MediaWare Solutions MPEG SDK

An MpegDecoder knows how to navigate and decode an MPEG stream.

It uses the global singleton object error defined in Basic.h for error reporting. When an error occurs during of of its operations, an error will be pushed and error.empty() will be false. The error can then be retrieved by error.pop().

Source:

MpegDecoder.h:38

public MpegDecoder ( ) ;

Default constructor.

Constructs a MpegDecoder with no file. Most functions except the openFile function will push an error.

public MpegDecoder ( const string & filename ,
                     CallBack cb = 0 ) ;

Construct a MpegDecoder for the given file.

public ~ MpegDecoder ( ) ;

Destructor.

public static void setAuxFilesPath ( const string & aux_path ) ;

Set the path for loading and saving of auxiliary files (e.g. .mpf and .idx).

Auxiliary files are searched in the following order:

 1. aux_path (if set)
 2. where the mpeg file is
 3. where the program is executing from
 4. $TMP in win32 or /tmp in UNIX
 

If aux_path is set to "NULL", auxiliary files will not be used.

public void openFile ( const string & filename ,
                       CallBack cb = 0 ) ;

Open a new file with this decoder and reset all variables.

public bool hasVideo ( ) const ;

Does this MPEG contain a video stream.

public bool hasAudio ( ) const ;

Does this MPEG contain an audio stream.

public const MpegInfo & getMpegInfo ( CallBack cb = 0 ) ;

Return an MpegInfo object containing the information about the current MPEG.

The MPEG is only ever queried once about its information, and the result stored internally for reuse.

public static MpegHeaderInfo getMpegHeaderInfo ( const string & pathname ) ;

Static method to return an MpegHeaderInfo object containing all the information about a particular MPEG file.

public static MpegInfo getMpegInfo ( const string & pathname ,
                                     CallBack cb = 0 ) ;

Static method to return an MpegInfo object containing all the information about a particular MPEG file.

public const string & getFilename ( ) const ;

Return the complete pathname with filename.

public int getLastFrame ( ) ;

Return the number of frames in the MPEG.

Exception:

mws.exception.MWSException if there was an error in the code

public int getFrameNumber ( const TimeCode & timecode ) const ;

Return the frame number for the given timecode.

public TimeCode getTimeCode ( int frame ) const ;

Return the SMPTE timecode for the given frame number.

public float getFrameRate ( ) ;

Return the frame rate of the MPEG.

public float getFramesPerSecond ( ) ;

Return the number of frames/sec for the MPEG.

public int getImageWidth ( float zoom = 1 . 0 ) ;

Return the width of the frames returned by getRGBImage() etc.

Note that image width is affected by the zoom factor and whether useAspectRatio() was set to true or false.

public int getImageHeight ( float zoom = 1 . 0 ) ;

Return the height of the frames returned by getRGBImage() etc.

Note that image height is affected by the zoom factor and whether useAspectRatio() was set to true or false.

public float getTotalTime ( ) ;

Return total time in seconds.

public int getNFrames ( ) ;

Return total number of frames.

public fpos_t picOffset ( int frame ) const ;

Get the Offset of the picture with the given frame number.

public int picFrameNum ( fpos_t offset ) const ;

Get the frame number of the first picture after offset.

Return -1 if not found.

public fpos_t prevIOffset ( fpos_t offset ) const ;

Get offset of the previous I frame.

Return 0 if not found.

public fpos_t nextIOffset ( fpos_t offset ) const ;

Get offset of the next I frame.

Return 0 if not found.

public void setUseAspectRatio ( bool flag ) ;

Set whether to use the video's aspect ratio when retrieving an image from an MPEG-2 video.

If set to true, getRGBImage() etc will shape the output image so that its width and height has the same ratio as the aspect ratio nominated in the MPEG. If set to false, the extracted image has the same width and height ratio as the pixels in the video. The default setting is false.

public void setDeinterlace ( bool flag ) ;

Set whether to deinterlace the image when retrieving an image from an MPEG-2 video.

The default is false.

public const unsigned char * getRGBImage ( int frame ,
                                           float zoom = 1 . 0 ) const ;

Return an array of 24 bit unsigned chars containing the pixels of the given image, scaled and in the format of RGB.

public const unsigned char * getBGRImage ( int frame ,
                                           float zoom = 1 . 0 ) const ;

Return an array of 24 bit unsigned chars containing the pixels of the given image, scaled and in the format of BGR.

public const unsigned char * getXRGBImage ( int frame ,
                                            float zoom = 1 . 0 ) const ;

Return an array of 32 bit unsigned chars containing the pixels of the given image, scaled and in the format of XRGB.

public const unsigned char * getXBGRImage ( int frame ,
                                            float zoom = 1 . 0 ) const ;

Return an array of 32 bit unsigned chars containing the pixels of the given image, scaled and in the format of XBGR.

public const unsigned char * getRGBXImage ( int frame ,
                                            float zoom = 1 . 0 ) const ;

Return an array of 32 bit unsigned chars containing the pixels of the given image, scaled and in the format of RGBX.

public const unsigned char * getBGRXImage ( int frame ,
                                            float zoom = 1 . 0 ) const ;

Return an array of 32 bit unsigned chars containing the pixels of the given image, scaled and in the format of BGRX.

public const PCMBite * getPCMBite ( int frame ) ;

Return the first PCMBite after video frame frame.

A PCMBite consists of N channels of M 16-bit samples. N is obtained from the function PCMBite::nch() and M is obtained from the function PCMBite::getNumSamples(). The data in each channel is obtained with operator[](int ch).

Normally, a single call to getPCMBite(frame) is followed by a series of getNextPCMBite() and currentPCMBiteFrame() calls in a loop.