Fix one comment (bitrate.c no longer uses a circular packet queue)

Correct a bug-that-isn't-a-bug; the bitrate manager's setpoint gravity
code relied on subtlety that just took me a while to figure out even
though I wrote it.  Given that, I could see it causing trouble in the
future if other changes broke the subtlety, so I increased the
heavy-handed logic explicitness to bulletproof the gravity code in the
cases where there's a minimum but not a maximum and vice versa.

The only change that makes a difference: the bit reservoir is set to
the bias setpoint in initialization as opposed to always starting with
a full reservoir.  This is unrelated to above, but seemed like a good
idea.

svn path=/trunk/vorbis/; revision=7185

diff --git a/lib/bitrate.c b/lib/bitrate.c
index 18cf6eb..5ecbf97 100644 (file)
--- a/lib/bitrate.c
+++ b/lib/bitrate.c
@@ -25,7 +25,7 @@
 #include "misc.h"
 #include "bitrate.h"
 
-/* compute bitrate tracking setup, allocate circular packet size queue */
+/* 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;
@@ -45,6 +45,14 @@ void vorbis_bitrate_init(vorbis_info *vi,bitrate_manager_state *bm){
     
     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;
+    }
+
   }    
 }
 
@@ -80,7 +88,7 @@ int vorbis_bitrate_addblock(vorbis_block *vb){
   long desired_fill=bi->reservoir_bits*bi->reservoir_bias;
   if(!bm->managed){
     /* not a bitrate managed stream, but for API simplicity, we'll
-       buffer one packet to keep the code path clean */
+       buffer the packet to keep the code path clean */
     
     if(bm->vb)return(-1); /* one has been submitted without
                             being claimed */
@@ -193,11 +201,19 @@ int vorbis_bitrate_addblock(vorbis_block *vb){
     }else{
       /* inbetween; we want to take reservoir toward but not past desired_fill */
       if(bm->minmax_reservoir>desired_fill){
-       bm->minmax_reservoir+=(this_bits-max_target_bits);
-       if(bm->minmax_reservoir<desired_fill)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{
-       bm->minmax_reservoir+=(this_bits-min_target_bits);
-       if(bm->minmax_reservoir>desired_fill)bm->minmax_reservoir=desired_fill;
+       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;
+       }
       }
     }
   }
@@ -211,6 +227,7 @@ int vorbis_bitrate_addblock(vorbis_block *vb){
   return(0);
 }
 
+#include <stdio.h>
 int vorbis_bitrate_flushpacket(vorbis_dsp_state *vd,ogg_packet *op){
   private_state         *b=vd->backend_state;
   bitrate_manager_state *bm=&b->bms;
@@ -224,6 +241,8 @@ int vorbis_bitrate_flushpacket(vorbis_dsp_state *vd,ogg_packet *op){
     if(vorbis_bitrate_managed(vb))
       choice=bm->choice;
 
+    fprintf(stderr,"%d ",choice);
+
     op->packet=oggpack_get_buffer(vbi->packetblob[choice]);
     op->bytes=oggpack_bytes(vbi->packetblob[choice]);
     op->b_o_s=0;