[ Feature Request ] Maximum bitrate and sound volume

[Augusto7743]

If not using an maximum bitrate value will be used an automatic value.
Nvencc use --max-bitrate --vbv-bufsize to select an maximum bitrate value.
FastFlix has the options maxrate and bufsize, but need both value enabled to work.
Using only an value in --max-bitrate does --vbv-bufsize auto too being more simple.
Is possible select a sound volume value using the nvencc command
for track 1
--audio-filter volume=4dB
for track 2
--audio-filter 2?volume=4dB

lowering the volume
--audio-filter volume=-4dB

both settings will be good to be added in FastFlix.
Have a nice week.