Cinema DTS / Home Video Mixes - Waveform Comparisons

[Turisu]

What was that compared against? Could this be a 70mm change like star wars

Compared against the LD stereo. It could be a 70mm change - nobody can know for sure. But that would still mean that the UHD 2.0 is not the original 35mm stereo as claimed; it would be a downmix of the 70mm in that case. To me the most likely explanation is that it's a revisionist remix as it's clearly 'correcting' a line that sounded weird in the original.

Stripping dialnorm shouldn't change the dynamic range in any way, just remove an arbitrary negative gain, usually -4dB

That's what I thought Dialnorm was. But here is an untouched DVD AC-3 and the same file converted to FLAC.

DVD AC-3


DVD FLAC


Many of the peaks are the same. If the gain were increased any more then there would be clipping. Any idea what's going on? 

[spoRv]

Written an article about waveform comparison - including ten different dynamic range from 18dB up to 24bit full scale 145dB

http://blog.sporv.com/comparing-tracks-waveforms

Just to be clear: I appreciate your work here Turisu, but IMHO 24dB dynamic range is too low to represent properly movie waveform; I've decided to go with 72dB because it's a good compromise.

[dwalkerdon]

Turisu, what program did you use to convert AC3 to Flac?

[weegee2392]

Are you sure?

Pretty sure.
https://fanrestore.com/thread-1077-post-...l#pid75387

George Lucas was involved in the production of Labyrinth, so there might of been multiple mixes. George likes to change his audio tracks for his movies on the fly back in the day depending on the theater Format he was preparing for

[dvdmike]

The laserdisc may be a remix

[Turisu]

Written an article about waveform comparison - including ten different dynamic range from 18dB up to 24bit full scale 145dB

http://blog.sporv.com/comparing-tracks-waveforms

Just to be clear: I appreciate your work here Turisu, but IMHO 24dB dynamic range is too low to represent properly movie waveform; I've decided to go with 72dB because it's a good compromise.

I accept what you're saying but I can't find the setting in Audition that makes the change you describe. So it is what it is for now.

Turisu, what program did you use to convert AC3 to Flac?

MeGUI.

The laserdisc may be a remix

There's just no way to know. There's also the missing 'gasp' in the 5.1 and UHD 2.0 tracks (see a few posts up in the Labyrinth thread). Make of that what you will. I guess we could compare the new UHD 5.1 with the old BD 5.1 to see if Sony just dumped that on the disc.

[deleted user]

It's possible I'm once again missing the context, but... Idk if Dialnorm is the correct term for what I mean, but ac-3 definitely seems to have massive issues with playing back at full dynamic range. I don't think it's necessarily an issue with the format, more with the playback software I've used. It's almost impossible to get a proper playback at full dynamic range in something like VLC or MPC-HC, last I checked.

I distinctly remember being impressed by how loud the gunshots were in Mission Impossible:Fallout in cinema. But then when watching the movie with AC-3 audio, they fell flat. Strange, I thought. I had disabled all dynamic range compression in the input filters and whatnot and in the settings. Still no good.

So I googled around and found that ffmpeg has a "-drc_scale" parameter. If you set it to 0.0000 (maybe a simple 0 is enough, but that's how I saw it), it deactivates any form of dynamic range compression. Lo and behold, the resulting wav file sounded absolutely amazing and just like I had remembered it from cinema.

For the record, I also verified this by recording my system sound with audacity. The base level volume was identical in both playbacks, but with the .ac3 the peaks were significantly lowered, taking all punch out of them.

Maybe this issue wouldn't exist with a properly set up receiver that lets you deactivate DRC. I don't know. But I know that ever since, I haven't trusted AC-3 and the only reason I ever use it is in cases where I can preserve the original ac-3 track without transcoding, simply because I like to preserve the original data. Otherwise I will always transcode to FLAC or WAV using drc_scale 0.0000.

I believe back then I also tested Adobe Audition and it imported it correctly too. But I wouldn't trust that as Adobe seems to sometimes change their import plugins from version to version... for example some of my older Premiere projects are no longer frame accurate when opened with a newer Premiere version.

[zoidberg]

Tom the problem isn't the codec, it's the implementation

[Turisu]

So does converting to WAV/FLAC give the true waveform in Audition?

[allldu]

So when you convert ac-3 to wav/flac with eac3to, it removes the dialogue normalization, is this the same what drc_scale 0.0000 command does?