ref: 274b7550ba3dab157c2b5ed40710dbce694ea167
parent: fbaabc13f0111296a64e565f7b8779b7f67602ca
author: Jean-Marc Valin <[email protected]>
date: Mon Jul 5 12:56:42 EDT 2010
IETF draft
--- a/doc/draft-valin-codec-prototype.xml
+++ b/doc/draft-valin-codec-prototype.xml
@@ -48,7 +48,8 @@
<abstract>
<t>
This document provides a quick overview of a prototype codec combining a linear
-prediction layer (SILK) with an MDCT-based layer (CELT). These codecs are
+prediction layer (SILK) with an MDCT-based layer (CELT).
+These codecs are
used because of the authors' familiarity with the source code, but it does
not prevent inclusion of code from other codecs as well. This is a
work in progress.
@@ -71,10 +72,11 @@
</t>
<t>
-In this proposed prototype, the LP layer is based on the SILK codec and the
-MDCT layer is based on CELT codec. These codecs are
+In this proposed prototype, the LP layer is based on the SILK codec
+<xref target="SILK"></xref> and the MDCT layer is based on CELT codec
+ <xref target="CELT"></xref>. These codecs are
used because of the authors' familiarity with the source code, but it does
-not prevent inclusion of code from other codecs as well.
+not prevent inclusion of code from other codecs in the future.
</t>
<t>This is a work in progress.</t>
@@ -88,7 +90,10 @@
layer, all bands below 8 kHz are discarded, such that there is no coding
redundancy between the two layers. Also both layers use the same instance of
the range coder to encode the signal, which ensures that no "padding bits" are
-wasted.
+wasted. The hybrid approach makes it easy to support both constant bit-rate
+(CBR) and varaible bit-rate (VBR) coding. Although the SILK layer used is VBR,
+it is easy to make the bit allocation of the CELT layer produce a final stream
+that is CBR by using all the bits left unused by the SILK layer.
</t>
<section title="Source Code">
@@ -99,7 +104,9 @@
repositories (for SILK and CELT). Although the build system is very primitive
(and inconsistent), some instructions are provided in the toplevel README file.
This is very early development so both the quality and feature set should
-greatly improve over time.
+greatly improve over time. In the current version, only 48 kHz audio with 20 ms
+frames are supported, but support for all configurations listed in
+<xref target="modes"></xref> is planned.
</t>
</section>
@@ -275,7 +282,43 @@
<back>
-<references title="Normative References">
+<references title="Informative References">
+
+<reference anchor='SILK'>
+<front>
+<title>SILK Speech Codec</title>
+<author initials='K.' surname='Koen' fullname='K. Vos'>
+<organization /></author>
+<author initials='S.' surname='Soeren Skak' fullname='S. Jensen'>
+<organization /></author>
+<author initials='K.' surname='Karsten Vandborg' fullname='K. Soerensen'>
+<organization /></author>
+<date year='2010' month='March' />
+<abstract>
+<t></t>
+</abstract></front>
+<seriesInfo name='Internet-Draft' value='draft-vos-silk-01' />
+<format type='TXT' target='http://tools.ietf.org/html/draft-vos-silk-01' />
+</reference>
+
+<reference anchor='CELT'>
+<front>
+<title>Constrained-Energy Lapped Transform (CELT) Codec</title>
+<author initials='J.' surname='Jean-Marc' fullname='J. Valin'>
+<organization /></author>
+<author initials='T.' surname='Timothy' fullname='T. Terriberry'>
+<organization /></author>
+<author initials='G.' surname='Gregory' fullname='G. Maxwell'>
+<organization /></author>
+<author initials='C.' surname='Christopher' fullname='C. Montgomery'>
+<organization /></author>
+<date year='2009' month='July' />
+<abstract>
+<t></t>
+</abstract></front>
+<seriesInfo name='Internet-Draft' value='draft-valin-celt-codec-01' />
+<format type='TXT' target='http://tools.ietf.org/html/draft-valin-celt-codec-01' />
+</reference>
<reference anchor='DOS'>
<front>
--- a/src/hybrid_decoder.c
+++ b/src/hybrid_decoder.c
@@ -34,6 +34,7 @@
#endif
#include <stdlib.h>
+#include <stdio.h>
#include "hybrid_decoder.h"
#include "celt/libcelt/entdec.h"
#include "celt/libcelt/modes.h"
@@ -86,6 +87,7 @@
silk_ret = SKP_Silk_SDK_Decode( st->silk_dec, &DecControl, 0, &dec, len, pcm, &silk_frame_size );
if (silk_ret)
{+ fprintf (stderr, "SILK decode error\n");
/* Handle error */
}