Variables

Variables are used to adapt and alter your workflow jobs to fit your output needs and incoming media. A variable is represented by a text string encapsulated with the percentage (%) character: %f_fps%, %username%, %s_original_name% etc… FFAStrans variables are always prefixed with a “s_” (string), “i_” (integer) or “f_” (float):

%s_v_codec% —> DNxHD120
%i_height% —> 1080
%f_fps% —> 29,97

FFAStrans has 3 kind of variables: Generic inbuilt variables, special inbuilt variables and user variables.

These variables are automatically populated. If variable cannot be populated, they will mostly have an empty string or a zero (0), (e.g: height or width for an audio file, number of audio channels for a video file, mxf version for a quicktime file, etc). FFAStrans has 5 types of generic inbuilt variables :

1. Media Variables
2. File Variables
3. Time Variables
4. OS Variables
5. FFAStrans Variable

Variables are generally populated on the fly when needed.

You can call all these generic inbuilt variables when you want and insert it by pressing the arrow-button next to a text field. All fields that has an arrow next to it supports variables.

Media properties are derived from the original input file. Different types of media can contain different kind of properties

Video Variables Only

%s_last_enc_cmd%

The latest calculated

Metadata Variables

File properties are derived from the original input file. ALL files has these properties so they will allways be populated with data.

This gives us the following different contents of the two variables:
%s_pickup_file% = c:\shortcut.lnk
%s_original_full% = \\server\share\cool.mp4

These variables, also called system enviroments, are the ones that resides within the OS independent of FFAStrans. But all can be utilized within FFAStrans. F.ex. the variable %username% is a part of the OS variables. OS variables are in fact statics(see user variable/statics) that don't change from job to job, or workflow to workflow.

These variables are specific and depend of each system. You can find the list of all variables here : https://en.wikipedia.org/wiki/Environment_variable#Windows

We can find for example %APPDATA% –>C:\Users\Share\AppData\Roaming.
Or %windir% –> C:\Windows
Etc.

These are a selection of time variables read from the system time.

These are variables generated by FFAStrans. F.ex. %s_wf_name% holds the name of the workflow on where the job runs.

There is currently one variable that behave a bit different than others:

%s_original_path~n% = Folder name n-steps backwards. (This variable supports minus notation for retrieving path names from the right side.)

%s_source% represent the input file for any processor. It can be altered using the “Populate variables”-node.

%s_success% represent the success message upon job completion. It can be altered using the “Populate variables”-node.

In this example, the objective is to ensure that the input file has a video stream to perform the H264 encoding. Otherwise a message in the status monitor and in Webinterface's jobs list will appear. In this particular workflow, each branch leads to a success(but “no video” node isn't one for the user). The trick is to turn that success into “error” for user. Don't forget to use “execute on success”(conditional “TRUE”) to continue to H264 node OR “execute on error”(conditional “FALSE”) to continue to another node.
You just have to finish your branch by populated the %s_success% variable to a message of your choice e.g: “error” or “failed” or for the example “No video in input file”.

%s_options% (since FFAStrans 1.4) advanced users can force special behaviour.

Mostly used by advanced users to change the encoding commands of internal encode processors to specific needs. You can enable/disable options by setting %s_options% to some value using a populate vars processor. Setting one a single option will not change possible existing options.

Note that skip_encoding=True|save_enc_cmd=True can be used to “not encode” but just calculate some encoding command string which you can change to your needs.

%s_last_enc_cmd%

Read only variable for retrieving the latest internally ffmpeg encoding command (after some encode processor)

Normal User Variable : User variables can be populated using the “Populate variables” node within a workflow, a number of other processors like the Loudness Analyzer and via API
Populate Variables help

Scope :

User Variable Values are valid only for the current Branch and it's Child-branches. User Variables cannot be passed directly from one Branch to another.

How to create and set :

• Press the arrow-button next to a text field,variables window appears.
• Select “user” category.
• Right-click into variables window and choose “new”.

• Set “variable” : Creates a normal user variable.
  • Field 1: Enter your variable name, this will always be lower case and spaces are not allowed.
  • Field 2: Here you can just write a description for the variable and its usage.
  • Set “variable“ and as ”string“: Sets the variable as a text string. This is default.
  • Set ”variable“ and as ”integer“: Sets the variable as an integer: whole number. Use this type if you need ffastrans to “guarantee” the value is of type integer. E.g. Spaces are removed and if the original value is a float, it will be rounded down. If the value is too big to fit into 64bit Int, it will be the maximum number an Int can be on your System.
  • Set ”variable“ and as ”float“: Sets the variable as floating point number. Same automatic internal value conversion as int above

• Set ”static” : This is a static that can not be populated dynamically in workflows.
  • Field 1: Enter your variable name, this will always be upper case and spaces are not allowed.
  • Field 2: this option will read “Content”. Here you set the content of the static.
  • Set “static“ and as ”string“: Sets the variable as a text string.
  • Set ”static“ and as ”integer“: Sets the variable as an integer: whole number.
  • Set ”static“ and as ”float“: Sets the variable as floating point number.

Static User Variable : This is another kind of variable. Unlike other variables, static variables are always written with upper case.Creating statics are very handy for example representing a very long path in a short static.

Example 1:
%S_MS_OUTPUT% = D:\Media\Customer previews\Huge important company\720p\Windows Media Video\500k bitrate with watermark

Example 2 :

In this example we have several monitor folder nodes with the same input folder.Only accept files or deny files are different.
If a full path is entered, it will work but all paths will have to be changed if the input folder is changed.
Static variables are handy to avoid this.

• Create a static variable like ”%S_INGEST_PATH%”
• Enter the appropriate content (the full path of monitored folder)
• Enter your new static variable instead of the full path into all your monitor nodes

If your input path change, just edit and modify the content of %S_INGEST_PATH% and all the paths will be changed at the same time.

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