Decoder(3pm)

NAME
Ogg::Vorbis::Decoder - An object-oriented Ogg Vorbis to decoder

SYNOPSIS
  use Ogg::Vorbis::Decoder;
  my $decoder = Ogg::Vorbis::Decoder->open("song.ogg");
  my $buffer;
  while ((my $len = $decoder->read($buffer) > 0) {
    # do something with the PCM stream
  }

  OR

  open OGG, "song.ogg" or die $!;
  my $decoder = Ogg::Vorbis::Decoder->open(\*OGG);

  OR

  # can also be IO::Socket or any other IO::Handle subclass.
  my $fh = IO::Handle->new("song.ogg");
  my $decoder = Ogg::Vorbis::Decoder->open($fh);

DESCRIPTION
This module provides users with Decoder objects for Ogg Vorbis files. One can read data in PCM format from the stream, seek by raw bytes, pcm samples, or time, and gather decoding-specific information not provided by Ogg::Vorbis::Header. Currently, we provide no support for the callback mechanism provided by the Vorbisfile API; this may be included in future releases.

CONSTRUCTOR

  "open ($filename)"
Opens an Ogg Vorbis file for decoding. It opens a handle to the file or uses an existing handle and initializes all of the internal vorbis decoding structures. Note that the object will maintain open file descriptors until the object is collected by the garbage handler. Returns "undef" on failure.

INSTANCE METHODS

  "read ($buffer, [$size, $word, $signed])"
Reads PCM data from the Vorbis stream into $buffer. Returns the number of bytes read, 0 when it reaches the end of the stream, or a value less than 0 on error.

The optional parameters include (with corresponding default values):

"size = 4096" "word = 2" "signed = 1"

Consult the Vorbisfile API (http://www.xiph.org/ogg/vorbis/doc/vorbisfile/reference.html) for an explanation of the various values.

  "sysread ($buffer, [$size, $word, $signed])"
An alias for "read"

  "raw_seek ($pos)"
Seeks through the compressed bitstream to the offset specified by $pos in raw bytes. Returns 0 on success.

  "pcm_seek ($pos, [$page])"
Seeks through the bitstream to the offset specified by $pos in pcm samples. The optional $page parameter is a boolean flag that, if set to true, will cause the method to seek to the closest full page preceding the specified location. Returns 0 on success.

  "time_seek ($pos, [$page])"
Seeks through the bitstream to the offset specified by $pos in seconds. The optional $page parameter is a boolean flag that, if set to true, will cause the method to seek to the closest full page preceding the specified location. Returns 0 on success.

  "current_bitstream ()"
Returns the current logical bitstream of the decoder. This matches the bitstream paramer optionally passed to "read". Useful for saving a bitstream to jump to later or to pass to various information methods.

  "bitrate ([$stream])"
Returns the average bitrate for the specified logical bitstream. If $stream is left out or set to -1, the average bitrate for the entire stream will be reported.

  "bitrate_instant ()"
Returns the most recent bitrate read from the file. Returns 0 if no read has been performed or bitrate has not changed.

  "streams ()"
Returns the number of logical bitstreams in the file.

  "seekable ()"
Returns non-zero value if file is seekable, 0 if not.

  "serialnumber ([$stream])"
Returns the serial number of the specified logical bitstream, or that of the current bitstream if $stream is left out or set to -1.

  "raw_total ([$stream])"
Returns the total number of bytes in the physical bitstream or the specified logical bitstream.

  "pcm_total ([$stream])"
Returns the total number of pcm samples in the physical bitstream or the specified logical bitstream.

  "time_total ([$stream])"
Returns the total number of seconds in the physical bitstream or the specified logical bitstream.

  "raw_tell ()"
Returns the current offset in bytes.

  "pcm_tell ()"
Returns the current offset in pcm samples.

  "time_tell ()"
Returns the current offset in seconds.

REQUIRES
libogg, libvorbis, libogg-dev, libvorbis-dev

CURRENT AUTHOR
Dan Sully <daniel@cpan.org>

AUTHOR EMERITUS
Dan Pemstein <dan@lcws.org>

COPYRIGHT
Copyright (c) 2004-2010, Dan Sully. All Rights Reserved.

Copyright (c) 2003, Dan Pemstein. All Rights Reserved.

This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. A copy of this license is included with this module (LICENSE.GPL).

SEE ALSO
Ogg::Vorbis::Header