Alternate Source Parameters

ParameterDescriptionAllowed ValuesDefault Value
sourceSpecify the URL to an alternate source file. If there is not alternate, the main source will be used.Valid URL.None
typeSpecify which streams will use – Everything but audio_only streams.
audio – for audio_only streams.
video_audio – for all streams.
video_nameSpecify the name of the video stream for the main source.StringNone
audio_nameSpecify the name of the audio stream for the main source.StringNone
use_stream_idComma separated list of steam IDs.StringNone
languageSpecify the language attribute for the main source.Video langauge name.None
autoAutomatically add all streams with a given type.yes, nono
alternate_defaultEnable the alternate source as, yes, noauto
alternate_autoselectIf playback environment is matched, the aternate_source will be automatically selected.yes, noyes
dvsAdd signaling to manifest that alternate source is a Descriptive Video Services.yes, nono
characteristicsCHARACTERISTICS attribute value for the EXT-X-MEDIA tag in HLS manifest according to RFC 8216Valid CHARACTERISTICS value
For example:
accessibility_scheme"schemeIdUri" attribute value for the Accessibility tag in DASH manifestValid SCHEME value
For example:
accessibility_value"value" attribute value for the Accessibility tag in DASH manifestValid stringnone
natural_orderIf set to yes then value of <use_stream_id /> will mean number of source's audio stream, not number of stream in all type streams list.yes, nono
damf_audioDAMF Audio aux fileValid URLnone
damf_metadataDAMF Metadata aud fileValid URLnone
sub_pathAlternate source sub directory relative to the output destinationStringnone
get_from_manifestUse data from external manifestyes, nono
add_to_manifestList of manifest names to include specified alternate source.
By default alternate source will be added to all manifests.
Comma separated stringsnone
roleMain Source Rolemain,
program_idDolbyE program ID starting from 0Non-negative integer numbernone


For auto parameter

If is set to 'yes' for <alternate_source/> then:

  • Only auto alternate sources will be applied, other custom alternate_sources will be skipped.
  • all other options(except for ) of <alternate_source/> section will be ignored.



<alternate_default /> and <alternate_autoselect /> are available only for advanced_hls, fmp4_hls, and advanced_fmp4 output formats.


For alternate_default parameter

If <alternate_default /> is set to ‘yes<alternate_autoselect /> must be set to ‘yes’ too.


For characteristics parameter

parameter are available only for advanced_hls, fmp4_hls, and HLS manifests of advanced_fmp4 output formats.


For accessibility_scheme and accessibility_value parameters

<accessibility_scheme /> and <accessibility_value /> parameters are available only for advanced_dash and DASH manifests of advanced_fmp4 output formats.


For damf_audio and damf_metadata

The damf_audio and damf_metadata parameters available only for advanced_dash, advanced_fmp4, and fmp4_hls output formats.


Dolby Atmos DAMF files

Dolby Atmos DAMF alternate source files are:

  • – XML file with DAMF file description (framerate, beds and objects number, FFoA, start time offset etc)
  • <damf_metadata /> – XML file with objects size and position coordinates over time
  • <damf_audio /> – CAF (Core Audio File) file. It may contains up to 128 tracks.


For get_from_manifest

The <get_from_manifest /> parameter available only if manifest are specified.


For sub_path parameter

These characters will be filtered out: "\", "`", "№", "$", "#", "?"