Inside Macintosh: Sound

| Previous | Chapter contents | Chapter top | Section top | Next |

Legacy Documentclose button

Important: Sound Input Manager is deprecated as of Mac OS X v10.5. For new audio development in Mac OS X, use Core Audio. See the Audio page in the ADC Reference Library.

Form Chunks

All sound files begin with a Form Chunk. This chunk defines the type and size of the file and can be thought of as enclosing the remaining chunks in the sound file. The ContainerChunk data type defines a Form Chunk.

TYPE ContainerChunk =
RECORD
    ckID:           ID;             {'FORM'}
    ckSize:         LongInt;        {number of bytes of data}
    formType:       ID;             {type of file}
END;

ckID

The ID of this chunk. For a Form Chunk, this ID is 'FORM' .

ckSize

The size of the data portion of this chunk. Note that the data portion of a Form Chunk is divided into two parts, formType and the remaining chunks of the sound file.

formType

The type of audio file. For AIFF files, formType is 'AIFF' . For AIFF-C files, formType is 'AIFC' .

The size of an entire sound file is ckSize+8 , because the ckSize field incorporates the size of all chunks of the sound file, except the sizes of the ckID and ckSize fields of the Form Chunk itself.


© 1999 Apple Computer, Inc.

Inside Macintosh: Sound

| Previous | Chapter contents | Chapter top | Section top | Next |

Legacy Documentclose button

Important: Sound Input Manager is deprecated as of Mac OS X v10.5. For new audio development in Mac OS X, use Core Audio. See the Audio page in the ADC Reference Library.