Youtube plugin - better audio for 1080p videos?

FRD version – 0.9u4
Youtube.com plugin - 2.8.1

Please, is it possible to merge again the highest quality audio DASH stream for 1080p MP4 videos? Now it's only 128 kbps AAC for 1080p but 192 kbps AAC for 720p. It looks like Youtube cut off 256 kbps AAC audios. I tried another ways to download videos from YT, but with the same result, only 128 kbps AAC for 1080p MP4.
I started to use FRD because it automatically download and merge the highest video and audio quality. Downloading so many separated streams and merge them manually in FFMPEG is really tiring, sorry

For example: [www.youtube.com]

Based on table from this wiki page: [en.wikipedia.org], YouTube indeed has discontinued 256kbps AAC for DASH audio. So we have funny situation here as you described: 720p MP4 has 192kbps AAC, meanwhile >=1080p MP4 only has max 128kbps AAC. The other option is 160kbps Opus (the plugin doesn't support downloading this yet) which is only applicable with WebM.

Our internal multiplexer/merger only supports MP4 (H.264 m4v + AAC m4a). There is request/plan to support auto-merger with external program (eg: FFmpeg, etc), so WebM can also be supported, but this feature hasn't been implemented yet.

Thanks a lot for your answer. I think Youtube did it due Apple/iTunes intervention. Freely extracting 256 kbps AAC audios... well... not good for business
Last time I used FRD to extract only 1080p video clip and merge it in FFMPEG with my own 256 AAC song. But this doesn't work everytime. I would like to ask how works "Extract Audio" in Youtube plugin. When I set up highest "Audio bitrate" 256 kbps, will be plugin downloading the best available audio no matter what type and bitrate it is? AAC, Vorbis, OPUS... Thank you.

YouTube plugin at this moment only supports MP3 and AAC audio extraction.

Copy that. And thank you. Over.