stream

Define video tracks. See Declaring Movie Track for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Just in <root> not in its nested	Yes	No

Attribute	Description	Example	Required
name	Name of a stream	my_stream	Not required
transition	Name of a transition from this link	fade	Not required
extended	Use <transition> if set 0 <extended_transition> otherwise	0	Not required
duration	Transition duration	1	Not required

export

Define a stream to export. See Exporting Multiple Streams for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Just in <root> not in its nested	No	No

Attribute	Description	Example	Required
stream	Name of a stream to export	my_stream	Yes
path	File path to export	output.mp4	Yes
audiotrack	Name of an audiotrack to attach	my_audiotrack	Not required
timestamp	1 or 0, indicating if timestamp is shown	1	Not required

material

Define a material to import. See Material Import for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Just in <root> not in its nested	No	No

Depending on the type of materials, required tags change.

• If you plan to import a video (e.g., .mp4, .mov .avi),

Attribute	Description	Example	Required
name	Reference name to assign	my_video	Yes
path	Path to the material	video.mp4	Yes

• If you plan to import a sequence of images,

Attribute	Description	Example	Required
name	Reference name to assign	my_video	Yes
path	Path to the images	images_%d.png	Yes
fps	FPS for the material	60	Yes

• If you plan to import a URL video material,

Attribute	Description	Example	Required
name	Reference name to assign	my_video	Yes
url	URL to the video	http://svr.com/video.mp4	Yes
username	Username for basic authentication	user	Not required
password	Password for basic authentication	passwd	Not required

reference

Define reference to a material or a stream.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <stream> and in its nested	No	Yes

Attribute	Description	Example	Required
name	Name to a reference defined by <material> or <stream>	my_video	Yes

pipe

Enter fluent interface. See Fluent Interface for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <stream> and in its nested	Yes	Yes

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A

group

Group nested references as an a set of inputs. This is used to provide multiple inputs in <pipe>. See an example code below.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Only in <pipe>	Yes	Yes

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A

Using <group>,

<stream>
    <composite name="comp2">
        <composite name="comp1">
            <reference name="ref1"/>
            <reference name="ref2"/>
        </composite>
    </composite>
</stream>

is equivalent to

<stream>
    <pipe>
        <group>
            <reference name="ref1"/>
            <reference name="ref2"/>
        </group>
        <composite name="comp1"/>
        <composite name="comp2">
    </pipe>
</stream>

rolling

Do rolling window calculation on incoming inputs provided by <pipe>. This is often used together with <group> tag. Windows size is currently fixed to two. See an example code below.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Only in <pipe>	Yes	Yes

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A

For example, the code below

<stream>
    <composite name="transition" type="fade"/>
        <composite name="transition" type="fade"/>
            <composite name="transition" type="fade"/>
                <reference name="ref1"/>
                <reference name="ref2"/>
            </composite>
            <reference name="ref3"/>
        <composite/>
        <reference name="ref4"/>
    <composite/>
</stream>

is equivalent to

<stream>
    <pipe>
        <group>
            <reference name="ref1"/>
            <reference name="ref2"/>
            <reference name="ref3"/>
            <reference name="ref4"/>
        </group>
        <rolling>
            <composite name="transition" type="fade"/>
        </rolling>
    </pipe>
</stream>

and it turns out that, using transiion attribute in <stream>, this is simply written as

<stream transition="fade" extended="0">
    <reference name="ref1"/>
    <reference name="ref2"/>
    <reference name="ref3"/>
    <reference name="ref4"/>
</stream>

for_each

Process each input using a same rule. Used together with <group> tag.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Only in <pipe>	Yes	Yes

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A

For example,

<stream>
    <composite name="negate">
        <reference name="ref1"/>
    </composite>
    <composite name="negate">
        <reference name="ref2"/>
    </composite>
    <composite name="negate">
        <reference name="ref3"/>
    </composite>
    <composite name="negate">
        <reference name="ref4"/>
    </composite>
</stream>

can be simplified to

<stream>
    <pipe>
        <group>
            <reference name="ref1"/>
            <reference name="ref2"/>
            <reference name="ref3"/>
            <reference name="ref4"/>
        </group>
        <for_each>
            <composite name="negate"/>
        <for_each/>
    </pipe>
</stream>

import

Import external XML files. See Importing External Files for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Just in <root> not in its nested	No	No

Attribute	Description	Example	Required
path	Path to an XML file	dir/myfile.xml	Yes

set

Define a local variable. See Variables for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <stream> and in its nested	No	Yes

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A

global

Define a global variable. See Variables for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Just in <root> not in its nested	No	No

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A

config

Specify a video setting. See Specifying Video Settings for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Just in <root> not in its nested	No	No

Attribute	Description	Example	Required
name	Configuration name	shape	Yes
value	Value	620x480	Yes

Currently, following name/value pairs are valid

Name	Description	Default	Example
shape	Video size	N/A	1280x720
fps	Video FPS	N/A	24
pixel_format	Pixel format	yuv420p	yuv420p
bitrate	Video bitrate	N/A	400k
crf	Constant Rate Factor (CRF)	N/A	18

ffmpeg_config

Specify a FFmpeg setting.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Just in <root> not in its nested	No	No

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A

For example,

<stream>
    <ffmpeg_config name="pix_fmt" value="yuv420p"/>
    <ffmpeg_config name="b:v" value="1200k"/>
</stream>

audiotrack

Define an audiotrack. See Inserting Audios for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Just in <root> not in its nested	No	No

Attribute	Description	Example	Required
name	Name of the audiotrack	my_audiotrack	No
volume	Audio volume. Default is 1.0.	1.25	No

print

Print a variable or expression. See Debugging for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <stream> and in its nested	Yes	Yes

Attribute	Description	Example	Required
name	Label name	checkpoint 1	No
value	What to print	eval($var+1)	No

assert

Assert check an expression.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <stream> and in its nested	Yes	Yes

Attribute	Description	Example	Required
name	Label name	checkpoint 1	Yes
value	What to verify	eval($var+1 > 10)	Yes

exit

Terminate parsing. See Debugging for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <stream> and in its nested	No	Yes

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A

if

Do if statement branch. See example codes below.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <stream> and in its nested	Yes	Yes

Attribute	Description	Example	Required
name	branch type	equal	Yes

<stream>
    <set name="var" value="4"/>
    <if name="equal">
        <variable value="$var"/>
        <variable value="4"/>
        <then>
            ...
        </then>
        <else>
            ...
        </else>
    </if>
</stream>

<stream>
    <if name="equal">
        <variable value="eval(get_material_duration() < 4)"/>
        <variable value="True"/>
        <then>
            ...
        </then>
        <else>
            ...
        </else>
    </if>
</stream>

<stream>
    <if name="switch">
        <variable value="$var"/>
        <case value="1">
            ...
        </case>
        <case value="2">
            ...
        </case>
        <otherwise>
            ...
        </otherwise>
    </if>
</stream>

clear

Clear local variables. See Variables for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <stream> and in its nested	No	Yes

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A

function

Define a new composition. See Defining New Composition for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
Just in <root> not in its nested	Yes	No

Attribute	Description	Example	Required
name	Composition name	my_composition	Yes

input

Insert an input. Used when defining a composition. See Defining New Composition for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <function> and in its nested	No	Yes

Attribute	Description	Example	Required
index	Numbered index starting from 0	0	No

all_inputs

Insert all the inputs. Used when defining a composition. See Defining New Composition for detail.

Allowed Location	Can Have Nested Tags	Can Be In <pipe>
In <function> and in its nested	No	Yes

Attribute	Description	Example	Required
N/A	No attribute is available	N/A	N/A