Audio volume fluctuations when transcoding

[chef 3749]

I was wondering if someone could give me some guidance to fix a small issue.

 

When watching media from my Xbox One in Emby Theater, I seem to be experiencing audio volume issues, where the the volume will fluctuate loud and then become inaudible.

 

It might be because the audio streams, the media is being transcoded from, are DTS or DTSHD, and converting to an ACC/AC3 stream. 

 

In some instances,  music audio will cause it to get louder, but speaking parts will drop substantially.

 

I could re-encode the media items, but it would be better to get an idea of what might be happening prior to re-encoding, to level out audio profiles.

 

I'm confident that this can be fixed by adding a specific argument to ffmpeg.

 

Thank you

 

Benny

Edited April 28, 2019 by chef

[rbjtech 4315]

I've gone the conversion route adding into the MKV but I've seen this on many media files where normalisation of the audio is just 'wrong' despite the best guesses from ffmpeg and other tools.

 

I spend a reasonable amount of time researching this and there are all sorts of wonderful per channel options you can add into ffmpeg to boost just the centre channel for example, but what works for one, fails to work for another.

 

In the end - for mixing to 2 channel AAC, I just used the -ac 2 -filter:a "volume=1.5" which (for me) keeps the audio at the same volume as the original audio and appears to (mostly) maintain the dialogue/music channel balance.

Edited April 28, 2019 by rbjtech