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<?xml version="1.0" encoding="iso-8859-1"?>
<!-- $Revision: 1.6 $ -->
<!-- Purpose: utilspec.audio -->
<!-- Membership: pecl, external -->
<reference id="ref.oggvorbis">
<title>oggvorbis</title>
<titleabbrev>OGG/Vorbis</titleabbrev>
<partintro>
<section id="oggvorbis.intro">
&reftitle.intro;
<simpara>
The OGG/Vorbis file format, as defined by <ulink
url="&url.ogg.vorbis;">&url.ogg.vorbis;</ulink>, is a scheme
for compressing audio streams by multiple factors with a minimum of
quality loss. This extension adds Ogg Vorbis support to PHP's
<link linkend="wrappers">URL Wrappers</link>. When used in read mode,
compressed OGG/Vorbis data is expanded to raw PCM audio in one of six PCM
encoding formats listed below.
</simpara>
</section>
<section id="oggvorbis.requirements">
&reftitle.required;
<para>
This extension requires <literal>PHP >= 4.3.0</literal>,
<ulink url="&url.ogg.vorbis.downloads;">libogg</ulink> >= 1.0, and
<ulink url="&url.ogg.vorbis.downloads;">libvorbis</ulink> >= 1.0.
</para>
</section>
<section id="oggvorbis.configuration">
&reftitle.runtime;
&no.config;
</section>
&reference.oggvorbis.configure;
&reference.oggvorbis.contexts;
&reference.oggvorbis.constants;
</partintro>
<refentry id="oggvorbis.usage">
<refnamediv>
<refname>Usage</refname>
<refpurpose>
Examples on using the ogg:// wrapper.
</refpurpose>
</refnamediv>
<refsect1 role="examples">
&reftitle.examples;
<para>
<example>
<title>Reading an OGG/Vorbis file</title>
<programlisting role="php">
<![CDATA[
<?php
dl("oggvorbis.so");
/* By default, ogg:// will decode to Signed 16-bit Little Endian */
$fp = fopen('ogg://myaudio.ogg', 'r');
/* Collect some information about the file. */
$metadata = stream_get_meta_data($fp);
/* Inspect the first song (usually the only song,
but OGG/Vorbis files may be chained) */
$songdata = $metadata['wrapper_data'][0];
echo "OGG/Vorbis file encoded by: {$songdata['vendor']}\n.";
echo " {$songdata['channels']} channels of {$songdata['rate']}Hz sampling encoded at {$songdata['bitrate_nominal']}bps.\n";
foreach($songdata['comments'] as $comment) {
echo " $comment\n";
}
while ($audio_data = fread($fp, 8192)) {
/* Do something with the PCM audio we're extracting from the OGG.
Copying to /dev/dsp is a good target on linux systems,
just remember to setup the device for your sampling mode first. */
}
fclose($fp);
?>
]]>
</programlisting>
</example>
</para>
<para>
<example>
<title>Encode an audio file to OGG/Vorbis</title>
<programlisting role="php">
<![CDATA[
<?php
dl('oggvorbis.so');
$context = stream_context_create(array('ogg'=>array(
'pcm_mode' => OGGVORBIS_PCM_S8, /* Signed 8bit audio */
'rate' => 44100, /* 44kHz CD quality */
'bitrate' => 0.5, /* Midquality VBR */
'channels' => 1, /* Mono */
'serialno' => 12345))); /* Unique within our stream */
/* Open file for appending. This will "chain" a second OGG stream at the end of the first. */
$ogg = fopen('ogg://mysong.ogg', 'a', false, $context);
$pcm = fopen('mysample.pcm', 'r');
/* Compress the raw PCM audio from mysample.pcm into mysong.ogg */
stream_copy_to_stream($pcm, $ogg);
fclose($pcm);
fclose($ogg);
?>
]]>
</programlisting>
</example>
</para>
</refsect1>
</refentry>
</reference>
<!-- Keep this comment at the end of the file
Local variables:
mode: sgml
sgml-omittag:t
sgml-shorttag:t
sgml-minimize-attributes:nil
sgml-always-quote-attributes:t
sgml-indent-step:1
sgml-indent-data:t
sgml-parent-document:nil
sgml-default-dtd-file:"../../../manual.ced"
sgml-exposed-tags:nil
sgml-local-catalogs:nil
sgml-local-ecat-files:nil
End:
vim600: syn=xml fen fdm=syntax fdl=2 si
vim: et tw=78 syn=sgml
vi: ts=1 sw=1
-->
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