp_bits;
// Default allocation based on bits left and relative
// complexity of the section
cpi->twopass.kf_group_bits = (int64_t)(cpi->twopass.bits_left *
(kf_group_err /
cpi->twopass.modified_error_left));
// Clip based on maximum per frame rate defined by the user.
max_grp_bits = (int64_t)max_bits * (int64_t)cpi->twopass.frames_to_key;
if (cpi->twopass.kf_group_bits > max_grp_bits)
cpi->twopass.kf_group_bits = max_grp_bits;
} else
cpi->twopass.kf_group_bits = 0;
// Reset the first pass file position
reset_fpf_position(cpi, start_position);
// determine how big to make this keyframe based on how well the subsequent frames use inter blocks
decay_accumulator = 1.0;
boost_score = 0.0;
loop_decay_rate = 1.00; // Starting decay rate
for (i = 0; i < cpi->twopass.frames_to_key; i++) {
double r;
if (EOF == input_stats(cpi, &next_frame))
break;
if (next_frame.intra_error > cpi->twopass.kf_intra_err_min)
r = (IIKFACTOR2 * next_frame.intra_error /
DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
else
r = (IIKFACTOR2 * cpi->twopass.kf_intra_err_min /
DOUBLE_DIVIDE_CHECK(next_frame.coded_error));
if (r > RMAX)
r = RMAX;
// Monitor for static sections.
if ((next_frame.pcnt_inter - next_frame.pcnt_motion) <
zero_motion_accumulator) {
zero_motion_accumulator =
(next_frame.pcnt_inter - next_frame.pcnt_motion);
}
// How fast is prediction quality decaying
if (!detect_flash(cpi, 0)) {
loop_decay_rate = get_prediction_decay_rate(cpi, &next_frame);
decay_accumulator = decay_accumulator * loop_decay_rate;
decay_accumulator = decay_accumulator < MIN_DECAY_FACTOR
? MIN_DECAY_FACTOR : decay_accumulator;
}
boost_score += (decay_accumulator * r);
if ((i > MIN_GF_INTERVAL) &&
((boost_score - old_boost_score) < 6.25)) {
break;
}
old_boost_score = boost_score;
}
{
FIRSTPASS_STATS sectionstats;
zero_stats(&sectionstats);
reset_fpf_position(cpi, start_position);
for (i = 0; i < cpi->twopass.frames_to_key; i++) {
input_stats(cpi, &next_frame);
accumulate_stats(&sectionstats, &next_frame);
}
avg_stats(&sectionstats);
cpi->twopass.section_intra_rating = (int)
(sectionstats.intra_error
/ DOUBLE_DIVIDE_CHECK(sectionstats.coded_error));
}
// Reset the first pass file position
reset_fpf_position(cpi, start_position);
// Work out how many bits to allocate for the key frame itself
if (1) {
int kf_boost = (int)boost_score;
int allocation_chunks;
int alt_kf_bits;
if (kf_boost < (cpi->twopass.frames_to_key * 5))
kf_boost = (cpi->twopass.frames_to_key * 5);
if (kf_boost < 300) // Min KF boost
kf_boost = 300;
// Make a note of baseline boost and the zero motion
// accumulator value for use elsewhere.
cpi->kf_boost = kf_boost;
cpi->kf_zeromotion_pct = (int)(zero_motion_accumulator * 100.0);
// We do three calculations for kf size.
// The first is based on the error score for the whole kf group.
// The second (optionaly) on the key frames own error if this is
// smaller than the average for the group.
// The final one insures that the frame receives at least the
// allocation it would have received based on its own error score vs
// the error score remaining
// Special case if the sequence appears almost totaly static
// In this case we want to spend almost all of the bits on the
// key frame.
// cpi->twopass.frames_to_key-1 because key frame itself is taken
// care of by kf_boost.
if (zero_motion_accumulator >= 0.99) {
allocation_chunks =
((cpi->twopass.frames_to_key - 1) * 10) + kf_boost;
} else {
allocation_chunks =
((cpi->twopass.frames_to_key - 1) * 100) + kf_boost;
}
// Prevent overflow
if (kf_boost > 1028) {
int divisor = kf_boost >> 10;
kf_boost /= divisor;
allocation_chunks /= divisor;
}
cpi->twopass.kf_group_bits = (cpi->twopass.kf_group_bits < 0) ? 0 : cpi->twopass.kf_group_bits;
// Calculate the number of bits to be spent on the key frame
cpi->twopass.kf_bits = (int)((double)kf_boost * ((double)cpi->twopass.kf_group_bits / (double)allocation_chunks));
// If the key frame is actually easier than the average for the
// kf group (which does sometimes happen... eg a blank intro frame)
// Then use an alternate calculation based on the kf error score
// which should give a smaller key frame.
if (kf_mod_err < kf_group_err / cpi->twopass.frames_to_key) {
double alt_kf_grp_bits =
((double)cpi->twopass.bits_left *
(kf_mod_err * (double)cpi->twopass.frames_to_key) /
DOUBLE_DIVIDE_CHECK(cpi->twopass.modified_error_left));
alt_kf_bits = (int)((double)kf_boost *
(alt_kf_grp_bits / (double)allocation_chunks));
if (cpi->twopass.kf_bits > alt_kf_bits) {
cpi->twopass.kf_bits = alt_kf_bits;
}
}
// Else if it is much harder than other frames in the group make sure
// it at least receives an allocation in keeping with its relative
// error score
else {
alt_kf_bits =
(int)((double)cpi->twopass.bits_left *
(kf_mod_err /
DOUBLE_DIVIDE_CHECK(cpi->twopass.modified_error_left)));
if (alt_kf_bits > cpi->twopass.kf_bits) {
cpi->twopass.kf_bits = alt_kf_bits;
}
}
cpi->twopass.kf_group_bits -= cpi->twopass.kf_bits;
// Add in the minimum frame allowance
cpi->twopass.kf_bits += cpi->min_frame_bandwidth;
// Peer frame bit target for this frame
cpi->per_frame_bandwidth = cpi->twopass.kf_bits;
// Convert to a per second bitrate
cpi->target_bandwidth = (int)(cpi->twopass.kf_bits *
cpi->output_frame_rate);
}
// Note the total error score of the kf group minus the key frame itself
cpi->twopass.kf_group_error_left = (int)(kf_group_err - kf_mod_err);
// Adjust the count of total modified error left.
// The count of bits left is adjusted elsewhere based on real coded frame sizes
cpi->twopass.modified_error_left -= kf_group_err;
}
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