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1<html>
2
3<head>
4<title>libvorbisenc - function - vorbis_encode_ctl</title>
5<link rel=stylesheet href="style.css" type="text/css">
6</head>
7
8<body bgcolor=white text=black link="#5555ff" alink="#5555ff" vlink="#5555ff">
9<table border=0 width=100%>
10<tr>
11<td><p class=tiny>libvorbisenc documentation</p></td>
12<td align=right><p class=tiny>libvorbisenc release 1.1 - 20040709</p></td>
13</tr>
14</table>
15
16<h1>vorbis_encode_ctl</h1>
17
18<p><i>declared in "vorbis/libvorbisenc.h";</i></p>
19
20<p>This function implements a generic interface to miscellaneous
21encoder settings similar to the clasasic UNIX 'ioctl()' system call.
22Applications may use vorbis_encode_ctl() to query or set bitrate
23management or quality mode details by using one of several
24<i>request</i> arguments detailed below.  Vorbis_encode_ctl() must be
25called after one of <a
26href="vorbis_encode_setup_managed.html">vorbis_encode_setup_managed()</a>
27or <a
28href="vorbis_encode_setup_vbr.html">vorbis_encode_setup_vbr()</a>.
29When used to modify settings, vorbis_encode_ctl() must be called
30before <a
31href="vorbis_encode_setup_init.html">vorbis_encode_setup_init()</a>.
32
33<p>
34<br><br>
35<table border=0 color=black cellspacing=0 cellpadding=7>
36<tr bgcolor=#cccccc>
37        <td>
38<pre><b>
39extern int vorbis_encode_ctl(vorbis_info *vi,int request,void *arg);
40
41</b></pre>
42        </td>
43</tr>
44</table>
45
46<h3>Parameters</h3>
47<dl>
48<dt><i>vi</i></dt>
49<dd>File pointer to an initialized <a href="vorbis_info.html">vorbis_info</a> struct.</dd><p>
50<dt><i>request</i></dt>
51<dd>Specifies the desired action; possible request fields are detailed below.</dd><p>
52<dt><i>arg</i></dt>
53<dd>void * pointing to a data structure matching the request argument.</dd><p>
54</dl><p>
55
56<h3>Requests</h3>
57<dl>
58
59<dt><i>OV_ECTL_RATEMANAGE2_GET</i></dt>
60
61<dd><b>Argument: <a href="ovectl_ratemanage2_arg.html">struct
62ovectl_ratemanage2_arg *</a></b><br> Used to query the current
63encoder bitrate management setting.  Also used to initialize fields of
64an ovectl_ratemanage2_arg structure for use with
65OV_ECTL_RATEMANAGE2_SET.</dd><p>
66
67<dt><i>OV_ECTL_RATEMANAGE2_SET</i></dt>
68<dd><b>Argument: <a href="ovectl_ratemanage2_arg.html">struct
69ovectl_ratemanage2_arg *</a></b><br> Used to set the current
70encoder bitrate management settings to the values listed in the
71ovectl_ratemanage2_arg.  Passing a NULL pointer will disable bitrate
72management.
73</dd><p>
74
75<dt><i>OV_ECTL_LOWPASS_GET</i></dt>
76<dd><b>Argument: double *</b><br> Returns the current encoder hard-lowpass
77setting (kHz) in the double pointed to by arg.
78</dd><p>
79
80<dt><i>OV_ECTL_LOWPASS_SET</i></dt>
81<dd><b>Argument: double *</b><br> Sets the encoder hard-lowpass to the value
82(kHz) pointed to by arg. Valid lowpass settings range from 2 to 99.
83</dd><p>
84
85<dt><i>OV_ECTL_IBLOCK_GET</i></dt>
86<dd><b>Argument: double *</b><br> Returns the current encoder impulse
87block setting in the double pointed to by arg.</dd><p>
88
89<dt><i>OV_ECTL_IBLOCK_SET</i></dt> <dd><b>Argument: double *</b><br> Sets
90the impulse block bias to the the value pointed to by arg; valid range
91is -15.0 to 0.0 [default].  A negative impulse block bias will direct
92to encoder to use more bits when incoding short blocks that contain
93strong impulses, thus improving the accuracy of impulse encoding.</dd><p>
94
95<dt><i>OV_ECTL_RATEMANAGE_GET [deprecated]</i></dt>
96<dd>
97
98<b>Argument: <a href="ovectl_ratemanage_arg.html">struct
99ovectl_ratemanage_arg *</a></b><br> Old interface to querying bitrate
100management settings; deprecated after move to bit-reservoir style
101management in 1.1 rendered this interface partially obsolete.  Please
102use OV_ECTL_RATEMANGE2_GET instead.
103
104</dd><p>
105
106<dt><i>OV_ECTL_RATEMANAGE_SET [deprecated]</i></dt>
107<dd>
108<b>Argument: <a href="ovectl_ratemanage_arg.html">struct
109ovectl_ratemanage_arg *</a></b><br> Old interface to modifying bitrate
110management settings; deprecated after move to bit-reservoir style
111management in 1.1 rendered this interface partially obsolete.  Please
112use OV_ECTL_RATEMANGE2_SET instead.
113</dd><p>
114
115<dt><i>OV_ECTL_RATEMANAGE_AVG [deprecated]</i></dt>
116<dd>
117<b>Argument: <a href="ovectl_ratemanage_arg.html">struct
118ovectl_ratemanage_arg *</a></b><br> Old interface to setting
119average-bitrate encoding mode; deprecated after move to bit-reservoir
120style management in 1.1 rendered this interface partially obsolete.
121Please use OV_ECTL_RATEMANGE2_SET instead. 
122</dd><p>
123
124<dt><i>OV_ECTL_RATEMANAGE_HARD [deprecated]</i></dt>
125<dd>
126<b>Argument: <a href="ovectl_ratemanage_arg.html">struct
127ovectl_ratemanage_arg *</a></b><br> Old interface to setting
128bounded-bitrate encoding modes; deprecated after move to bit-reservoir
129style management in 1.1 rendered this interface partially obsolete.
130Please use OV_ECTL_RATEMANGE2_SET instead. 
131</dd><p>
132
133
134</dl>
135
136
137<h3>Return Values</h3> vorbis_encode_ctl() returns zero on success,
138placing any further return information (such as the result of a query)
139into the storage pointed to by <i>*arg</i>.  On error,
140vorbis_encode_ctl() may return one of the following error codes:
141
142<dl>
143
144<dt>OV_EINVAL</dt><dd>Invalid argument, or an attempt to modify a
145setting after calling <a
146href="vorbis_encode_setup_init.html">vorbis_encode_setup_init()</a>.</dd><p>
147
148<dt>OV_EIMPL</dt><dd>Unimplemented or unknown request</dd><p>
149
150</dl>
151
152<p>
153
154<br><br>
155<hr noshade>
156<table border=0 width=100%>
157<tr valign=top>
158<td><p class=tiny>copyright &copy; 2004 xiph.org</p></td>
159<td align=right><p class=tiny><a href="http://www.xiph.org/ogg/vorbis/index.html">Ogg Vorbis</a><br><a href="mailto:team@vorbis.org">team@vorbis.org</a></p></td>
160</tr><tr>
161<td><p class=tiny>libvorbisenc documentation</p></td>
162<td align=right><p class=tiny>libvorbisenc release 1.1 - 20040709</p></td>
163</tr>
164</table>
165
166
167</body>
168
169</html>
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