[RESOLVED] EAC-3 7.1 in m2ts

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tormento
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[RESOLVED] EAC-3 7.1 in m2ts

Post by tormento » Fri Feb 01, 2019 11:29 am

I have some troubles when feeding DGIndexNV with a m2ts containing some E-AC3 audio, that is commonly used as a poor man version of 7.1 channel track.

I sent a small part by FTP as "First man.m2ts".

Please notice than when the whole m2ts is given to DGIndexNV, I get some PMT/PAT advice and, whatever the answer I give, I get badly recognized audio tracks.

With this partial chunk, you simply get badly recognized audio tracks with no notice.

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Re: E-AC3 7.1 in m2ts

Post by admin » Fri Feb 01, 2019 12:21 pm

Specifically, what do you mean by "badly recognized audio tracks"? I load the stream, hit F5, and I see the E-AC3 tracks listed in the info display. If I demux one of them it plays fine in MPC-HC.

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Re: E-AC3 7.1 in m2ts

Post by tormento » Fri Feb 01, 2019 2:18 pm

admin wrote:
Fri Feb 01, 2019 12:21 pm
Specifically, what do you mean by "badly recognized audio tracks"?
The audio tracks are (from MediaInfo):

Audio #1 Dolby TrueHD with Dolby Atmos 7.1 L R C LFE Ls Rs Lb Rb
Audio #2 E-AC-3 7.1 L R C LFE Ls Rs Lb Rb
Audio #3 E-AC-3 7.1 L R C LFE Ls Rs Lb Rb
Audio #4 E-AC-3 7.1 L R C LFE Ls Rs Lb Rb
Audio #5 AC-3 2.0 L R

DGIndexNV sees them as:

1100 THD (ok)
1101 E-AC3 3.2
1102 E-AC3 3.1
1103 E-AC3 3.2
1101 AC3 2.0

Plus if you open the complete stream (40GB) and not the single chunk it gives you the PAT/PMT mismatch error too.

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Re: E-AC3 7.1 in m2ts

Post by admin » Fri Feb 01, 2019 7:13 pm

OK, thank you. Investigating...

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Re: E-AC3 7.1 in m2ts

Post by admin » Tue Feb 05, 2019 5:51 pm

OK, I have to redesign my parser, as it was only looking at the first audio header. But for this stream you need to look at both the independent AC3 header and the EAC3 substream header. Also, I have to honor the chanmape flag in case a custom channel map is included, as it is for your stream.

This may take a while as redesigning the parser is a non-trivial thing and needs to be carefully thought through and implemented. Fortunately it's mainly cosmetic as demuxing is working fine.

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Re: E-AC3 7.1 in m2ts

Post by admin » Tue Feb 12, 2019 9:32 pm

The parser is now re-designed as needed and is collecting all the correct fields from the AC3 core stream and the E-AC3 substream. The next step is to decode the rather obscure text in the A/52 specification to allow me to map the relevant fields to a proper channel description for the Info dialog and the demuxed file name. I've already got the sample rate and overall bitrate working (matching MediaInfo output); it's just the channel map I have left to figure out.

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Re: E-AC3 7.1 in m2ts

Post by tormento » Fri Feb 15, 2019 9:59 am

admin wrote:
Tue Feb 12, 2019 9:32 pm
it's just the channel map I have left to figure out.
I know you like to dig thru strange things and I make my best to make your day :mrgreen:

If you need testing, tell me.

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Re: E-AC3 7.1 in m2ts

Post by admin » Fri Feb 15, 2019 10:55 am

I'll definitely take up your testing offer when I have it ready. Thanks. I have the channel map worked out but now I get a wrong bitrate for some streams, so looking into that.

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Re: E-AC3 7.1 in m2ts

Post by tormento » Sat Feb 16, 2019 4:06 am

admin wrote:
Fri Feb 15, 2019 10:55 am
I'll definitely take up your testing offer when I have it ready. Thanks. I have the channel map worked out but now I get a wrong bitrate for some streams, so looking into that.
While you are touching parsing, would you please consider the possibility to extract chapters from mpls and m2ts?

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Re: E-AC3 7.1 in m2ts

Post by DJATOM » Sat Feb 16, 2019 4:33 am

If you need a mpls parser and chapter generator, I wrote some on python3: https://pastebin.com/VdW9LRSP. You will need pyqt5 in your python3 installation and probably some other dependencies, I don't remember.
Usage is simple: if you're making a chapters from vol.2, vol.3 or so, adjust counter in the right top corner of app. In the left corner you can set file name prefix.
Chapter files will be split based on mpls internal information. In my case Japanese blurays often have episodes separated, so mpls structure have marks for every m2ts file linked into playlist. I'm using that information to make separated chapter files. In case of single m2ts file it will make one or two files, depending on what we have linked into playlist.
Well, once GUI is configured, press Open and Write chapters, it will ask you to select source .mpls file and a folder for output chapters files.
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