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| Since | 17.5 |
Note
For information about the opposite operation of compiling frame images into a video, see the 
FFmpeg Encode Video node documentation.
Overview ¶
You can use this node in two ways:
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If the node has no inputs, you can specify a video file from which to extract images.
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If the node has incoming work items with a video file
output, you can extract frames for each incoming work item.This node generates one work item to extract all images from the input video. It does not generate separate work items for each frame.
The
outputof the work item is an array of output file names. If you want to wire the output to nodes that expect separate work items per file, use the
Work Item Expand node to split out the output files in the work item(s).
Installation ¶
This node is a wrapper around the ffmpeg command line tool. By default, it uses the version of FFmpeg that ships with Houdini as `$HFS/bin/hffmpeg. You can also install your own version of FFmpeg and use that instead.
For the node to find a custom installation of the FFmpeg command line tool, the path to the tool’s executable binary must be available via one of the following methods:
-
The system path.
-
Specified in an environment variable
PDG_FFMPEG. -
Specified directly in the node by the FFmpeg Binary Path parameter.
Tip
The $HH/help/files/pdg_examples/top_multishot and $HH/help/files/pdg_examples/top_rop examples show how you can use this node to create a movie from rendered images.
TOP Attributes ¶
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integer |
The height of the outputted images. |
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integer |
The width of the outputted images. |
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float |
The frames per second. |
Parameters ¶
Node ¶
Generate When
Determines when this node will generate work items. You should generally leave this set to “Automatic” unless you know the node requires a specific generation mode, or that the work items need to be generated dynamically.
All Upstream Items are Generated
This node will generate work items once all of the input nodes have generated their work items.
All Upstream Items are Cooked
This node will generate work items once all of the input nodes have cooked their work items.
Each Upstream Item is Cooked
This node will generate work items each time a work item in an input node is cooked.
Automatic
The generation mode is selected based on the generation mode of the input nodes. If any of the input nodes are generating work items when their inputs cook, this node will be set to Each Upstream Item is Cooked. Otherwise, it will be set to All Upstream Items are Generated.
Cook Type
Determines how work items in the node should cook, e.g. if they should run in process, out of process, or using services.
Run on Service Block
Determines whether or not work items in this node should run on the parent service block, if one exists.
Always
Always run work items on the block’s service, regardless of any other service settings on this node.
Match
Only run work items on the block’s service if Service Name matches the service name that’s used by the block.
Never
Never run work items on the block’s service.
Service Name
When Cook Type is set to the Service, this parameter is used to specify the name of the service. For more information on using services, see the PDG Service Manager documentation.
Input Source
Specifies the input source.
Upstream Output File
Sets the input as the first output file from the upstream work item with the tag specified by the File Tag parameter.
Custom File Path
Sets the input as the video specified by the File Path parameter.
File Tag
Specifies the file tag of the input source.
File Path
Specifies the file path of the input source.
Frames per Second
Sets the number of images to extract per second.
Output File Pattern
Specifies the output pattern of the extracted images.
File Tag
Specifies the file tag of the outputted images.
Width
When on, specifies the width of the output images.
Height
When on, specifies the height of the output images.
FFmpeg Binary
Specifies how FFmpeg is called.
System Path
Calls FFmpeg from the system path (if available).
$PDG_FFMPEG
Calls FFmpeg using the path stored in the PDG_FFMPEG environment variable. This environment variable must be user-created.
Custom Path
Calls the FFmpeg binary using the path specified by the FFmpeg Binary Path parameter.
Houdini FFmpeg
Uses the copy of FFmpeg that ships with Houdini, i.e. $HFS/bin/hffmpeg.
FFmpeg Binary Path
Specifies the path to the FFmpeg binary.
This parameter is only available when FFmpeg Binary is set to Custom Path.
FFmpeg Command
When on, specifies the FFmpeg command that is called when the work item cooks. You can modify this command, but it will not automatically update if the other parameters change.
Schedulers ¶
TOP Scheduler Override
This parameter overrides the TOP scheduler for this node.
Schedule When
When enabled, this parameter can be used to specify an expression that determines which work items from the node should be scheduled. If the expression returns zero for a given work item, that work item will immediately be marked as cooked instead of being queued with a scheduler. If the expression returns a non-zero value, the work item is scheduled normally.
Add Job Parms
Opens the Edit Parameter Interface window for the purpose of adding scheduler parameters to the node’s interface.
In-Process Scheduler
The Edit Parameter Interface window opens with the 
In-Process Scheduler’s parameter folder selected in the Create Parameters column.
Local Scheduler
The Edit Parameter Interface window opens with the Local Scheduler’s parameter folder selected in the Create Parameters column.
HQueue Scheduler
The Edit Parameter Interface window opens with the 
HQueue Scheduler’s parameter folder selected in the Create Parameters column.
Work Item Label
Determines how the node should label its work items. This parameter allows you to assign non-unique label strings to your work items which are then used to identify the work items in the attribute panel, task bar, and scheduler job names.
Use Default Label
The work items in this node will use the default label from the TOP network, or have no label if the default is unset.
Inherit From Upstream Item
The work items inherit their labels from their parent work items.
Custom Expression
The work item label is set to the Label Expression custom expression which is evaluated for each item.
Node Defines Label
The work item label is defined in the node’s internal logic.
Label Expression
When on, this parameter specifies a custom label for work items created by this node. The parameter can be an expression that includes references to work item attributes or built-in properties. For example, $OS: @pdg_frame will set the label of each work item based on its frame value.
Work Item Priority
This parameter determines how the current scheduler prioritizes the work items in this node.
Inherit From Upstream Item
The work items inherit their priority from their parent items. If a work item has no parent, its priority is set to 0.
Custom Expression
The work item priority is set to the value of Priority Expression.
Node Defines Priority
The work item priority is set based on the node’s own internal priority calculations.
This option is only available on the 
Python Processor TOP, 
ROP Fetch TOP, and ROP Output TOP nodes. These nodes define their own prioritization schemes that are implemented in their node logic.
Priority Expression
This parameter specifies an expression for work item priority. The expression is evaluated for each work item in the node.
This parameter is only available when Work Item Priority is set to Custom Expression.
Examples ¶
example_top_ffmpegextractimages Example for FFmpeg Extract Images TOP node
This example demonstrates how to use FFmpeg Extract Images node to extract images from a video file.
| See also |
