VCD2LXT(1) Filetype Conversion VCD2LXT(1)

vcd2lxt - Converts VCD files to interlaced or linear LXT files

vcd2lxt [VCDFILE] [LXTFILE] [option]...

Converts VCD files to interlaced or linear LXT files. Noncompressed interlaced files will provide the fastest access, linear files will provide the slowest yet have the greatest compression ratios.

Prints out statistics on all nets in VCD file in addition to performing the conversion.
Apply two-way subtraction algorithm in order to identify nets whose value changes by a constant XOR or whose value increases/decreases by a constant amount per constant unit of time. This option can reduce dumpfile size dramatically as value changes can be represented by an equation rather than explicitly as a triple of time, net, and value.
Emit data to file after being filtered through zlib (gzip).
Write out LXT in "linear" format with no backpointers. These are re-generated during initialization in gtkwave. Additionally, use libbz2 (bzip2) as the compression filter.
Store value changes greater than or equal to size bits as an index into a dictionary. Experimentation shows that a value of 18 is optimal for most cases.

Note that you should specify dumpfile.vcd directly or use "-" for stdin.

This turns on clock packing, zlib compression, and enables the dictionary encoding. Note that using no options writes out a normal LXT file.
Uses linear mode for even smaller files.

Anthony Bybell <>

lxt2vcd(1) vcd2lxt2(1) gtkwave(1)

1.3.34 Anthony Bybell