bitrate.c

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/********************************************************************
 *                                                                  *
 * THIS FILE IS PART OF THE OggVorbis SOFTWARE CODEC SOURCE CODE.   *
 * USE, DISTRIBUTION AND REPRODUCTION OF THIS LIBRARY SOURCE IS     *
 * GOVERNED BY A BSD-STYLE SOURCE LICENSE INCLUDED WITH THIS SOURCE *
 * IN 'COPYING'. PLEASE READ THESE TERMS BEFORE DISTRIBUTING.       *
 *                                                                  *
 * THE OggVorbis SOURCE CODE IS (C) COPYRIGHT 1994-2002             *
 * by the XIPHOPHORUS Company http://www.xiph.org/                  *
 *                                                                  *
 ********************************************************************

 function: bitrate tracking and management
 last mod: $Id: bitrate.c,v 1.21 2002/10/11 11:14:41 xiphmont Exp $

 ********************************************************************/

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <math.h>
#include "../ogg/ogg.h"
#include "../vorbis/codec.h"
#include "codec_internal.h"
#include "os.h"
#include "misc.h"
#include "bitrate.h"


static long BINBYTES(bitrate_manager_state *bm,long pos,long bin){
  int bins=bm->queue_bins;
  return(bm->queue_binned[pos*bins+bin]);
}

#define LIMITBYTES(pos,bin) (bm->minmax_binstack[(pos)*bins*2+((bin)+bins)])

static long LACING_ADJUST(long bytes){
  int addto=bytes/255+1;
  return(bytes+addto);
}

static int floater_interpolate(bitrate_manager_state *bm,vorbis_info *vi,
                                  double desired_rate){
  int bin=rint(bm->avgfloat);
  double lobitrate,hibitrate;


  lobitrate=(double)(bm->avg_binacc[bin]*8)/bm->avg_sampleacc*vi->rate;
  while(lobitrate>desired_rate && bin>0){
    bin--;
    lobitrate=(double)(bm->avg_binacc[bin]*8)/bm->avg_sampleacc*vi->rate;
  }

  if(bin+1<bm->queue_bins){
    hibitrate=(double)(bm->avg_binacc[bin+1]*8)/bm->avg_sampleacc*vi->rate;
    if(fabs(hibitrate-desired_rate) < fabs(lobitrate-desired_rate))bin++;
  }
  return(bin);
}

/* try out a new limit */
static long limit_sum(bitrate_manager_state *bm,int limit){
  int i=bm->minmax_stackptr;
  long acc=bm->minmax_acctotal;
  long bins=bm->queue_bins;
  
  acc-=LIMITBYTES(i,0);
  acc+=LIMITBYTES(i,limit);

  while(i-->0){
    if(bm->minmax_limitstack[i]<=limit)break;
    acc-=LIMITBYTES(i,bm->minmax_limitstack[i]);
    acc+=LIMITBYTES(i,limit);
  }
  return(acc);
}

/* compute bitrate tracking setup, allocate circular packet size queue */
void vorbis_bitrate_init(vorbis_info *vi,bitrate_manager_state *bm){
  int i;
  codec_setup_info *ci=vi->codec_setup;
  bitrate_manager_info *bi=&ci->bi;
  long maxlatency;

  memset(bm,0,sizeof(*bm));
  
  if(bi){
    
    bm->avg_sampledesired=bi->queue_avg_time*vi->rate;
    bm->avg_centerdesired=bi->queue_avg_time*vi->rate*bi->queue_avg_center;
    bm->minmax_sampledesired=bi->queue_minmax_time*vi->rate;
    
    /* first find the max possible needed queue size */
    maxlatency=max(bm->avg_sampledesired-bm->avg_centerdesired,
                   bm->minmax_sampledesired)+bm->avg_centerdesired;
    
    if(maxlatency>0 &&
       (bi->queue_avgmin>0 || bi->queue_avgmax>0 || bi->queue_hardmax>0 ||
        bi->queue_hardmin>0)){
      long maxpackets=maxlatency/(ci->blocksizes[0]>>1)+3;
      long bins=PACKETBLOBS;
      
      bm->queue_size=maxpackets;
      bm->queue_bins=bins;
      bm->queue_binned=_ogg_calloc(maxpackets,bins*sizeof(*bm->queue_binned));
      bm->queue_actual=_ogg_calloc(maxpackets,sizeof(*bm->queue_actual));
      
      if((bi->queue_avgmin>0 || bi->queue_avgmax>0) &&
         bi->queue_avg_time>0){
        
        bm->avg_binacc=_ogg_calloc(bins,sizeof(*bm->avg_binacc));
        bm->avgfloat=PACKETBLOBS/2;
        
      }else{
        bm->avg_tail= -1;
      }
      
      if((bi->queue_hardmin>0 || bi->queue_hardmax>0) &&
         bi->queue_minmax_time>0){
        
        bm->minmax_binstack=_ogg_calloc((bins*2+1)*bins*2,
                                        sizeof(*bm->minmax_binstack));
        bm->minmax_posstack=_ogg_calloc((bins*2+1),
                                      sizeof(*bm->minmax_posstack));
        bm->minmax_limitstack=_ogg_calloc((bins*2+1),
                                          sizeof(*bm->minmax_limitstack));
      }else{
        bm->minmax_tail= -1;
      }
      
      /* space for the packet queueing */
      bm->packetbuffers=_ogg_calloc(maxpackets,sizeof(*bm->packetbuffers));
      bm->packets=_ogg_calloc(maxpackets,sizeof(*bm->packets));
      for(i=0;i<maxpackets;i++)
        oggpack_writeinit(bm->packetbuffers+i);
      
    }else{
      bm->packetbuffers=_ogg_calloc(1,sizeof(*bm->packetbuffers));
      bm->packets=_ogg_calloc(1,sizeof(*bm->packets));
      oggpack_writeinit(bm->packetbuffers);

    }      
  }
}

void vorbis_bitrate_clear(bitrate_manager_state *bm){
  int i;
  if(bm){
    if(bm->queue_binned)_ogg_free(bm->queue_binned);
    if(bm->queue_actual)_ogg_free(bm->queue_actual);
    if(bm->avg_binacc)_ogg_free(bm->avg_binacc);
    if(bm->minmax_binstack)_ogg_free(bm->minmax_binstack);
    if(bm->minmax_posstack)_ogg_free(bm->minmax_posstack);
    if(bm->minmax_limitstack)_ogg_free(bm->minmax_limitstack);

    if(bm->packetbuffers){
      if(bm->queue_size==0){
        oggpack_writeclear(bm->packetbuffers);
      }else{
        for(i=0;i<bm->queue_size;i++)
          oggpack_writeclear(bm->packetbuffers+i);      
      }
      _ogg_free(bm->packetbuffers);
    }
    if(bm->packets)_ogg_free(bm->packets);
    
    memset(bm,0,sizeof(*bm));
  }
}

int vorbis_bitrate_managed(vorbis_block *vb){
  vorbis_dsp_state      *vd=vb->vd;
  private_state         *b=vd->backend_state; 
  bitrate_manager_state *bm=&b->bms;

  if(bm->queue_binned)return(1);
  return(0);
}

/* finish taking in the block we just processed */
int vorbis_bitrate_addblock(vorbis_block *vb){
  int i; 
  vorbis_block_internal *vbi=vb->internal;
  vorbis_dsp_state      *vd=vb->vd;
  private_state         *b=vd->backend_state; 
  bitrate_manager_state *bm=&b->bms;
  vorbis_info           *vi=vd->vi;
  codec_setup_info      *ci=vi->codec_setup;
  bitrate_manager_info  *bi=&ci->bi;
  int                    eofflag=vb->eofflag;
  int                    head=bm->queue_head;
  int                    next_head=head+1;
  int                    bins=bm->queue_bins;
  int                    minmax_head,new_minmax_head;
  
  ogg_uint32_t           *head_ptr;
  oggpack_buffer          temp;

  if(!bm->queue_binned){
    oggpack_buffer temp;
    /* not a bitrate managed stream, but for API simplicity, we'll
       buffer one packet to keep the code path clean */
    
    if(bm->queue_head)return(-1); /* one has been submitted without
                                     being claimed */
    bm->queue_head++;

    bm->packets[0].packet=oggpack_get_buffer(&vb->opb);
    bm->packets[0].bytes=oggpack_bytes(&vb->opb);
    bm->packets[0].b_o_s=0;
    bm->packets[0].e_o_s=vb->eofflag;
    bm->packets[0].granulepos=vb->granulepos;
    bm->packets[0].packetno=vb->sequence; /* for sake of completeness */

    memcpy(&temp,bm->packetbuffers,sizeof(vb->opb));
    memcpy(bm->packetbuffers,&vb->opb,sizeof(vb->opb));
    memcpy(&vb->opb,&temp,sizeof(vb->opb));

    return(0);
  }

  /* add encoded packet to head */
  if(next_head>=bm->queue_size)next_head=0;
  head_ptr=bm->queue_binned+bins*head;

  /* is there room to add a block? In proper use of the API, this will
     never come up... but guard it anyway */
  if(next_head==bm->avg_tail || next_head==bm->minmax_tail)return(-1);

  /* add the block to the toplevel queue */
  bm->queue_head=next_head;
  bm->queue_actual[head]=(vb->W?0x80000000UL:0);

  /* buffer packet fields */
  bm->packets[head].packet=oggpack_get_buffer(&vb->opb);
  bm->packets[head].bytes=oggpack_bytes(&vb->opb);
  bm->packets[head].b_o_s=0;
  bm->packets[head].e_o_s=vb->eofflag;
  bm->packets[head].granulepos=vb->granulepos;
  bm->packets[head].packetno=vb->sequence; /* for sake of completeness */

  /* swap packet buffers */
  memcpy(&temp,bm->packetbuffers+head,sizeof(vb->opb));
  memcpy(bm->packetbuffers+head,&vb->opb,sizeof(vb->opb));
  memcpy(&vb->opb,&temp,sizeof(vb->opb));

  /* save markers */
  head_ptr[0]=vbi->packetblob_markers[0];
  for(i=1;i<PACKETBLOBS;i++){
    head_ptr[i]=vbi->packetblob_markers[i]-vbi->packetblob_markers[i-1];
  }

  if(bm->avg_binacc)
    new_minmax_head=minmax_head=bm->avg_center;
  else
    new_minmax_head=minmax_head=head;

  /* the average tracking queue is updated first; its results (if it's
     in use) are taken into account by the min/max limiter (if min/max
     is in use) */
  if(bm->avg_binacc){
    unsigned long desired_center=bm->avg_centerdesired;
    if(eofflag)desired_center=0;

    /* update the avg head */
    for(i=0;i<bins;i++)
      bm->avg_binacc[i]+=LACING_ADJUST(head_ptr[i]);
    bm->avg_sampleacc+=ci->blocksizes[vb->W]>>1;
    bm->avg_centeracc+=ci->blocksizes[vb->W]>>1;

    if(bm->avg_sampleacc>bm->avg_sampledesired || eofflag){

      /* update the avg center */
      if(bm->avg_centeracc>desired_center){
        /* choose the new average floater */
        int samples=ci->blocksizes[vb->W]>>1;
        double upper=floater_interpolate(bm,vi,bi->queue_avgmax);
        double lower=floater_interpolate(bm,vi,bi->queue_avgmin);
        double new=PACKETBLOBS/2.,slew;
        int bin;
        
        if(upper<new)new=upper;
        if(lower>new)new=lower;
        
        slew=(new-bm->avgfloat)/samples*vi->rate;
        
        if(slew<bi->avgfloat_downslew_max)
          new=bm->avgfloat+bi->avgfloat_downslew_max/vi->rate*samples;
        if(slew>bi->avgfloat_upslew_max)
          new=bm->avgfloat+bi->avgfloat_upslew_max/vi->rate*samples;
        
        bm->avgfloat=new;
        /* apply the average floater to new blocks */
        bin=rint(bm->avgfloat);

        /*fprintf(stderr,"%d ",bin);*/
        
        while(bm->avg_centeracc>desired_center){
          samples=ci->blocksizes[bm->queue_actual[bm->avg_center]&
                                0x80000000UL?1:0]>>1;
          
          bm->queue_actual[bm->avg_center]|=bin;
          
          bm->avg_centeracc-=samples;
          bm->avg_center++;
          if(bm->avg_center>=bm->queue_size)bm->avg_center=0;
        }
        new_minmax_head=bm->avg_center;
        
      }
      
      /* update the avg tail if needed */
      while(bm->avg_sampleacc>bm->avg_sampledesired){
        int samples=
          ci->blocksizes[bm->queue_actual[bm->avg_tail]&0x80000000UL?1:0]>>1;
        for(i=0;i<bm->queue_bins;i++)
          bm->avg_binacc[i]-=LACING_ADJUST(bm->queue_binned[bins*bm->avg_tail+i]);
        bm->avg_sampleacc-=samples;
        bm->avg_tail++;
        if(bm->avg_tail>=bm->queue_size)bm->avg_tail=0;
      }
      
      
    }
  }else{
    /* if we're not using an average tracker, the 'float' is nailed to
       the avgfloat_initial value.  It needs to be set for the min/max
       to deal properly */
    long bin=PACKETBLOBS/2;
    bm->queue_actual[head]|=bin;
    new_minmax_head=next_head;
  }     
  
  /* update the min/max queues and enforce limits */
  if(bm->minmax_binstack){
    unsigned long sampledesired=eofflag?0:bm->minmax_sampledesired;
    
    /* add to stack recent */
    while(minmax_head!=new_minmax_head){
      unsigned int i;
      int samples=ci->blocksizes[bm->queue_actual[minmax_head]&
                                0x80000000UL?1:0]>>1;
      int actual=bm->queue_actual[minmax_head]&0x7fffffffUL;

      for(i=0;i<(unsigned int)bins;i++){
        bm->minmax_binstack[bm->minmax_stackptr*bins*2+bins+i]+=
          LACING_ADJUST(BINBYTES(bm,minmax_head,
                                actual>i?actual:i));
        
        bm->minmax_binstack[bm->minmax_stackptr*bins*2+i]+=
          LACING_ADJUST(BINBYTES(bm,minmax_head,
                                actual<i?actual:i));
      }
      
      bm->minmax_posstack[bm->minmax_stackptr]=minmax_head; /* not one
                                                               past
                                                               like
                                                               typical */
      bm->minmax_limitstack[bm->minmax_stackptr]=0;
      bm->minmax_sampleacc+=samples;
      bm->minmax_acctotal+=
        LACING_ADJUST(BINBYTES(bm,minmax_head,actual));
      
      minmax_head++;
      if(minmax_head>=bm->queue_size)minmax_head=0;


    }
    
    /* check limits, enforce changes */
    if(bm->minmax_sampleacc>sampledesired){
      double bitrate=(double)(bm->minmax_acctotal*8)/
        bm->minmax_sampleacc*vi->rate;
      int limit=0;
      
      if((bi->queue_hardmax>0 && bitrate>bi->queue_hardmax) || 
         (bi->queue_hardmin>0 && bitrate<bi->queue_hardmin)){
        int newstack;
        int stackctr;
        long bitsum=bm->minmax_acctotal*8;

        bitrate=(double)bitsum/bm->minmax_sampleacc*vi->rate;

        /* we're off rate.  Iteratively try out new hard floater
           limits until we find one that brings us inside.  Here's
           where we see the whole point of the limit stacks.  */
        if(bi->queue_hardmax>0 && bitrate>bi->queue_hardmax){
          for(limit=-1;limit>-bins+1;limit--){
            long bitsum=limit_sum(bm,limit)*8;
            bitrate=(double)bitsum/bm->minmax_sampleacc*vi->rate;
            if(bitrate<=bi->queue_hardmax)break;
          }
        }else if(bitrate<bi->queue_hardmin){
          for(limit=1;limit<bins-1;limit++){
            long bitsum=limit_sum(bm,limit)*8;
            bitrate=(double)bitsum/bm->minmax_sampleacc*vi->rate;
            if(bitrate>=bi->queue_hardmin)break;
          }
          if(bitrate>bi->queue_hardmax)limit--;
        }

        /* trace the limit backward, stop when we see a lower limit */
        newstack=bm->minmax_stackptr-1;
        while(newstack>=0){
          if(bm->minmax_limitstack[newstack]<limit)break;
          newstack--;
        }
        
        /* update bit counter with new limit and replace any stack
           limits that have been replaced by our new lower limit */
        stackctr=bm->minmax_stackptr;
        while(stackctr>newstack){
          bm->minmax_acctotal-=
            LIMITBYTES(stackctr,bm->minmax_limitstack[stackctr]);
          bm->minmax_acctotal+=LIMITBYTES(stackctr,limit);
          
          if(stackctr<bm->minmax_stackptr)
            for(i=0;i<bins*2;i++)
              bm->minmax_binstack[stackctr*bins*2+i]+=
                bm->minmax_binstack[(stackctr+1)*bins*2+i];

          stackctr--;
        }
        stackctr++;
        bm->minmax_posstack[stackctr]=bm->minmax_posstack[bm->minmax_stackptr];
        bm->minmax_limitstack[stackctr]=limit;

        /* set up new blank stack entry */
        stackctr++;
        bm->minmax_stackptr=stackctr;
        memset(&bm->minmax_binstack[stackctr*bins*2],
               0,
               sizeof(*bm->minmax_binstack)*bins*2);
        bm->minmax_limitstack[stackctr]=0;
        bm->minmax_posstack[stackctr]=-1;
        
      }
    }
    
    /* remove from tail */
    while(bm->minmax_sampleacc>sampledesired){
      int samples=
        ci->blocksizes[bm->queue_actual[bm->minmax_tail]&0x80000000UL?1:0]>>1;
      int actual=bm->queue_actual[bm->minmax_tail]&0x7fffffffUL;

      for(i=0;i<bins;i++){
        bm->minmax_binstack[bins+i]-= /* always comes off the stack bottom */
          LACING_ADJUST(BINBYTES(bm,bm->minmax_tail,
                                actual>i?
                                actual:i));
        bm->minmax_binstack[i]-= 
          LACING_ADJUST(BINBYTES(bm,bm->minmax_tail,
                                actual<i?
                                actual:i));
      }

      if(bm->minmax_limitstack[0]>actual)
        actual=bm->minmax_limitstack[0];
      if(bins+bm->minmax_limitstack[0]<actual)
        actual=bins+bm->minmax_limitstack[0];
      
      bm->minmax_acctotal-=LACING_ADJUST(BINBYTES(bm,bm->minmax_tail,actual));
      bm->minmax_sampleacc-=samples;

      /* revise queue_actual to reflect the limit */
      bm->queue_actual[bm->minmax_tail]&=0x80000000UL;
      bm->queue_actual[bm->minmax_tail]|=actual;
      
      if(bm->minmax_tail==bm->minmax_posstack[0]){
        /* the stack becomes a FIFO; the first data has fallen off */
        memmove(bm->minmax_binstack,bm->minmax_binstack+bins*2,
                sizeof(*bm->minmax_binstack)*bins*2*bm->minmax_stackptr);
        memmove(bm->minmax_posstack,bm->minmax_posstack+1,
                sizeof(*bm->minmax_posstack)*bm->minmax_stackptr);
        memmove(bm->minmax_limitstack,bm->minmax_limitstack+1,
                sizeof(*bm->minmax_limitstack)*bm->minmax_stackptr);
        bm->minmax_stackptr--;
      }
      
      bm->minmax_tail++;
      if(bm->minmax_tail>=bm->queue_size)bm->minmax_tail=0;

    }
    
    
    bm->last_to_flush=bm->minmax_tail;
  }else{
    bm->last_to_flush=bm->avg_center;
  }
  if(eofflag)
    bm->last_to_flush=bm->queue_head;
  return(0);
}

int vorbis_bitrate_flushpacket(vorbis_dsp_state *vd,ogg_packet *op){
  private_state         *b=vd->backend_state;
  bitrate_manager_state *bm=&b->bms;

  if(bm->queue_size==0){
    if(bm->queue_head==0)return(0);

    memcpy(op,bm->packets,sizeof(*op));
    bm->queue_head=0;

  }else{

    if(bm->next_to_flush==bm->last_to_flush)return(0);

    {
      long bin=bm->queue_actual[bm->next_to_flush]&0x7fffffff,i;
      long bins=bm->queue_bins;
      ogg_uint32_t *markers=bm->queue_binned+bins*bm->next_to_flush;
      long bytes=markers[bin];

      memcpy(op,bm->packets+bm->next_to_flush,sizeof(*op));

      /* we have [PACKETBLOBS] possible packets all squished together in
         the buffer, in sequence.  count in to number [bin] */
      for(i=0;i<bin;i++)
        op->packet+=markers[i];
      op->bytes=bytes;
        
    }

    bm->next_to_flush++;
    if(bm->next_to_flush>=bm->queue_size)bm->next_to_flush=0;

  }

  return(1);
}