track

The <track> element contains the information that constitutes a track in an Open Clip. Each track represents a distinct element from the clip.

Examples of tracks in an Open Clip context include:

A layer in a Photoshop file
A video, or one of multiple audio tracks, in a QuickTime file
One of multiple render passes contained in a multi-channel OpenEXR file

Attributes

Attribute	Data Type	Allowed Values	Occurrence	Description
type	string	`track`	0-1	Type of the element.
version	unsigned integer	`7`	0-1	Version of the XML element.
uid	string	any	1	Each `uid` must be unique across track elements when contained in a `<tracks>` element.
currentVersion	string	any	0-1	Version UID of the current version. Will be synced with the one in `<versions>` XML element if missing.

Note: Optional attributes (0 occurrence attributes) will be inferred from the parent node.

Children

Element	Data Type	Occurrence	Description
`<trackType>`	string	1	Track's type. Typically `video`, `audio`, or `generic`.
`<extendedType>`	string	0-1	Extended track's type. The extended track type refines the type of a given track. For example, for video, it could describe the layer pass (shadow, occlusion, normal, etc.). Inferred from the parent node if missing.
`<feeds>`	feeds	0-1	Each feed contained in the list of feeds. Each feed is associated with a version in the clip `<versions>` element.
`<handler>`	handler	0-1	Track's handler information.
`<name>`	string	0-1	Name of the track.
`<sourceName>`	string	0-1	Source name of the track. Sometimes referred to as tape name in older workflows.
`<comment>`	string	0-1	Unparsed text converted into a clip note.
`<editRate>`	rate	0-1	Edit rate of the track. An edit rate can be defined when all feeds' sample rates do not match in order to explicitly define the working rate for the ensemble. If not defined, a common rate based on the feeds' sample rates will be computed.
`<dropMode>`	string	0-1	The drop frame mode of the media. Only required for those timings with a possible drop-frame mode. Allowed values for `<dropMode>`: DF: drop-frame media NDF: non drop-frame media
`<duration>`	time	0-1	Time duration of the track. If not defined, the union of all the feeds' duration will be computed.
`<startTimecode>`	time	0-1	Start timecode of the track. If not defined, the earliest start timecode of all the feeds will be used.
`<userData>`	dict	0-1	Dictionary of metadata that is passed through without interpretation.

Note: Child elements with the attribute computed=1 will be ignored when parsed.

Examples

Example 1

The simplest track object can only point to media it is referencing.

<track uid="t0">
    <trackType>video</trackType>
    <feeds>
        <feed vuid="v0" uid="f0">
            <spans>
                <span>
                    <path encoding="file">Media/Video1.mov</path>
                </span>
            </spans>
        </feed>
    </feeds>
</track>

Example 2

Any additional elements added override the media metadata or add metadata to media without changing their header.

<track uid="t0">
    <trackType>video</trackType>
    <name>My name</name>
    <sourceName>My tape name</sourceName>
    <comment>My comment</comment>
    <feeds>
        <feed vuid="v0" uid="f0">
            <spans>
                <span>
                    <path encoding="file">Media/Video1.mov</path>
                </span>
            </spans>
        </feed>
    </feeds>
    <userData>
        <assetId type="string">11231-2312323</assetId>
    </userData>
</track>

Example 3

Track start timecode and duration can be modified to force a specific timing, ignoring the media's actual duration. This example demonstrates how to create a track with a duration longer than the existing media. Gaps where no media exist are padded with No Media content.

<track uid="t0">
    <trackType>video</trackType>
    <startTimecode type="time">
        <nbTicks>86400</nbTicks>
        <rate type="rate">24</rate>
    </startTimecode>
    <duration type="time">
        <nbTicks>8640</nbTicks>
        <rate type="rate">24</rate>
    </duration>
    <feeds>
        <feed vuid="v0" uid="f0">
            <spans>
                <span>
                    <path encoding="file">Media/Video1.[1000-2000].dpx</path>
                </span>
            </spans>
        </feed>
        <feed vuid="v1" uid="f1">
            <spans>
                <span>
                    <path encoding="file">Media/Video2.[1000-1500].dpx</path>
                </span>
            </spans>
        </feed>
    </feeds>
</track>