blob: 5ca83568dec01470e6f61e2add19dab9039bb086 (
plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
|
<refentry id="lpanal">
<refentryinfo><title>Utilities</title></refentryinfo>
<refmeta>
<refentrytitle>lpanal</refentrytitle>
</refmeta>
<refnamediv>
<refname>lpanal</refname>
<refpurpose>
Performs both linear predictive and pitch-tracking analysis on a soundfile.
<indexterm id="IndexLpanal"><primary>lpanal</primary></indexterm>
</refpurpose>
</refnamediv>
<refsect1>
<title>Description</title>
<para>
Linear predictive analysis for the Csound <link linkend="SpectralLpcresyn"><citetitle>Linear Predictive Coding (LPC) Resynthesis</citetitle></link> opcodes.
</para>
</refsect1>
<refsect1>
<title>Syntax</title>
<synopsis><command>csound -U lpanal</command> [flags] infilename outfilename</synopsis>
<synopsis><command>lpanal</command> [flags] infilename outfilename</synopsis>
</refsect1>
<refsect1>
<title>Initialization</title>
<para>
<emphasis>lpanal</emphasis> performs both lpc and pitch-tracking analysis on a soundfile to produce a time-ordered sequence of <emphasis>frames</emphasis> of control information suitable for Csound resynthesis. Analysis is conditioned by the control flags below. A space is optional between the flag and its value.
</para>
<para>
<emphasis>-a</emphasis> -- [alternate storage] asks lpanal to write a file with filter poles values rather than the usual filter coefficient files. When <emphasis>lpread</emphasis> / <emphasis>lpreson</emphasis> are used with pole files, automatic stabilization is performed and the filter should not get wild. (This is the default in the Windows GUI) - Changed by Marc Resibois.
</para>
<para>
<emphasis>-s srate</emphasis> -- sampling rate of the audio input file. This will over-ride the srate of the soundfile header, which otherwise applies. If neither is present, the default is 10000.
</para>
<para>
<emphasis>-c channel</emphasis> -- channel number sought. The default is 1.
</para>
<para>
<emphasis>-b begin</emphasis> -- beginning time (in seconds) of the audio segment to be analyzed. The default is 0.0
</para>
<para>
<emphasis>-d duration</emphasis> -- duration (in seconds) of the audio segment to be analyzed. The default of 0.0 means to the end of the file.
</para>
<para>
<emphasis>-p npoles</emphasis> -- number of poles for analysis. The default is 34, the maximum 50.
</para>
<para>
<emphasis>-h hopsize</emphasis> -- hop size (in samples) between frames of analysis. This determines the number of frames per second (srate / hopsize) in the output control file. The analysis framesize is hopsize * 2 samples. The default is 200, the maximum 500.
</para>
<para>
<emphasis>-C string</emphasis> -- text for the comments field of the lpfile header. The default is the null string.
</para>
<para>
<emphasis>-P mincps</emphasis> -- lowest frequency (in Hz) of pitch tracking. -P0 means no pitch tracking.
</para>
<para>
<emphasis>-Q maxcps</emphasis> -- highest frequency (in Hz) of pitch tracking. The narrower the pitch range, the more accurate the pitch estimate. The defaults are -P70, -Q200.
</para>
<para>
<emphasis>-v verbosity</emphasis> -- level of terminal information during analysis.
<itemizedlist>
<listitem><para>0 = none</para></listitem>
<listitem><para>1 = verbose</para></listitem>
<listitem><para>2 = debug</para></listitem>
</itemizedlist>
The default is 0.
</para>
</refsect1>
<refsect1>
<title>Examples</title>
<para>
<!-- <informalexample> -->
<programlisting>
<emphasis>lpanal</emphasis> -a -p26 -d2.5 -P100 -Q400 audiofile.test lpfil22</programlisting>
<!-- </informalexample> -->
will analyze the first 2.5 seconds of file "audiofile.test", producing srate/200 frames per second, each containing 26-pole filter coefficients and a pitch estimate between 100 and 400 Hertz. Stabilized (<emphasis>-a</emphasis>) output will be placed in "lpfil22" in the current directory.
</para>
<refsect2>
<title>File Format </title>
<para>
Output is a file comprised of an identifiable header plus a set of frames of floating point analysis data. Each frame contains four values of pitch and gain information, followed by <emphasis>npoles</emphasis> filter coefficients. The file is readable by Csound's <link linkend="lpread"><citetitle>lpread</citetitle></link>.
</para>
<para>
<emphasis>lpanal</emphasis> is an extensive modification of Paul Lanksy's lpc analysis programs.
</para>
</refsect2>
</refsect1>
</refentry>
|
