updating update draft

parent 38688317
......@@ -10,7 +10,7 @@
<?rfc inline="yes"?>
<?rfc compact="yes"?>
<?rfc subcompact="no"?>
<rfc category="std" docName="draft-ietf-codec-opus-update-03"
<rfc category="std" docName="draft-ietf-codec-opus-update-04"
ipr="trust200902">
<front>
<title abbrev="Opus Update">Updates to the Opus Audio Codec</title>
......@@ -47,7 +47,7 @@
<date day="1" month="September" year="2016" />
<date day="21" month="October" year="2016" />
<abstract>
<t>This document addresses minor issues that were found in the specification
......@@ -276,6 +276,26 @@ silk_ADD_SAT16( NLSF_Q15[i-1], NDeltaMin_Q15[i] ) );
</section>
<section title="Cap on Band Energy">
<t>On extreme bit-streams, it is possible for log-domain band energy levels
to exceed the maximum single-precision floating point value once converted
to a linear scale. This would later cause the decoded values to be NaN,
possibly causing problems in the software using the PCM values. This can be
avoided with the following patch to line 552 of celt/quant_bands.c:
</t>
<figure>
<artwork><![CDATA[
{
opus_val16 lg = ADD16(oldEBands[i+c*m->nbEBands],
SHL16((opus_val16)eMeans[i],6));
+ lg = MIN32(QCONST32(32.f, 16), lg);
eBands[i+c*m->nbEBands] = PSHR32(celt_exp2(lg),4);
}
for (;i<m->nbEBands;i++)
]]></artwork>
</figure>
</section>
<section title="Hybrid Folding" anchor="folding">
<t>When encoding in hybrid mode at low bitrate, we sometimes only have
enough bits to code a single CELT band (8 - 9.6 kHz). When that happens,
......
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