commit b08c4ca3f54c964f1108170d0e4b7df2200b6a82
author Jean-Marc Valin <jmvalin@jmvalin.ca> Fri Apr 26 16:32:10 2013 -0400
committer Jean-Marc Valin <jmvalin@jmvalin.ca> Sun May 05 02:31:38 2013 -0400
tree 86cd3807c3a7df88a3a220851b5fcd49c22a1ef2
parent 1b72386a7c44857fe5b35fbfbce6b11c367f0e10

Surround: Better LFE handling

Forces CELT-only mode for LFE (despite the rate) and "locks" most of the
CELT analysis:
- No transient or TF
- Band boost on first band
- Only first two bands get PVQ bits
- Forced energy decay after the first two bands

src/opus_multistream_encoder.c

diff --git a/src/opus_multistream_encoder.c b/src/opus_multistream_encoder.c
index b3e0ccc..9dcbb71 100644
--- a/src/opus_multistream_encoder.c
+++ b/src/opus_multistream_encoder.c
@@ -329,7 +329,7 @@
       int total = ((st->layout.nb_streams-st->layout.nb_coupled_streams-(st->lfe_stream!=-1))<<8) /* mono */
             + coupled_ratio*st->layout.nb_coupled_streams /* stereo */
             + (st->lfe_stream!=-1)*lfe_ratio;
-      channel_rate = 256*st->bitrate_bps/total;
+      channel_rate = 256*(st->bitrate_bps-2000)/total;
    }
 #ifndef FIXED_POINT
    if (st->variable_duration==OPUS_FRAMESIZE_VARIABLE && frame_size != Fs/50)
@@ -347,7 +347,7 @@
       else if (i!=st->lfe_stream)
          rate[i] = channel_rate;
       else
-         rate[i] = channel_rate*lfe_ratio>>8;
+         rate[i] = 2000+(channel_rate*lfe_ratio>>8);
    }