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Old 2nd October 2020, 11:57   #15021  |  Link
tebasuna51
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To view AC3 metadata you can use MediaInfo or my LeeAudBi tool.

I don't know other tool to edit AC3 metadata, only eac3to for set DN to -31dB or specific tools for instance the attached ones:

- DN27_Ac3 restore the Dolby DN default value to -27 dB (a decoder Dolby compliant must attenuate in 4dB the full stream by default)

- DN31_Ac3 remove the DN, setting the value to -31 dB (a decoder must decode without attenuate nothing, recommended for recode in ac3to by default)

- DplAc3 set the Dolby Pro Logic flag in stereo AC3's

I don't know other metadata than can be safely changed without recode.
BTW there are the sources to do other changes.
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File Type: 7z Ac3_tools.7z (48.7 KB, 15 views)
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Old 2nd October 2020, 12:05   #15022  |  Link
NiN3
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Quote:
Originally Posted by tebasuna51 View Post
To view AC3 metadata you can use MediaInfo or my LeeAudBi tool.

I don't know other tool to edit AC3 metadata, only eac3to for set DN to -31dB or specific tools for instance the attached ones:

- DN27_Ac3 restore the Dolby DN default value to -27 dB (a decoder Dolby compliant must attenuate in 4dB the full stream by default)

- DN31_Ac3 remove the DN, setting the value to -31 dB (a decoder must decode without attenuate nothing, recommended for recode in ac3to by default)

- DplAc3 set the Dolby Pro Logic flag in stereo AC3's

I don't know other metadata than can be safely changed without recode.
BTW there are the sources to do other changes.
DRC profiles can't be edited or removed from an AC3 file? I've read dynamic range compression doesn't actually change the soundwaves but is instead saved as metadata for the receiver to decode. Would be interesting if there was a way to remove it from an AC3 or TrueHD stream since most DVD's and Blurays seem to have "Film Standard" applied by default.
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Old 2nd October 2020, 12:46   #15023  |  Link
SeeMoreDigital
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Quote:
Originally Posted by NiN3 View Post
DRC profiles can't be edited or removed from an AC3 file? I've read dynamic range compression doesn't actually change the soundwaves but is instead saved as metadata for the receiver to decode....
I can't speak for AC3 audio streams but I've used UsEac3To to remove the dialnorm from DTS audio streams. It worked perfectly with 'Peter Gabriel's - Play' DVD: -

https://forums.stevehoffman.tv/threa...urround.63579/
https://forums.stevehoffman.tv/threa...ls-play.45319/
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Old 2nd October 2020, 12:51   #15024  |  Link
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Quote:
Originally Posted by NiN3 View Post
DRC profiles can't be edited or removed from an AC3 file?
It is difficult because DRC info is provided in audioblocks (6 for each frame) not with common metadata in BSI (Bit Stream Information) header frame info.

All decoders can be instructed to ignore DRC (or apply only a part).
You can recode these ac3 streams with ffmpeg and -drc_scale 0
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Old 2nd October 2020, 17:51   #15025  |  Link
Forteen88
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Thanks for LeeAudBi tool.
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Old 11th October 2020, 17:14   #15026  |  Link
villaquien
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I delayed the audio 400ms but the program copied part of the previous dialog. The silence should start at minute 22:25:780, why does this happen?

https://imgur.com/Vtt9exm.jpg
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Old 11th October 2020, 20:51   #15027  |  Link
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Try with:

-edit=0:22:25.780,400ms -silence
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Old 12th October 2020, 18:32   #15028  |  Link
villaquien
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Thank you. I tried that and the program cuts the last part of the dialogue and moves it forward. I don't understand why the program doesn't create a silence from the exact point.

https://imgur.com/OGOspPl.jpg
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Old 12th October 2020, 20:01   #15029  |  Link
tebasuna51
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Seems the cut point is calculated like: 0:22:25.780 -400 = 0:22:25.380

Then to obtain the desired point need:

-edit=0:22:26.180,400ms -silence
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Old 13th October 2020, 18:18   #15030  |  Link
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It worked, thank you.
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Old 17th October 2020, 09:17   #15031  |  Link
dade49
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Quote:
Originally Posted by Forteen88 View Post
Is eac3to the only software that can remove AC3 dialog normalization?
Thanks
MKVToolNix can remove dialog normalization from AC3 and DTS-HD tracks, from both the master and the embedded core track.

https://gitlab.com/mbunkus/mkvtoolnix/issues/2377
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Old 17th October 2020, 12:13   #15032  |  Link
tebasuna51
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MKVToolNix can remove dialog normalization from AC3 and DTS-HD tracks, from both the master and the embedded core track.
All days I learn one more thing.

Yes, in MKVToolNix GUI -> Preferences -> Default values we can "Enable dialog_normalization gain removal for audio tracks"

But maybe the correct text was:
"Enable dialog_normalization attenuation removal for audio tracks"
because enabling the removal we obtain a more loud track.

Remove the Dialog Normalization in a AC3 track means put -31 dB in the field of each header. A standard value is -27 dB than say to decoders dolby compliants attenuate the track by 4 dB (-27-4=31)
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