Thanx for the help with AAC-HE
Bitrate in Audio per Channel:
Ok. Maybe I thought this to be too simple.. I had something like this in mind:
Stream 1: 8 Channels (7.1)
Stream 2: 2 Channels (Stereo, other language)
Stream 3: 1 Channel (Commentary)
Right now there seemes no way to convert these audiostreams in one batch to give everyone the bitrate that would be appropriate.
But if bitrate was set "per channel" in the GUI, it could be parsed to the encoder simply by multiplying with the amounts of channels (which are already known).
For example, set Bitrate per channel: 64 kbit/s
So Stream
1 gets 8 x 64 = 512 kbit/s
2 gets 2 x 64 = 128...
3 gets 1 x 64 ...
Sounds simple, but probably isnīt easy to implement.
About -grain:
I didn't try within ffmpeg, but presets, tune settings etc... can be set in ffmpeg for x265 and x264.. And since both have the -grain option, I thought this would be a no brainer. Why should the ffmpeg implementation of x265 leave this out?
Addition: Just noticed that ripbot is using ffmpeg as well - and here --grain can be used. Maybe this helps?