Recent versions of eac3to split THD+AC3...

[JimmyBarnes]

If and Blu-ray is mounted in Z:, then

eac3to Z: 1) -demux

will extract the video, audio and subtitle streams.

If the audio is THD+AC3, the most recent versions of eac3to split this into its component THD and AC3 streams, whereas older versions created the THD+AC3 stream intact.

Is there an eac3to switch to prevent this splitting?

[tebasuna51]

Recent changes about this (changelog.txt):
v3.49

* Removed automatic invocation of thdmerge.exe for technical reasons
(eac3to performs delay correction for AC3 but not for THD, leading to
a misaligned thd+ac3 file when the THD stream has a delay).

v3.40

* Added the thdmerge algorithm to create thd+ac3 without re-encoding. To use
this do not specify a .thd+ac3 extension. Just make sure both the THD and AC3 streams
are demuxed and then eac3to_mod automatically creates the .thd+ac3 file using thdmerge.

But still work this:
eac3to v3.51
command line: eac3to Core.m2ts 3: Core.m2ts_3eng.thd+ac3 -progressnumbers -log=UsEac3To.log
------------------------------------------------------------------------------
Running in fast mode
Removing dialnorm
M2TS, 2 video tracks, 3 audio tracks, 0:03:08
1: h265/HEVC, 2160p24/1.001 (16:9), 10 bits
2: h265/HEVC, 1080p24/1.001 (16:9), 10 bits
3: TrueHD/AC3 (Atmos), 7.1 channels, 48kHz, dialnorm: -25dB
(embedded: AC3, 5.1 channels, 640kbps, 48kHz, dialnorm: -31dB)
4: E-AC3 EX, 7.1 channels, 1664kbps, 48kHz, dialnorm: -25dB
(core: AC3 EX, 5.1 channels, 640kbps, 48kHz, dialnorm: -25dB)
5: AC3, 5.1 channels, 640kbps, 48kHz, dialnorm: -31dB
[a03] Extracting audio track number 3...
[a03] Skipping AC3 dialog normalization (already at -31 dB)...
[a03] Removing TrueHD dialog normalization...
[a03] Creating file Core.m2ts_3eng.thd+ac3"...
Video track 1 contains 4487 frames.
Video track 2 contains 4487 frames.
eac3to processing took 9 seconds.
Done.

Maybe with a seamless branching BD can't work the same.
Try with eac3to 3.36 or make yourself the merge with the thdmerge.exe included:

thdmerge thd_file ac3_file output_file

[JimmyBarnes]

Thanks for the explanation tebasuna51.

Is there a simple way to tell if THD and AC3 streams have a delay or not?

[tebasuna51]

eac3to or MediaInfo must show the delay between video and audio in the container.

[SeeMoreDigital]

Out of interest...

Are we able to merge our own Dolby Digital 'core' into a TrueHD audio stream using Eac3to or UsEac3to?

[tebasuna51]

Use eac3to in command line does not have sense if we can use thdmerge.exe at same folder.

With UsEac3to I can add a option to 'A/V Recode' button, if source is NAME.thd and exist the NAME.ac3 and exist thdmerge in eac3to folder ask if you want merge it. Maybe in next version.

[SeeMoreDigital]

Thanks for the feedback ;)

[Hellboy.]

v3.49

* Removed automatic invocation of thdmerge.exe for technical reasons
(eac3to performs delay correction for AC3 but not for THD, leading to
a misaligned thd+ac3 file when the THD stream has a delay).

I wrote about that bug on "https://www.rationalqm.us/board/index.php" and they banned me, don't ask me why???. I said that I recommended not using eac3to
for audio that had a delay and that it was better to extract the audio with another program. I use MKVToolNix with gMKVExtractGUI.

I also mentioned another bug, when you remove or add delay, it introduces a strange sound. But I don't remember well anymore.

Edit: I remember I also wrote that it is better to remove eac3to behavior of automatic delay fixing.

[tebasuna51]

... I said that I recommended not using eac3to
for audio that had a delay and that it was better to extract the audio with another program. I use MKVToolNix with gMKVExtractGUI.
But gMKVExtractGUI is a GUI to mkvextract.exe than only support mkv files where the tracks THD and AC3 are separated already.
Without support for m2ts with thd+ac3 tracks.

With UsEac3to GUI you can extract tracks from m2ts or mkv with eac3to but also with mkvextract.exe from mkv's like with gMKVExtractGUI.

I also mentioned another bug, when you remove or add delay, it introduces a strange sound. But I don't remember well anymore.
I never see that problem, when add delay insert silence frames without problems.

Maybe when cut frames with high volume at the begining the decoder is bad initialized but it is not usual in correct tracks.
And this behaviour is the same with mkvmerge because only support delay +, when need a delay - mkvmerge cut also the first frames.

Edit: I remember I also wrote that it is better to remove eac3to behavior of automatic delay fixing.
It is your opinion, I recommended to madshi that behavior longtime ago.

[Hellboy.]

I only use MKVToolNix with gMKVExtractGUI when the movie is already in mkv.

About the audio bug i don't remember correctly but i do something with eac3to and the bug was there. And then I did the same with MKVToolNix and no bug.