How to tell ffdcaenc to deal with DTS-ES 6.1?

[Perenista]

I have picked a DVD of my own in PAL, so I changed to NTSC using MKVToolnix.

But the 3 audio tracks need to be "converted", too.

This is what MEDIAINFO says about all 3:

https://pastebin.com/up74KrDN

1st one is DD 5.1 EX, 2nd DTS-ES 6.1, and the 3rd DD 2.0

What I did so far:

+++++++++++
eac3to track1.ac3 track1_ntsc.ac3 -slowdown
+++++++++++

+++++++++++
eac3to track2.dts track2_slow.wav -slowdown
+++++++++++

+++++++++++
eac3to track3.ac3 track3_ntsc.ac3 -slowdown
+++++++++++

Tracks 1 and 3 are in sync with the new MKV, which is now NTSC.

But track #2, which is the DTS-ES 6.1, needs an additional step to be done with a program called "ffdcaenc"

The goal here is to not "reencode" or (since a "fps" change is needed) do this in the best quality possible. What is not acceptable is to generate a 4 GB filesize from a track that is 1 GB. So no "FLAC".

I asked AI what to do, and was told for the DTS-ES 6.1 one, to do that WAV step, then a final with "ffdcaenc". But the AI is also telling me "ffdcaenc" does not support a DTS-ES 6.1 track. So it offers me multiple choices to convert this, but they are not exactly DTS-ES 6.1.

Any ideas?

P.S. Original MKV (PAL):

https://pastebin.com/PQ3pQvpD

New MKV:

https://pastebin.com/S37N2atJ

[Columbo]

But track #2, which is the DTS-ES 6.1, needs an additional step to be done with a program called "ffdcaenc"
https://pastebin.com/S37N2atJ Can you explain why? Is eac3to having a problem with it?

It would be helpful to have the MKV files.

[Perenista]

Can you explain why? Is eac3to having a problem with it?

It would be helpful to have the MKV files.I looked into this more carefully and discovered that WAV command is actually creating an incomplete file. Instead of 3h, we have less than 1. Probably because the end result is bigger than 4 GB.

So I decided to put it in DD Plus 5.1 anyway

This is what I did:

1st, convert the "fps" from 25 (PAL) to NTSC:

eac3to track2.dts track2_23976.flac -slowdown

track2.dts = the DTS-ES 6.1 one, from the DVD

2nd step:

ffmpeg -i track2_23976.flac -c:a eac3 -b:a 768k -ac 6 track2_ntsc.eac3

As you can see, converting to FLAC 1st does not create an incomplete file. It still has over 3h.

The resulting file has a similar size of 1 GB.

It's not DTS-ES 6.1 anymore, but I don't think there's a way to change the "fps" and also keep being DTS-ES 6.1. Not that I know.

[tebasuna51]

With ffmpeg you have 2 ways to do the eac3to slowdown:

-af "atempo=0.959041"
or
-af "aresample=50050, asetrate=48000"

also you can make a proper downmix (https://forum.doom9.org/showthread.php?p=1983390#post1983390) instead the default -ac 6

[Columbo]

eac3to track2.dts track2_slow.wav -slowdown
...
the end result is bigger than 4 GB


Have you tried outputting to .w64 instead of .wav to get around the size limit?

[Perenista]

Have you tried outputting to .w64 instead of .wav to get around the size limit?This may have worked, because from what I can see WAV has a 4 GB problem. But FLAC is lossless and achieves the same result, no?

FLAC retained the 3h14m of the content, WAV reduced to less than 1h.

With ffmpeg you have 2 ways to do the eac3to slowdown:

-af "atempo=0.959041"
or
-af "aresample=50050, asetrate=48000"

also you can make a proper downmix (https://forum.doom9.org/showthread.php?p=1983390#post1983390) instead the default -ac 6About your 2nd point:

I revisited my original conversion and made one important change.

Originally, I converted the slowed-down 6.1 FLAC to Dolby Digital Plus 5.1 using:

ffmpeg -i track2_23976.flac -c:a eac3 -b:a 768k -ac 6 track2_ntsc.eac3

This works, but FFmpeg performs the 6.1-to-5.1 downmix automatically. I have no control over how the DTS-ES rear center channel is handled.

After checking the channel layout, I found that the DTS-ES Discrete track was mapped as:

FL + FR + FC + LFE + BC + SL + SR

(where BC is the Back Center channel).

I then created a second encode using an explicit downmix matrix:

ffmpeg -i track2_23976.flac -af "pan=5.1(side)|FL=FL|FR=FR|FC=FC|LFE=LFE|SL=SL+0.5*BC|SR=SR+0.5*BC" -c:a eac3 -b:a 768k track2_ntsc_better.eac3

This version still outputs standard 5.1 Dolby Digital Plus, but instead of relying on FFmpeg's automatic downmix, the DTS-ES Back Center channel is intentionally redistributed into the left and right surround channels.

In other words:

SL = SL + 0.5 × BC

SR = SR + 0.5 × BC

The goal was to preserve the information contained in the DTS-ES rear center channel rather than leaving the handling of that channel entirely to FFmpeg's default downmix behavior.

The workflow became:

DTS-ES 6.1 (PAL DVD)
→ eac3to -slowdown
→ FLAC 6.1 (23.976)
→ FFmpeg custom 6.1-to-5.1 downmix
→ Dolby Digital Plus 5.1 (768 kbps)

I cannot claim this is audibly superior without direct comparison, but it gives explicit control over the DTS-ES rear center channel during the 6.1-to-5.1 conversion.

Note:

The command used now, after creating the FLAC again, was:

ffmpeg -i track2_23976.flac -af "pan=5.1(side)|FL=FL|FR=FR|FC=FC|LFE=LFE|SL=SL+0.5*BC|SR=SR+0.5*BC" -c:a eac3 -b:a 768k track2_ntsc_better.eac3

Based on your linked post, here (https://forum.doom9.org/showthread.php?p=1983390#post1983390)

This, again, resulting in a DD Plus 5.1 track, from the DTS-ES 6.1 one from the DVD.

Also,

ffmpeg -layouts

Showed this before:

6.1 = FL+FR+FC+LFE+BC+SL+SR

And MEDIAINFO:

L R C LFE Cb Ls Rs

The AI recommended me this command:

ffmpeg -i track2_23976.flac -af "pan=5.1(side)|FL=FL|FR=FR|FC=FC|LFE=LFE|SL=SL+0.5*BC|SR=SR+0.5*BC" -c:a eac3 -b:a 768k track2_ntsc_better.eac3

Or this alternative:

ffmpeg -i track2_23976.flac -af "pan=5.1(side)|c0=c0|c1=c1|c2=c2|c3=c3|c4=c5+0.5*c4|c5=c6+0.5*c4" -c:a eac3 -b:a 768k track2_ntsc_better.eac3

[Columbo]

This may have worked, because from what I can see WAV has a 4 GB problem. But FLAC is lossless and achieves the same result, no? Just completing the record for those who may have erroneously concluded that eac3to could not surpass 4GB for PCM audio output. Carry on.

[tebasuna51]

The workflow became:

DTS-ES 6.1 (PAL DVD)
→ eac3to -slowdown
→ FLAC 6.1 (23.976)
→ FFmpeg custom 6.1-to-5.1 downmix
→ Dolby Digital Plus 5.1 (768 kbps)
...
ffmpeg -i track2_23976.flac -af "pan=5.1(side)|c0=c0|c1=c1|c2=c2|c3=c3|c4=c5+0.5*c4|c5=c6+0.5*c4" -c:a eac3 -b:a 768k track2_ntsc_better.eac3
Of course flac is a lossless conversion, and wav/w64 with eac3to retain the full length but you don't need use eac3to -slowdown and do that in a single pass:

ffmpeg -i track_pal.dts -af "aresample=50050, asetrate=48000,pan=5.1(side)|c0=c0|c1=c1|c2=c2|c3=c3|c4=c5+0.5*c4|c5=c6+0.5*c4" -c:a eac3 -b:a 768k track2_ntsc_better.eac3

Also that simple downmix: c4=c5+0.5*c4|c5=c6+0.5*c4
can produce peaks (rarely of course) at 1.5 than can be cutted to 1.0
In my post I suggest the equivalent:
pan=stereo|c0=0.412*c4+0.588*c5|c1=0.412*c4+0.588*c6, compand=attacks=0:decays=0:points=-90/-85.4|-8/-3.4|-5/-1|-0/-0.1
to avoid volume over 1.0, but can be unnecesary and ignored.