<?xml version="1.0"?>
<query>
    <userid>[UserID]</userid> <!-- required-->
    <userkey>[UserKey]</userkey> <!-- required-->
    <action>[Action]</action> <!-- required-->
    <source>[SourceFile]</source> <!-- required-->
    <format>
        <!-- Format params -->
        <text_overlay>
            <!-- Common overlay params -->
            <text>[Text1]</text> <!-- required-->
            <font_source>[Font1Source]</font_source> <!-- required-->
            <font_size>[Font1Size]</font_size>
            <font_rotate>[Font1Rotate]</font_rotate>
            <font_color>[Font1Color]</font_color>
            <align_center>[0|1]</align_center>
            <overlay_x>[TextOverlay1PositionX]</overlay_x>
            <overlay_y>[TextOverlay1PositionY]</overlay_y>
            <size>[TextOverlay1Size]</size>
        </text_overlay>
        <!-- ... -->
        <text_overlay>
            <!-- Overlay params -->
        </text_overlay>
    </format>
</query>

{
    "query": {
        "userid": "[UserID]", // required
        "userkey": "[UserKey]", // required
        "action": "[Action]", // required
        "source": "[SourceFile]", // required
        "format": {
            // Format params
            "text_overlay": [
                {
                    // Common overlay params
                    "text": "[Text1]",
                    "font_source": "[Font1Source]",
                    "font_size": "[Font1Size]",
                    "font_rotate": "[Font1Rotate]",
                    "font_color": "[Font1Color]",
                    "align_center": "[0|1]",
                    "overlay_x": "[TextOverlay1PositionX]",
                    "overlay_y": "[TextOverlay1PositionY]",
                    "size": "[TextOverlay1Size]"
                },
                {
                    // Overlay params
                }
            ]
        }
    }
}

Parameter	Description	Allowed Values	Default Value
text	Specify the text for the overlay.	Text	None
font_source	Specify the URL for the font file.	Valid URL.	None
font_size	Specify the text font size.	Non-negative integer	0
font_rotate	Specify the angle on which text should be rotated.	Non-negative integer	0
font_color	Specify the font color.	6-digits hexadecimal 000000-FFFFFF	000000
align_center	Align text in the center.	0 or 1. 0 = disabled, 1 = enabled.	0
overlay_x	Specify the text overlay position on the x axis.	Non-negative integer	0
overlay_y	Specify the text overlay position on the y axis.	Non-negative integer	0
size	Specify the size of the text block in pixels.	WxH where W and H – positive integers	None

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Note
<text /> and <font_source /> are the required parameters.