[Technologist]

NGA encompass AD as part of the overall specification
But just as part of how object audio works Which is very good ……

But the AD we have on DTT ..”receiver mix” is object audio
As the narration is a mono audio plus a byte to pan the audio across the stereo scene,
And a byte to dim the programme audio …

Just reflecting back on the proportion of AD etc
The BBC play out facilities from the start (on air 1998) were designed in the basis that the system
Would always carry video , stereo audio, subtitles and AD, (embedded in the video )
And monitoring was in to ensure that video audio and subtitles were there 100%
Itv etc had a separate AES 3 audio circuit which they added to do,AD.at it’s launch in 2000.