WriteFile
(clip, string filename, string expression1 [, string
expression2 [, ...]], bool "append", bool "flush")
WriteFileIf
(clip, string filename, string expression1 [, string
expression2 [, ...]], bool "append", bool "flush")
WriteFileStart
(clip, string filename, string expression1
[, string expression2 [, ...]], bool "append")
WriteFileEnd
(clip, string filename, string expression1
[, string expression2 [, ...]], bool "append")
WriteFile
evaluates each expressionN, converts the result to a string and puts the concatenated results into a file, followed by a newline.
The "run-time" variable current_frame is set so that you
can use it in an "expression"
(this works similar as with ScriptClip, look there in the docu for more infos).
current_frame is set to -1 when the script is loaded and to -2 when
the script is closed.
WriteFile
evaluates the ''expression''s
and generates output for each frame rendered
by the filter. WriteFileIf
is
similar, but generates output only if the first expression is true.
In both cases, there is no output at script opening or closure. Note
that since output is produced only for ''rendered'' frames, there will be no
output at all if the result of the filter is not used in deriving the final
result of the script.
WriteFileStart
and WriteFileEnd
generate
output only on script opening and closure respectively,
there is no action on each frame. In both cases, the
''expression''s are evaluated exactly once, at the location of the filter in the
script.
When append = true, the result(s) will be appended to any existing file. The default for
append is always true, except for WriteFileStart
(here it is false).
When flush = true, the file is closed and reopened after each operation so you can see the result immediately (this may be slower). The default for
flush (WriteFile
and WriteFileIf
) is true.
For WriteFileStart
and WriteFileEnd
, the file is always closed immediately after writing.
filename = "c:\myprojects\output.txt" # create a test video to get frames Version() # the expression here is only a variable, which is evaluated and put in the file # you will get a file with the framenumber in each line WriteFile(filename, "current_frame") # this line is written when the script is opened WriteFileStart(filename, """ "This is the header" """) # and this when the script is closed WriteFileEnd(filename, """ "Now the script was closed" """)
Look how you can use triple-quotes to type a string in a string!
If the expression cannot be evaluated, the error message is written instead.
In case this happens with the If-expression in WriteFileIf
the result is assumed to be true
.
# will result in "I don't know what "this" means" WriteFile(filename, "this is nonsense")
... with this example you can see how to use the "runtime function" AverageLuma:
# create a test video to get different frames Version.FadeIn(50).ConvertToYV12 # this will print the frame number, a ":" and the average luma for that frame colon = ": " WriteFile("F:\text.log", "current_frame", "colon", "AverageLuma")
Or maybe you want the actual time printed too:
# create a test video to get different frames Version.FadeIn(50).ConvertToYV12 # this will print the frame number, the current time and the average luma for that frame # the triple quotes are necessary to put quotes inside a string WriteFile(last, filename, "current_frame", """ time(" %H:%M:%S") """, "AverageLuma")
In WriteFileIf
the FIRST expression is expected to be boolean (true
or false). Only if it is TRUE the other expressions are evaluated and the line is printed.
(Remember: && is AND, || is OR, == is EQUAL, != is NOT EQUAL) That way you can
omit lines completely from your file.
# create a test video to get different frames Version.FadeIn(50).ConvertToYV12 # this will print the frame number, but only of frames where AverageLuma is between 30 and 60 WriteFileIf(last, filename, "(AverageLuma>30) && (AverageLuma<60)", "current_frame", """ ":" """, "AverageLuma")
Changes:
v2.60 | Number of expressions changed from 16 to nearly unlimited. |
v2.55 | Initial release. |
$Date: 2010/01/06 16:01:28 $