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- added legal header - added function descriptions
/***************************************************************************** * * XVID MPEG-4 VIDEO CODEC * - Rate Controler module - * * This program is free software ; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation ; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY ; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program ; if not, write to the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA * ****************************************************************************/ /***************************************************************************** * * History * * - Mon Jun 17 13:04:15 2002 Added legal header * * $Id: ratecontrol.c,v 1.13 2002-06-17 12:23:32 edgomez Exp $ * ****************************************************************************/ /* For the fabs function */ #include <math.h> #include "ratecontrol.h" /***************************************************************************** * Local prototype - defined at the end of the file ****************************************************************************/ static int get_initial_quant(int bpp); /***************************************************************************** * RateControlInit * * This function initialize the structure members of 'rate_control' argument * according to the other arguments. * * Returned value : None * ****************************************************************************/ void RateControlInit(RateControl * rate_control, uint32_t target_rate, uint32_t reaction_delay_factor, uint32_t averaging_period, uint32_t buffer, int framerate, int max_quant, int min_quant) { int i; rate_control->frames = 0; rate_control->total_size = 0; rate_control->framerate = framerate / 1000.0; rate_control->target_rate = target_rate; rate_control->rtn_quant = get_initial_quant(0); rate_control->max_quant = max_quant; rate_control->min_quant = min_quant; for (i = 0; i < 32; ++i) { rate_control->quant_error[i] = 0.0; } rate_control->target_framesize = (double) target_rate / 8.0 / rate_control->framerate; rate_control->sequence_quality = 2.0 / (double) rate_control->rtn_quant; rate_control->avg_framesize = rate_control->target_framesize; rate_control->reaction_delay_factor = reaction_delay_factor; rate_control->averaging_period = averaging_period; rate_control->buffer = buffer; } /***************************************************************************** * RateControlGetQ * * Returned value : - the current 'rate_control' quantizer value * ****************************************************************************/ int RateControlGetQ(RateControl * rate_control, int keyframe) { return rate_control->rtn_quant; } /***************************************************************************** * RateControlUpdate * * This function is called once a coded frame to update all internal * parameters of 'rate_control'. * * Returned value : None * ****************************************************************************/ void RateControlUpdate(RateControl * rate_control, int16_t quant, int frame_size, int keyframe) { int64_t deviation; double overflow, averaging_period, reaction_delay_factor; double quality_scale, base_quality, target_quality; int32_t rtn_quant; rate_control->frames++; rate_control->total_size += frame_size; deviation = (int64_t) ((double) rate_control->total_size - ((double) ((double) rate_control->target_rate / 8.0 / (double) rate_control->framerate) * (double) rate_control->frames)); DEBUGCBR((int32_t) (rate_control->frames - 1), rate_control->rtn_quant, (int32_t) deviation); if (rate_control->rtn_quant >= 2) { averaging_period = (double) rate_control->averaging_period; rate_control->sequence_quality -= rate_control->sequence_quality / averaging_period; rate_control->sequence_quality += 2.0 / (double) rate_control->rtn_quant / averaging_period; if (rate_control->sequence_quality < 0.1) rate_control->sequence_quality = 0.1; if (!keyframe) { reaction_delay_factor = (double) rate_control->reaction_delay_factor; rate_control->avg_framesize -= rate_control->avg_framesize / reaction_delay_factor; rate_control->avg_framesize += frame_size / reaction_delay_factor; } } quality_scale = rate_control->target_framesize / rate_control->avg_framesize * rate_control->target_framesize / rate_control->avg_framesize; base_quality = rate_control->sequence_quality; if (quality_scale >= 1.0) { base_quality = 1.0 - (1.0 - base_quality) / quality_scale; } else { base_quality = 0.06452 + (base_quality - 0.06452) * quality_scale; } overflow = -((double) deviation / (double) rate_control->buffer); target_quality = base_quality + (base_quality - 0.06452) * overflow / rate_control->target_framesize; if (target_quality > 2.0) target_quality = 2.0; else if (target_quality < 0.06452) target_quality = 0.06452; rtn_quant = (int32_t) (2.0 / target_quality); if (rtn_quant < 31) { rate_control->quant_error[rtn_quant] += 2.0 / target_quality - rtn_quant; if (rate_control->quant_error[rtn_quant] >= 1.0) { rate_control->quant_error[rtn_quant] -= 1.0; 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; } /***************************************************************************** * Local functions ****************************************************************************/ static int get_initial_quant(int bpp) { return 5; }
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