We’ve recently teamed up with colleagues from SWR.Online to implement
alternative audio tracks in the “ARD Player” for mobile and desktop
Internet browsers. This allows ARD broadcasters now to distribute alternative audio
versions in addition to the default mix in an efficient manner without extra
bandwidth usage. Such alternatives can be for example a “Dialog+”
version for better speech intelligibility or a binaural version for 3D audio on
headphones. You can try the new feature on our demo page.
The reason why we’ve
done this is to allow consumers to experience audio content in optimised quality
wherever and however they consume it. Be it a special version with better speech
intelligibility and reduced background sounds, a version which works well in noisy
environments or a version including audio description. Such versions can be either
manually mixed or automatically generated with e.g. tools for dialogue enhancement.
It can be also very useful for the distribution of NGA productions
when the end device is not capable of decoding an NGA stream. In this case, the NGA
versions for different mixes or user personalisation can be automatically
pre-rendered before the distribution and transported as DASH or HLS audio tracks.
HLS
and DASH are (adaptive) streaming protocols which
are widely used for Internet delivery. A simplified workflow is illustrated below:
Simplified overview of HLS audio track flow
Even though the ARD Player features several plugins for the transport of audio and
video, it is mostly used in conjunction with HLS reception for adaptive streaming.
Hence, we focused our solution on this plugin type. The technical support for this
feature is now included in version 5.4.0 of the ARD Player which is rolled out as
part of the current ARD Mediathek
– however the option can only be offered to end-users whenever properly
processed audio content will be made available.
Depending on the end device capabilities, this feature could be also used to
transport not just an alternative stereo version but also a multichannel (e.g. 5.1)
mix. It has to be mentioned, however, even though the ARD Player is now capable of
transporting and playing alternative versions or loudspeaker formats that these will
not be always available. This joint development is only opening the technical
opportunity for ARD broadcasters to extend their service.
We’re hoping that this feature will be used extensively in the future to deliver better suitable audio for the audience of ARD.
Update 29.06.2020: The WDR is using the feature now for an experimental radio drama to switch between different perspectives. This is indeed one of the many creative possibilities for alternative audio tracks.