MMH - New Atmos Decoder (beta) discussion


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I can’t think of anything else.

You will have to upload the file somewhere and PM me the link so I can test it here.
Hello, all. I have a strange problem when using the channel remapping function in v7.1.15. HDTT has a new 4 channel recording of Mahler’s third symphony that has surround information in ch 3 and height information in ch 4. I have a 5.1.2 setup in my main audio system so I used the remapper to route ch 3 to both SL and SR and ch 4 to FLH and FRH. It creates a 5.1.4 output, as 5.1.2 is not a choice (feature request here!). I then used Audacity to manually remove channels 9 and 10, which gets me back to 5.1.2. Roon can then play out the resulting audio, as it’s limited to eight channels (as is my system, of course).

Sonically, this works great.

My problem: the remapper is cutting off the length of the saved remapped files at 12.25 minutes. I can find no setting in MMH to adjust for this. I’ve tried on two different PCs, with the same truncated result.

What am I doing wrong? Thanks. JCR


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What am I doing wrong?

It is probably a wav file size limitation. That original quad file is probably very large.

When you say ‘Remapper’ do you mean the MMH Channel Remix tool?

Can you please provide a little more info so I can try and replicate and resolve?
Correct, the Remix Channel Layout. I've attached how I have set it up and you can see that the quad files in wav that truncate at 12.25 are indeed each over 2 Gb. I did get the same result when shrinking the wav files to FLAC and then running through MMH -- but I bet that MMH auto converts back to wav to process and thus that would explain why a less than 2 Gb FLAC file would yield the same truncated result.

If you need me to upload track 1 to test, kindly provide a private message link that I can share with you.

And while I'm at on this particular album, when I do the channel remap and remove channels 9 and 10 to get back to 5.1.2, I note that the surround/height channels are at a higher volume level than the mains. I assume that is because I am doubling up perhaps? I know that I can edit the FFMPEG dialog at the bottom of the MMH screen, but I'm not sure how I would do that properly. Perhaps you can show me? Thanks. JCR


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kindly provide a private message link

I’ve just sent you a PM, you can reply with a link.

Yes, you are adding the original rears to both rears and heights so playback will double up on those channels drowning out the fronts.

Try editing the 4 new channels by adding =0.707*cx (where x is the input channel index) to each new channel in your ffmeg commandline.

Example: c4=c2 becomes c4=0.707*c2

Garry, Chris Connaker has been able to reproduce the error. It is dependent on the playback software, however. For example with track 1 that I sent you, when opening the file in JRiver, it reports as the full 33.58 length. But in Roon and Audacity, the same file reports as 15.25 in length.
Music Media Helper 6.3.13 Released:

Version 6.3.13 (January 18 2023)
Atmos Helper: Added Atmos Decoding (beta version) to MCH WAV option - Only if user has a Dolby Reference Player (DRP) installed

About the Atmos Decoder tool beta:

This tool not formally documented yet. I'll do that ASAP. This is an experimental beta release.

The new Atmos Helper Atmos Decoding tool is a beta and is currently undocumented. It only appears as an option on the MMH Atmos Helper main dialog if a user has the Dolby Reference Player (DRP) installed on same PC as MMH.

View attachment 87526

This uses the DRP to decode a file with an Atmos stream contained in any of supported files to either multiple mono wavs or a single multichannel interleaved wav. Users can add multiple files from a single folder (it will batch decode):

Supported Input Files (With Atmos - TrueHD or Dolby Digital Plus JOC):

For each of the above the tool extracts mlp or eac3 then decodes to the selected output wav type (Interleaved MCH or mono).

This tool will probably fail where a user has split any mkv into chapter files as the DRP is not compatible with splitting MLP streams. In this case users should decode from the original MKV rip containing all the chapters (songs).

For MKV and MKA files containing chapters the tool first Decodes the entire MKV/MKA file (takes quite a while). Then it splits the huge wav (.w64 file) into chapter files. Be patient.

The Atmos Decoder supports the following WAV output (Channel Layouts):

The DRP remixes the Atmos stream to selected output channel layout, just like an Atmos AVR remixes to the user's AVR speaker layout. Nothing is lost.

The decoder creates a relatively quiet pcm wav. There is a user option to apply a volume gain to all channels. Please experiment. Of course, MMH's Channel Volume tool can also be used to apply channel gains to specific channels (i.e. boost rears or tops only)

Interleaved MCH wav files have correct channel mask (channel IDs) for wav players that support this and are compatible with the Atmos Helper‘s Atmos Encoder tool (allowing, for example, channel volume edits and re-encode to back to Atmos). Mono files are named in Dolby channel order and with channel name suffix.

Please post questions/feedback here.

How can I go about installing Dolby Reference Player (DRP) ?
hi Garry, fist of all i want to say many thanks for your masterpiece, salute ! i compare with dolby media encoder, and i found yours still better and more advanced

btw there's some issue i found, i guess its related to DRC used by DEE which reduce loudness and vibrant even when i set to -31db
hopefully it will solved in the future release

I use MMH version 7.2.10.
Dolby Reference Player version 3.2.0

It's just a remuxed english atmos from web.

See screens in attach.
i use latest version of MMH and also found same error like u mate, already found the solution?
Try changing the ‘TrueHD Channel Presentation’ to 8
always works when output channel 5.1.2 but if set to 5.1.4 / 7.1.2 / 7.1.4 which channel presentation should set to 16, some file work, some not, i thought it was because the size, but after i trimmed below 1 gb, it still got an error
Is there a way for the .mlp file to add the information on the artist, song, cover etc... I can only get my pioneer vsx 933 to read the mlp atmos truehd, the m4a, mkv etc via USB... nothing


I don’t know of any way to tag mlp files. Many AVRs won’t recognise files on USB drives, especially Atmos/TrueHD.

You may need to play via a BD player via HDMI with a USB drive or over a network. Or use a media player or media player software from a PC via HDMI.

You could also start a new thread here on QQ about playing Atmos files on your system as it’s ‘hidden’ here in this thread (most QQ users do not encode their own Atmos files). The most common way is to have mlp in a MKV or MKA file played with a BD player or media player.
I don’t know of any way to tag mlp files. Many AVRs won’t recognise files on USB drives, especially Atmos/TrueHD.
Indeed... It's not possible to tag mlp (Packed PCM (PPCM)) files. And even if you extracted the LPCM stream and muxed it within the .wav container very few playback devices can read their meta-data tags either.

Personally I would re-encode mlp (and lpcm in wav) to flac, which does support meta-data tagging. But as @HomerJAU has already mentioned its doubtful that your AVR will be able to recognise the files via a USB (or network) connected HDD.
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