4.1 Dolby Surround is louder on the right side. about ffmpeg-normalize HOT 3 OPEN

You can't pass -af through extra options because ffmpeg-normalize internally sets up a complex filtergraph, and any addition to that would have to be made through the --pre-filter and --post-filter options.

Also, didn't we have a discussion about opus not supporting surround sound properly? #237 (comment)

I think it would make sense to first try to reproduce the issue with raw ffmpeg commands, just to figure out what is actually going on. In other words, when you manually run your input file through ffmpeg and re-encode, can you get it to output the correct channel map (without normalizing anything)? Once you have that figured out, what happens when you apply the normalization manually, i.e., run it once with the loudnorm filter?

Because the processing pipeline in ffmpeg-normalize is more or less static, it's going to be hard to accommodate all these special cases. Especially when ffmpeg doesn't output properties similar to its input, it's going to be even more effort …

from ffmpeg-normalize.

Also, didn't we have a discussion about opus not supporting surround sound properly? #237 (comment)

Specifically, opus was the problem there, not libopus.

from ffmpeg-normalize.

I think it would make sense to first try to reproduce the issue with raw ffmpeg commands, just to figure out what is actually going on. In other words, when you manually run your input file through ffmpeg and re-encode, can you get it to output the correct channel map (without normalizing anything)?

Yeah, this isn't an issue with ffmpeg-normalize, but the regular ffmpeg.
It just doesn't seem to "understand" that the input 4.1 is not the same as what I want it to also output as 4.1, it also re-organizes the channels the same way as above.
I don't know how to tell it what I want it to do.
ffmpeg -layouts spits out one 4.1 mapping: 4.1 FL+FR+FC+LFE+BC which is what the input is, but ffmpeg only produces Channel layout : L R Lb Rb LFE.
No matter what I specify, for example ffmpeg -i input.mkv -map 0:a:0 -c:a libopus -filter_complex "channelmap=channel_layout=4.1:map=FL-FL|FR-FR|FC-FC|LFE-LFE|BC-BC[out]" -map "[out]" -ac 5 out.mka -y, the output has a different mapping, which I do not understand.

from ffmpeg-normalize.