>>169
Official Telegram group が作ったFAQ にこれがあったよ
（ぼくはまだ試してないので、ダメだったらごめん）

How to get 5.1 audio in SmartTube?
・In the sound settings, you need to select mp4a.
・Not all videos really have a 5.1 audio track.
・In addition, it is pointless to throw the sound “as is”.
・There is no DD or DTS on YouTube. In the mp4a container, the sound is encoded in the AAC format; the receiver often does not understand it. Therefore, the PCM should be in the TV settings.