NAME

       Video::Info::MPEG - Basic MPEG bitstream attribute parser.

SYNOPSIS

         use strict;
         use Video::Info::MPEG;

         my $video = Video::Info::MPEG->new( -file => $filename );
         $video->probe();

         print $file->type;          ## MPEG

         ## Audio information
         print $file->acodec;        ## MPEG Layer 1/2
         print $file->acodecraw;     ## 80
         print $file->achans;        ## 1
         print $file->arate;         ## 128000 (bits/sec)
         print $file->astreams       ## 1

         ## Video information
         printf "%0.2f", $file->fps  ## 29.97
         print $file->height         ## 240
         print $file->width          ## 352
         print $file->vstreams       ## 1
         print $file->vcodec         ## MPEG1
         print $file->vframes        ## 529
         print $file->vrate          ## 1000000 (bits/sec)

DESCRIPTION

       The Moving Picture Experts Group (MPEG) is a working group in charge of the development of
       standards for coded representation of digital audio and video.

       MPEG audio and video clips are ubiquitous but using Perl to programmatically collect
       information about these bitstreams has to date been a kludge at best.

       This module parses the raw bitstreams and extracts information from the packet headers.
       It supports Audio, Video, and System (multiplexed audio and video) packets so it can be
       used on nearly every MPEG you encounter.

METHODS

       Video::Info::MPEG is a derived class of Video::Info, a factory module "designed to meet
       your multimedia needs for many types of files".

       new( -file => FILE )
           Constructor.  Requires the -file argument and returns an Video::Info::MPEG object.

       probe()
           Parses the bitstreams in the FILE provided to the constructor.  Returns 1 on success
           or 0 if the FILE could not be parsed as a valid MPEG audio, video, or system stream.

INHERITED METHODS

       These methods are inherited from Video::Info.  While Video::Info may have changed since
       this documentation was written, they are provided here for convenience.

       type()
           Returns the type of file.  This should always be MPEG.

       comments()
           Returns the contents of the userdata MPEG extension.  This often contains information
           about the encoder software.

   Audio Methods
       astreams()
           Returns the number of audio bitstreams in the file.  Usually 0 or 1.

       acodec()
           Returns the audio codec

       acodecraw()
           Returns the hexadecimal audio codec.

       achans()
           Returns the number of audio channels.

       arate()
           Returns the audio rate in bits per second.

   Video Methods
       vstreams()
           Returns the number of video bitstreams in the file.  Usually 0 or 1.

       fps()
           Returns the floating point number of frames per second.

       height()
           Returns the number of vertical pixels (the video height).

       width()
           Returns the number of horizontal pixels (the video width).

       vcodec()
           Returns the video codec (e.g. MPEG1 or MPEG2).

       vframes()
           Returns the number of video frames.

       vrate()
           Returns the video bitrate in bits per second.

EVIL DIRECT ACCESS TO CLASS DATA

       So you secretly desire to be the evil Spock, eh?  Well rub your goatee and read on.

       There are some MPEG-specific attributes that don't yet fit nicely into Video::Info.  I am
       documenting them here for the sake of completeness.

       Note that if you use these, you may have to make changes when new versions of this package
       are released.  There will be elegant ways to access them in the future but we wanted to
       get this out there.

       These apply to audio bitstreams:

       version
           The MPEG version.  e.g. 1, 2, or 2.5

       layer
           The MPEG layer.  e.g. 1, 2, 3.

       mode
           The audio mode.  This is one of:

             Mono
             Stereo
             Dual Channel
             Intensity stereo on bands 4-31/32
             Intensity stereo on bands 8-31/32
             Intensity stereo on bands 12-31/32
             Intensity stereo on bands 16-31/32
             Intensity stereo off, M/S stereo off
             Intensity stereo on, M/S stereo off
             Intensity stereo off, M/S stereo on
             Intensity stereo on, M/S stereo on

       emphasis
           The audio emphasis, if any.

             No Emphasis
             50/15us
             Unknown
             CCITT J 17
             Undefined

       sampling
           The sampling rate (e.g. 22050, 44100, etc.)

       protect
           The value of the protection bit.  This is used to indicate copying is prohibited but
           is different than copyright().

           These apply to video:

       aspect
           The aspect ratio if the ratio falls into one of the defined standards.  Otherwise,
           it's Reserved.

             Forbidden
             1/1 (VGA)
             4/3 (TV)
             16/9 (Large TV)
             2.21/1 (Cinema)
             Reserved

AUTHORS

       Benjamin R. Ginter, <bginter@asicommunications.com> Allen Day, <allenday@ucla.edu>

COPYRIGHT

        Copyright (c) 2001-2002
        Aladdin Free Public License (see LICENSE for details)
        Benjamin R. Ginter <bginter@asicommunications.com>, Allen Day <allenday@ucla.edu>

SEE ALSO

       Video::Info Video::Info::RIFF Video::Info::ASF