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IDProjectCategoryView StatusLast Update
0000542eac3tobugpublic2022-05-09 08:38
Reporterbananajoe25 Assigned Tomadshi  
Status assignedResolutionopen 
Summary0000542: Sync issues when demuxing UHD BluRays with seamless branching.
Descriptionwhen demuxing the UHDs of Straight Outta Compton Unrated (2015), Coco (2017), Bad Santa 2 Unrated (2016), Close Encounters of the Third Kind (1977), Independence Day (1996), and many other UHDs, Audio and subtitles will get out of sync. eac3to "2ndpass/fixing" will make it go out of sync. sometimes the audio and subtitles will get out of sync even when using "-no2ndpass". for some reason -no2ndpass doesn't apply to subtitles. I've been using MakeMKV in the meantime. No sync issues with that program.
Steps To ReproduceCoco (2017)
just try demuxing the 800.mpls playlist. Atmos won't be able to get "fixed", but the ac3 track will. when you merge the streams with mkvmerge, you can hear atmos is in sync, but the ac3 track isn't. subtitles are also out of sync.

Straight Outta Compton (2015)
I've been trying to demux it with no2ndpass and 2ndpass. both times audio and subtitles are out of sync.

Additional Informationeac3to is useless for UHD BluRays that have seamless branching. eac3to can demux UHD BluRay Playlists with just one m2ts file completely fine no sync issues.
TagsNo tags attached.
eac3to Version3.34



2018-04-24 04:25

reporter   ~0002280

eac3to does not have a problem with UHD and Seamless Branching for extracting Chapter Information and Video Streams. The problem seems to be with extracting Dolby TrueHD and Dolby Atmos (specifically with creating the embedded AC-3). The root of this problem looks to be with "libav/ffmpeg"; when using "-nero" (Nero 7 with Blu-ray/HD DVD Plug-in) there is no error. I was able to successfully extract Chapters, Video and Audio from an UHD with Seamless Branching by either doing the Chapters & Video without Audio or all three by including "-nero". Only when trying to extract audio and using the default "libav/ffmpeg" does the extraction have errors & fail. I have not tried a disc with DTS (DTS-HD MA or DTS-X), yet (ArcSoft or "libav/ffmpeg").


2018-04-25 09:25

reporter (2,281 bytes)


2018-04-25 09:36

reporter   ~0002281

I decided to double check that it was "libav/ffmpeg" causing the problem. So, I attempted to extract the Dolby TrueHD (Atmos) track to LPCM (W64) from an UHD with Seamless Branching. It, still, had all the same errors. I uploaded the LOGs from using Nero and "libav/ffmpeg".


2018-04-26 18:28

reporter (4,225 bytes)


2018-04-26 18:35

reporter   ~0002283

I have UHD Blu-rays with E-AC-3 Audio as well. I decided to see if, along with Dolby TrueHD (Atmos), eac3to had an issue with UHD Dolby Digital Plus. It turns out, yes, that eac3to cannot extract E-AC-3 Audio from UHD Blu-ray Discs. The UHD Blu-ray Discs with E-AC-3 Audio are, also, seamless branching discs. I do not have any UHD Blu-rays with E-AC-3 Audio that are not seamless branching. So, I cannot verify if this is exclusive to seamless branching like Dolby TrueHD (Atmos) is. However, it seemed likely since both are Dolby. I uploaded the logs from my attempts to extract E-AC-3 Audio with and without Nero; as well as, extracting the AC-3 Core.


2018-12-28 13:16

reporter   ~0002456

Last edited: 2018-12-28 19:25

I have the same issue. It happens with seamless branching discs. eac3to detects gaps for every kind of track.

-no2ndpass seems to give correct results (in sync) for ac3 and dts tracks. I was able to compare them with the audio tracks (same format) extracted from a blu-ray disc of the that movie. dts and ac3 tracks from uhd bd and bd seemed identical.

For truehd (with atmos) eac3to doesn't produce correct output (in sync). It's confirmed. -no2ndpass doesn't make any difference since gaps cannot be fixed in the truehd bitstream.

For e-ac3 I was not able to test if with -no2ndpass the output is correct.

Please madshi fix this! eac3to is one of a kind tool and provides functionality no other software does.

Thanks for the support!


2019-12-07 16:55

reporter   ~0002598

Having the same problem with the Dolby Atmos track from the seamless branching BD and UHD of Baywatch ( The audio gets mor out of sync with the video, the longer the video lasts.

I came here, trying eac3to as a workaround suggested by Moritz Bunkus from MKVToolNix (

According to Nevcairiel from LAV Filters, the TrueHD streams have a timestamp, which has to be continuous and needs to be patched when (de)muxing from a seamless branching disc. (


2022-05-02 01:11

reporter   ~0002898

For reference, here is open source tool that correctly stitches truehd stream


2022-05-07 11:38

administrator   ~0002899

Can you guys list a couple of UHD discs which are well suited for me to analyze this problem?


2022-05-07 16:49

reporter   ~0002900

I can provide some of the titles to consider:
Cars (2006)
Close Encounters of the Third Kind (1977)
Dirty Dancing (1987)
Encanto (2021)
Eternals (2021)
F9 The Fast Saga (2021)
Frozen II (2019)
Halloween Kills (2021)
Luca (2021)
Midway (2019)
Monsters University (2013)
Onward (2020)
Pitch Black (2000)
Psycho (1960)
Raya and the Last Dragon (2021)
Requiem for a Dream (2000)
Rogue One (2016)
Star Trek II: The Wrath of Khan (1982)
Star Wars: Episode IX - The Rise of Skywalker (2019)
The Suicide Squad (2021)
Thor: Ragnarok (2017)
True Romance (1993)
Turning Red (2022)
Underworld (2003)

While mlp (which I linked) looked promising, seems like author is not maintaining it anymore and according to reports it is not always working. I think nowadays DGDemux is goto tool. But people still love eac3to! :)


2022-05-07 16:58

administrator   ~0002901

I'll see what I can do. I'm also considering open-sourcing eac3to. Though, it's Delphi code, not C++, and the source code is not in great shape (due to constant lack of time).


2022-05-08 20:58

reporter   ~0002902

Hi madshi, hope you're doing well.

This opensource tool claims to doe the best job in correcting truehd / mlp streams.

Regards, nautilus7


2022-05-08 21:33

administrator   ~0002903

Yeah, kasper93 already mentioned that tool, but he also said there are reports that it doesn't always work. @kasper93, in which way does it not always work? Does it crash? Or are there still audible pops/noises? Or does sync get lost? Do you have information about which movie the tool has problems with? Maybe a link to a forum?


2022-05-08 23:05

administrator   ~0002904

New build available on doom9. The new build *only* tries to get rid of any TrueHD audio artifacts caused by seamless branching. It does not do any sync related stuff. Also, I don't know why eac3to detects gaps in various audio tracks when handling UHD Blu-Rays. However, the new build now auto-disables 2nd pass gap processing for Blu-Rays and UHD Blu-Rays, since that's usually not needed for this type of content, anyway.


2022-05-09 00:37

reporter   ~0002905

@madshi, About mlp, you can look at the github issues. Specifically the last comment of author (from Dec 6, 2020) (where he mentions his tool is missing audio samples, while makemkv "somehow magically" extract them) and since then there wasn't any update. Because of that, even tho tool looks promising it never got adopted by community, simply because DGDemux and MakeMKV are more compatible and people trust them more to produce proper output. (btw. from MakeMKV v1.15.4 changelog "Implemented seamless joining of TrueHD streams with overlapping frames based on Dominik Mydlil's idea") so the method is working, just there are other issues on top.

Sorry, I don't have more info, I haven't really dive into the issue.


2022-05-09 08:38

administrator   ~0002906

Ok, let's leave it to users to test these issues with eac3to. I don't think eac3to should have the issue that mpl seems to have.

Issue History

Date Modified Username Field Change
2018-03-02 14:29 bananajoe25 New Issue
2018-03-02 14:34 madshi Assigned To => madshi
2018-03-02 14:34 madshi Status new => assigned
2018-04-24 04:25 SLKabaker Note Added: 0002280
2018-04-25 09:25 SLKabaker File Added:
2018-04-25 09:36 SLKabaker Note Added: 0002281
2018-04-26 18:28 SLKabaker File Added:
2018-04-26 18:35 SLKabaker Note Added: 0002283
2018-12-28 13:16 nautilus7 Note Added: 0002456
2018-12-28 13:27 nautilus7 Note Edited: 0002456
2018-12-28 13:27 nautilus7 Note Edited: 0002456
2018-12-28 13:28 nautilus7 Note Edited: 0002456
2018-12-28 13:37 nautilus7 Note Edited: 0002456
2018-12-28 19:25 nautilus7 Note Edited: 0002456
2018-12-28 19:25 nautilus7 Note Edited: 0002456
2019-12-07 16:55 deathbringer Note Added: 0002598
2022-05-02 01:11 kasper93 Note Added: 0002898
2022-05-07 11:38 madshi Note Added: 0002899
2022-05-07 16:49 kasper93 Note Added: 0002900
2022-05-07 16:58 madshi Note Added: 0002901
2022-05-08 20:58 nautilus7 Note Added: 0002902
2022-05-08 21:33 madshi Note Added: 0002903
2022-05-08 23:05 madshi Note Added: 0002904
2022-05-09 00:37 kasper93 Note Added: 0002905
2022-05-09 08:38 madshi Note Added: 0002906