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oggvorbis
The OGG/Vorbis file format, as defined by » 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.
This extension requires PHP >= 4.3.0,
» libogg >= 1.0, and
» libvorbis >= 1.0.
Information for installing this PECL extension may be found in the manual chapter titled Installation of PECL extensions. Additional information such as new releases, downloads, source files, maintainer information, and a CHANGELOG, can be located here: » http://pecl.php.net/package/oggvorbis
Table 231. OGG/Vorbis tuning options
| Option | Definition | Relevance | Default |
|---|---|---|---|
| pcm_mode | PCM byte encoding used. See constants below. | Read / Write | OGGVORBIS_PCM_S16_LE |
| rate | PCM Sampling rate. Measured in Hz. | Write only | 44100 |
| 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 only | 128000 |
| channels | Number of PCM channels. 1 == Mono, 2 == Stereo. | Write only | 2 |
| 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 only | Random |
| 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 only | array('ENCODER' => 'PHP/OggVorbis, http://pear.php.net/oggvorbis') |
The constants below are defined by this extension, and will only be available when the extension has either been compiled into PHP or dynamically loaded at runtime.
Table 232. OGG/Vorbis supports PCM encodings in the following formats
| Constant | Definition |
|---|---|
OGGVORBIS_PCM_U8 | Unsigned 8-bit PCM. |
OGGVORBIS_PCM_S8 | Signed 8-bit PCM. |
OGGVORBIS_PCM_U16_LE | Unsigned 16-bit PCM. Little Endian byte order. |
OGGVORBIS_PCM_U16_BE | Unsigned 16-bit PCM. Big Endian byte order. |
OGGVORBIS_PCM_S16_LE | Signed 16-bit PCM. Little Endian byte order. |
OGGVORBIS_PCM_S16_BE | Signed 16-bit PCM. Big Endian byte order. |
Table of Contents
- Usage — Examples on using the ogg:// wrapper.