Metadata Elements
<ndi_product> Element
<ndi_product> ElementInitial Implementation: Vizrt
Location: Connection Metadata
Used by both NDI senders and receivers to indicate product details.
<ndi_product> Attributes
<ndi_product> Attributeslong_name
Full human readable product name
short_name
Abbreviated human readable product name
manufacturer
Product manufacturer
version
Product firmware version
model_name
Product model name
serial
Product serial number
session_name
Session name for TriCaster or similar products General product information for other devices
<ndi_capabilities> Element
<ndi_capabilities> ElementInitial Implementation: Vizrt
Location: Connection Metadata
Indicated product capabilities for both NDI senders and receivers. Most capabilities are sender specific (ptz and exposure control) but NDI receivers will often have a web_control URL.
<ndi_capabilities> Attributes
<ndi_capabilities> Attributesweb_control="URL"
The URL to the local device webpage. If %IP% is present in the value, it will be replaced with the local IP of the NIC in which the NDI receiver is connected to.
ntk_ptz="true"
Signifies that this NDI sender is capable of processing PTZ commands sent from the NDI receiver. The NDI receiver will only assume the NDI sender can support PTZ commands if this attribute is received and set to the value “true”.
ntk_pan_tilt="true"
The NDI sender supports pan and tilt control.
ntk_zoom="true"
The NDI sender supports zoom control.
ntk_iris="true"
The NDI sender supports iris control.
ntk_white_balance="true"
The NDI sender supports white balance control.
ntk_exposure="true"
The NDI sender supports exposure control.
ntk_exposure_v2="true"
The NDI sender supports detailed control over exposure such as iris, gain, and shutter speed.
ntk_focus="true"
The NDI sender supports manual focus control.
ntk_autofocus="true"
The NDI sender supports setting auto focus.
ntk_preset_speed="true"
The NDI sender has preset speed support.
<ndi_format> Element
<ndi_format> ElementInitial Implementation: Vizrt
Location: Connection Metadata
Sent by an NDI receiver to indicate it's preferred or native format.
<ndi_format> Children
<ndi_format> ChildrenAt least one of the following child elements is required.
<video_format>
Video format details
<audio_format>
Audio format details
<video_format> Attributes
xres
Horizontal resolution in pixels
yres
Vertical resolution in lines
frame_rate_n
Numerator portion of the frame rate
frame_rate_d
Denominator portion of the frame rate
aspect_ratio
The picture aspect ratio, 0 means square pixel
progressive
Indicates progressive format when "true" or interlaced format when "false"
<audio_format> Attributes
no_channels
The number of audio channels
sample_rate
The number of audio samples per second
<ndi_color_info> Element
<ndi_color_info> ElementLocation: Video Frame Metadata
Initial NDI Version: 6.0
The <ndi_color_info> element provides colorimetry details for the associated video frame.
<ndi_color_info> Attributes
<ndi_color_info> Attributesprimaries
Specifies the chromaticity coordinates of the color primaries of the video frame. One of: “bt_601”, “bt_709”, “bt_2020”, or “bt_2100”
transfer
Specifies the brightness transfer characteristic. One of: “bt_601”, “bt_709”, “bt_2020”, “bt_2100_hlg”, or “bt_2100_pq”
matrix
Specifies the matrix coefficients used in deriving luma and chroma from RGB or XYZ primaries. One of: “bt_601”, “bt_709”, “bt_2020”, or “bt_2100”
<ndi_metadata_group> Element
<ndi_metadata_group> ElementInitial Implementation: Vizrt
Location: Metadata (all flavors)
Initial NDI Version: 6.0 for video frame metadata, 6.1 for generic metadata frames
Properly formatted XML allows only one root element. If multiple metadata elements need to be attached to a single audio or video frame, they should be grouped together as child elements of an ndi_metadata_group root element.
<ndi_tracking_info> Element
<ndi_tracking_info> ElementInitial Implementation: Vizrt
Location: Video Frame Metadata
Initial NDI Version: 5.x
<ndi_tracking_info> Attributes
<ndi_tracking_info> Attributesversion
The <ndi_tracking_info> element must have a version attribute. The version attribute is defined as string with the regex format: [0-9]+.[0- 9]+.[0-9]+
<ndi_tracking_info> Children
<ndi_tracking_info> Children<package>
<ndi_tracking_info> can contain zero or more <package> elements
<package> Element
<package> ElementThe <package> element holds one single tracking package. This element contains no text.
or
<package> Attributes
<package> Attributestype
The <package> element must have an attribute named type with a value of either binary or axis
protocol
The value of the attribute protocol is the name of the tracking protocol which is embedded in the XML description of <package>. This attribute is mandatory
<package> Children
<package> Children<timestamp>
The <timestamp> element is optional
<data>
If the type of the is binary then exactly one <data> element is mandatory.
<axis>
If the type of the is axis then one or more <axis> elements must be present.
<timestamp> Element
When present, the element can provide some additional timestamp information different from the timestamp on the NDI video frame. This element contains no text and has no children.
<timestamp> Attributes
name
Is optional and defines the process step when the timestamp was taken. If name is not given, the timestamp will be marked as capture which means the time the video frame was recorded. If the name attribute is not capture, then the timestamp on the NDI video frame is taken as capture timestamp. Please see Appendix Timestamp names.
type
<data> Element
<axis> Element
The <axis> element contains data for one axis. This element contains no text and has no children.
<axis> Attributes
name
Identifies the axis. If the name is known by the Tracking Hub, the assignment to the rig axis can be done automatically. If not, the assignment must be done by the operator. Either way, a unique name must be given.
type
Identifies the format of the content of the <axis> element. The type attribute must be one of the following:
xs:integerxs:floatxs:booleanxs:doublexs:long
value
The value of the axis. The type must match the attribute type.
<ndi_video_codec> Element
<ndi_video_codec> ElementInitial Implementation: Vizrt
Location: Metadata
Sent via NDIlib_recv_send_metadata() by the application which created the NDI receive instance.
This requests the NDI library use the specified decoding method for H.264 and H.265 NDI video streams. Note that the internal heuristics should generally be allowed to select the codec type in most circumstances.
<ndi_video_codec> Attributes
<ndi_video_codec> Attributestype
Video codec type One of: "hardware" or "software"
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