Audio Subtitles track properties

When we talk about audio/subtitles track properties, we are talking about track properties such as default track, impaired (description) track, forced track, original (language) track, ... which can be viewed also in Kodi audio/subtitles OSD settings while playing. Whenever possible these properties are automatically parsed/assigned from the manifest data. But there are particular situations that may need some fine tuning, so we provide some special tags but for DASH manifests only.

Meaning of "default" track property in Kodi

The meaning of "default" on Kodi may differ from the specifications of manifest types (DASH, HLS, ...). Assigning these properties on Kodi tracks has the following meanings:

What it means set an audio track as default

The "default" property is used to give priority to a track in the playback selection when is similar to another, same language but usually may differs for channels or codec used.

Consider the following example, we have a manifest with 2 audio tracks:

• Audio track english - channels 5.1 - codec ec-3
• Audio track english - channels 2.0 - codec ec-3

Both track are same language and differ only in the number of channels. To allow Kodi to automatically select (prioritise) track 5.1, we have to set the track 5.1 to default. If not set, Kodi will select the first one in index order, without distinction.

What it means set a subtitles track as default

The "default" property is used to give priority to a track in the playback selection when is equal to another (unusual but only to understand the functionality) for example it may differs for the content e.g. different author.

Consider the following example, we have a manifest with 2 subtitles tracks:

• Subtitles track italian - (an author version 1)
• Subtitles track italian - (an author version 2)

Both track are same language and differ only for the author. To allow Kodi to automatically select (prioritise) a preferred track, we have to set to default one of the two tracks. If not set, Kodi will select the first one in index order, without distinction.

Additional DASH tags to add or override stream properties

For DASH manifests we provide the support to some tags that are not part of the DASH specification, to allows set or override manifest streams properties. These will have to be added to the manifest manually by using a proxy.

Audio tags

Each property accept true or false value, and must be set in AdaptationSet tag:

• default: Set the track as default (for cases above)
• original: Set the track as original language
• impaired: Set the track for impaired

Example:

<AdaptationSet lang="fr" contentType="audio" mimeType="audio/mp4" impaired="false" original="true" default="false">

Subtitles tags

Each property accept true or false value, and must be set in AdaptationSet tag:

• default: Set the track as default (for cases above)
• forced: Set the track as forced subtitle
• impaired: Set the track for impaired

Example:

<AdaptationSet lang="fr" codecs="wvtt" contentType="text" mimeType="text/vtt" impaired="false" forced="true" default="false">