XCII. oggvorbis

Einführung

The OGG/Vorbis file format, as defined by http://www.vorbis.com/ and http://www.vorbis.com/, 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 URL Wrappers. When used in read mode, compressed OGG/Vorbis data is expanded to raw PCM audio in one of six PCM encoding formats listed below.

Anforderungen

This extension requires PHP >= 4.3.0, libogg >= 1.0, and libvorbis >= 1.0.

Laufzeit Konfiguration

Diese Erweiterung definiert keine Konfigurationseinstellungen in der php.ini.

Installation

oggvorbis is installed through the usual PECL package installation process.

  • $ pear install oggvorbis

  • Copy the resulting oggvorbis.so to an appropriate location and add extension=oggvorbis.so to your php.ini file or load it dynamically in your PHP script using dl('oggvorbis.so');

Context options

Tabelle 1. OGG/Vorbis tuning options

OptionDefinitionRelevanceDefault
pcm_modePCM byte encoding used. See constants below.Read / WriteOGGVORBIS_PCM_S16_LE
ratePCM Sampling rate. Measured in Hz.Write only44100
bitrate Vorbis Average Bitrate Encoding / Variable Bitrate Encoding. Measured in bps (ABR) or Quality level (VBR: 0.0 to 1.0). 128000 ABR is rough equal to 0.4 VBR. Write only128000
channelsNumber of PCM channels. 1 == Mono, 2 == Stereo.Write only2
serialno Serial Number of stream within file. Must be unique within file. Because of the potential to select a duplicate serial number within a chained file, make efforts to manually assign unique numbers when encoding. Write onlyRandom
comments Associative array of file comments. Will be translated to strtoupper($name) . "=$value". Note: This context option is not available in oggvorbis-0.1 Write onlyarray('ENCODER' => 'PHP/OggVorbis, http://pear.php.net/oggvorbis')

Vordefinierte Konstanten

Folgende Konstanten werden von dieser Erweiterung definiert und stehen nur zur Verfügung, wenn die Erweiterung entweder statisch in PHP kompiliert oder dynamisch zur Laufzeit geladen wurde.

Tabelle 2. OGG/Vorbis supports PCM encodings in the following formats

ConstantDefinition
OGGVORBIS_PCM_U8Unsigned 8-bit PCM.
OGGVORBIS_PCM_S8Signed 8-bit PCM.
OGGVORBIS_PCM_U16_LEUnsigned 16-bit PCM. Little Endian byte order.
OGGVORBIS_PCM_U16_BEUnsigned 16-bit PCM. Big Endian byte order.
OGGVORBIS_PCM_S16_LESigned 16-bit PCM. Little Endian byte order.
OGGVORBIS_PCM_S16_BESigned 16-bit PCM. Big Endian byte order.
Inhaltsverzeichnis
Usage --  Examples on using the ogg:// wrapper.

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Generated: 2007-01-26 17:57:11