Digital Cinema Arts-Houdini CHOP File Out Extension

Houdini CHOP File Out Extension

The File Out CHOP will write data to disk in a user specified format.
The first input will accept up to 65535 channels.
The second input provides a gate/trigger signal (to enable, check the Use Event Gate).

Features:

65535 channels of data
"Time stamp" insertion w/offset to accommodate any frame range (for ASCII files only)
Text line comment into "header" (for ASCII files only)
Event gate input for toggling data write
ASCII or binary format
"C" style format string specifier
Option to echo data to the console

Example #1
A simple example writing an ASCII file with 3 data channels.

Example #2
An example of writing to a binary file with 8 channels of data (4 constants and 4 waveforms). The second input, the Event Gate, is being triggered by an oscillator to toggle the data being written to disk at periodic intervals.

Example #3
An example writing to an ASCII file with a "header" included and inserting a time stamp into the beginning of the data line. The format string is demonstrating a number of different ways to format the data; in addition there's an "EOL" at the end of the line should one want to parse for that type of token rather \n, \r, or NULL. The manner in which you format the data is entirely up to you and your specific requirements.

Example #4
This example writes 16 channels of data to an ASCII file and is using 2 File Out CHOPs, writing to the files at the same time but from to different nodes in the CHOP network. A "time stamp" is inserted into the beginning of the data line.

Source Code:
Doxygen Documentation

Download:

Linux:
Houdini version 8.0
file_out_demo_Linux.tar.gz
CHOP_file_out.so.tar.gz (DSO only)

Windows:
Houdini version 8.0
file_out_demo_WIN.tar.gz
CHOP_file_out.dll.tar.gz (DLL only)

Note: Set the $HOUDINI_PATH variable to include the demo directory, i.e:
setenv HOUDINI_PATH $HFS/houdini:$HOME/houdini8.0:$JOB/houdini:./houdini

Troubleshooting tips:
From the Houdini textport, type "dsoinfo -h " and look for the file_out DSO/DLL under the CHOP section.
/ -> dsoinfo -h >> CHOPs handle /usr/hfs/houdini/dso/CHOP_IKHandle.so image /usr/hfs/houdini/dso/CHOP_Image.so inversekin /usr/hfs/houdini/dso/CHOP_InverseKin.so particle /usr/hfs/houdini/dso/CHOP_Particle.so pretransform /usr/hfs/houdini/dso/CHOP_PreTransform.so spatial /usr/hfs/houdini/dso/CHOP_SpatialAudio.so audioperiod /usr/hfs/houdini/dso/CHOP_AudioPeriod.so file_out ./houdini/dso/CHOP_file_out.so voicesync /usr/hfs/houdini/dso/CHOP_VoiceSync.so / ->

The interface:

Filename:
The name of the data file

File Format:
Select the format for the file: ASCII or binary

Format Specifier:
The format specifier for the ACSII file format (see below).

Include header (ASCII only):
When checked, a header will be written to the file including the date/time, and the contents of the Header field

Header:
A single line of text written to the header section of the data file

Insert Time Stamp (ASCII only):
When checked, a time stamp is inserted into the beginning of the data line.

Add offset to time stamp:
When checked, the value in the Offset field will be added to the time.

Offset (Frames)
The amount of offset to add to the time value for the time stamp.

Use Event Gate:
When checked, the data will only be written to the file when the second input's value is non-zero

Echo Data to Console:
When checked, the data will only be printed to the system console

The "Format Specifier" string follows the "C" conventions.

From the IRIX man page(s):

f The floating arg is converted to decimal notation in the style [-]ddd.ddd, where the number of digits after the decimal-point character [see setlocale(3C)] is equal to the precision specification. If the precision is missing, it is taken as 6; if the precision is zero and the # flag is not specified, no decimal-point character appears. If a decimal-point character appears, at least one digit appears before it. The value is rounded to the appropriate number of digits.
e, E The floating arg is converted to the style [-]d.ddde+dd, where there is one digit before the decimal-point character (which is nonzero if the argument is nonzero) and the number of digits after it is equal to the precision. If the precision is missing, it is taken as 6; if the precision is zero and the # flag is not specified, no decimal-point character appears. The value is rounded to the appropriate number of digits. The E conversion character will produce a number with E instead of e introducing the exponent. The exponent always contains at least two digits. If the value is zero, the exponent is zero.
g, G The floating arg is converted in style f or e (or in style E in the case of a G conversion character), with the precision specifying the number of significant digits. If the precision is zero, it is taken as one. The style used depends on the value converted; style e (or E) will be used only if the exponent resulting from the conversion is less than -4 or greater than or equal to the precision. Trailing zeros are removed from the fractional part of the result; a decimal-point character appears only if it is followed by a digit.