Appendix
Chunk
Chunks are structured like boxes that hold data. A chunk consists of a unique name (four characters long), data
size, data, and end marker.
The data size indicates the size of the stored raw data; it does not include the size of the chunk name, the value
field (which indicates the data size) or the end marker. The total chunk size is raw data + 16 bytes. To use the
information in a WDF file, there is no need to read the raw data in every chunk; the chunks in the file can be
scanned or skipped until the appropriate one is found.
Offset Type Identifier byte Description
0x0000 CHR ChunkType 4 Chunk name string
0x0004 UINT64 Length 8 Data size in chunk
0x000C - Data - Raw data (data size in length)
UINT EndMark 4 0xffffffff or the data’s CRC32 value
Waveform Analysis Information Chunk
Analysis information are stored in XHDR chunks. Analysis information of dual capture waveforms during dual
capturing is stored in DHDR chunks.
An analysis information chunk starts with a 4-byte “XHDR” identifier and ends with a 4-byte 0xFFFFFFFF end
mark. The eight bytes immediately after the “XHDR” identifier contains the data size (in bytes) of the analysis
information chunk. The content of the data is text information (described later), which closely resembles the
information in YOKOGAWA’s legacy WVF and HDR files.
Offset Type Identifier byte Description
0x0000 CHR ChunkType 4 Chunk type “XHDR” or ”DHDR”
0x0004 UINT64 Length 8 Data size
0x000C - Data - Analysis information (text information)
UINT EndMark 4 0xffffffff or the data’s CRC32 value
Analysis Information Overview
Analysis information data is big endian. The data in analysis information chunks is text. The line feed code is
“0x0A.”
Analysis Information Example
The following example shows the waveform file analysis information containing four channels and five history
entries.
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