comparison src/libvorbis-1.3.3/lib/bitrate.c @ 86:98c1576536ae

Bring in flac, ogg, vorbis

+/********************************************************************
+ *                                                                  *
+ * 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 1994-2009             *
+ * by the Xiph.Org Foundation http://www.xiph.org/                  *
+ *                                                                  *
+ ********************************************************************
+
+ function: bitrate tracking and management
+ last mod: $Id: bitrate.c 16227 2009-07-08 06:58:46Z xiphmont $
+
+ ********************************************************************/
+
+#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"
+
+/* compute bitrate tracking setup  */
+void vorbis_bitrate_init(vorbis_info *vi,bitrate_manager_state *bm){
+  codec_setup_info *ci=vi->codec_setup;
+  bitrate_manager_info *bi=&ci->bi;
+
+  memset(bm,0,sizeof(*bm));
+
+  if(bi && (bi->reservoir_bits>0)){
+    long ratesamples=vi->rate;
+    int  halfsamples=ci->blocksizes[0]>>1;
+
+    bm->short_per_long=ci->blocksizes[1]/ci->blocksizes[0];
+    bm->managed=1;
+
+    bm->avg_bitsper= rint(1.*bi->avg_rate*halfsamples/ratesamples);
+    bm->min_bitsper= rint(1.*bi->min_rate*halfsamples/ratesamples);
+    bm->max_bitsper= rint(1.*bi->max_rate*halfsamples/ratesamples);
+
+    bm->avgfloat=PACKETBLOBS/2;
+
+    /* not a necessary fix, but one that leads to a more balanced
+       typical initialization */
+    {
+      long desired_fill=bi->reservoir_bits*bi->reservoir_bias;
+      bm->minmax_reservoir=desired_fill;
+      bm->avg_reservoir=desired_fill;
+    }
+
+  }
+}
+
+void vorbis_bitrate_clear(bitrate_manager_state *bm){
+  memset(bm,0,sizeof(*bm));
+  return;
+}
+
+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 && bm->managed)return(1);
+  return(0);
+}
+
+/* finish taking in the block we just processed */
+int vorbis_bitrate_addblock(vorbis_block *vb){
+  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  choice=rint(bm->avgfloat);
+  long this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
+  long min_target_bits=(vb->W?bm->min_bitsper*bm->short_per_long:bm->min_bitsper);
+  long max_target_bits=(vb->W?bm->max_bitsper*bm->short_per_long:bm->max_bitsper);
+  int  samples=ci->blocksizes[vb->W]>>1;
+  long desired_fill=bi->reservoir_bits*bi->reservoir_bias;
+  if(!bm->managed){
+    /* not a bitrate managed stream, but for API simplicity, we'll
+       buffer the packet to keep the code path clean */
+
+    if(bm->vb)return(-1); /* one has been submitted without
+                             being claimed */
+    bm->vb=vb;
+    return(0);
+  }
+
+  bm->vb=vb;
+
+  /* look ahead for avg floater */
+  if(bm->avg_bitsper>0){
+    double slew=0.;
+    long avg_target_bits=(vb->W?bm->avg_bitsper*bm->short_per_long:bm->avg_bitsper);
+    double slewlimit= 15./bi->slew_damp;
+
+    /* choosing a new floater:
+       if we're over target, we slew down
+       if we're under target, we slew up
+
+       choose slew as follows: look through packetblobs of this frame
+       and set slew as the first in the appropriate direction that
+       gives us the slew we want.  This may mean no slew if delta is
+       already favorable.
+
+       Then limit slew to slew max */
+
+    if(bm->avg_reservoir+(this_bits-avg_target_bits)>desired_fill){
+      while(choice>0 && this_bits>avg_target_bits &&
+            bm->avg_reservoir+(this_bits-avg_target_bits)>desired_fill){
+        choice--;
+        this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
+      }
+    }else if(bm->avg_reservoir+(this_bits-avg_target_bits)<desired_fill){
+      while(choice+1<PACKETBLOBS && this_bits<avg_target_bits &&
+            bm->avg_reservoir+(this_bits-avg_target_bits)<desired_fill){
+        choice++;
+        this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
+      }
+    }
+
+    slew=rint(choice-bm->avgfloat)/samples*vi->rate;
+    if(slew<-slewlimit)slew=-slewlimit;
+    if(slew>slewlimit)slew=slewlimit;
+    choice=rint(bm->avgfloat+= slew/vi->rate*samples);
+    this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
+  }
+
+
+
+  /* enforce min(if used) on the current floater (if used) */
+  if(bm->min_bitsper>0){
+    /* do we need to force the bitrate up? */
+    if(this_bits<min_target_bits){
+      while(bm->minmax_reservoir-(min_target_bits-this_bits)<0){
+        choice++;
+        if(choice>=PACKETBLOBS)break;
+        this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
+      }
+    }
+  }
+
+  /* enforce max (if used) on the current floater (if used) */
+  if(bm->max_bitsper>0){
+    /* do we need to force the bitrate down? */
+    if(this_bits>max_target_bits){
+      while(bm->minmax_reservoir+(this_bits-max_target_bits)>bi->reservoir_bits){
+        choice--;
+        if(choice<0)break;
+        this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
+      }
+    }
+  }
+
+  /* Choice of packetblobs now made based on floater, and min/max
+     requirements. Now boundary check extreme choices */
+
+  if(choice<0){
+    /* choosing a smaller packetblob is insufficient to trim bitrate.
+       frame will need to be truncated */
+    long maxsize=(max_target_bits+(bi->reservoir_bits-bm->minmax_reservoir))/8;
+    bm->choice=choice=0;
+
+    if(oggpack_bytes(vbi->packetblob[choice])>maxsize){
+
+      oggpack_writetrunc(vbi->packetblob[choice],maxsize*8);
+      this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
+    }
+  }else{
+    long minsize=(min_target_bits-bm->minmax_reservoir+7)/8;
+    if(choice>=PACKETBLOBS)
+      choice=PACKETBLOBS-1;
+
+    bm->choice=choice;
+
+    /* prop up bitrate according to demand. pad this frame out with zeroes */
+    minsize-=oggpack_bytes(vbi->packetblob[choice]);
+    while(minsize-->0)oggpack_write(vbi->packetblob[choice],0,8);
+    this_bits=oggpack_bytes(vbi->packetblob[choice])*8;
+
+  }
+
+  /* now we have the final packet and the final packet size.  Update statistics */
+  /* min and max reservoir */
+  if(bm->min_bitsper>0 || bm->max_bitsper>0){
+
+    if(max_target_bits>0 && this_bits>max_target_bits){
+      bm->minmax_reservoir+=(this_bits-max_target_bits);
+    }else if(min_target_bits>0 && this_bits<min_target_bits){
+      bm->minmax_reservoir+=(this_bits-min_target_bits);
+    }else{
+      /* inbetween; we want to take reservoir toward but not past desired_fill */
+      if(bm->minmax_reservoir>desired_fill){
+        if(max_target_bits>0){ /* logical bulletproofing against initialization state */
+          bm->minmax_reservoir+=(this_bits-max_target_bits);
+          if(bm->minmax_reservoir<desired_fill)bm->minmax_reservoir=desired_fill;
+        }else{
+          bm->minmax_reservoir=desired_fill;
+        }
+      }else{
+        if(min_target_bits>0){ /* logical bulletproofing against initialization state */
+          bm->minmax_reservoir+=(this_bits-min_target_bits);
+          if(bm->minmax_reservoir>desired_fill)bm->minmax_reservoir=desired_fill;
+        }else{
+          bm->minmax_reservoir=desired_fill;
+        }
+      }
+    }
+  }
+
+  /* avg reservoir */
+  if(bm->avg_bitsper>0){
+    long avg_target_bits=(vb->W?bm->avg_bitsper*bm->short_per_long:bm->avg_bitsper);
+    bm->avg_reservoir+=this_bits-avg_target_bits;
+  }
+
+  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;
+  vorbis_block          *vb=bm->vb;
+  int                    choice=PACKETBLOBS/2;
+  if(!vb)return 0;
+
+  if(op){
+    vorbis_block_internal *vbi=vb->internal;
+
+    if(vorbis_bitrate_managed(vb))
+      choice=bm->choice;
+
+    op->packet=oggpack_get_buffer(vbi->packetblob[choice]);
+    op->bytes=oggpack_bytes(vbi->packetblob[choice]);
+    op->b_o_s=0;
+    op->e_o_s=vb->eofflag;
+    op->granulepos=vb->granulepos;
+    op->packetno=vb->sequence; /* for sake of completeness */
+  }
+
+  bm->vb=0;
+  return(1);
+}