CMP3Info - Implementation for Retrieving Information about MP3 Files

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• Download source - 5.5 KB

Introduction

Ever wanted to make a program to organize your MP3s, or just wanted to implement a feature in your existing application for viewing details about an MP3 file? If so, then the CMP3Info class is for you. It provides a simple method of accessing an MP3's ID3 tag (artist, title, album...) as well as several details concerning the MP3 data itself--the length of the song, the MPEG encoding type, bit rate, sample rate, channel mode, etc. Simply put, you can retrieve all the information you need about an MP3 file, except for the MP3 data itself... :), by using the intuitive interface provided by the CMP3Info class.

An excerpt from the header is shown below, describing the main functions of the class:

CMP3Info(CString strFile = "");         // constructor, calls Open if 
virtual ~CMP3Info();                    //    strFile is not ""

// operations
BOOL Open(CString strFile);	        // opens a file

// writes or clears the ID3v1 tag to (the/a) file
BOOL WriteID3V1(CString strDestFile, BOOL bClear...);	

void Clear();

void SetArtist(CString strArtist);      // self-explanatory, eh?
void SetTitle(CString strTitle);
void SetAlbum(CString strAlbum);
void SetComment(CString strComment);
void SetYear(CString strYear);
void SetTrack(int nTrack);

// see the global array in MP3Info.h for a list of genre
void SetGenreIndex(int nGenre); 

// attributes
// get the name of the file that was Open'd
CString GetFileName() const; 

// retrieve a bitmask of valid parts of the MP3 (frames/ID3 tag)
DWORD GetValidity() const;	  

CString GetArtist() const;
CString GetTitle() const;
CString GetAlbum() const;
CString GetComment() const;
CString GetYear() const;
int GetTrack() const;
int GetGenreIndex() const;

UINT GetNumFrames() const;
UINT GetLength() const;

// see the enumerations for more info
ENMPEGVER GetMPEGVersion() const; 

int GetMPEGLayer() const;
BOOL HasCRC() const;
int GetBitRate() const;
int GetSampleRate() const;
ENCHANNELMODE GetChannelMode() const;
ENEMPHASIS GetEmphasis() const;
BOOL IsCopyrighted() const;
BOOL IsOriginal() const;

// functions
// get string for a genre index in the array
static CString GetGenreString(int nIndex);

// create a string 'mm:ss' from the length
static CString GetLengthString(int nSeconds);

As you can see, the class is pretty simple, and is rather small.

Notes

• A Unicode version hasn't yet been implemented
• The algorithm for retrieving the MP3 frame information is mostly taken from MPEG Audio Frame Header
• NOT ALL TYPES OF MP3 FILES HAVE BEEN THOROUGHLY TESTED
• USE AT YOUR OWN RISK, I AM NOT LIABLE FOR DAMAGES

History

• 12^th June, 2002 - Updated demo to include missing .rc file

License

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