ratecontrol_new.c

gm8120的video控制

/* rate control */
#include "ratecontrol.h"

#define FRAMERATE_INCR		1001
#define SMALL_EPS 1e-10


int get_framerate(float fFrameRate)
{
    int fincr,fbase,i;

	if ((fFrameRate - (int)fFrameRate) < SMALL_EPS) {
		fincr = 1;
		fbase = (int)fFrameRate;
	}
	else {
		fincr = FRAMERATE_INCR;
		fbase = (int)(FRAMERATE_INCR * fFrameRate);
	}
	if (fincr <= 0 || fbase <= 0) {
		fincr = 1;
		fbase = 25;
	}
	i = fincr; //i = pParam->fincr;
	while (i > 1) {
		if (fincr % i == 0 && fbase % i == 0) {
			fincr /= i;
			fbase /= i;
			i = fincr;
			continue;
		}
		i--;
	}
	if (fbase > 65535) {
		float div = (float) fbase / 65535;
		fbase = (int) (fbase / div);
		fincr = (int) (fincr / div);
	}
	if (fbase > 65535) {
		float div = (float) fbase / 65535;
		fbase = (int) (fbase / div);
		fincr = (int) (fincr / div);
	}   
	//printf("get_framerate =%d\n",fbase*1000/fincr);
	return (fbase*1000/fincr);
}


void RateControlInit(RateControl * rate_control,
				unsigned int target_rate,
				unsigned int reaction_delay_factor,
				unsigned int averaging_period,
				unsigned int buffer,
				int framerate,
				int max_quant,
				int min_quant,
				unsigned int initq)
{
	int i;
	rate_control->frames = 0;
	rate_control->total_size = 0;
	rate_control->framerate = framerate / 1000.0;
	//printf("framerate=%f\n",  rate_control->framerate);
	rate_control->target_rate = (int) target_rate;
//	rate_control->rtn_quant = get_initial_quant(target_rate);
	rate_control->rtn_quant = initq;
	rate_control->max_quant = (short) max_quant;
	rate_control->min_quant = (short) min_quant;
	for (i = 0; i < 32; ++i) {
		rate_control->quant_error[i] = 0;
	}
	rate_control->target_framesize =
		target_rate / 8.0 / rate_control->framerate;
	rate_control->sequence_quality = 2000 / rate_control->rtn_quant;
	rate_control->avg_framesize = (int)rate_control->target_framesize;
	rate_control->reaction_delay_factor = (int) reaction_delay_factor;
	rate_control->averaging_period = (int) averaging_period;
	rate_control->buffer = (int) buffer;
}


void RateControlUpdate(RateControl *rate_control,
				  short quant,
				  int frame_size,
				  int keyframe)
{
	long long deviation;
	int overflow, averaging_period, reaction_delay_factor, base_quality;
	int quality_scale, target_quality;
	int rtn_quant;

	rate_control->frames++;
	rate_control->total_size += frame_size;

	deviation =
		(long long) ( rate_control->total_size -
				   ((rate_control->target_rate / 8.0 /
					  rate_control->framerate) *  rate_control->frames));

	if (rate_control->rtn_quant >= 2) {
		averaging_period = rate_control->averaging_period;
		//printf("averaging_period = %f\n", averaging_period);
		rate_control->sequence_quality -=
			rate_control->sequence_quality / averaging_period;
		//printf("sequence_quality = %f\n", rate_control->sequence_quality);	
		rate_control->sequence_quality +=
			2000 / rate_control->rtn_quant / averaging_period;
		if (rate_control->sequence_quality < 100)
			rate_control->sequence_quality = 100;

		if (!keyframe) {
			reaction_delay_factor =
				rate_control->reaction_delay_factor;
			rate_control->avg_framesize -=
				(int)(rate_control->avg_framesize / reaction_delay_factor);
			rate_control->avg_framesize += (int)(frame_size / reaction_delay_factor);
			
			//printf("avg_framesize =%d\n", rate_control->avg_framesize);
		}
	}

	quality_scale =
		( 1000 * rate_control->target_framesize * rate_control->target_framesize) / (rate_control->avg_framesize * rate_control->avg_framesize);
	//printf("quality_scale = %d\n", quality_scale);
	
	base_quality = rate_control->sequence_quality;
	if (quality_scale >= 1000) {
		base_quality = 1000 - 1000 * (1000 - base_quality) / quality_scale;
	} else {
		base_quality = 65 + ((base_quality - 65) * quality_scale) / 1000 ;
	}

	overflow = -(deviation /rate_control->buffer);
	//printf("overflow =%d\n", overflow);
	target_quality =
		base_quality + (base_quality - 64) * overflow / rate_control->target_framesize;

	if (target_quality > 2000)
		target_quality = 2000;
	else if (target_quality < 65)
		target_quality = 65;

	rtn_quant = (int) (2000 / target_quality);

	if (rtn_quant < 31) {
		rate_control->quant_error[rtn_quant] +=
			2000000 / target_quality - 1000 * rtn_quant;
		if (rate_control->quant_error[rtn_quant] >= 1000) {
			rate_control->quant_error[rtn_quant] -= 1000;
			rtn_quant++;
		}
		//printf("quant = %d\n", rate_control->quant_error[rtn_quant]);
	}

	if (rtn_quant > rate_control->rtn_quant + 1)
		rtn_quant = rate_control->rtn_quant + 1;
	else if (rtn_quant < rate_control->rtn_quant - 1)
		rtn_quant = rate_control->rtn_quant - 1;

	if (rtn_quant > rate_control->max_quant)
		rtn_quant = rate_control->max_quant;
	else if (rtn_quant < rate_control->min_quant)
		rtn_quant = rate_control->min_quant;
	rate_control->rtn_quant = rtn_quant;
}