can eac3to preserve dialnorm / drc profiles when transcoding

[Blue_MiSfit]

I know it's a bad idea to have DRC / dialnorm enabled when decoding AC3 during a re-encode, but is there any way to re-insert this metadata into the new AC3?

For example, if I have a 640kbps 5.1ch AC3 with dialnorm at -27 and the "film standard" drc profile, and want to generate both a 2ch AC3 at 192kbps and a 5.1ch AC3 at 384kbps, I'd like to keep this metadata, so playback with DRC enabled will be done correctly.

Any way to do this?

Also, with other apps using Aften (like Avisynth's SoundOut, and EncWAVtoAC3), there is some support for the more advanced parameters, like the bandwidth lowpass, DC filter, LFE filter, and the exponenent search strategy.

Is there any support, or planned future support within eac3to for these parameters? eac3to is such a wonderful tool, and is a real swiss army knife for audio transcoding, but without these features I have to use other tools frequently, and would love to have eac3to do it all automagically :)

Thanks in advance

~MiSfit

[tebasuna51]

Eac3to can preserve the dialnorm:
"-keepDialnorm" switch disables removal of E-AC3 dialnorm information

But the DRC metadata can't be preserved because must be generated with the new codification. Two comment:
- The Aften implementation of DRC metadata isn't correct: http://forum.doom9.org/showthread.php?p=893111#post893111
- The modern receivers have the "night" mode to make the DRC on the fly without need the metadata values.
Then I never recommend use Aften with DRC.

You can always use the external encoder Aften, and the parameters required, with eac3to using this syntax:
eac3to input_audio stdout.wav | Aften -b 384 -pad 0 -readtoeof 1 -exps 32 -s 1 -bwfilter 1 - output.ac3

Maybe madshi can add some parameter to obtain the best aften quality (slow encode) like jruggle recommend here:
http://forum.doom9.org/showthread.php?p=1344624#post1344624

[Blue_MiSfit]

I see. Maybe Madshi knew the DRC implementation in Aften was bugged, and worked around it by NOT writing any metadata via eac3to!

Interesting stuff.

~MiSfit