Cue chunk (of a Wave file)


The cue chunk specifies cues / markers in the wave file, such as the beginning of a verse or the end of a solo.

A cue chunk in the Wave file format has the following structure.

Byte sequence descriptionLength in bytesStarts at byte in the chunkValue
chunk ID40x00The ASCII character string "cue " (note the space)
size40x04The size of the cue chunk (number of bytes) less 8 (less the "chunk ID" and the "size")
number of cue points40x08The number of cue points in the list of cue points that follows
datavarious0x0CA list of cue points. Each cue point uses 24 bytes of data

The cue chunk is optional, but, if it exists, at most one cue chunk per file is allowed. Thus, the single cue chunk should contain all cue points in the file.

A cue point uses 24 bytes of data as follows.

Byte sequence descriptionLength in bytesStarts at byte in the cue pointValue
ID40x00A unique number for the point used by other chunks to identify the cue point. For example, a playlist chunk creates a playlist by referring to cue points, which themselves define points somewhere in the file
position40x04If there is no playlist chunk, this value is zero. If there is a playlist chunk, this value is the sample at which the cue point should occur
data chunk ID40x08Either "data" or "slnt" depending on whether the cue occurs in a data chunk or in a silent chunk
chunk start40x0CThe position of the start of the data chunk that contains the cue point. If there is a wave list chunk, this value is the byte position of the chunk that contains the cue. If there is no wave list chunk, there is only one data chunk in the file and this value is zero
block start40x10The byte position of the cue in the "data" or "slnt" chunk. If this is an uncompressed PCM file, this is counted from the beginning of the chunk's data. If this is a compressed file, the byte position can be counted from the last byte from which one can start decompressing to find the cue
sample start40x14The position of the cue in number of bytes from the start of the block

See also:
Wave file format

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