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
|
<HTML>
<HEAD>
<TITLE>TSP (libtsp/AF) - AFsetNHpar</TITLE>
</HEAD>
<BODY BGCOLOR="#FFFACD">
<H2>AFsetNHpar</H2>
<HR>
<H4>Routine</H4>
<DL>
<DT>
int AFsetNHpar (const char String[])
</DL>
<H4>Purpose</H4>
<DL>
<DT>
Set defaults for headerless audio files from a string specification
</DL>
<H4>Description</H4>
This routine sets or gets default audio file data parameters. These
parameters are used for files with unrecognized (non-standard) headers or
files with no headers (raw audio files). This routine must be called before
opening the file with AFopenRead. The parameters for AFsetNHpar are
determined from an input string which consists of a list of parameters
separated by commas. The form of the list is
<PRE>
"Format, Start, Sfreq, Swapb, Nchan, ScaleF"
</PRE>
<DL>
<DT>
Format: File data format
<DD>
<PRE>
"undefined" - Headerless files will be rejected
"mu-law8" - 8-bit mu-law data
"A-law8" - 8-bit A-law data
"unsigned8" - offset-binary 8-bit integer data
"integer8" - two's-complement 8-bit integer data
"integer16" - two's-complement 16-bit integer data
"float32" - 32-bit floating-point data
"float64" - 64-bit floating-point data
"text" - text data
</PRE>
<DT>
Start: byte offset to the start of data (integer value)
<DT>
Sfreq: sampling frequency in Hz (floating-point number)
<DT>
Swapb: Data byte swap parameter
<DD>
<PRE>
"native" - no byte swapping
"little-endian" - file data is in little-endian byte order and
will be swapped if the current host uses big-endian byte order
"big-endian" - data is in big-endian byte order and will be
swapped swapped if the current host uses little-endian byte
order
"swap" - swap the data bytes
</PRE>
<DT>
Nchan: number of channels
<DD>
The data consists of interleaved samples from Nchan channels
<DT>
ScaleF: Scale factor
<DD>
Scale factor applied to the data from the file
</DL>
The default values correspond to the following string
<PRE>
"undefined, 0, 8000., native, 1, 1.0"
</PRE>
<P>
Leading and trailing white-space (as defined by isspace) is removed from
each item. In the input string, any of the parameters may be omitted, in
which case whatever value has been previously set remains in effect for
that parameter. The string ",512, 10000." would set the Start and Sfreq
parameters and leave the other parameters undisturbed.
<P>
If the input string contains has a leading '$', the string is assumed to
specify the name of an environment variable after the '$'. This routine uses
the value of this environment variable to determine the parameters. If this
routine is called as AFsetNHpar("$AF_NOHEADER"), this routine would look for
the parameter string in environment variable AF_NOHEADER.
<H4>Parameters</H4>
<DL>
<DT>
<- int AFsetNHpar
<DD>
Error flag, zero for no error
<DT>
-> const char String[]
<DD>
String containing the list of parameters for headerless files or the name
of an environment variable (with a leading $)
</DL>
<H4>Author / revision</H4>
P. Kabal Copyright (C) 1997
/ Revision 1.42 1997/11/27
<H4>See Also</H4>
<A HREF="AFopenRead.html">AFopenRead</A>
<P>
<HR>
Main Index <A HREF="../libtsp.html">libtsp</A>
</BODY>
</HTML>
|
