[xiph-cvs] cvs commit: vorbis/doc/xml 04-codec.xml 07-floor1.xml 08-residue.xml
Monty
xiphmont at xiph.org
Tue Mar 11 03:02:17 PST 2003
xiphmont 03/03/11 06:02:17
Modified: doc/xml 04-codec.xml 07-floor1.xml 08-residue.xml
Added: doc xifish.pdf
Log:
Many small but vital fixes to the spec pseudocode pointed out by
jripley at sonicblue.com.
Revision Changes Path
1.1 vorbis/doc/xifish.pdf
Index: xifish.pdf
===================================================================
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<p><p>1.8 +7 -8 vorbis/doc/xml/04-codec.xml
Index: 04-codec.xml
===================================================================
RCS file: /usr/local/cvsroot/vorbis/doc/xml/04-codec.xml,v
retrieving revision 1.7
retrieving revision 1.8
diff -u -r1.7 -r1.8
--- 04-codec.xml 27 Oct 2002 16:20:47 -0000 1.7
+++ 04-codec.xml 11 Mar 2003 11:02:17 -0000 1.8
@@ -7,8 +7,8 @@
<section id="vorbis-spec-codec">
<sectioninfo>
<releaseinfo>
- $Id: 04-codec.xml,v 1.7 2002/10/27 16:20:47 giles Exp $
- <emphasis>Last update to this document: October 15, 2002</emphasis>
+ $Id: 04-codec.xml,v 1.8 2003/03/11 11:02:17 xiphmont Exp $
+ <emphasis>Last update to this document: March 11, 2003</emphasis>
</releaseinfo>
</sectioninfo>
<title>Codec Setup and Packet Decode</title>
@@ -357,7 +357,6 @@
<orderedlist>
<listitem><simpara> <varname>[window_center]</varname> = <varname>[n]</varname> / 2</simpara></listitem>
- <listitem><simpara> <varname>[left_window_start]</varname></simpara></listitem>
<listitem><para> if (<varname>[vorbis_mode_blockflag]</varname> is set and <varname>[previous_window_flag]</varname> is
not set) then
<orderedlist>
@@ -393,7 +392,7 @@
<listitem><simpara> for <varname>[i]</varname> in range <varname>[left_window_start]</varname> ...
<varname>[left_window_end]</varname>-1, window(<varname>[i]</varname>) = sin(.5 * π * sin^2( (<varname>[i]</varname>-<varname>[left_window_start]</varname>+.5) / <varname>[left_n]</varname> * .5 * π) )</simpara></listitem>
<listitem><simpara> window from range <varname>[left_window_end]</varname> ... <varname>[right_window_start]</varname>-1
-inclusive is one</simpara></listitem><listitem><simpara> for <varname>[i]</varname> in range <varname>[right_window_start]</varname> ... <varname>[right_window_end]</varname>-1, window(<varname>[i]</varname>) = sin(.5 * π * sin^2( (<varname>[i]</varname>-<varname>[right_window_start]</varname>+.5) / <varname>[right_n]</varname> * .5 * π/2. + .5 * π) )</simpara></listitem>
+inclusive is one</simpara></listitem><listitem><simpara> for <varname>[i]</varname> in range <varname>[right_window_start]</varname> ... <varname>[right_window_end]</varname>-1, window(<varname>[i]</varname>) = sin(.5 * π * sin^2( (<varname>[i]</varname>-<varname>[right_window_start]</varname>+.5) / <varname>[right_n]</varname> * .5 * π + .5 * π) )</simpara></listitem>
<listitem><simpara> window from range <varname>[rigth_window_start]</varname> ... <varname>[n]</varname>-1 is
zero</simpara></listitem>
</orderedlist>
@@ -483,17 +482,17 @@
<orderedlist>
<listitem><simpara><varname>[ch]</varname> = 0</simpara></listitem>
- <listitem><simpara>for each channel <varname>[j]</varname> in order from 0 ... <varname>[audio_channels]</varname></simpara>
+ <listitem><simpara>for each channel <varname>[j]</varname> in order from 0 ... <varname>[audio_channels]</varname> - 1</simpara>
<orderedlist>
- <listitem><simpara>if channel <varname>[j]</varname> is in submap <varname>[i]</varname> (vector <varname>[vorbis_mapping_mux]</varname> element <varname>[j]</varname> is equal to <varname>[i]</varname>)</simpara>
+ <listitem><simpara>if channel <varname>[j]</varname> in submap <varname>[i]</varname> (vector <varname>[vorbis_mapping_mux]</varname> element <varname>[j]</varname> is equal to <varname>[i]</varname>)</simpara>
<orderedlist>
<listitem><para>if vector <varname>[no_residue]</varname> element <varname>[j]</varname> is true
<orderedlist>
- <listitem><simpara>vector <varname>[do_not_decode_flag]</varname> element <varname>[channels_in_bundle]</varname> is set</simpara></listitem>
+ <listitem><simpara>vector <varname>[do_not_decode_flag]</varname> element <varname>[ch]</varname> is set</simpara></listitem>
</orderedlist>
else
<orderedlist>
- <listitem><simpara>vector <varname>[do_not_decode_flag]</varname> element <varname>[channels_in_bundle]</varname> is unset</simpara></listitem>
+ <listitem><simpara>vector <varname>[do_not_decode_flag]</varname> element <varname>[ch]</varname> is unset</simpara></listitem>
</orderedlist></para>
</listitem>
<listitem><simpara>increment <varname>[ch]</varname></simpara></listitem>
<p><p>1.5 +4 -5 vorbis/doc/xml/07-floor1.xml
Index: 07-floor1.xml
===================================================================
RCS file: /usr/local/cvsroot/vorbis/doc/xml/07-floor1.xml,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- 07-floor1.xml 27 Oct 2002 16:20:47 -0000 1.4
+++ 07-floor1.xml 11 Mar 2003 11:02:17 -0000 1.5
@@ -7,8 +7,8 @@
<section id="vorbis-spec-floor1">
<sectioninfo>
<releaseinfo>
- $Id: 07-floor1.xml,v 1.4 2002/10/27 16:20:47 giles Exp $
- <emphasis>Last update to this document: October 15, 2002</emphasis>
+ $Id: 07-floor1.xml,v 1.5 2003/03/11 11:02:17 xiphmont Exp $
+ <emphasis>Last update to this document: March 11, 2003</emphasis>
</releaseinfo>
</sectioninfo>
<title>Floor type 1 setup and decode</title>
@@ -185,9 +185,8 @@
20) iterate [j] over the range 0 ... ([floor1_class_dimensions] element [current_class_number])-1 {
21) vector [floor1_X_list] element ([j] + [floor1_values]) =
read [rangebits] bits as unsigned integer
- }
-
- 22) [floor1_values] = [floor1_values] + [floor1_class_dimensions] element [i]
+ 22) increment [floor1_values] by one
+ }
}
23) done
<p><p>1.5 +37 -36 vorbis/doc/xml/08-residue.xml
Index: 08-residue.xml
===================================================================
RCS file: /usr/local/cvsroot/vorbis/doc/xml/08-residue.xml,v
retrieving revision 1.4
retrieving revision 1.5
diff -u -r1.4 -r1.5
--- 08-residue.xml 27 Oct 2002 16:20:47 -0000 1.4
+++ 08-residue.xml 11 Mar 2003 11:02:17 -0000 1.5
@@ -7,8 +7,8 @@
<section id="vorbis-spec-residue">
<sectioninfo>
<releaseinfo>
- $Id: 08-residue.xml,v 1.4 2002/10/27 16:20:47 giles Exp $
- <emphasis>Last update to this document: July 19, 2002</emphasis>
+ $Id: 08-residue.xml,v 1.5 2003/03/11 11:02:17 xiphmont Exp $
+ <emphasis>Last update to this document: March 11, 2003</emphasis>
</releaseinfo>
</sectioninfo>
<title>Residue setup and decode</title>
@@ -286,8 +286,8 @@
the decode process:</para>
<programlisting>
- 1) [classvals_per_codeword] = [codebook_dimensions] value of codebook [residue_classbook]
- 2) [n_to_read] = [residue_end] - [residue-begin]
+ 1) [classwords_per_codeword] = [codebook_dimensions] value of codebook [residue_classbook]
+ 2) [n_to_read] = [residue_end] - [residue_begin]
3) [partitions_to_read] = [n_to_read] / [residue_partition_size]
</programlisting>
@@ -298,6 +298,7 @@
2) iterate [pass] over the range 0 ... 7 {
3) [partition_count] = 0
+
4) if ([pass] is zero) {
5) iterate [j] over the range 0 .. [ch]-1 {
@@ -305,9 +306,9 @@
6) if vector [j] is not marked 'do not decode' {
7) [temp] = read from packet using codebook [residue_classbook] in scalar context
- 8) iterate [k] descending over the range [classvals_per_codeword]-1 ... 0 {
+ 8) iterate [i] descending over the range [classwords_per_codeword]-1 ... 0 {
- 9) array [classifications] element [j],([partition_count]+[k]) =
+ 9) array [classifications] element [j],([i]+[partition_count]) =
[temp] integer modulo [residue_classifications]
10) [temp] = [temp] / [residue_classifications] using integer division
@@ -319,32 +320,29 @@
}
- 11) [classword_count] = 0
- 12) iterate [j] over the range 0 .. [ch]-1 {
-
- 13) if vector [j] is not marked 'do not decode' {
+ 11) iterate [i] over the range 0 .. ([classwords_per_codeword] - 1) while [partition_count]
+ is also less than [partitions_to_read] {
-
- 14) [vqclass] = array [classifications] element [j],([partition_count]+[classword_count])
- 15) [vqbook] = array [residue_books] element [vqclass],[pass]
- 16) if ([vqbook] is not 'unused') {
+ 12) iterate [j] over the range 0 .. [ch]-1 {
- 17) decode partition into output vector number [j], starting at scalar
+ 13) if vector [j] is not marked 'do not decode' {
+
+ 14) [vqclass] = array [classifications] element [j],[partition_count]
+ 15) [vqbook] = array [residue_books] element [vqclass],[pass]
+ 16) if ([vqbook] is not 'unused') {
+
+ 17) decode partition into output vector number [j], starting at scalar
offset [residue_begin]+[partition_count]*[residue_partition_size] using
codebook number [vqbook] in VQ context
}
- }
+ }
+
+ 18) increment [partition_count] by one
}
-
- 18) increment [classword_count]
- 19) increment [partition_count]
- 20) if ([classword_count] is less than [classvals_per_codeword]) AND
- ([partition_count] is less than [partitions_to_read) then continue at step 11
- 21) if ([partition_count] is less than [partitions_to_read) then continue at step 4
- }
+ }
- 22) done
+ 19) done
</programlisting>
@@ -424,18 +422,27 @@
<section><title>format 2 specifics</title>
<para>
-Format 2 is reducible to format 1 through the following steps, performed in order:
+Format 2 is reducible to format 1. It may be implemented as an additional stepprior to and an additional post-decode step after a normal format 1 decode.
+</para>
+
+<para>
+Format 2 handles 'do not decode' vectors differently than residue 0 or
+1; if all vectors are marked 'do not decode', no decode occurrs.
+However, if at least one vector is to be decoded, all the vectors are
+decoded. We then request normal format 1 to decode a single vector
+representing all output channels, rather than a vector for each
+channel. After decode, deinterleave the vector into independent vectors, one for each output channel. That is:</para>
<orderedlist>
- <listitem><simpara>Assume format 2 is to decode <emphasis>ch</emphasis> vectors of length <emphasis>n</emphasis>.</simpara></listitem>
- <listitem><simpara>Decode, using format 1, a single vector <varname>[v]</varname>of length <emphasis>ch</emphasis>*<emphasis>n</emphasis>.</simpara></listitem>
- <listitem><para>Deinterleave this single vector <varname>[v]</varname> into <emphasis>ch</emphasis> independent vectors according to:
+ <listitem><simpara>If all vectors 0 through <emphasis>ch</emphasis>-1 are marked 'do not decode', allocate and clear a single vector <varname>[v]</varname>of length <emphasis>ch*n</emphasis> and skip step 2 below; proceed directly to the post-decode step.</simpara></listitem>
+ <listitem><simpara>Rather than performing format 1 decode to produce <emphasis>ch</emphasis> vectors of length <emphasis>n</emphasis> each, call format 1 decode to produce a single vector <varname>[v]</varname> of length <emphasis>ch*n</emphasis>. </simpara></listitem>
+ <listitem><para>Post decode: Deinterleave the single vector <varname>[v]</varname> returned by format 1 decode as described above into <emphasis>ch</emphasis> independent vectors, one for each outputchannel, according to:
<programlisting>
1) iterate [i] over the range 0 ... [n]-1 {
2) iterate [j] over the range 0 ... [ch]-1 {
- 3) output vector number [j] element [i] = vector [t] element ([i] * [ch] +[j])
+ 3) output vector number [j] element [i] = vector [v] element ([i] * [ch] + [j])
}
}
@@ -444,16 +451,10 @@
</programlisting>
</para></listitem>
</orderedlist>
-</para>
-
-<para>
-Format 2 handles 'do not decode' vectors differently that residue 0 or
-1; if all vectors are marked 'do not decode', no decode occurrs.
-However, if at least one vector is to be decoded, all the vectors are
-decoded.</para>
</section>
</section>
</section>
+
<p><p>--- >8 ----
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