E-AC3 7.1Ch

[hubblec4]

Hi all

Now I have also a Blu-ray with such an audio stream.
The issue is reported here (http://bugs.madshi.net/view.php?id=450).

Is there a working chain to preserve all 7.1 channels? (sample (https://forum.videohelp.com/attachments/45411-1524761965/00925.m2ts))

MKVToolNix uses the core only, also extracting with eac3to keeps the core only.

The Blu-ray is Multi-Edition authored and has several m2ts files.

[nevcairiel]

Recent FFmpeg versions can process full Blu-ray E-AC3 7.1

[hubblec4]

Hi nevcairiel

Can I load multiple m2ts files as input like eac3to do?
Can FFmpeg detect identical frames like eac3to, and remove Dialog Normalization?

[mkver]

MKVToolNix uses the core only, also extracting with eac3to keeps the core only.
Proof? Sample? Last time I checked (https://forum.doom9.org/showthread.php?p=1820593#post1820593) mkvmerge didn't strip any extension away.
ffmpeg has a concat (and a subfile) protocol which allows you to specify ranges of files to process; but you should probably use a build with libbluray included because then ffmpeg can handle playlists directly.
I don't know ffmpeg's exact behaviour wrt seamless branching.

[hubblec4]

Proof? Sample? Last time I checked (https://forum.doom9.org/showthread.php?p=1820593#post1820593) mkvmerge didn't strip any extension away.

When I load this sample (https://forum.videohelp.com/attachments/45411-1524761965/00925.m2ts)(Thor 3) file to MKVToolNix(MTX), it shows me 6 channels only (german and french audio).
MediaInfo shows also the 6channel core data (500 kbps).


ffmpeg has a concat (and a subfile) protocol which allows you to specify ranges of files to process;

OK fine....

but you should probably use a build with libbluray included because then ffmpeg can handle playlists directly.
I can't use the mpls because not all m2ts of all editions stored there. I have to use always the m2ts files.

[mkver]

I just checked your file and everything is like last time:
1. Mediainfo doesn't show me 500kb/s core data; it shows 500 b/s -- ridiciously low. Also notice that 500kb/s isn't even an allowed bitrate for ac3 (you could achieve it by mixing frames of different sizes (uncommon for ac3)). So mediainfo is buggy. (I'm using mediainfo 18.03.1.)
2. If I mux exactly one of the E-AC3 streams, the resulting file has a channel count of six in its track header; if I use a recent version of ffmpeg for the muxing, it is eight. But if I decode the audio (with ffmpeg), it of course decodes to eight channels, not six. In other words: The only thing that mkvmerge does wrong is the channel count, but that's not important (and could be repaired with mkvpropedit lateron if you want to use mkvmerge).
3. Notice that mediainfo always thinks that the audio actually has only six channels -- if I remux it with ffmpeg I get "channels: 8" and "channels_original: 6".
4. You might report to mosu that the channel count is wrong.

[SeeMoreDigital]

Can somebody confirm...

Years ago when both HD-DVD and Blu-ray disc formats were battling it out for market dominance I seem to remember that Dolby Digital Plus audio streams were encoded/stored slightly differently for each disc format. Is this correct?

Also... Unless anyone knows any different, I don't remember ever seeing an HD-DVD disc with 7.1 channel DD+ audio. They were all 5.1 channel max!

[nevcairiel]

HD-DVD uses plain EAC3 encodes, one audio stream, no magic. Blu-ray creates a backwards-compatible stream instead, it has a plain AC3 Core (typically 5.1) and an E-AC3 extension that adds more channel (typically 4 channel, replacing the surround side channel from the core, and adding rear channel).

[SeeMoreDigital]

HD-DVD uses plain EAC3 encodes, one audio stream, no magic. Blu-ray creates a backwards-compatible stream instead, it has a plain AC3 Core (typically 5.1) and an E-AC3 extension that adds more channel (typically 4 channel, replacing the surround side channel from the core, and adding rear channel).Does this also mean that when E-AC3 streams from Blu-ray disc sources are muxed into the MKV container, that the AC3 core is removed? Like it is with Dolby TrueHD sources.

Also... Does anyone have an example of a plain 7.1 channel E-AC3 audio stream?

[nevcairiel]

Does this also mean that when E-AC3 streams from Blu-ray disc sources are muxed into the MKV container, that the AC3 core is removed? Like it is with Dolby TrueHD sources.


No. This is more like DTS Core + DTS HD, the core is absolutely required to decode it properly. You get some channels out of the core, and extra channel out of the extension.

TrueHD+AC3 is different, the AC3 part is entirely useless when you decode TrueHD.

[SeeMoreDigital]

No. This is more like DTS Core + DTS HD, the core is absolutely required to decode it properly. You get some channels out of the core, and extra channel out of the extension.I wonder what the reasoning was for the HD-DVD format not to include an AC3 core. It's such a long time ago I can't remember if there was a reason!

Does anybody know what flavour of E-AC3 the streaming services use?

[nevcairiel]

This combined core+extension layout is only used on Blu-ray, nowhere else that I am aware of. Streaming services use plain EAC3 streams.

[SeeMoreDigital]

This combined core+extension layout is only used on Blu-ray, nowhere else that I am aware of. Streaming services use plain EAC3 streams.Thanks for the confirmation Nev.

I was round at a friends house a few days ago setting-up a new 2017 LG Oled TV and Onkyo 7.2.4 AVR along with dedicated ceiling speakers. We played a few minutes of Okja on Netflix and I must say that the Dolby Digital Plus with Atmos audio was most impressive.