[FFmpeg-user] Compressed audio streams (DTS, Dolby) decoding

[Frédéric]

Hi!

I'm using a NUC to run Kodi, sending the audio signal to my HC amplifier
through HDMI. I let the amplifier decode compressed audio streams, by
activating the passthrough param in Kodi.

But I plan to use a nanoAVR HD sound processor, to make some audio
correction. This device uses HDMI as in/out. The problem is it can't
correct compressed streams; it needs PCM streams (it can handle up to 8
channels).

So, the idea is to let Kodi - ffmpeg - decode the compressed audio streams,
and send a multi-channels PCM stream to the amplifier, which nanoAVR will
be able to correct.

The problem is I have big differences in the audio image when I let ffmpeg
decode the stream or if I let the amplifier does the job. For example, the
balance between front and rear speakers is very strange with ffmpeg (way
too much level on rear speakers).

I'm wondering what can cause such differences? Are there different way to
decode DTS/Dolby streams? Is it something ffmpeg good at? Are there some
tuning parameters I can use?

Thanks for your help.

PS : are there some documentations you recommande me to read to
better understand compressed audio stream decoding?

-- 
    Frédéric